Science.gov

Sample records for concrete runway materials

  1. Test of LOX compatibility for asphalt and concrete runway materials

    NASA Technical Reports Server (NTRS)

    Moyers, C. V.; Bryan, C. J.; Lockhart, B. J.

    1973-01-01

    A literature survey and a telephone canvass of producers and users of LOX is reported which yielded one report of an accident resulting from a LOX spill on asphalt, one discussion of hazardous conditions, and an unreferenced mention of an incident. Laboratory tests using standard LOX impact apparatus yielded reactions with both old and new alphalt, but none with concrete. In the final test, using a larger sample of asphalt, the reaction caused extensive damage to equipment. Initial field experiments using 2-meter square asphalt slabs covered with LOX, conducted during rainy weather, achieved no reaction with plummets, and limited reaction with a blasting cap as a reaction initiator. In a final plummet-initiated test on a dry slab, a violent reaction, which appeared to have propagated over the entire slab surface, destroyed the plummet fixture and threw fragments as far as 48 meters.

  2. Water-compatible polymer concrete materials for use in rapid repair systems for airport runways. Final report

    SciTech Connect

    Sugama, T.; Kukacka, L.E.; Horn, W.

    1981-03-01

    Water-compatible polymer concrete (PC) formulations have been developed which appear to have potential for use in all-weather rapid repair procedures for bomb-damaged runways. Formulations consisting of furfuryl alcohol, water-saturated aggregate, dry silica flour, promoters, and catalysts produced composites with properties suitable for repair purposes when mixed and polymerized at temperatures from -20/sup 0/ to 30/sup 0/C. Calcium-unsaturated polyester complexed PC also produced excellent properties. However, the early strength criteria (2000 psi (13.78 MPa) at 1 h) and other requirements such as compatibility of the formulation with water and practical working times could be attained only at temperatures >20/sup 0/C. This system can be polymerized under water. Studies of the polymerization reaction mechanisms, materials properties, costs, and potential placement methods were performed.

  3. AERIAL OF SHUTTLE LANDING FACILITY [SLF] POURING CONCRETE ON RUNWAY

    NASA Technical Reports Server (NTRS)

    1975-01-01

    AERIAL OF SHUTTLE LANDING FACILITY [SLF] POURING CONCRETE ON RUNWAY KSC-375C-10036.32 108-KSC-375C-10036.32, P-21425, ARCHIVE-04501 Aerial oblique of Shuttle Landing Facility. Pouring concrete on runway. Direction North - Altitude 100'.

  4. Tests of highly loaded skids on a concrete runway

    NASA Technical Reports Server (NTRS)

    Stubbs, Sandy M.; Daugherty, Robert H.

    1994-01-01

    Skids have been used at various times for aircraft landing gear ever since the Wright Flyer appeared in the early 1900's. Typically, skids have been employed as aircraft landing gear either at low speeds or at low bearing pressures. Tests were conducted to examine the friction and wear characteristics of various metals sliding on a rough, grooved concrete runway. The metals represented potential materials for an overload protection skid for the Space Shuttle orbiter. Data from tests of six skid specimens conducted at higher speeds and bearing pressures than those of previous tests in the open literature are presented. Skids constructed of tungsten with embedded carbide chips exhibited the lowest wear, whereas a skid constructed of Inconel 718 exhibited high wear rates. Friction coefficients for all the skid specimens were moderate and would provide adequate stopping performance on a long runway. Because of its low wear rate, a skid constructed of tungsten with embedded carbide chips is considered to be a likely candidate for an aircraft skid or overload protection skid.

  5. Remote sensing of voids in large concrete structures: runways, taxiways, bridges, and building walls and roofs

    NASA Astrophysics Data System (ADS)

    Weil, Gary J.

    1998-10-01

    Maintenance of our world's infrastructure presents many unique challenges. Engineering and maintenance personnel must maintain around the clock service to millions of people each year while maintaining millions of cubic meters of concrete distributed throughout facilities. This infrastructure includes runways, taxiways, roadways, walkways, bridges, building walls and roofs. Presently only a limited number of accurate and economical techniques exist to test this myriad of concrete structures for integrity and safety as well as insure that they meet original design specifications. Remote sensing, non-destructive testing techniques, such as Infrared Thermography, Ground Penetrating Radar, Magnetometer and Pachometer, measure physical properties affected by the various materials and conditions found within, and under, concrete infrastructure. These techniques have established reputations for accurate investigations of concrete anomalies. This paper will review the applications of different non- destructive testing techniques on many concrete infrastructure components.

  6. Nondestructive testing of airport concrete structures: runways, taxiways, roads, bridges, building walls, and roofs

    NASA Astrophysics Data System (ADS)

    Weil, Gary J.

    1998-03-01

    Maintenance of airport infrastructure presents many unique challenges. Airport engineering and maintenance personnel must maintain around the clock service to millions of people each year while maintaining millions of cubic meters of concrete distributed throughout the facilities. This infrastructure includes runways, taxiways, roadways, walkways, bridges, building walls and roofs. Presently only a limited number of accurate and economical techniques exist to test this myriad of concrete structures for integrity and safety as well as insure that they meet original design specifications. Remote sensing, non-destructive testing techniques, such as IR thermography, ground penetrating radar, magnetometer and pachometer, measure physical properties affected by the various materials and conditions found within, and under, concrete infrastructure. These techniques have established reputations for accurate investigations of concrete anomalies.

  7. STS-40 Columbia, OV-102, lands on concrete runway 22 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1991-01-01

    STS-40 Columbia's, Orbiter Vehicle (OV) 102's, main landing gear (MLG) touches down on concrete runway 22 at Edwards Air Force Base (EAFB), California at 8:29:11 am (Pacific Daylight Time (PDT)). OV-102's port side is captured in this profile view as its nose landing gear (NLG) glides above the runway before touch down and wheel stop.

  8. STS-40 Columbia, OV-102, lands on concrete runway 22 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1991-01-01

    STS-40 Columbia's, Orbiter Vehicle (OV) 102's, main landing gear (MLG) touches down on concrete runway 22 at Edwards Air Force Base (EAFB), California at 8:29:11 am (Pacific Daylight Time (PDT)). OV-102's starboard side is captured in this profile view as its nose landing gear (NLG) glides above the runway before touch down and wheel stop.

  9. STS-33 Discovery, OV-103, MLG touches down on concrete runway 04 at EAFB

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-33 Discovery, Orbiter Vehicle (OV) 103, main landing gear (MLG) touches down on concrete runway 04 at Edwards Air Force Base (EAFB), California, at 16:31:02 pm Pacific Standard Time (PST). This view captures OV-103's profile (port side) as it glides down the runway.

  10. STS-33 Discovery, OV-103, MLG touches down on EAFB concrete runway 04

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-33 Discovery, Orbiter Vehicle (OV) 103, main landing gear (MLG) touchdown is documented at Edwards Air Force Base (EAFB), California, on concrete runway 04. Views look forward from the space shuttle main engines (SSMEs) to the crew compartment as OV-103 glides down the runway. The landing occurred at 16:31:02 pm Pacific Standard Time (PST).

  11. STS-29 Discovery, OV-103, lands on Edwards AFB concrete runway 22

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-29 Discovery, Orbiter Vehicle (OV) 103, main landing gear (MLG) touches down at a speed of approximately 205 knots (235 miles per hour) on concrete runway 22 at Edwards Air Force Base (AFB), California. Nose landing gear (NLG) is deployed and rides above runway surface prior touchdown. Mojave desert scrub brush appears in the foreground with mountain range appearing in the background.

  12. STS-33 Discovery, OV-103, MLG touches down on EAFB concrete runway 04

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-33 Discovery, Orbiter Vehicle (OV) 103, main landing gear (MLG) touchdown is documented at Edwards Air Force Base (EAFB), California, on concrete runway 04. Views look forward from the space shuttle main engines (SSMEs) to the crew compartment as OV-103 glides down the runway. The landing occurred at 16:31:02 pm Pacific Standard Time (PST).

  13. STS-33 Discovery, OV-103, MLG touches down on concrete runway 04 at EAFB

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-33 Discovery, Orbiter Vehicle (OV) 103, main landing gear (MLG) touches down on concrete runway 04 at Edwards Air Force Base (EAFB), California, at 16:31:02 pm Pacific Standard Time (PST). This view captures OV-103's profile (port side) as it glides down the runway.

  14. STS-40 Columbia, OV-102, lands on concrete runway 22 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1991-01-01

    STS-40 Columbia's, Orbiter Vehicle (OV) 102's, main landing gear (MLG) touches down on concrete runway 22 at Edwards Air Force Base (EAFB), California at 8:29:11 am (Pacific Daylight Time (PDT)). OV-102's starboard side is captured in this profile view as its nose landing gear (NLG) glides above the runway before touch down and wheel stop.

  15. STS-29 Discovery, OV-103, lands on Edwards AFB concrete runway 22

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-29 Discovery, Orbiter Vehicle (OV) 103, main landing gear (MLG) touches down at a speed of approximately 205 knots (235 miles per hour) on concrete runway 22 at Edwards Air Force Base (AFB), California. Nose landing gear (NLG) is deployed and rides above runway surface prior touchdown. Mojave desert scrub brush appears in the foreground with mountain range appearing in the background.

  16. STS-40 Columbia, OV-102, lands on concrete runway 22 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1991-01-01

    STS-40 Columbia's, Orbiter Vehicle (OV) 102's, main landing gear (MLG) touches down on concrete runway 22 at Edwards Air Force Base (EAFB), California at 8:29:11 am (Pacific Daylight Time (PDT)). OV-102's port side is captured in this profile view as its nose landing gear (NLG) glides above the runway before touch down and wheel stop.

  17. STS-41 Discovery, OV-103, glides over concrete runway 22 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-41 Discovery, Orbiter Vehicle (OV) 103, with nose landing gear (NLG) and main landing gear (MLG) deployed, glides over concrete runway 22 at Edwards Air Force Base (EAFB), California, prior to touchdown.

  18. STS-41 Discovery, OV-103, glides over concrete runway 22 at EAFB, California

    NASA Image and Video Library

    1990-10-10

    STS-41 Discovery, Orbiter Vehicle (OV) 103, with nose landing gear (NLG) and main landing gear (MLG) deployed, glides over concrete runway 22 at Edwards Air Force Base (EAFB), California, prior to touchdown.

  19. STS-41 Discovery, OV-103, glides over concrete runway 22 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-41 Discovery, Orbiter Vehicle (OV) 103, with nose landing gear (NLG) and main landing gear (MLG) deployed, glides over concrete runway 22 at Edwards Air Force Base (EAFB), California, prior to touchdown.

  20. Rapid Runway Repair Program Subtask 1.07 - Rapid Concrete Cutting.

    DTIC Science & Technology

    1983-06-01

    AD-Rl3i 771 RRPID RUNWAY’REPAIR PROGRAM SUBTA5K 187 - RAPID 1/3 CONCRETE CUTTING (U) 8DM CORP MCLEAN YVA RKMOATS ET IL. JUN 83 8DM/W-82-778 TR 7...I RAPID RUNWAY REPAIR PROGRAM SUBTASK 1.07 - RAPID CONCRETE CUTTING MOATS, R.K. [BOM), WANG, F.D., DEARS, WILLIAM (ENGINEERING & SCIENCE TECHNOLOGY...Program Final Technical ReportMarch 1982 - January 1983 -’’ • Subtask 1.07 - Rapid Concrete Cutting 1982N - Janury 1983 6. PERFORMING ORG. REPORT NUMBER

  1. STS-31 Discovery, Orbiter Vehicle (OV) 103, lands on EAFB concrete runway 22

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The main landing gear (MLG) of Discovery, Orbiter Vehicle (OV) 103, rides along concrete runway 22 at Edwards Air Force Base (EAFB), California, bringing mission STS-31 to an end. The nose landing gear (NLG) is suspended above the runway prior to touchdown and wheel stop which occurred at 6:51:00 am (Pacific Daylight Time (PDT)). View shows OV-103's starboard side and deployed rudder/speedbrake. EAFB facilities are seen in the distance.

  2. STS-31 Discovery, Orbiter Vehicle (OV) 103, lands on EAFB concrete runway 22

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The main landing gear (MLG) of Discovery, Orbiter Vehicle (OV) 103, rides along concrete runway 22 at Edwards Air Force Base (EAFB), California, bringing mission STS-31 to an end. The nose landing gear (NLG) is suspended above the runway prior to touchdown and wheel stop which occurred at 6:51:00 am (Pacific Daylight Time (PDT)). View shows OV-103's starboard side and deployed rudder/speedbrake. EAFB facilities are seen in the distance.

  3. STS-49 Endeavour, OV-105, landing on concrete runway 22 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-49 Endeavour, Orbiter Vehicle (OV) 105, glides above concrete runway 22 at Edwards Air Force Base (EAFB), California, just before main landing gear (MLG) touchdown. Nose landing gear (NLG) is also deployed during the landing sequence. Landing occurred at 1:36:38 pm (Pacific Daylight Time (PDT)).

  4. STS-49 Endeavour, OV-105, landing on concrete runway 22 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-49 Endeavour, Orbiter Vehicle (OV) 105, glides above concrete runway 22 at Edwards Air Force Base (EAFB), California, just before main landing gear (MLG) touchdown. Nose landing gear (NLG) is also deployed during the landing sequence. Landing occurred at 1:36:38 pm (Pacific Daylight Time (PDT)).

  5. STS-29 Discovery, OV-103, lands on Edwards AFB concrete runway 22

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-29 Discovery, Orbiter Vehicle (OV) 103, main landing gear (MLG) touches down at a speed of approximately 205 knots (235 miles per hour) on concrete runway 22 at Edwards Air Force Base (AFB), California. Nose landing gear (NLG) is deployed and rides above runway surface prior touchdown. Rear view captures OV-103 as it glides past photographer to wheel stop showing the tail section (speedbrake/rudder) and three space shuttle main engines (SSMEs). Mojave desert scrub brush appears in the foreground with aircraft hangar appearing in the background.

  6. STS-29 Discovery, OV-103, lands on Edwards AFB concrete runway 22

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-29 Discovery, Orbiter Vehicle (OV) 103, main landing gear (MLG) touches down at a speed of approximately 205 knots (235 miles per hour) on concrete runway 22 at Edwards Air Force Base (AFB), California. Nose landing gear (NLG) is deployed and rides above runway surface prior touchdown. Rear view captures OV-103 as it glides past photographer to wheel stop showing the tail section (speedbrake/rudder) and three space shuttle main engines (SSMEs). Mojave desert scrub brush appears in the foreground with aircraft hangar appearing in the background.

  7. Polymer Research in Rapid Runway Repair Materials.

    DTIC Science & Technology

    1979-11-01

    to asphalt and Portland cement concrete and gcod wear characteristics were demonstrated. Flexural strength properties are satis- factory after cool...20 5.3.2 Substrate Selection ..... ............... ... 22 5.3.3 Results of Bonding Study .... ............. ... 22 5.4 Adhesive Strength to Asphalt ...32 4. Flexural Testing of Beams ...... .................. ... 32 5. Device for Durability Tests ...... ................. ... 36 6. Asphalt

  8. STS-41 crew poses in front of OV-103 on concrete runway 22 at EAFB, Calif

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-41 crewmembers pose in front of Discovery, Orbiter Vehicle (OV) 103, parked on concrete runway 22 at Edwards Air Force Base (EAFB), California. Having just completed their mission, the crewmembers are still wearing their launch and entry suits (LESs). From left to right are Mission Specialist (MS) Thomas D. Akers, Pilot Robert D. Cabana, Commander Richard N. Richards, MS Bruce E. Melnick, and MS William M. Shepherd.

  9. STS-41 crew poses in front of OV-103 on concrete runway 22 at EAFB, Calif

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-41 crewmembers pose in front of Discovery, Orbiter Vehicle (OV) 103, parked on concrete runway 22 at Edwards Air Force Base (EAFB), California. Having just completed their mission, the crewmembers are still wearing their launch and entry suits (LESs). From left to right are Mission Specialist (MS) Thomas D. Akers, Pilot Robert D. Cabana, Commander Richard N. Richards, MS Bruce E. Melnick, and MS William M. Shepherd.

  10. Plastic (wire-combed) grooving of a slip-formed concrete runway overlay at Patrick Henry Airport: An initial evaluation

    NASA Technical Reports Server (NTRS)

    Marlin, E. C.; Horne, W. B.

    1977-01-01

    A wire-comb technique is described for transversely grooving the surface of a freshly laid (plastic state) slip-formed concrete overlay installed at Patrick Henry Airport. This method of surface texturing yields better water drainage and pavement skid resistance than that obtained with an older conventional burlap drag concrete surface treatment installed on an adjacent portion of the runway.

  11. STS-31 Discovery, Orbiter Vehicle (OV) 103, lands on EAFB concrete runway 22

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-31 Discovery, Orbiter Vehicle (OV) 103, rolls along concrete runway 22 at Edwards Air Force Base (EAFB), California, after nose landing gear (NLG) and main landing gear (MLG) touchdown. This view looks down OV-103's port side from the space shuttle main engines (SSMEs) to the nose section. The SSMEs are gimbaled to their descent position and the rudder/speedbrake is deployed on the vertical stabilizer. Wheel stop occurred at 6:51 am (Pacific Daylight Time (PDT)). In the distance EAFB facilities are visible.

  12. STS-31 crew poses on EAFB concrete runway after egressing OV-103

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-31 crewmembers, wearing their launch and entry suits (LESs), pose for an informal portrait on Edwards Air Force Base (EAFB) concrete runway 22 after egressing Discovery, Orbiter Vehicle (OV) 103. Left to right are Mission Specialist (MS) Steven A. Hawley, Pilot Charles F. Bolden, MS Kathryn D. Sullivan, Commander Loren J. Shriver, and MS Bruce McCandless II. A service vehicle and OV-103's main landing gear (MLG) are visible in the background. The highly successful five-day mission concluded at EAFB with wheel stop at 6:51:00 am (Pacific Daylight Time (PDT)).

  13. STS-41 crew poses in front of OV-103 on concrete runway 22 at EAFB, Calif

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-41 crewmembers give 'thumbs up' signal while standing in front of Discovery, Orbiter Vehicle (OV) 103, parked on concrete runway 22 at Edwards Air Force Base (EAFB), California. Having just completed their mission, the crewmembers are still wearing their launch and entry suits (LESs). From left to right are Mission Specialist (MS) Thomas D. Akers, Pilot Robert D. Cabana, Commander Richard N. Richards, MS Bruce E. Melnick, and MS William M. Shepherd. Set up at OV-103's side hatch is a mobile stairway which the crew uses to egress the vehicle and which technicians use when safing the vehicle during postflight operations.

  14. STS-41 crew poses in front of OV-103 on concrete runway 22 at EAFB, Calif

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-41 crewmembers give 'thumbs up' signal while standing in front of Discovery, Orbiter Vehicle (OV) 103, parked on concrete runway 22 at Edwards Air Force Base (EAFB), California. Having just completed their mission, the crewmembers are still wearing their launch and entry suits (LESs). From left to right are Mission Specialist (MS) Thomas D. Akers, Pilot Robert D. Cabana, Commander Richard N. Richards, MS Bruce E. Melnick, and MS William M. Shepherd. Set up at OV-103's side hatch is a mobile stairway which the crew uses to egress the vehicle and which technicians use when safing the vehicle during postflight operations.

  15. STS-31 crew poses on EAFB concrete runway after egressing OV-103

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-31 crewmembers, wearing their launch and entry suits (LESs), pose for an informal portrait on Edwards Air Force Base (EAFB) concrete runway 22 after egressing Discovery, Orbiter Vehicle (OV) 103. Left to right are Mission Specialist (MS) Steven A. Hawley, Pilot Charles F. Bolden, MS Kathryn D. Sullivan, Commander Loren J. Shriver, and MS Bruce McCandless II. A service vehicle and OV-103's main landing gear (MLG) are visible in the background. The highly successful five-day mission concluded at EAFB with wheel stop at 6:51:00 am (Pacific Daylight Time (PDT)).

  16. STS-31 Discovery, Orbiter Vehicle (OV) 103, lands on EAFB concrete runway 22

    NASA Technical Reports Server (NTRS)

    1990-01-01

    STS-31 Discovery, Orbiter Vehicle (OV) 103, rolls along concrete runway 22 at Edwards Air Force Base (EAFB), California, after nose landing gear (NLG) and main landing gear (MLG) touchdown. This view looks down OV-103's port side from the space shuttle main engines (SSMEs) to the nose section. The SSMEs are gimbaled to their descent position and the rudder/speedbrake is deployed on the vertical stabilizer. Wheel stop occurred at 6:51 am (Pacific Daylight Time (PDT)). In the distance EAFB facilities are visible.

  17. Structural Materials: 95. Concrete

    SciTech Connect

    Naus, Dan J

    2012-01-01

    Nuclear power plant concrete structures and their materials of construction are described, and their operating experience noted. Aging and environmental factors that can affect the durability of the concrete structures are identified. Basic components of a program to manage aging of these structures are identified and described. Application of structural reliability theory to devise uniform risk-based criteria by which existing facilities can be evaluated to achieve a desired performance level when subjected to uncertain demands and to quantify the effects of degradation is outlined. Finally, several areas are identified where additional research is desired.

  18. STS-33 Discovery, OV-103, approaches concrete runway 04 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-33 Discovery, Orbiter Vehicle (OV) 103, approaches runway 04 at Edwards Air Force Base (EAFB), California. OV-103 with landing gear deployed is silhouetted against the orange sky of a sunset as it glides over the mountains. The landing occurred at 16:31:02 pm Pacific Standard Time (PST).

  19. STS-33 Discovery, OV-103, approaches concrete runway 04 at EAFB, California

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-33 Discovery, Orbiter Vehicle (OV) 103, approaches runway 04 at Edwards Air Force Base (EAFB), California. OV-103 with landing gear deployed is silhouetted against the orange sky of a sunset as it glides over the mountains. The landing occurred at 16:31:02 pm Pacific Standard Time (PST).

  20. STS-29 Discovery, OV-103, lands on Edwards AFB concrete runway 22

    NASA Image and Video Library

    1989-03-18

    STS029-S-064 (18 Mar 1989) --- A rear view photographed from the ground just after Discovery's main landing gear touches down on Runway 22 at Edwards Air Force Base in California following a successful five-day mission in Earth orbit. Onboard the spacecraft were Astronauts Michael L. Coats, John E. Blaha, James F. Buchli, Robert C. Springer and James P. Bagian. Wheels came to a stop at 6:36:40 a.m. (PST), March 18, 1989.

  1. STS-29 Discovery, OV-103, lands on Edwards AFB concrete runway 22

    NASA Image and Video Library

    1989-03-18

    STS029-S-063 (18 March 1989) --- Discovery's main landing gear touches down on Runway 22 at Edwards Air Force Base in California following a successful five-day mission in Earth orbit. Onboard the spacecraft were Astronauts Michael L. Coats, John E. Blaha, James F. Buchli, Robert C. Springer and James P. Bagian. Wheels came to a stop at 6:36:40 a.m. (PST), March 18, 1989.

  2. North End Runway Material Extraction and Transport Environmental Assessment

    DTIC Science & Technology

    2006-05-01

    Contaminants include chlorinated solvent products and hydrocarbons, primarily benzene (EAFB, 2003). Levels of chlorinated solvents at FT23 must attenuate to... etg . 0 a l.SY~3~ {\\(SYJL ..------ v~&;41r~ eobr) (a =t= I ,-·- ~~ t2-- ------ ~8~\\e.,. Hydric Soil Indicators: _& Histosol _ Concretions Histic

  3. STS-33 Discovery, OV-103, approaches concrete runway 04 at EAFB, California

    NASA Image and Video Library

    1989-11-27

    STS033-S-014 (27 Nov 1989) --- The Space Shuttle Discovery is silhouetted against late afternoon California skies as it approaches the runway for landing at Edwards Air Force Base in southern California. A five-member crew aboard was about to complete the DOD-devoted STS-33 mission. The landing occurred at 16:31:02 p.m. (PST), Nov. 27, 1989. Onboard Discovery for the mission were Astronauts Frederick D. Gregory, John E. Blaha, Kathryn C. Thornton, F. Story Musgrave and Manley L. Carter.

  4. Self Healing in Concrete Materials

    NASA Astrophysics Data System (ADS)

    Li, Victor C.; Yang, En-Hua

    The phenomenon of self healing in concrete has been known for many years. It has been observed that some cracks in old concrete structures are lined with white crystalline material suggesting the ability of concrete to self-seal the cracks with chemical products by itself, perhaps with the aid of rainwater and carbon dioxide in air. Later, a number of researchers [1, 2] in the study of water flow through cracked concrete under a hydraulic gradient, noted a gradual reduction of permeability over time, again suggesting the ability of the cracked concrete to self-seal itself and slow the rate of water flow. The main cause of self-sealing was attributed to the formation of calcium carbonate, a result of reaction between unhydrated cement and carbon dioxide dissolved in water [1]. Thus, under limited conditions, the phenomenon of self-sealing in concrete is well established. Self-sealing is important to watertight structures and to prolonging service life of infrastructure.

  5. Properties of Sulfur Concrete.

    DTIC Science & Technology

    1979-07-06

    This report summarizes the state of the art of sulfur concrete . Sulfur concrete is created by mixing molten sulfur with aggregate and allowing the...and many organic compounds. It works well as a rapid runway repair material. Sulfur concrete also has unfavorable properties. It has poor durability

  6. Technical Note: Outlays on Construction of Airport Runways with Prestressed and Dowelled Pavements

    NASA Astrophysics Data System (ADS)

    Więckowski, Andrzej; Sznurawa, Alicja

    2015-09-01

    For two variants of runways with abrasive concrete pavements in the prestressed and dowelled technologies, analyses have been presented regarding labour, materials, use of machinery, and financial outlays, together with the necessary technological-organisational analyses and assessment of work execution cycles, by the example of construction of a runway at the Katowice Airport.

  7. Nuclear Concrete Materials Database Phase I Development

    SciTech Connect

    Ren, Weiju; Naus, Dan J

    2012-05-01

    The FY 2011 accomplishments in Phase I development of the Nuclear Concrete Materials Database to support the Light Water Reactor Sustainability Program are summarized. The database has been developed using the ORNL materials database infrastructure established for the Gen IV Materials Handbook to achieve cost reduction and development efficiency. In this Phase I development, the database has been successfully designed and constructed to manage documents in the Portable Document Format generated from the Structural Materials Handbook that contains nuclear concrete materials data and related information. The completion of the Phase I database has established a solid foundation for Phase II development, in which a digital database will be designed and constructed to manage nuclear concrete materials data in various digitized formats to facilitate electronic and mathematical processing for analysis, modeling, and design applications.

  8. Concrete: Potential material for Space Station

    NASA Technical Reports Server (NTRS)

    Lin, T. D.

    1992-01-01

    To build a permanent orbiting space station in the next decade is NASA's most challenging and exciting undertaking. The space station will serve as a center for a vast number of scientific products. As a potential material for the space station, reinforced concrete was studied, which has many material and structural merits for the proposed space station. Its cost-effectiveness depends on the availability of lunar materials. With such materials, only 1 percent or less of the mass of a concrete space structure would have to be transported from earth.

  9. Sludge ash as lightweight concrete material

    SciTech Connect

    Tay, J.H.; Yip, W.K.

    1989-02-01

    Sludge is an inevitable by-product of wastewater treatment. Its abundance poses disposal problems that can be drastically reduced if sludge can be converted for economical uses in construction as substitute materials. Digested and dewatered sludge, after incineration at a high temperature, yields a hard, cellular, porous mass with low unit weight. This hardened mass of sludge ash can be crushed to smaller-sized aggregates, which, when graded in suitable proportions, manifest the basic attributes required of lightweight aggregates. When used as aggregates in the production of lightweight concrete, experimental results show that the resulting concrete satisfies the physical requirements of a lightweight concrete in terms of unit weight, strength, heat-insulating properties, and fire resistance, thus indicating that sludge ash could be a potential source of suitable lightweight aggregates.

  10. Material and Flexural Properties of Fiber-reinforced Rubber Concrete

    NASA Astrophysics Data System (ADS)

    Helminger, Nicholas P.

    The purpose of this research is to determine the material properties of rubber concrete with the addition of fibers, and to determine optimal mixture dosages of rubber and fiber in concrete for structural applications. Fiber-reinforced concrete and rubberized concrete have been researched separately extensively, but this research intends to combine both rubber and fiber in a concrete matrix in order to create a composite material, fiber-reinforced rubber concrete (FRRC). Sustainability has long been important in engineering design, but much of the previous research performed on sustainable concrete does not result in a material that can be used for practical purposes. While still achieving a material that can be used for structural applications, economical considerations were given when choosing the proportions and types of constituents in the concrete mix. Concrete mixtures were designed, placed, and tested in accordance with common procedures and standards, with an emphasis on practicality. Properties that were investigated include compressive strength, tensile strength, modulus of elasticity, toughness, and ductility. The basis for determining the optimal concrete mixture is one that is economical, practical, and exhibits ductile properties with a significant strength. Results show that increasing percentages of rubber tend to decrease workability, unit weight, compressive strength, split tensile strength, and modulus of elasticity while the toughness is increased. The addition of steel needle fibers to rubber concrete increases unit weight, compressive strength, split tensile strength, modulus of elasticity, toughness, and ductility of the composite material.

  11. Water-Compatible Polymer Concrete Materials for use in Rapid Repair Systems for Airport Runways

    DTIC Science & Technology

    1981-03-01

    resin systems, resorcinol phenol- formaldehyde (RPF), urea- formaldehyde (UF), melamine - formaldehyde (MF), and furfuryl alcohol (FA), were selected for...type polymer systems. Phenol- formaldehyde (PF), melamine - formaldehyde (MF), urea-formalde- hyde (UF), and furfuryl alcohol (FA) monomers contain OH and...1-1.5) (1-2) Urea- formaldehyde NH2 CONH2 - HCHO Liquid 7150 (1.0) (1.5-2.5) Melamine - formaldehyde NH2 C:NC(NH2 ):NC(N’H2 ):N-HCHO Powder 16 5b (3-4

  12. Guidelines for identification of concrete in a materials property database

    SciTech Connect

    Oland, C.B.; Frohnsdorff, G.

    1995-12-31

    Guidelines for the identification of concrete in a materials property database are presented to address the complex problem of distinguishing one concrete from another. These guidelines are based on a logical scheme for systematically organizing and subdividing data and information about concrete and its constituents; they reflect consensus recommendations for a multilevel material description and designation system. Aspects of the guidelines include a classification system used to establish a series of primary identifiers, methods for reporting constituent information and mixture proportions, fields describing the source of the concrete and its processing history, and recommendations for reporting baseline or reference properties.

  13. Frost resistance of concrete surfaces coated with waterproofing materials

    NASA Astrophysics Data System (ADS)

    Klovas, A.; Dauksys, M.; Ciuprovaite, G.

    2015-03-01

    Present research lays emphasis on the problem of concrete surface exposed to aggressive surrounding quality. The test was conducted with concrete surfaces coated with different waterproofing materials exposed in solution of 3 % of sodium sulphate. Research was performed according to LST EN 1338:2003 standard requirements. Technological properties of concrete mixture as well as physical-mechanical properties of formed concrete specimens were established. The resistance of concrete to freezing - thawing cycles was prognosticated according to the porosity parameters established by the kinetic of water absorption. Five different waterproofing materials (coatings) such as liquid bitumen-rubber based, elastic fiber-strengthened, silane-siloxane based emulsion, mineral binder based and liquid rubber (caoutchouc) based coatings were used. Losses by mass of coating materials and specimens surface fractures were calculated based on the results of frost resistance test. Open code program "ImageJ" was used for visual analysis of concrete specimens. Based on the results, aggressive surrounding did not influence specimens coated with elastic, fibre-strengthened, mineral materials. On the other hand, specimens coated with liquid rubber (caoutchouc) based material were greatly influenced by aggressive surrounding. The biggest losses of specimen surface concrete (fractures) were obtained with silane-siloxane based emulsion coating. Generally, specimens coated with waterproofing materials were less influenced by aggressive surrounding compared with those without.

  14. Evaluation and Repair of Concrete Structures: Annotated Bibliography 1978 - 1988. Volume 2. (Repair, Evaluation, Maintenance and Rehabilitation Research Program)

    DTIC Science & Technology

    1991-06-01

    concrete pores. C-37 Bretz, T. E., Jr. 1979 -(Jul). "Properties of Sulfur Concrete ," Report AFIT-CI-79-170T, Air Force Institute of Technology, Wright...Patterson-Air Force- Base, OH. This report summarizes the state of the art of sulfur concrete . Sulfur concrete is creatod by mixing molten sulfur with...excellent resistance -to acids, salts, and many organic compounds. It works well as a rapid runway repair material. Sulfur concrete also has unfavorable 21

  15. Micromechanical study of concrete materials with interfacial transition zone

    NASA Astrophysics Data System (ADS)

    Gambheera, Ramesh

    This thesis describes analytical and finite element micromechanical studies for investigating the mechanical behavior of concrete materials. A concrete material is treated as a three phase composite consisting of aggregate, bulk paste and an interfacial transition zone around the aggregate. Experimental work on the microstructure of concrete has demonstrated the existence of interfacial transition zone and that this is the weakest link in the composite system of concrete material. Hence, the main focus of this thesis is to understand the role of the interfacial transition zone on the overall mechanical behavior of concrete materials. A four phase composite model consisting of aggregate, ITZ, bulk paste and an equivalent homogeneous medium is proposed to represent the concrete material. Analytical solutions are derived for the overall elastic moduli of the four phase composite model. The effects of volume fraction and the elastic moduli of the transition zone on the overall elastic moduli are investigated. The results obtained using the analytical model are in good agreement with those obtained from experiments. Analytical stress solutions are also derived for the four phase composite model subjected to uniaxial compression in two and three dimensions. The stress concentration and the tensile stress development in the interfacial transition zone are investigated. The effect of imperfect shear interfacial bond on the overall elastic moduli and on the stresses in the transition zone is also investigated. Basic concepts of damage mechanics are applied to model the damage in the transition zone. The effect of local damage in the transition zone on the overall damage in a concrete material is illustrated. For the specific case of uniaxial compression, the pre-peak stress-strain curves are generated. Computational analysis of micromechanical models of concrete materials requires efficient finite elements. This thesis proposes the use of hybrid finite elements for the

  16. Use of selected waste materials in concrete mixes.

    PubMed

    Batayneh, Malek; Marie, Iqbal; Asi, Ibrahim

    2007-01-01

    A modern lifestyle, alongside the advancement of technology has led to an increase in the amount and type of waste being generated, leading to a waste disposal crisis. This study tackles the problem of the waste that is generated from construction fields, such as demolished concrete, glass, and plastic. In order to dispose of or at least reduce the accumulation of certain kinds of waste, it has been suggested to reuse some of these waste materials to substitute a percentage of the primary materials used in the ordinary portland cement concrete (OPC). The waste materials considered to be recycled in this study consist of glass, plastics, and demolished concrete. Such recycling not only helps conserve natural resources, but also helps solve a growing waste disposal crisis. Ground plastics and glass were used to replace up to 20% of fine aggregates in concrete mixes, while crushed concrete was used to replace up to 20% of coarse aggregates. To evaluate these replacements on the properties of the OPC mixes, a number of laboratory tests were carried out. These tests included workability, unit weight, compressive strength, flexural strength, and indirect tensile strength (splitting). The main findings of this investigation revealed that the three types of waste materials could be reused successfully as partial substitutes for sand or coarse aggregates in concrete mixtures.

  17. Use of selected waste materials in concrete mixes

    SciTech Connect

    Batayneh, Malek Marie, Iqbal; Asi, Ibrahim

    2007-07-01

    A modern lifestyle, alongside the advancement of technology has led to an increase in the amount and type of waste being generated, leading to a waste disposal crisis. This study tackles the problem of the waste that is generated from construction fields, such as demolished concrete, glass, and plastic. In order to dispose of or at least reduce the accumulation of certain kinds of waste, it has been suggested to reuse some of these waste materials to substitute a percentage of the primary materials used in the ordinary portland cement concrete (OPC). The waste materials considered to be recycled in this study consist of glass, plastics, and demolished concrete. Such recycling not only helps conserve natural resources, but also helps solve a growing waste disposal crisis. Ground plastics and glass were used to replace up to 20% of fine aggregates in concrete mixes, while crushed concrete was used to replace up to 20% of coarse aggregates. To evaluate these replacements on the properties of the OPC mixes, a number of laboratory tests were carried out. These tests included workability, unit weight, compressive strength, flexural strength, and indirect tensile strength (splitting). The main findings of this investigation revealed that the three types of waste materials could be reused successfully as partial substitutes for sand or coarse aggregates in concrete mixtures.

  18. Steel - Concrete Materials Performance in Composite Joints Configuration

    NASA Astrophysics Data System (ADS)

    Pop, M.; Corbu, O.; Pernes, P.

    2017-06-01

    In many buildings there is a need to combine reinforced concrete, steel or composite members. The paper aims to an experimental program focused on the behaviour of the materials steel and concrete what makes up for a composite joint configuration. Material tests were performed prior each type of testing. The main purpose is to investigate the main parameters that affect the response and the contribution of the two materials. The tests were performed at the TUCN - Laboratory of Civil Engineering Faculty, Romania. The results of the tests on the materials were used for preliminary experimental analysis and presented in the paper.

  19. Insitu electrical sensing and material health monitoring in concrete structures

    NASA Astrophysics Data System (ADS)

    Rajabipour, Farshad

    While several structural health monitoring methods are available for assessing the applied loads, displacements, stresses, and strains in a concrete structure, very few techniques are available to enable condition assessment from a material durability viewpoint. Material health monitoring provides a valuable tool in assessing the current durability condition of a concrete structure (i.e., diagnosis), determining if and what preventative measures need to be taken to reduce future maintenance (i.e., prescription), and evaluating the remaining life and the future performance of the material (i.e., prognosis). The objective of this research is development of a new material sensing system that is designed to measure several properties and state parameters of concrete necessary for evaluation of the material's performance. This sensing system is composed of three electrical conductivity-based sensors and a temperature sensor. The electrical sensors include a concrete conductivity (sigma t) sensor (that monitors setting and hardening and measures microstructural and transport properties of concrete), a pore solution conductivity (sigma o) sensor (that monitors changes in the internal chemistry of the system due to ion penetration or carbonation), and a conductivity-based relative humidity (RH) sensor (to monitor moisture transport and shrinkage of the material). The temperature (T) sensor enables determination of the rate of hydration and strength development of concrete while it provides information needed for temperature calibration of the electrical sensors. It is shown that the combined measurements of the three electrical sensors and the temperature sensor provide sufficient calibration information that enables determination of the desired material properties and state parameters of concrete. This document provides a comprehensive description of several phases of the process used for development of the three conductivity-based sensors. To develop the prototype of

  20. AERIAL OF SHUTTLE LANDING FACILITY [SLF] POURING OF CONCRETE

    NASA Technical Reports Server (NTRS)

    1975-01-01

    AERIAL OF SHUTTLE LANDING FACILITY [SLF] POURING OF CONCRETE KSC-375C-10036.31 108-KSC-375C-10036.31, P-21426, ARCHIVE-04502 Aerial oblique of Shuttle runway facilities. Pouring concrete on runway. Direction north - altitude 100'.

  1. Eco-efficient concretes: the effects of using recycled ceramic material from sanitary installations on the mechanical properties of concrete.

    PubMed

    Guerra, I; Vivar, I; Llamas, B; Juan, A; Moran, J

    2009-02-01

    The aim of this research was to investigate some of the physical and mechanical properties of concrete mixed under laboratory conditions, where different proportions of coarse aggregate materials were substituted by porcelain from sanitary installations. The results of the tests show that the concrete produced has the same mechanical characteristics as conventional concrete, thus opening a door to selective recycling of sanitary porcelain and its use in the production of concrete.

  2. Leachability of dissolved chromium in asphalt and concrete surfacing materials.

    PubMed

    Kayhanian, Masoud; Vichare, Akshay; Green, Peter G; Harvey, John

    2009-08-01

    Leachate metal pollutant concentrations produced from different asphalt and concrete pavement surfacing materials were measured under controlled laboratory conditions. The results showed that, in general, the concentrations of most metal pollutants were below the reporting limits. However, dissolved chromium was detected in leachate from concrete (but not asphalt) specimens and more strongly in the early-time leachate samples. As the leaching continued, the concentration of Cr decreased to below or close to the reporting limit. The source of the chromium in concrete pavement was found to be cement. The concentration of total Cr produced from leachate of different cement coming from different sources that was purchased from retail distributors ranged from 124 to 641mug/L. This result indicates that the potential leachability of dissolved Cr from concrete pavement materials can be reduced through source control. The results also showed that the leachability of dissolved Cr in hardened pavement materials was substantially reduced. For example, the concentration of dissolved Cr measured in actual highway runoff was found to be much lower than the Cr concentration produced from leachate of both open and dense graded concrete pavement specimens under controlled laboratory study. It was concluded that pavement materials are not the source of pollutants of concern in roadway runoff; rather most pollutants in roadway surface runoff are generated from other road-use or land-use sources, or from (wet or dry) atmospheric deposition.

  3. Studies of Contaminated Runways,

    DTIC Science & Technology

    1980-01-01

    CON A INATIONS 11 4.1. Hydrodynamic resistance 11 4.2. Water contaminated runway 11 4.2.1. Viscous hydroplaning 12 4.2.2. Dynamic hydroplaning 13... hydroplaning model 16 5. FRICTION CHARACTERISTICS OF TYPICAL RUNWAYS 17 5.1. Characterization of the surface structure of a runway 17 .5.2. Runway with smooth...of the parameters involved the concepts of "viscous" and "dynamic" hydroplaning have been introduced in the literature. By definition there are

  4. Volcano-related materials in concretes: a comprehensive review.

    PubMed

    Cai, Gaochuang; Noguchi, Takafumi; Degée, Hervé; Zhao, Jun; Kitagaki, Ryoma

    2016-04-01

    Massive volcano-related materials (VRMs) erupted from volcanoes bring the impacts to natural environment and humanity health worldwide, which include generally volcanic ash (VA), volcanic pumice (VP), volcanic tuff (VT), etc. Considering the pozzolanic activities and mechanical characters of these materials, civil engineers propose to use them in low carbon/cement and environment-friendly concrete industries as supplementary cementitious materials (SCMs) or artificial/natural aggregates. The utilization of VRMs in concretes has attracted increasing and pressing attentions from research community. Through a literature review, this paper presents comprehensively the properties of VRMs and VRM concretes (VRMCs), including the physical and chemical properties of raw VRMs and VRMCs, and the fresh, microstructural and mechanical properties of VRMCs. Besides, considering environmental impacts and the development of long-term properties, the durability and stability properties of VRMCs also are summarized in this paper. The former focuses on the resistance properties of VRMCs when subjected to aggressive environmental impacts such as chloride, sulfate, seawater, and freezing-thawing. The latter mainly includes the fatigue, creep, heat-insulating, and expansion properties of VRMCs. This study will be helpful to promote the sustainability in concrete industries, protect natural environment, and reduce the impacts of volcano disaster. Based on this review, some main conclusions are discussed and important recommendations regarding future research on the application of VRMs in concrete industries are provided.

  5. Radiological and material characterization of high volume fly ash concrete.

    PubMed

    Ignjatović, I; Sas, Z; Dragaš, J; Somlai, J; Kovács, T

    2017-03-01

    The main goal of research presented in this paper was the material and radiological characterization of high volume fly ash concrete (HVFAC) in terms of determination of natural radionuclide content and radon emanation and exhalation coefficients. All concrete samples were made with a fly ash content between 50% and 70% of the total amount of cementitious materials from one coal burning power plant in Serbia. Physical (fresh and hardened concrete density) and mechanical properties (compressive strength, splitting tensile strength and modulus of elasticity) of concrete were tested. The radionuclide content ((226)Ra, (232)Th and (40)K) and radon massic exhalation of HVFAC samples were determined using gamma spectrometry. Determination of massic exhalation rates of HVFAC and its components using radon accumulation chamber techniques combined with a radon monitor was performed. The results show a beneficial effect of pozzolanic activity since the increase in fly ash content resulted in an increase in compressive strength of HVFAC by approximately 20% for the same mass of cement used in the mixtures. On the basis of the obtained radionuclide content of concrete components the I -indices of different HVFAC samples were calculated and compared with measured values (0.27-0.32), which were significantly below the recommended 1.0 index value. The prediction was relatively close to the measured values as the ratio between the calculated and measured I-index ranged between 0.89 and 1.14. Collected results of mechanical and radiological properties and performed calculations clearly prove that all 10 designed concretes with a certain type of fly ash are suitable for structural and non-structural applications both from a material and radiological point of view.

  6. Bridge deck repairs with polymer concrete patching materials

    NASA Astrophysics Data System (ADS)

    Edgecomb, W. C., Jr.

    1983-01-01

    The FHWA polymer concrete as formulated at Brookhaven National laboratory (BNL) was mixed, placed into spalls and finished on grade with steel trowels on more than a dozen bridges. This polymer concrete was a two-component system consisting of a liquid monomer component comprised of methyl methacrylate base, which contained a cross linking agent with promoters and an inhibitor, and a powder component which contained reactive polymers, blend of silica sands, initiator, and color pigments. These formed an impregnable material of approximately 8000 psi. Cure time for this project's cold weather formulation to obtain this strength was approximately 2 hours at 40 F.

  7. HTGR Base Technology Program. Task 2: concrete properties in nuclear environment. A review of concrete material systems for application to prestressed concrete pressure vessels

    SciTech Connect

    Naus, D.J.

    1981-05-01

    Prestressed concrete pressure vessels (PCPVs) are designed to serve as primary pressure containment structures. The safety of these structures depends on a correct assessment of the loadings and proper design of the vessels to accept these loadings. Proper vessel design requires a knowledge of the component (material) properties. Because concrete is one of the primary constituents of PCPVs, knowledge of its behavior is required to produce optimum PCPV designs. Concrete material systems are reviewed with respect to constituents, mix design, placing, curing, and strength evaluations, and typical concrete property data are presented. Effects of extreme loadings (elevated temperature, multiaxial, irradiation) on concrete behavior are described. Finally, specialty concrete material systems (high strength, fibrous, polymer, lightweight, refractory) are reviewed. 235 references.

  8. Characterization of Concrete Material Flow During Projectile Penetration

    NASA Astrophysics Data System (ADS)

    Sobeski, Robert

    The Department of Defense (DoD) has an operational requirement to predict, quickly and accurately, the depth of penetration that a projectile can achieve for a given target and impact scenario. Fast-running analytical models can provide reliable predictions, but they often require the use of one or more dimensionless parameters that are derived from experimental data. These analytical models are continually evolving, and the dimensionless parameters are often adjusted to obtain new analytical models without a true understanding of the change in characteristics of material flow across targets of varying strength and projectile impact velocities. In this dissertation, the penetration of ogive-nose projectiles into concrete targets is investigated using finite element analyses. The Elastic-Plastic Impact Computation (EPIC) code is used to examine the velocity vector fields and their associated direction cosines for high and low-strength concrete target materials during projectile penetration. Two methodologies, referred as Normal Expansion Comparison Methodology (NECM) and Spherical Expansion Comparison Methodology (SECM), are developed in MATLAB to quantify the change in concrete material flow during this short-duration dynamic event. Improved velocity profiles are proposed for better characterization of cavity expansion stresses based on the application of NECM and SECM to EPIC outputs. Structural engineers and model developers working on improving the accuracy of current analytical concrete penetration models and potentially reducing their reliance on fitting parameters will benefit from the findings of this research.

  9. Durability of concrete materials in high-magnesium brine

    SciTech Connect

    Wakeley, L.D.; Poole, T.S.; Burkes, J.P.

    1994-03-01

    Cement pastes and mortars representing 11 combinations of candidate concrete materials were cast in the laboratory and monitored for susceptibility to chemical deterioration in high-magnesium brine. Mixtures were selected to include materials included in the current leading candidate concrete for seals at the Waste Isolation Pilot Plant (WIPP). Some materials were included in the experimental matrix to answer questions that had arisen during study of the concrete used for construction of the liner of the WIPP waste-handling shaft. Mixture combinations compared Class C and Class F fly ashes, presence or absence of an expansive component, and presence or absence of salt as a mixture component. Experimental conditions exposed the pastes and mortars to extreme conditions, those being very high levels of Mg ion and an effectively unlimited supply of brine. All pastes and mortars showed deterioration with brine exposure. In general, mortars deteriorated more extensively than the corresponding pastes. Two-inch cube specimens of mortar were not uniformly deteriorated, but showed obvious zoning even after a year in the brine, with a relatively unreacted zone remaining at the center of each cube. Loss of calcium from the calcium hydroxide of paste/aggregate interfaces caused measurable strength loss in the reacted zone comprising the outer portion of every mortar specimen. The current candidate mass concrete for WIPP seals includes salt as an initial component, and has a relatively closed initial microstructure. Both of these features contribute to its suitability for use in large placements within the Salado Formation.

  10. Use of concrete polymer materials in the transportation industry

    SciTech Connect

    Fontana, J J; Bartholomew, J

    1980-01-01

    Under contract to the FHWA, Brookhaven National Laboratory has developed a polymer concrete patching material that combines the premix characteristics of PCC with strength and durability properties that are higher than PCC. PC overlays have been shown to be highly impermeable to water and chlorides. Laydown techniques have been developed to allow bridge maintenance crews to place the overlays with little or no problems. Today several manufacturers are marketing PC materials, and their acceptance is becoming widespread.

  11. Crushed cement concrete substitution for construction aggregates; a materials flow analysis

    USGS Publications Warehouse

    Kelly, Thomas

    1998-01-01

    An analysis of the substitution of crushed cement concrete for natural construction aggregates is performed by using a materials flow diagram that tracks all material flows into and out of the cement concrete portion of the products made with cement concrete: highways, roads, and buildings. Crushed cement concrete is only one of the materials flowing into these products, and the amount of crushed cement concrete substituted influences the amount of other materials in the flow. Factors such as availability and transportation costs, as well as physical properties, that can affect stability and finishability, influence whether crushed cement concrete or construction aggregates should be used or predominate for a particular end use.

  12. Status of runway slipperiness research

    NASA Technical Reports Server (NTRS)

    Horne, W. B.

    1976-01-01

    Runway slipperiness research performed in the United States and Europe since 1968 is reviewed. Topics discussed include: (1) runway flooding during rainstorms; (2) hydroplaning; (3) identification of slippery runways including the results from ground vehicle friction measurements and attempts to correlate these measurements with aircraft stopping performance; (4) progress and problems associated with the development of antihydroplaning runway surface treatments such as pavement grooving and porous friction course (PFC); and (5) runway rubber deposits and their removal.

  13. The use of waste materials in asphalt concrete mixtures.

    PubMed

    Tuncan, Mustafa; Tuncan, Ahmet; Cetin, Altan

    2003-04-01

    The purpose of this study was to investigate (a) the effects of rubber and plastic concentrations and rubber particle sizes on properties of asphalt cement, (b) on properties of asphalt concrete specimens and (c) the effects of fly ash, marble powder, rubber powder and petroleum contaminated soil as filler materials instead of stone powder in the asphalt concrete specimens. One type of limestone aggregate and one penetration-graded asphalt cement (75-100) were used. Three concentrations of rubber and plastic (i.e. 5%, 10% and 20% of the total weight of asphalt cement), three rubber particle sizes (i.e. No. 4 [4.75mm] - 20 [0.85 mm], No. 20 [0.85mm] - 200 [0.075mm] and No. 4 [4.75mm] - 200 [0.075mm]) and one plastic particle size (i.e. No. 4 [4.75mm] - 10 [2.00mm]) were also used. It was found that while the addition of plastic significantly increased the strength of specimens, the addition of rubber decreased it. No. 4 [4.75mm] - 200 [0.075mm] rubber particles showed the best results with respect to the indirect tensile test. The Marshall stability and indirect tensile strength properties of plastic modified specimens increased. Marble powder and fly ash could be used as filler materials instead of stone powder in the asphalt concrete pavement specimens.

  14. The Effect of Elevated Temperature on Concrete Materials and Structures - a Literature Review.

    SciTech Connect

    Naus, Dan J

    2006-03-01

    The objective of this limited study was to provide an overview of the effects of elevated temperature on the behavior of concrete materials and structures. In meeting this objective the effects of elevated temperatures on the properties of ordinary Portland cement concrete constituent materials and concretes are summarized. The effects of elevated temperature on high-strength concrete materials are noted and their performance compared to normal strength concretes. A review of concrete materials for elevated-temperature service is presented. Nuclear power plant and general civil engineering design codes are described. Design considerations and analytical techniques for evaluating the response of reinforced concrete structures to elevated-temperature conditions are presented. Pertinent studies in which reinforced concrete structural elements were subjected to elevated temperatures are described.

  15. EXECUTION AND MAINTENANCE OF D-RUNWAY IN HANEDA AIRPORT

    NASA Astrophysics Data System (ADS)

    Noguchi, Takatoshi; Watabe, Yoichi; Suzuki, Hiroyuki; Oku, Nobuyuki; Yamatoya, Ryuji; Watanabe, Masaya

    In the Tokyo International Airport (Haneda Airport), a new runway named "D-runway" was constructed from March 2007 to October 2010. Because some part of the D-runway is located in a river mouth, a hybrid structure consisted of piled pier and reclamation fill was adopted. In the reclamation section, not only the ground improvement technologies (SD, CPD and CDM) but also the new developed construction materials (pneumatic mixing cement treated soil and air-foam treated lightweight soil) were utilized. This technical report describes the outline of the execution, quality control, and maintenance plan of the D-runway structure, from a view point of geotechnical engineering.

  16. DESIGN OF D-RUNWAY IN HANEDA AIRPORT

    NASA Astrophysics Data System (ADS)

    Noguchi, Takatoshi; Watabe, Yoichi; Suzuki, Hiroyuki; Sakaiya, Tsunehiro; Kakehashi, Koichiro; Ogura, Katsutoshi; Mizuno, Kenta

    In the Tokyo International Airport (Haneda Airport), a new runway named "D-runway" was planned and constructed from March 2007 to October 2010. Because some part of the D-runway is located in a river mouth, a hybrid structure consisting of piled pier and reclamation fill was adopted. In the reclamation section, not only the ground improvement technologies (SD, CPD and CDM) but also the new developed construction materials (pneumatic mixing cement treated soil and air-foam treated lightweight soil) were utilized. This technical report describes the outline of the project, ground investigation, and design of the D-runway structure, from a geotechnical point of view.

  17. Methane biofiltration using autoclaved aerated concrete as the carrier material.

    PubMed

    Ganendra, Giovanni; Mercado-Garcia, Daniel; Hernandez-Sanabria, Emma; Boeckx, Pascal; Ho, Adrian; Boon, Nico

    2015-09-01

    The methane removal capacity of mixed methane-oxidizing bacteria (MOB) culture in a biofilter setup using autoclaved aerated concrete (AAC) as a highly porous carrier material was tested. Batch experiment was performed to optimize MOB immobilization on AAC specimens where optimum methane removal was obtained when calcium chloride was not added during bacterial inoculation step and 10-mm-thick AAC specimens were used. The immobilized MOB could remove methane at low concentration (~1000 ppmv) in a biofilter setup for 127 days at average removal efficiency (RE) of 28.7 %. Unlike a plug flow reactor, increasing the total volume of the filter by adding a biofilter in series did not result in higher total RE. MOB also exhibited a higher abundance at the bottom of the filter, in proximity with the methane gas inlet where a high methane concentration was found. Overall, an efficient methane biofilter performance could be obtained using AAC as the carrier material.

  18. Modelling runway incursion severity.

    PubMed

    Wilke, Sabine; Majumdar, Arnab; Ochieng, Washington Y

    2015-06-01

    Analysis of the causes underlying runway incursions is fundamental for the development of effective mitigation measures. However, there are significant weaknesses in the current methods to model these factors. This paper proposes a structured framework for modelling causal factors and their relationship to severity, which includes a description of the airport surface system architecture, establishment of terminological definitions, the determination and collection of appropriate data, the analysis of occurrences for severity and causes, and the execution of a statistical analysis framework. It is implemented in the context of U.S. airports, enabling the identification of a number of priority interventions, including the need for better investigation and causal factor capture, recommendations for airfield design, operating scenarios and technologies, and better training for human operators in the system. The framework is recommended for the analysis of runway incursions to support safety improvements and the methodology is transferable to other areas of aviation safety risk analysis.

  19. Applying Grounded Coordination Challenges to Concrete Learning Materials: A Study of Number Line Estimation

    ERIC Educational Resources Information Center

    Vitale, Jonathan M.; Black, John B.; Swart, Michael I.

    2014-01-01

    Do concrete learning materials promote strong learning outcomes, or do they simply make learning tasks more initially accessible? Although concrete materials may offer an intuitive foothold on a topic, research on desirable difficulties suggests that more challenging tasks facilitate greater retention and transfer. In the approach introduced here,…

  20. Applying Grounded Coordination Challenges to Concrete Learning Materials: A Study of Number Line Estimation

    ERIC Educational Resources Information Center

    Vitale, Jonathan M.; Black, John B.; Swart, Michael I.

    2014-01-01

    Do concrete learning materials promote strong learning outcomes, or do they simply make learning tasks more initially accessible? Although concrete materials may offer an intuitive foothold on a topic, research on desirable difficulties suggests that more challenging tasks facilitate greater retention and transfer. In the approach introduced here,…

  1. Concrete material characterization reinforced concrete tank structure Multi-Function Waste Tank Facility

    NASA Astrophysics Data System (ADS)

    Winkel, B. V.

    1995-03-01

    The purpose of this report is to document the Multi-Function Waste Tank Facility (MWTF) Project position on the concrete mechanical properties needed to perform design/analysis calculations for the MWTF secondary concrete structure. This report provides a position on MWTF concrete properties for the Title 1 and Title 2 calculations. The scope of the report is limited to mechanical properties and does not include the thermophysical properties of concrete needed to perform heat transfer calculations. In the 1970's, a comprehensive series of tests were performed at Construction Technology Laboratories (CTL) on two different Hanford concrete mix designs. Statistical correlations of the CTL data were later generated by Pacific Northwest Laboratories (PNL). These test results and property correlations have been utilized in various design/analysis efforts of Hanford waste tanks. However, due to changes in the concrete design mix and the lower range of MWTF operating temperatures, plus uncertainties in the CTL data and PNL correlations, it was prudent to evaluate the CTL data base and PNL correlations, relative to the MWTF application, and develop a defendable position. The CTL test program for Hanford concrete involved two different mix designs: a 3 kip/sq in mix and a 4.5 kip/sq in mix. The proposed 28-day design strength for the MWTF tanks is 5 kip/sq in. In addition to this design strength difference, there are also differences between the CTL and MWTF mix design details. Also of interest, are the appropriate application of the MWTF concrete properties in performing calculations demonstrating ACI Code compliance. Mix design details and ACI Code issues are addressed in Sections 3.0 and 5.0, respectively. The CTL test program and PNL data correlations focused on a temperature range of 250 to 450 F. The temperature range of interest for the MWTF tank concrete application is 70 to 200 F.

  2. Concrete material characterization reinforced concrete tank structure Multi-Function Waste Tank Facility

    SciTech Connect

    Winkel, B.V.

    1995-03-03

    The purpose of this report is to document the Multi-Function Waste Tank Facility (MWTF) Project position on the concrete mechanical properties needed to perform design/analysis calculations for the MWTF secondary concrete structure. This report provides a position on MWTF concrete properties for the Title 1 and Title 2 calculations. The scope of the report is limited to mechanical properties and does not include the thermophysical properties of concrete needed to perform heat transfer calculations. In the 1970`s, a comprehensive series of tests were performed at Construction Technology Laboratories (CTL) on two different Hanford concrete mix designs. Statistical correlations of the CTL data were later generated by Pacific Northwest Laboratories (PNL). These test results and property correlations have been utilized in various design/analysis efforts of Hanford waste tanks. However, due to changes in the concrete design mix and the lower range of MWTF operating temperatures, plus uncertainties in the CTL data and PNL correlations, it was prudent to evaluate the CTL data base and PNL correlations, relative to the MWTF application, and develop a defendable position. The CTL test program for Hanford concrete involved two different mix designs: a 3 kip/in{sup 2} mix and a 4.5 kip/in{sup 2} mix. The proposed 28-day design strength for the MWTF tanks is 5 kip/in{sup 2}. In addition to this design strength difference, there are also differences between the CTL and MWTF mix design details. Also of interest, are the appropriate application of the MWTF concrete properties in performing calculations demonstrating ACI Code compliance. Mix design details and ACI Code issues are addressed in Sections 3.0 and 5.0, respectively. The CTL test program and PNL data correlations focused on a temperature range of 250 to 450 F. The temperature range of interest for the MWTF tank concrete application is 70 to 200 F.

  3. Progress Toward Future Runway Management

    NASA Technical Reports Server (NTRS)

    Lohr, Gary W.; Brown, Sherilyn A.; Atkins, Stephen; Eisenhawer, Stephen W.; Bott, Terrance F.; Long, Dou; Hasan, Shahab

    2011-01-01

    The runway is universally acknowledged as a constraining factor to capacity in the National Airspace System (NAS). It follows that investigation of the effective use of runways, both in terms of selection and assignment, is paramount to the efficiency of future NAS operations. The need to address runway management is not a new idea; however, as the complexities of factors affecting runway selection and usage increase, the need for effective research in this area correspondingly increases. Under the National Aeronautics and Space Administration s Airspace Systems Program, runway management is a key research area. To address a future NAS which promises to be a complex landscape of factors and competing interests among users and operators, effective runway management strategies and capabilities are required. This effort has evolved from an assessment of current practices, an understanding of research activities addressing surface and airspace operations, traffic flow management enhancements, among others. This work has yielded significant progress. Systems analysis work indicates that the value of System Oriented Runway Management tools is significantly increased in the metroplex environment over that of the single airport case. Algorithms have been developed to provide runway configuration recommendations for a single airport with multiple runways. A benefits analysis has been conducted that indicates the SORM benefits include supporting traffic growth, cost reduction as a result of system efficiency, NAS optimization from metroplex operations, fairness in aircraft operations, and rational decision making.

  4. Evaluation of high pressure water blast with rotating spray bar for removing paint and rubber deposits from airport runways, and review of runway slipperiness problems created by rubber contamination

    NASA Technical Reports Server (NTRS)

    Horne, W. B.; Griswold, G. D.

    1975-01-01

    A high pressure water blast with rotating spray bar treatment for removing paint and rubber deposits from airport runways is studied. The results of the evaluation suggest that the treatment is very effective in removing above surface paint and rubber deposits to the point that pavement skid resistance is restored to trafficked but uncontaminated runway surface skid resistance levels. Aircraft operating problems created by runway slipperiness are reviewed along with an assessment of the contributions that pavement surface treatments, surface weathering, traffic polishing, and rubber deposits make in creating or alleviating runway slipperiness. The results suggest that conventional surface treatments for both portland cement and asphaltic concrete runways are extremely vulnerable to rubber deposit accretions which can produce runway slipperiness conditions for aircraft operations as or more slippery than many snow and ice-covered runway conditions. Pavement grooving surface treatments are shown to be the least vulnerable to rubber deposits accretion and traffic polishing of the surface treatments examined.

  5. Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress

    PubMed Central

    Wang, Hailong; Sun, Xiaoyan; Wang, Junjie; Monteiro, Paulo J.M.

    2016-01-01

    The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete (RAC) without external loads decreased with time, and the permeability of RAC is much lower than that of the reference concrete due to the on-going hydration and the pozzolanic reaction provided by the PHS and GGBS additives in the RAC mixture. The permeability of chloride under flexural load is much more sensitive than that under compressive load due to the differences in porosity and cracking pattern. At low compressive stress levels, the permeability of chloride decreased by the closing of pores and microcracks within RAC specimens. However, in a relatively short time the chloride diffusion coefficient and the chloride content increased rapidly with the increase of compressive stress when it exceeded a threshold stress level of approximate 35% of the ultimate compressive strength. Under flexural stress, the chloride transport capability increased with the increase of stress level and time. At high compressive and flexural stress levels, creep had a significant effect on the permeability of chloride in the RAC specimens due to the damage from the nucleation and propagation of microcracks over time. It is apparent that mortar cracking has more of a significant effect on the chloride transport in concrete than cracking in the interfacial transition zone (ITZ). PMID:28773376

  6. Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress.

    PubMed

    Wang, Hailong; Sun, Xiaoyan; Wang, Junjie; Monteiro, Paulo J M

    2016-03-30

    The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete (RAC) without external loads decreased with time, and the permeability of RAC is much lower than that of the reference concrete due to the on-going hydration and the pozzolanic reaction provided by the PHS and GGBS additives in the RAC mixture. The permeability of chloride under flexural load is much more sensitive than that under compressive load due to the differences in porosity and cracking pattern. At low compressive stress levels, the permeability of chloride decreased by the closing of pores and microcracks within RAC specimens. However, in a relatively short time the chloride diffusion coefficient and the chloride content increased rapidly with the increase of compressive stress when it exceeded a threshold stress level of approximate 35% of the ultimate compressive strength. Under flexural stress, the chloride transport capability increased with the increase of stress level and time. At high compressive and flexural stress levels, creep had a significant effect on the permeability of chloride in the RAC specimens due to the damage from the nucleation and propagation of microcracks over time. It is apparent that mortar cracking has more of a significant effect on the chloride transport in concrete than cracking in the interfacial transition zone (ITZ).

  7. Rapid Runway Repair Study.

    DTIC Science & Technology

    This report describes a series of tests to evaluate a system for rapidly repairing airfield pavement using polymer concrete (synthetic polymer plus...aggregate), thermally cured by microwave power. The technique, developed by the Syracuse University Research Corporation (SURC) for highway...maintenance, uses a truck-mounted 50-kilowatt microwave generator to irradiate areas patched with polymer concrete . Test results indicate that the polymer

  8. Material Concerns: Evaluating Sulfur Concrete for use in the Lunar Environment

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N.; Toutanji, Houssam

    2006-01-01

    On Earth sulfur "concrete" is an established construction material that has good mechanical properties, generally better than Portland cement, and can be used in corrosive environments. Troilite (FeS) has been found on the moon and raises the question of using extracted sulfur as a lunar construction material, an attractive alternative to conventional concrete as it does not require water. Troilite reduction to elemental sulfur and using it to make concrete in a lunar setting has been previously discussed. However, little has been experimentally done to evaluate its performance in the extreme lunar environment. This study subjected sets of sulfur concrete samples, prepared using JSC-1 lunar simulant, to I ) extended periods of high vacuum and 2) extreme temperature cycles. Here an overview of sulfur concrete and experimentally assessed properties, put in context of the lunar environment, is presented and discussed.

  9. Material Concerns: Evaluating Sulfur Concrete for use in the Lunar Environment

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N.; Toutanji, Houssam

    2006-01-01

    On Earth sulfur "concrete" is an established construction material that has good mechanical properties, generally better than Portland cement, and can be used in corrosive environments. Troilite (FeS) has been found on the moon and raises the question of using extracted sulfur as a lunar construction material, an attractive alternative to conventional concrete as it does not require water. Troilite reduction to elemental sulfur and using it to make concrete in a lunar setting has been previously discussed. However, little has been experimentally done to evaluate its performance in the extreme lunar environment. This study subjected sets of sulfur concrete samples, prepared using JSC-1 lunar simulant, to I ) extended periods of high vacuum and 2) extreme temperature cycles. Here an overview of sulfur concrete and experimentally assessed properties, put in context of the lunar environment, is presented and discussed.

  10. Effect of Material Composition and Environmental Condition on Thermal Characteristics of Conductive Asphalt Concrete.

    PubMed

    Pan, Pan; Wu, Shaopeng; Hu, Xiaodi; Liu, Gang; Li, Bo

    2017-02-23

    Conductive asphalt concrete with high thermal conductivity has been proposed to improve the solar energy collection and snow melting efficiencies of asphalt solar collector (ASC). This paper aims to provide some insight into choosing the basic materials for preparation of conductive asphalt concrete, as well as determining the evolution of thermal characteristics affected by environmental factors. The thermal properties of conductive asphalt concrete were studied by the Thermal Constants Analyzer. Experimental results showed that aggregate and conductive filler have a significant effect on the thermal properties of asphalt concrete, while the effect of asphalt binder was not evident due to its low proportion. Utilization of mineral aggregate and conductive filler with higher thermal conductivity is an efficient method to prepare conductive asphalt concrete. Moreover, change in thermal properties of asphalt concrete under different temperature and moisture conditions should be taken into account to determine the actual thermal properties of asphalt concrete. There was no noticeable difference in thermal properties of asphalt concrete before and after aging. Furthermore, freezing-thawing cycles strongly affect the thermal properties of conductive asphalt concrete, due to volume expansion and bonding degradation.

  11. Effect of Material Composition and Environmental Condition on Thermal Characteristics of Conductive Asphalt Concrete

    PubMed Central

    Pan, Pan; Wu, Shaopeng; Hu, Xiaodi; Liu, Gang; Li, Bo

    2017-01-01

    Conductive asphalt concrete with high thermal conductivity has been proposed to improve the solar energy collection and snow melting efficiencies of asphalt solar collector (ASC). This paper aims to provide some insight into choosing the basic materials for preparation of conductive asphalt concrete, as well as determining the evolution of thermal characteristics affected by environmental factors. The thermal properties of conductive asphalt concrete were studied by the Thermal Constants Analyzer. Experimental results showed that aggregate and conductive filler have a significant effect on the thermal properties of asphalt concrete, while the effect of asphalt binder was not evident due to its low proportion. Utilization of mineral aggregate and conductive filler with higher thermal conductivity is an efficient method to prepare conductive asphalt concrete. Moreover, change in thermal properties of asphalt concrete under different temperature and moisture conditions should be taken into account to determine the actual thermal properties of asphalt concrete. There was no noticeable difference in thermal properties of asphalt concrete before and after aging. Furthermore, freezing–thawing cycles strongly affect the thermal properties of conductive asphalt concrete, due to volume expansion and bonding degradation. PMID:28772580

  12. Durability of recycled aggregate concrete using pozzolanic materials.

    PubMed

    Ann, K Y; Moon, H Y; Kim, Y B; Ryou, J

    2008-01-01

    In this study, pulverized fuel ash (PFA) and ground granulated blast furnace slag (GGBS) were used to compensate for the loss of strength and durability of concrete containing recycled aggregate. As a result, 30% PFA and 65% GGBS concretes increased the compressive strength to the level of control specimens cast with natural granite gravel, but the tensile strength was still lowered at 28 days. Replacement with PFA and GGBS was effective in raising the resistance to chloride ion penetrability into the concrete body, measured by a rapid chloride ion penetration test based on ASTM C 1202-91. It was found that the corrosion rate of 30% PFA and 65% GGBS concretes was kept at a lower level after corrosion initiation, compared to the control specimens, presumably due to the restriction of oxygen and water access. However, it was less effective in increasing the chloride threshold level for steel corrosion. Hence, it is expected that the corrosion time for 30% PFA and 65% GGBS concrete containing recycled aggregate mostly equates to the corrosion-free life of control specimens.

  13. Materials development and field demonstration of high-recycled-content concrete for energy-efficient building construction

    SciTech Connect

    Ostowari, Ken; Nosson, Ali

    2000-09-30

    The project developed high-recycled-content concrete material with balanced structural and thermal attributes for use in energy-efficient building construction. Recycled plastics, tire, wool, steel and concrete were used as replacement for coarse aggregates in concrete and masonry production. With recycled materials the specific heat and thermal conductivity of concrete could be tailored to enhance the energy-efficiency of concrete buildings. A comprehensive field project was implemented which confirmed the benefits of high-recycled-content concrete for energy-efficient building construction.

  14. RESTORING A DAMAGED 16-YEAR -OLD INSULATING POLYMER CONCRETE DIKE OVERLAY: REPAIR MATERIALS AND TECHNOLOGIES.

    SciTech Connect

    SUGAMA,T.

    2007-01-01

    The objective of this program was to design and formulate organic polymer-based material systems suitable for repairing and restoring the overlay panels of insulating lightweight polymer concrete (ILPC) from the concrete floor and slope wall of a dike at KeySpan liquefied natural gas (LNG) facility in Greenpoint, Brooklyn, NY, just over sixteen years ago. It also included undertaking a small-scale field demonstration to ensure that the commercial repairing technologies were applicable to the designed and formulated materials.

  15. National Runway Friction Measurement Program.

    DTIC Science & Technology

    1980-12-01

    wet Mu values less than 50. Of the 122 runways with low segments, 64 runways (52.5%) had wet Mu values less than 50 for less than 1000 feet. Other data...friction enhancement due to grooving is greater in areas of rubber accumulation than in uncontaminated areas for most pavement types. 4. For low -use...friction, as identified 4n Fiqure 9, should be considered in the planning and design of rpw -unway surfaces, particularly for low -use runways. 2. The

  16. Shuttle landing runway modification to improve tire spin-up wear performance

    NASA Technical Reports Server (NTRS)

    Daugherty, Robert H.; Yager, Thomas J.; Stubbs, Sandy M.

    1988-01-01

    This paper presents the results of a series of tire spin-up wear tests on a simulated Kennedy Space Center (KSC) runway that were carried out to investigate the tire wear problem for Space Shuttle landings on the KSC runway and to test several modifications of the runway surface designed to alleviate the problem. It was found that the runway surface produced by a concrete smoothing machine using cutters spaced one and three-quarters blades per centimeter provided adequate wet cornering while limiting spin-up wear. Based on the test results, the KSC runway was smoothed for about 1066 m at each end, leaving the original high friction surface, for better wet steering and braking, in the 2438-m central section.

  17. Runway Safety Monitor Algorithm for Runway Incursion Detection and Alerting

    NASA Technical Reports Server (NTRS)

    Green, David F., Jr.; Jones, Denise R. (Technical Monitor)

    2002-01-01

    The Runway Safety Monitor (RSM) is an algorithm for runway incursion detection and alerting that was developed in support of NASA's Runway Incursion Prevention System (RIPS) research conducted under the NASA Aviation Safety Program's Synthetic Vision System element. The RSM algorithm provides pilots with enhanced situational awareness and warnings of runway incursions in sufficient time to take evasive action and avoid accidents during landings, takeoffs, or taxiing on the runway. The RSM currently runs as a component of the NASA Integrated Display System, an experimental avionics software system for terminal area and surface operations. However, the RSM algorithm can be implemented as a separate program to run on any aircraft with traffic data link capability. The report documents the RSM software and describes in detail how RSM performs runway incursion detection and alerting functions for NASA RIPS. The report also describes the RIPS flight tests conducted at the Dallas-Ft Worth International Airport (DFW) during September and October of 2000, and the RSM performance results and lessons learned from those flight tests.

  18. Utility of Wastage Material as Steel Fibre in Concrete Mix M-20

    NASA Astrophysics Data System (ADS)

    Parashar, Ashish Kumar; Parashar, Rinku

    2012-10-01

    Fiber Reinforced Concrete (FRC) is a composite material consisting of cement based matrix with an ordered or random distribution of fiber which can be steel, nylon, polythene etc. The addition of steel fibre increases the properties of concrete, viz., flexural strength, impact strength and shrinkage properties to name a few. A number of papers have already been published on the use of steel fibres in concrete and a considerable amount of research has been directed towards studying the various properties of concrete as well as reinforced concrete due to the addition of steel fibres. Hence, an attempt has been made in the present investigations to study the influence of addition of Lathe Machines wastematerial as fibers at a dosage of 5% to 30% by weight of cement. The properties studied include compressive strength. The studies were conducted on a M20 mix and tests have been carried out. The results are compared and conclusions are made.

  19. Lightweight concrete materials and structural systems for water tanks for thermal storage. Final report

    SciTech Connect

    Buckman, R.W. Jr.; Elia, G.G.; Ichikawa, Y.

    1980-12-01

    Thermally efficient hot water storage tanks were designed, fabricated and evaluated. The tanks were made using cellular concrete at a nominal density of 100 lb/ft/sup 3/ for the structural elements and at a 30 lb/ft/sup 3/ density for the insulating elements. Thermal performance testing of the tanks was done using a static decay test since the test procedure specified in ASHRAE 94-77 was not experimentally practical. A series of composition modifications to the cellular concrete mix were investigated and the addition of alkaline resistant glass fibers was found to enhance the mechanical properties at no sacrifice in thermal behavior. Economic analysis indicated that cellular concrete provides a cost-effective insulating material. The total portability of the plant for producing cellular concrete makes cellular concrete amenable to on-site fabrication and uniquely adaptable to retrofit applications.

  20. Evaluation of Sulfur 'Concrete' for Use as a Construction Material on the Lunar Surface

    NASA Technical Reports Server (NTRS)

    Grugel, R. N.

    2008-01-01

    Combining molten sulfur with any number of aggregate materials forms, when solid, a mixture having attributes similar, if not better, to conventional water-based concrete. As a result the use of sulfur "concrete" on Earth is well established, particularly in corrosive environments. Consequently, discovery of troilite (FeS) on the lunar surface prompted numerous scenarios about its reduction to elemental sulfur for use, in combination with lunar regolith, as a potential construction material; not requiring water, a precious resource, for its manufacture is an obvious advantage. However, little is known about the viability of sulfur concrete in an environment typified by extreme temperatures and essentially no atmosphere. The experimental work presented here evaluates the response of pure sulfur and sulfur concrete subjected to laboratory conditions that approach those expected on the lunar surface, the results suggesting a narrow window of application.

  1. Evaluation of Sulfur 'Concrete' for Use as a Construction Material on the Lunar Surface

    NASA Technical Reports Server (NTRS)

    Grugel, R. N.

    2008-01-01

    Combining molten sulfur with any number of aggregate materials forms, when solid, a mixture having attributes similar, if not better, to conventional water-based concrete. As a result the use of sulfur "concrete" on Earth is well established, particularly in corrosive environments. Consequently, discovery of troilite (FeS) on the lunar surface prompted numerous scenarios about its reduction to elemental sulfur for use, in combination with lunar regolith, as a potential construction material; not requiring water, a precious resource, for its manufacture is an obvious advantage. However, little is known about the viability of sulfur concrete in an environment typified by extreme temperatures and essentially no atmosphere. The experimental work presented here evaluates the response of pure sulfur and sulfur concrete subjected to laboratory conditions that approach those expected on the lunar surface, the results suggesting a narrow window of application.

  2. Performance of Styrene Butadiene Rubber as a Concrete Repair Material in tropical climate

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, R.; Prakash, V. Syam; Thampan, C. K.; Varma, Prasad

    2012-11-01

    Deterioration of Concrete due to variety of reasons like corrosion of steel, inferior quality of materials as well as workmanship and exposure to aggressive environment like thermal cycling affect the performance or damage a number of Reinforced cement concrete structures. In order to repair these structures for enhancing the service life, number of methods and materials are available. But the degree of success of any repair in concrete depends mainly on the correct choice and the method of application of repair materials. This paper discusses the details of an experimental investigation on the performance of Styrene ñ Butadiene Rubber (SBR) as a concrete repair material in tropical climatic conditions. Resistance to water penetration and tensile cracking are two important performance criteria for any repair material. Cement mortar cubes of mix proportion 1:3 with SBR added at the rate of 20% of the weight of cement, and control specimens without SBR were made. Compressive strength and sorptivity values of the cubes were determined. Shear Bond strength (by slant shear test) and splitting tensile strength of the repaired cylinder specimens of standard dimensions, in which SBR used as a bonding agent were determined. These values were compared with the values obtained for the similar specimens, in which the bonding agent applied was conventional cement slurry. The influence of thermal cycling on the properties of repaired concrete specimens were also studied. A comparison has also been made with the values required to meet the standard specifications of a repair material.

  3. Evaluation of the environmental, material, and structural performance of recycled aggregate concrete

    NASA Astrophysics Data System (ADS)

    Michaud, Katherine Sarah

    Concrete is the most commonly used building material in the construction industry, and contributes to 52% of construction and demolition waste in Canada. Recycled concrete aggregate (RCA) is one way to reduce this impact. To evaluate the performance of coarse and granular (fine and coarse) RCA in structural concrete applications, four studies were performed: an environmental assessment, a material testing program, a shear performance study, and a flexural performance study. To determine the environmental benefits of recycled aggregate concrete (RAC), three case studies were investigated using different populations and proximities to city centres. Environmental modelling suggested that RCA replacement could result in energy savings and greenhouse gas emission reductions, especially in remote areas. Tests were performed to determine if the volumetric replacement of up to 30% coarse RCA and 20% granular RCA is suitable for structural concrete applications in Canada. Fresh, hardened, and durability properties were evaluated. All five (5) of the RCA mixes showed equivalent material performance to the control mixes and met the requirements for a structural concrete mix. The five (5) RAC mixes were also used in structural testing. One-way reinforced concrete slab specimens were tested to failure to evaluate the shear and flexural performance of the RAC members. Peak capacities of and crack formation within each member were analyzed to evaluate the performance of RAC compared to conventional concrete. The shear capacity of specimens made from four (4) of the five (5) RAC mixtures was higher or equivalent to the control specimens. Specimens of the concrete mixture containing the highest content of recycled aggregate, 20% volumetric replacement of granular RCA, had shear capacities 14.1% lower, and exhibited cracking at lower loads than the control. The average flexural capacities of all RAC specimens were within 3.7% of the control specimens. Results from this research

  4. Health monitoring of a concrete structure using piezoceramic materials

    NASA Astrophysics Data System (ADS)

    Song, G.; Gu, H.; Mo, Y. L.; Hsu, T.; Dhonde, H.; Zhu, R. R. H.

    2005-05-01

    Health monitoring for reinforced concrete bridges and other large-scale civil infrastructure has received considerable attention in recent years. Traditional inspection methods (x-ray, C-scan etc.) are expensive and sometimes ineffective for large-scale structures. Piezoceramic transducers have emerged as new tools to health monitoring of large size structures due to the advantages of active sensing, low cost, quick response, availability in different shapes, and simplicity for implementation. In this research, piezoceramic transducers in the form of patches are used to detect internal cracks of a 6.1-meter long reinforced concrete bridge bent-cap. Piezoceramic patches are embedded in the concrete structure at pre-determined spatial locations prior to casting. This research can be considered as a continuation of an early work, where four piezoceramic patches were embedded in planar locations near one end of the bent-cap. This research involves ten piezoceramic patches embedded at spatial locations in four different cross-sections. To induce cracks in the bent-cap, the structure is subjected to loads from four hydraulic actuators with capacities of 80-ton and 100-ton. In addition to the piezoceramic sensors, strain gages, LVDTs, and microscopes are used in the experiment. During the experiment, one embedded piezoceramic patch is used as an actuator to generate sweep sinusoidal waves, and the other piezoceramic patches are used as sensors to detect the propagating waves. With the increase of number of and severity of cracks, the magnitude of the sensor output decreases. Wavelet packet analysis is used to analyze the recorded sensor signals. A damage index is formed on the basis of the wavelet packet analysis. The experimental results show that the proposed methods using piezoceramic transducers along with the damage index based on wavelet packet analysis is effective in identifying the existence and severity of cracks inside the concrete structure. The experimental

  5. Phenomena of Foamed Concrete under Rolling of Aircraft Wheels

    NASA Astrophysics Data System (ADS)

    Jiang, Chun-shui; Yao, Hong-yu; Xiao, Xian-bo; Kong, Xiang-jun; Shi, Ya-jie

    2014-04-01

    Engineered Material Arresting System (EMAS) is an effective technique to reduce hazards associated with aircraft overrunning runway. In order to ascertain phenomena of the foamed concrete used for EMAS under rolling of aircraft wheel, a specially designed experimental setup was built which employed Boeing 737 aircraft wheels bearing actual vertical loads to roll through the foamed concrete. A number of experiments were conducted upon this setup. It is discovered that the wheel rolls the concrete in a pure rolling manner and crushes the concrete downwards, instead of crushing it forward, as long as the concrete is not higher than the wheel axle. The concrete is compressed into powder in-situ by the wheel and then is brought to bottom of the wheel. The powder under the wheel is loose and thus is not able to sustain wheel braking. It is also found that after being rolled by the wheel the concrete exhibits either of two states, i.e. either 'crushed through' whole thickness of the concrete or 'crushed halfway', depending on combination of strength of the concrete, thickness of the concrete, vertical load the wheel carries, tire dimension and tire pressure. A new EMAS design concept is developed that if an EMAS design results in the 'crushed through' state for the main gears while the 'crushed halfway' state for the nose gear, the arresting bed would be optimal to accommodate the large difference in strength between the nose gear and the main gear of an aircraft.

  6. Damage evaluation for concrete structures using fiber-reinforced composites as self-diagnosis materials

    NASA Astrophysics Data System (ADS)

    Yoshitake, Kenji; Shiba, Keiji; Suzuki, Makoto; Sugita, Minoru; Okuhara, Yoshiki

    2004-07-01

    Health monitoring techniques that utilize structural materials with the ability to diagnose their own condition, so-called self-diagnosis materials, have been under development. The authors have developed two types of electrically conductive fiber reinforced composite to diagnose cracks in concrete structures: a high sensitivity detection sensor and maximum strain memory sensor. Three points bending tests on pre-notched reinforced concrete beam under the cyclic loading is presented using these two self-diagnosis materials, with attention towards the relationship between crack width of the concrete beam and electric resistance. Moreover, effects of volume fraction of carbon particle on memorizing maximum strain are investigated. It has been proved that both self-diagnosis materials are highly effective to detect the cracks in the concrete. And present strain can be obtained by the proposed fiber reinforced plastic composites. Although volume fraction of carbon particle has significant influence on the characteristics of memorizing maximum strain, maximum strain of the concrete structures can be memorized using the appropriate self-diagnosis materials.

  7. Dynamic Fracture of Concrete and other Heterogeneous Materials.

    DTIC Science & Technology

    1984-11-01

    Concrete and . Geomaterials, Northwestern University, Evanston, Illinois, Jan . 1984. 16. Bazant , Z.P. and Chang, T.P., "Nonlocal Continuum ard Strain...UNCLASSIFIED) 12. PERSONAL AUTHOR(S) T. Belytscnko and Z. Bazant , C. Chang, H. Hyun 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT ’Yr.. Mo.. Day...202/767-4935 AFOSR/NA DO FORM 1473,,83 APR EDITION OF I JAN 73 IS OBSOLETE UNCLASSIFIED SECURiTy CLASSIFICATION OF THIS PAGE • °’. . o0 ’-, o f

  8. Photocatalytic activity of titanium dioxide modified concrete materials - influence of utilizing recycled glass cullets as aggregates.

    PubMed

    Chen, Jun; Poon, Chi-Sun

    2009-08-01

    Combining the use of photocatalysts with cementitious materials is an important development in the field of photocatalytic air pollution mitigation. This paper presents the results of a systematic study on assessing the effectiveness of pollutant degradation by concrete surface layers that incorporate a photocatalytic material - Titanium Dioxide. The photocatalytic activity of the concrete samples was determined by photocatalytic oxidation of nitric oxide (NO) in the laboratory. Recycled glass cullets, derived from crushed waste beverage bottles, were used to replace sand in preparing the concrete surface layers. Factors, which may affect the pollutant removal performance of the concrete layers including glass color, aggregate size and curing age, were investigated. The results show a significant enhancement of the photocatalytic activity due to the use of glass cullets as aggregates in the concrete layers. The samples fabricated with clear glass cullets exhibited threefold NO removal efficiency compared to the samples fabricated with river sand. The light transmittance property of glass was postulated to account for the efficiency improvement, which was confirmed by a separate simulation study. But the influence of the size of glass cullets was not evident. In addition, the photocatalytic activity of concrete surface layers decreased with curing age, showing a loss of 20% photocatalytic activity after 56-day curing.

  9. BUILDING MATERIAL CHARACTERIZATION USING A CONCRETE FLOOR AND WALL CONTAMINATION PROFILING TECHNOLOGY

    SciTech Connect

    Aggarwal, Dr. S.,; Charters, G.; Thacker, Dr. D.

    2003-02-27

    Certain radioisotopes can penetrate concrete and contaminate the concrete well below the surface. The challenge is to determine the extent and magnitude of the contamination problem in real-time. The concrete profiling technology, TRUPROSM in conjunction with portable radiometric instrumentation produces a profile of radiological or chemical contamination through the material being studied. The data quality, quantity, and representativeness may be used to produce an activity profile from the hot spot surface into the material being sampled. This activity profile may then be expanded to ultimately characterize the facility and expedite waste segregation and facility closure at a reduced cost and risk. Performing a volumetric concrete or metal characterization safer and faster (without lab intervention) is the objective of this characterization technology. This way of determining contamination can save considerable time and money. Currently, concrete core bores are shipped to certified laboratories where the concrete residue is run through a battery of tests to determine the contaminants. The existing core boring operation volatilizes or washes out some of the contaminants (like tritium) and oftentimes cross-contaminates the area around the core bore site. The volatilization of the contaminants can lead to airborne problems in the immediate vicinity of the core bore. Cross-contamination can increase the contamination area and thereby increase the amount of waste generated. The goal is to avoid those field activities that could cause this type of release.

  10. Investigation of the Suitability of the Bazant Endochronic Material Model for Modelling the Concrete in a SAMSON Analysis of a Reinforced Concrete Beam.

    DTIC Science & Technology

    1979-07-01

    I I ‘ S I I I ( ~~NVESTIGATION OF THE I SUITABILITY OF THE BAZANT ENDOCHRONIC I MATERIAL MODEL FOR MODELLING THE CONCRETE IN A SAMSON ~NALYSIS OF I A...4. T ITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED INVESTIGATION OF THE SUITABILITY OF THE BAZANT FINAL ENDOCHRONIC...MATERIAL MO-DEL FOR MODELLING THE JAN — May 1979 CONC RETE IN A SAMSON ANALYSIS OF A REINFORCED 6. PERFORMING ORG. REPORT NUMBER CONCRETE BEAM

  11. Material property assessment and crack identification of recycled concrete with embedded smart cement modules

    NASA Astrophysics Data System (ADS)

    Qiao, Pizhong; Fan, Wei; Chen, Fangliang

    2011-04-01

    In this paper, the material property assessment and crack identification of concrete using embedded smart cement modules are presented. Both the concrete samples with recycled aggregates (RA) and natural aggregates (NA) were prepared. The smart cement modules were fabricated and embedded in concrete beams to serve as either the actuators or sensors, and the elastic wave propagation-based technique was developed to detect the damage (crack) in the recycled aggregate concrete (RAC) beams and monitor the material degradation of RAC beams due to the freeze/thaw (F/T) conditioning cycles. The damage detection results and elastic modulus reduction monitoring data demonstrate that the proposed smart cement modules and associated damage detection and monitoring techniques are capable of identifying crack-type damage and monitoring material degradation of the RAC beams. Both the RAC and natural aggregate concrete (NAC) beams degrade with the increased F/T conditioning cycles. Though the RAC shows a lower reduction percentage of the modulus of elasticity from both the dynamic modulus and wave propagation tests at the given maximum F/T conditioning cycle (i.e., 300 in this study), the RAC tends to degrade faster after the 180 F/T cycles. As observed in this study, the material properties and degradation rate of RAC are comparable to those of NAC, thus making the RAC suitable for transportation construction. The findings in development of damage detection and health monitoring techniques using embedded smart cement modules resulted from this study promote the widespread application of recycled concrete in transportation construction and provide viable and effective health monitoring techniques for concrete structures in general.

  12. Modeling Concrete Material Structure: A Two-Phase Meso Finite Element Model

    NASA Astrophysics Data System (ADS)

    Bonifaz, E. A.; Baus, Juan; Lantsoght, Eva O. L.

    Concrete is a compound material where aggregates are randomly placed within the cement paste. To describe the behavior of concrete structures at the ultimate, it is necessary to use nonlinear finite element models, which for shear and torsion problems do not always give satisfactory results. The current study aims at improving the modeling of concrete at the meso-level, which eventually can result in an improved assessment of existing structures. Concrete as a heterogeneous material is modeled consisting of hydrated cement paste and aggregates. The stress-strain curves of the hydrated cement paste and aggregates are described with results from the literature. A three-dimensional (3D) finite element model was developed to determine the influence of individual phases on the inelastic stress-strain distribution of concrete structures. A random distribution and morphology of the cement and aggregate fractions are achieved by using DREAM.3D. Two affordable computational dual-phase representative volume elements (RVEs) are imported to ABAQUS to be studied in compression and tension. The virtual specimens (concrete mesh) subjected to continuous monotonic strain loading conditions were constrained with 3D boundary conditions. Results demonstrate differences in stress-strain mechanical behavior in both compression and tension test simulations. A strong dependency of flow stress and plastic strain on phase type, aggregate (andesite) size, shape and distribution upon the composite local response are clearly observed. It is noted that the resistance to flow is higher in concrete meshes composed of finer and homogeneous aggregate particles because the Misses stresses and effective plastic strains are better distributed. This study shows that at the meso-level, concrete can be modeled consisting of aggregates and hydrated cement paste.

  13. Runway drainage characteristics related to tire friction performance

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1991-01-01

    The capability of a runway pavement to rapidly drain water buildup during periods of precipitation is crucial to minimize tire hydroplaning potential and maintain adequate aircraft ground operational safety. Test results from instrumented aircraft, ground friction measuring vehicles, and NASA Langley's Aircraft Landing Dynamics Facility (ALDF) track have been summarized to indicate the adverse effects of pavement wetness conditions on tire friction performance. Water drainage measurements under a range of rainfall rates have been evaluated for several different runway surface treatments including the transversely grooved and longitudinally grinded concrete surfaces at the Space Shuttle Landing Facility (SLF) runway at NASA Kennedy Space Center in Florida. The major parameters influencing drainage rates and extent of flooding/drying conditions are identified. Existing drainage test data are compared to a previously derived empirical relationship and the need for some modification is indicated. The scope of future NASA Langley research directed toward improving empirical relationships to properly define runway drainage capability and consequently, enhance aircraft ground operational safety, is given.

  14. Tire and runway surface research

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1986-01-01

    The condition of aircraft tires and runway surfaces can be crucial in meeting the stringent demands of aircraft ground operations, particularly under adverse weather conditions. Gaining a better understanding of the factors influencing the tire/pavement interface is the aim of several ongoing NASA Langley research programs which are described in this paper. Results from several studies conducted at the Langley Aircraft Landing Dynamics Facility, tests with instrumented ground vehicles and aircraft, and some recent aircraft accident investigations are summarized to indicate effects of different tire and runway properties. The Joint FAA/NASA Runway Friction Program is described together with some preliminary test findings. The scope of future NASA Langley research directed towards solving aircraft ground operational problems related to the tire/pavement interface is given.

  15. Comparison of responses of concrete damage material models with respect to optimization-based material parameter identification

    NASA Astrophysics Data System (ADS)

    Král, Petr; Hradil, Petr; Hušek, Martin; Hokeš, Filip

    2017-07-01

    Today, the inverse identification or optimization of material model parameters is very often used to find input parameter values for use in relevant nonlinear material models. These parameter values should enable the responses of structures obtained from numerical simulations to very closely approximate the real responses of such structures obtained from experiments. Due to the popularity of concrete as a construction material, much attention is paid to nonlinear material models that aim to describe its behavior. This paper is focused on the optimization-based inverse identification of the parameters of two related nonlinear concrete material models which are known as the Karagozian & Case Concrete model and the Karagozian & Case Concrete model - Release III. Within this paper, the identification of the material model parameters is performed on the basis of interaction between nonlinear numerical simulations, optimization algorithms and experimental data, the latter of which take the form of a loading curve measured during a triaxial compression test. A comparison of the responses of both of the used material models when the optimized parameters are employed is, of course, part of this paper.

  16. Microwave processing of cement and concrete materials – towards an industrial reality?

    SciTech Connect

    Buttress, Adam Jones, Aled; Kingman, Sam

    2015-02-15

    Each year a substantial body of literature is published on the use of microwave to process cement and concrete materials. Yet to date, very few if any have lead the realisation of a commercial scale industrial system and is the context under which this review has been undertaken. The state-of the–art is evaluated for opportunities, and the key barriers to the development of new microwave-based processing techniques to enhance production, processing and recycling of cement and concrete materials. Applications reviewed include pyro-processing of cement clinker; accelerated curing, non-destructive testing and evaluation (NDT&E), and end-of-life processing including radionuclide decontamination.

  17. Studies of ancient concrete as analogs of cementitious sealing materials for a repository in tuff

    SciTech Connect

    Roy, D.M.; Langton, C.A.

    1989-03-01

    The durability of ancient cementitious materials has been investigated to provide data applicable to determining the resistance to weathering of concrete materials for sealing a repository for storage of high-level radioactive waste. Because tuff and volcanic ash are used in the concretes in the vicinity of Rome, the results are especially applicable to a waste repository in tuff. Ancient mortars, plasters, and concretes collected from Rome, Ostia, and Cosa dating to the third century BC show remarkable durability. The aggregates used in the mortars, plasters, and concretes included basic volcanic and pyroclastic rocks (including tuff), terra-cotta, carbonates, sands, and volcanic ash. The matrices of ancient cementitious materials have been characterized and classified into four categories: (1) hydraulic hydrated lime and hydrated lime cements, (2) hydraulic aluminous and ferruginous hydrated lime cements ({plus_minus} siliceous components), (3) pozzolana/hydrated lime cements, and (4) gypsum cements. Most of the materials investigated are in category (3). The materials were characterized to elucidate aspects of the technology that produced them and their response to the environmental exposure throughout their centuries of existence. Their remarkable properties are the result of a combination of chemical, mineralogical, and microstructural factors. Their durability was found to be affected by the matrix mineralogy, particle size, and porosity; aggregate type, grading and proportioning; and the methodology of placement. 30 refs.

  18. Balanced improvement of high performance concrete material properties with modified graphite nanomaterials

    NASA Astrophysics Data System (ADS)

    Peyvandi, Amirpasha

    Graphite nanomaterials offer distinct features for effective reinforcement of cementitious matrices in the pre-crack and post-crack ranges of behavior. Thoroughly dispersed and well-bonded nanomaterials provide for effective control of the size and propagation of defects (microcracks) in matrix, and also act as closely spaced barriers against diffusion of moisture and aggressive solutions into concrete. Modified graphite nanomaterials can play multi-faceted roles towards enhancing the mechanical, physical and functional attributes of concrete materials. Graphite nanoplatelets (GP) and carbon nanofibers (CNF) were chosen for use in cementitious materials. Experimental results highlighted the balanced gains in diverse engineering properties of high-performance concrete realized by introduction of graphite nanomaterials. Nuclear Magnetic Resonance (NMR) spectroscopy was used in order to gain further insight into the effects of nanomaterials on the hydration process and structure of cement hydrates. NMR exploits the magnetic properties of certain atomic nuclei, and the sensitivity of these properties to local environments to generate data which enables determination of the internal structure, reaction state, and chemical environment of molecules and bulk materials. 27 Al and 29Si NMR spectroscopy techniques were employed in order to evaluate the effects of graphite nanoplatelets on the structure of cement hydrates, and their resistance to alkali-silica reaction (ASR), chloride ion diffusion, and sulfate attack. Results of 29Si NMR spectroscopy indicated that the percent condensation of C-S-H in cementitious paste was lowered in the presence of nanoplatelets at the same age. The extent of chloride diffusion was assessed indirectly by detecting Friedel's salt as a reaction product of chloride ions with aluminum-bearing cement hydrates. Graphite nanoplatelets were found to significantly reduce the concentration of Friedel's salt at different depths after various periods

  19. Nuclear Technology. Course 29: Civil/Structural Inspection. Module 29-3, Concrete Materials.

    ERIC Educational Resources Information Center

    Groseclose, Richard

    This third in a series of six modules for a course titled Civil/Structural Inspection deals with concrete component materials and discusses their properties, methods of handling and storage, selection, uniformity, and methods of acceptance. The module follows a typical format that includes the following sections: (1) introduction, (2) module…

  20. Nuclear Technology. Course 29: Civil/Structural Inspection. Module 29-3, Concrete Materials.

    ERIC Educational Resources Information Center

    Groseclose, Richard

    This third in a series of six modules for a course titled Civil/Structural Inspection deals with concrete component materials and discusses their properties, methods of handling and storage, selection, uniformity, and methods of acceptance. The module follows a typical format that includes the following sections: (1) introduction, (2) module…

  1. Aerial view of Runway 33 at SLF

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This aerial view shows the approach on Runway 33 at the KSC Shuttle Landing Facility. The runway is 15,000 feet long, with 1,000-foot paved overruns at each end; 300 feet wide (about length of football field), with 50-foot asphalt shoulders each side; 16 inches thick in the center, and 15 inches thick on sides. It has a slope of 24 inches from the center line to the edge for drainage. The single landing strip is considered two runways, depending on approach -- Runway 15 from northwest, Runway 33 from southeast.

  2. Aerial view of Runway 33 at SLF

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This aerial view shows the approach on Runway 33 at the KSC Shuttle Landing Facility. The runway is 15,000 feet long, with 1,000-foot paved overruns at each end; 300 feet wide (about length of football field), with 50-foot asphalt shoulders each side; 16 inches thick in the center, and 15 inches thick on sides. It has a slope of 24 inches from the center line to the edge for drainage. The single landing strip is considered two runways, depending on approach -- Runway 15 from northwest, Runway 33 from southeast.

  3. Field applications of a carbon fiber sheet material for strengthening reinforced concrete structure

    SciTech Connect

    Thomas, J.; Kliger, H.S.; Yoshizawa, Hiroyuki

    1996-12-31

    Forca Tow Sheet is now being introduced into the USA as a viable alternative to conventional concrete strengthen techniques. This carbon fiber shoot material is externally bonded to reinforced concrete and masonry structures and serves to strengthen existing conditions. Based on the growing use of Tow Sheet in the Japanese market die US infrastructure market is beginning to apply this technology on a number of diverse repair projects. This paper describes actual field applications on industrial and public structures in the US and Japan. Also included are the results of one yen of monitoring of die Japanese structure.

  4. Diffusion of Iodine and Rhenium in Category 3 Waste Encasement Concrete and Soil Fill Material

    SciTech Connect

    Wellman, Dawn M.; Mattigod, Shas V.; Whyatt, Greg A.; Powers, Laura; Parker, Kent E.; Wood, Marcus I.

    2006-12-15

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e. sorption or precipitation). This understanding will enable accurate prediction of radionuclide fate when the waste forms come in contact with groundwater. A set of diffusion experiments using carbonated and non-carbonated concrete-soil half cells was conducted under unsaturated conditions (4% and 7% by wt moisture content). Spiked concrete half-cell specimens were prepared with and without colloidal metallic iron addition and were carbonated using supercritical carbon dioxide. Spikes of I and Re were added to achieve measurable diffusion profile in the soil part of the half-cell. In addition, properties of concrete materials likely to influence radionuclide migration such as carbonation were evaluated in an effort to correlate these properties with the release of iodine and rhenium.

  5. The Influence of Phase Change Materials on the Properties of Self-Compacting Concrete

    PubMed Central

    Fenollera, María; Míguez, José Luis; Goicoechea, Itziar; Lorenzo, Jaime; Ángel Álvarez, Miguel

    2013-01-01

    The aim of this paper is to research new thermally-efficient concrete walls, analyzing the mechanical behavior of a self-compacting concrete to manufacture an uncoated solid structural panel, with the incorporation of a micro-encapsulated phase change material as additive. Different dosages are tested and mechanical properties of the product obtained from the molding of concrete specimens are evaluated, testing mechanical compressive strength, slump flow, and density. The results reveal the optimum percentage of additive in the mixture that enables compliance with the technical specifications required by the product to be manufactured. A test is also performed for measuring the thermal conductivity for the optimal sample obtained and it evidences the reduction thereof. PMID:28811450

  6. NASA diagonal-braked test vehicle evaluation of traction characteristics of grooved and ungrooved runway surfaces at Miami International Airport, Miami, Florida, 8-9 May 1973

    NASA Technical Reports Server (NTRS)

    Horne, W. B.

    1977-01-01

    Two runways were evaluated under artificially wetted conditions with the NASA diagonal-braked vehicle (DBV). Results of the evaluation which included a pavement drainage analysis, a pavement skid resistance analysis, and a DBV wet/dry stopping distance ratio analysis indicated that the ungrooved runway surfaces had poor water drainage characteristics and poor skid resistance under wet conditions at high speeds especially in rubbercoated areas of the runways. Grooving runways to a transverse 1-1/4 x 1/4 x 1/4 inch pattern greatly improved both the water drainage and pavement skid resistance capability of these asphaltic concrete surfaces.

  7. Concrete crushing and sampling, a methodology and technology for the unconditional release of concrete material from decommissioning

    SciTech Connect

    Gills, R.; Lewandowski, P.; Ooms, B.; Reusen, N.; Van Laer, W.; Walthery, R.

    2007-07-01

    Belgoprocess started the industrial decommissioning of the main process building of the former Eurochemic reprocessing plant in 1990, after completion of a pilot project. Two small storage buildings for final products from reprocessing were dismantled to verify the assumptions made in a previous paper study on decommissioning, to demonstrate and develop dismantling techniques and to train personnel. Both buildings were emptied and decontaminated to background levels. They were demolished and the remaining concrete debris was disposed of as industrial waste and green field conditions restored. Currently, the decommissioning operations carried out at the main building have made substantial progress. They are executed on an industrial scale. In view of the final demolition of the building, foreseen to start in the middle of 2008, a clearance methodology for the concrete from the cells into the Eurochemic building has been developed. It considers at least one complete measurement of all concrete structures and the removal of all detected residual radionuclides. This monitoring sequence is followed by a controlled demolition of the concrete structures and crushing of the resulting concrete parts to smaller particles. During the crushing operations, metal parts are separated from the concrete and representative concrete samples are taken. The frequency of sampling meets the prevailing standards. In a further step, the concrete samples are milled, homogenised, and a smaller fraction is sent to the laboratory for analyses. The paper describes the developed concrete crushing and sampling methodology. (authors)

  8. Tire/runway friction interface

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1990-01-01

    An overview is given of NASA Langley's tire/runway pavement interface studies. The National Tire Modeling Program, evaluation of new tire and landing gear designs, tire wear and friction tests, and tire hydroplaning studies are examined. The Aircraft Landing Dynamics Facility is described along with some ground friction measuring vehicles. The major goals and scope of several joint FAA/NASA programs are identified together with current status and plans.

  9. Development of construction materials like concrete from lunar soils without water

    NASA Technical Reports Server (NTRS)

    Desai, Chandra S.; Saadatmanesh, H.; Frantziskonis, G.

    1989-01-01

    The development of construction materials such as concrete from lunar soils without the use of water requires a different methodology than that used for conventional terrestrial concrete. A unique approach is attempted that utilizes factors such as initial vacuum and then cyclic loading to enhance the mechanical properties of dry materials similar to those available on the moon. The application of such factors is expected to allow reorientation, and coming together, of particles of the materials toward the maximum theoretical density. If such a density can provide deformation and strength properties for even a limited type of construction, the approach can have significant application potential, although other factors such as heat and chemicals may be needed for specific construction objectives.

  10. Evaluation of near surface material degradation in concrete using nonlinear Rayleigh surface waves

    NASA Astrophysics Data System (ADS)

    Gross, J.; Kim, J.-Y.; Jacobs, L. J.; Kurtis, K. E.; Qu, J.

    2013-01-01

    Comparative studies of nondestructive evaluation methods have shown that nonlinear ultrasonic techniques are more sensitive than conventional linear methods to changes in material microstructure and the associated small-scale damage. Many of the material degradation processes such as carbonation in concrete, corrosion in metals, etc., initiate at the surface. In such cases, ultrasonic Rayleigh surface waves are especially appropriate for detection and characterization of damage since their energy is concentrated in the top layer of the test object. For the civil engineering infrastructure, only a limited number of field applicable nonlinear ultrasonic techniques have been introduced. In this paper a nonlinear ultrasonic measurement technique based on the use of Rayleigh waves is developed and used to characterize carbonation in concrete samples. This work develops a collinear mixing technique for concrete structures. Wedge transducer is used for the generation and an accelerometer for the detection of the fundamental and nonlinearity modulated ultrasonic signal components. The measurements are made by varying the input voltage and along the propagation distance. The slope of the normalized modulation amplitudes is taken as the nonlinearity parameter. Concrete samples with two different levels of damage are examined, and the difference of the two fundamental frequencies is used to quantify damage state.

  11. Health monitoring and rehabilitation of a concrete structure using intelligent materials

    NASA Astrophysics Data System (ADS)

    Song, G.; Mo, Y. L.; Otero, K.; Gu, H.

    2006-04-01

    This paper presents the concept of an intelligent reinforced concrete structure (IRCS) and its application in structural health monitoring and rehabilitation. The IRCS has multiple functions which include self-rehabilitation, self-vibration damping, and self-structural health monitoring. These functions are enabled by two types of intelligent (smart) materials: shape memory alloys (SMAs) and piezoceramics. In this research, Nitinol type SMA and PZT (lead zirconate titanate) type piezoceramics are used. The proposed concrete structure is reinforced by martensite Nitinol cables using the method of post-tensioning. The martensite SMA significantly increases the concrete's damping property and its ability to handle large impact. In the presence of cracks due to explosions or earthquakes, by electrically heating the SMA cables, the SMA cables contract and close up the cracks. In this research, PZT patches are embedded in the concrete structure to detect possible cracks inside the concrete structure. The wavelet packet analysis method is then applied as a signal-processing tool to analyze the sensor signals. A damage index is defined to describe the damage severity for health monitoring purposes. In addition, by monitoring the electric resistance change of the SMA cables, the crack width can be estimated. To demonstrate this concept, a concrete beam specimen with reinforced SMA cables and with embedded PZT patches is fabricated. Experiments demonstrate that the IRC has the ability of self-sensing and self-rehabilitation. Three-point bending tests were conducted. During the loading process, a crack opens up to 0.47 inches. Upon removal of the load and heating the SMA cables, the crack closes up. The damage index formed by wavelet packet analysis of the PZT sensor data predicts and confirms the onset and severity of the crack during the loading. Also during the loading, the electrical resistance value of the SMA cable changes by up to 27% and this phenomenon is used to

  12. Construction Productivity Advancement Research (CPAR) Program: Improved Materials and Processes for Sealing and Resealing Joints in Portland Cement Concrete Pavements - Field Evaluation

    DTIC Science & Technology

    1993-10-01

    compositions of material- are currently used for scaling portland cement concrete (PCC) joints . These materials vary widely in chemi- cal complexity...PRODUCTIVITY ADVANCEMENT RESEARCH (CPAR) PROGRAM Improved Materials and Processes for Sealing and Resealing Joints in Portland Cement Concrete Pavements...Processes for Sealing and Resealing Joints in Portland Cement Concrete Pavements-Field Evaluation by Larry N. Lynch, Dewey W. White Accesion

  13. Evaluation of Rapid-Setting Concretes for Airfield Spall Repair

    DTIC Science & Technology

    1991-04-01

    repair concretes for Rapid Runway Repair (RRR). The three were a methyl methacrylate binder (Silikal RI7AF), a magnesium phosphate mortar mix (Set-45...Performance Reauirements Definition of small repair 5. The Rapid Runway Repair Program of the US Air Force (USAF) includes the activities that must be performed...scenario for wartime spall repair includes the expectation that a runway will be damaged by tens to hundreds of spalls at one time. The repair activity

  14. Pilot Evaluations of Runway Status Light System

    NASA Technical Reports Server (NTRS)

    Young, Steven D.; Wills, Robert W.; Smith, R. Marshall

    1996-01-01

    This study focuses on use of the Transport Systems Research Vehicle (TSRV) Simulator at the Langley Research Center to obtain pilot opinion and input on the Federal Aviation Administration's Runway Status Light System (RWSL) prior to installation in an operational airport environment. The RWSL has been designed to reduce the likelihood of runway incursions by visually alerting pilots when a runway is occupied. Demonstrations of the RWSL in the TSRV Simulator allowed pilots to evaluate the system in a realistic cockpit environment.

  15. Repair, Evaluation, Maintenance, and Rehabilitation Research Program: Factors Related to the Performance of Concrete Repair Materials.

    DTIC Science & Technology

    1988-03-01

    a photoelastic technique. Using this technique, he investigated the effects of temperature and relative humidity on the internal stresses induced due...have evaluated the effects of temperature cycling in air or water on the bond of various repair materials to concrete (GPD 80, GPP 76, GPP 78, Pac 79...4.2.1.3.2 Thermal Compatibility ................. 22 4.2.2 Effects of Temperature, Moisture, and Loading......... 23 4.2.3 Standards and

  16. 14 CFR 151.80 - Runway paving: Additional runway; other conditions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Runway paving: Additional runway; other conditions. 151.80 Section 151.80 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.80 Runway paving...

  17. 14 CFR 151.79 - Runway paving: Second runway; wind conditions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Runway paving: Second runway; wind conditions. 151.79 Section 151.79 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.79 Runway paving...

  18. 14 CFR 151.80 - Runway paving: Additional runway; other conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Runway paving: Additional runway; other conditions. 151.80 Section 151.80 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.80 Runway paving...

  19. 14 CFR 151.80 - Runway paving: Additional runway; other conditions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Runway paving: Additional runway; other conditions. 151.80 Section 151.80 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.80 Runway paving...

  20. 14 CFR 151.79 - Runway paving: Second runway; wind conditions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Runway paving: Second runway; wind conditions. 151.79 Section 151.79 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.79 Runway paving...

  1. 14 CFR 151.80 - Runway paving: Additional runway; other conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Runway paving: Additional runway; other conditions. 151.80 Section 151.80 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.80 Runway paving...

  2. 14 CFR 151.80 - Runway paving: Additional runway; other conditions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Runway paving: Additional runway; other conditions. 151.80 Section 151.80 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.80 Runway paving...

  3. 14 CFR 151.79 - Runway paving: Second runway; wind conditions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Runway paving: Second runway; wind conditions. 151.79 Section 151.79 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.79 Runway paving...

  4. STS-53 Discovery, Orbiter Vehicle (OV) 103, lands on runway 22 at EAFB, Calif

    NASA Image and Video Library

    1992-12-09

    STS-53 Discovery, Orbiter Vehicle (OV) 103, is slowed by a red, white, and blue drag chute during its landing on concrete runway 22 at Edwards Air Force Base (EAFB), California. Main landing gear (MLG) touchdown occurred at 12:43:17 pm (Pacific Standard Time (PST)). This aft view of OV-103 shows the drag chute deployed from its compartment at the base of the vertical tail, the speedbrake/rudder flaps open, and the space shuttle main engines (SSMEs). Both MLG and nose landing gear (NLG) ride along the runway surface. Desert scrub brush appears in the foreground and mountains are seen in the background.

  5. Analysis of Runway Incursion Data

    NASA Technical Reports Server (NTRS)

    Green, Lawrence L.

    2013-01-01

    A statistical analysis of runway incursion (RI) events was conducted to ascertain relevance to the top ten challenges of the National Aeronautics and Space Administration Aviation Safety Program (AvSP). The information contained in the RI database was found to contain data that may be relevant to several of the AvSP top ten challenges. When combined with other data from the FAA documenting air traffic volume from calendar year 2000 through 2011, the structure of a predictive model emerges that can be used to forecast the frequency of RI events at various airports for various classes of aircraft and under various environmental conditions.

  6. pH-dependent leaching of constituents of potential concern from concrete materials containing coal combustion fly ash.

    PubMed

    Kosson, David S; Garrabrants, Andrew C; DeLapp, Rossane; van der Sloot, Hans A

    2014-05-01

    Current concerns about the environmental safety of coal combustion fly ash have motivated this evaluation of the impact of fly ash use as a cement replacement in concrete materials on the leaching of constituents of potential concern. The chemical effects of fly ash on leaching were determined through characterization of liquid-solid partitioning using EPA Method 1313 for four fly ash materials as well as concrete and microconcrete materials containing 0% (control materials), 25% and 45% replacement of portland cement with the fly ash source. All source materials, concrete formulations and replacement levels are representative of US concrete industry practices. Eluate concentrations as a function of pH were compared to a broader range of available testing results for international concretes and mortars for which the leaching characteristics of the component fly ashes were unknown. The chemistry of the hydrated cement fraction was found to dominate the liquid-solid partitioning resulting in reduced leaching concentrations of most trace metals compared to concentrations from fly ash materials alone. Compared to controls, eluate concentrations of Sb, As, B, Cr, Mo, Se, Tl and V from concrete products containing fly ash were essentially the same as the eluate concentrations from control materials produced without fly ash replacement indicating little to no significant impact on aqueous partitioning.

  7. A sophisticated simulation for the fracture behavior of concrete material using XFEM

    NASA Astrophysics Data System (ADS)

    Zhai, Changhai; Wang, Xiaomin; Kong, Jingchang; Li, Shuang; Xie, Lili

    2017-07-01

    The development of a powerful numerical model to simulate the fracture behavior of concrete material has long been one of the dominant research areas in earthquake engineering. A reliable model should be able to adequately represent the discontinuous characteristics of cracks and simulate various failure behaviors under complicated loading conditions. In this paper, a numerical formulation, which incorporates a sophisticated rigid-plastic interface constitutive model coupling cohesion softening, contact, friction and shear dilatation into the XFEM, is proposed to describe various crack behaviors of concrete material. An effective numerical integration scheme for accurately assembling the contribution to the weak form on both sides of the discontinuity is introduced. The effectiveness of the proposed method has been assessed by simulating several well-known experimental tests. It is concluded that the numerical method can successfully capture the crack paths and accurately predict the fracture behavior of concrete structures. The infl uence of mode-II parameters on the mixed-mode fracture behavior is further investigated to better determine these parameters.

  8. The diagnostic X-ray protection characteristics of Ytong, an aerated concrete based building material.

    PubMed

    Tsalafoutas, I A; Yakoumakis, E; Manetou, A; Flioni-Vyza, A

    1998-09-01

    Ytong is a widely used building material. The X-ray attenuation properties of Ytong for broad beam geometry conditions and for tube potentials in the 50-140 kVp range are investigated. Comparisons with published data for concrete and other building materials are made. The results suggest that Ytong is not suitable for primary X-ray shielding in common diagnostic installations. However, walls of Ytong, typically 15-20 cm thick, may offer adequate protection in dental and mammography installations, as well as in low workload diagnostic installations as a secondary barrier.

  9. Flexural behavior of reinforced concrete beams strengthened with advanced composite materials

    SciTech Connect

    Shahawy, M.A.; Beitelman, T.

    1996-12-31

    This paper presents the results of a feasibility study to investigate the flexural behavior of structurally damaged reinforced and prestressed concrete members retrofitted with bonded carbon fiber materials. The effect of CFRP laminates, bonded to the soffit of precracked reinforced concrete rectangular and tee beams, is investigated in terms of flexural strength, deflections, cracking behavior and failure modes. The results indicate that strengthening of significantly cracked structural members by bonding Carbon laminates is structurally efficient and that the retrofitted members are restored to stiffness and strength values nearly equal to or greater than those of the original. The results indicate that the retrofitted members maintained adequate structural integrity and composite action at all stages of testing up to failure.

  10. High-strength fibrous concrete of Russian Far East natural materials

    NASA Astrophysics Data System (ADS)

    Fediuk, R.

    2016-02-01

    Fiber-reinforced concrete is designed on composite binder. At 1.6% of reinforcing steel anchoring fiber maximum physical and mechanical properties (Rcompr = 100.9 MPa) can be obtained. It was found that the combined effect of mechanical and chemical activation (the presence of limestone particles) increases the pozzolanic activity of acidic ashes. It has a catalytic effect on the reaction activity of the surface of ash and sand during machining in vario-planetary mill. Furthermore, the addition of limestone increases the alkalinity of the concrete, which leads to the formation of greater hydration products of cement per unit of time. Theoretical and experimental results can be recommended for expanded implementation of the construction in various regions of the Russian Federation, taking into account the availability of raw materials.

  11. Study on application of concrete sandwich insulation material in library building insulation

    NASA Astrophysics Data System (ADS)

    Yang, Zengzhang

    2017-06-01

    Energy shortage is the short slab that restricts the development of social economy, and the rational and effective use of energy is the principle of sustainable development. Building energy consumption accounts for about 30% of total social energy consumption, and this ratio has continued to rise, so the energy saving potential is great in the construction sector. In view of the building energy consumption problem, we produce green insulation building materials with the crop straw, and improve the construction of hot and humid environment. In this paper, we take concrete sandwich straw blocks in library building as the research object, through the experiment to test its winter heat consumption and summer power consumption indicators, carry out experimental study on thermal insulation performance, and explore the overall thermal and energy saving performance of concrete sandwich straw blocks in library building.

  12. Fly ash from cellulose industry as secondary raw material in autoclaved aerated concrete

    SciTech Connect

    Hauser, A.; Eggenberger, U.; Mumenthaler, T.

    1999-03-01

    Because fly ash from cellulose industries contains considerable amounts of free lime and sulfate, they are potential secondary raw materials for the production of autoclaved aerated concrete. Laboratory experiments were performed by replacing lime and sulfate in conventional autoclaved aerated concrete mixtures by fly ash. Compared to a reference series, samples with even higher compressive strength could be produced with lime-sulfate ash. At higher proportions of fly ash, the formation of calcium silicate hydrate phases is delayed and the presence of unreacted portlandite and newly formed scawtite produce a drop in strength and an increase in shrinkage. Low strength resulted by using Al-bearing ash with a lower amount of free CaO, which makes this type of ash not applicable in practice.

  13. Current Practices in Runway Configuration Management (RCM) and Arrival/Departure Runway Balancing (ADRB)

    NASA Technical Reports Server (NTRS)

    Lohr, Gary W.; Williams, Daniel M.

    2008-01-01

    Significant air traffic increases are anticipated for the future of the National Airspace System (NAS). To cope with future traffic increases, fundamental changes are required in many aspects of the air traffic management process including the planning and use of NAS resources. Two critical elements of this process are the selection of airport runway configurations, and the effective management of active runways. Two specific research areas in NASA's Airspace Systems Program (ASP) have been identified to address efficient runway management: Runway Configuration Management (RCM) and Arrival/Departure Runway Balancing (ADRB). This report documents efforts in assessing past as well as current work in these two areas.

  14. Spot and Runway Departure Advisor

    NASA Technical Reports Server (NTRS)

    Jung, Yoon Chul

    2013-01-01

    The Spot and Runway Departure Advisor (SARDA) is a research prototype of a decision support tool for ATC tower controllers to assist in manging and controlling traffic on the surface of an airport. SARDA employs a scheduler to generate an optimal runway schedule and gate push-back - spot release sequence and schedule that improves efficiency of surface operations. The advisories for ATC tower controllers are displayed on an Electronic Flight Strip (EFS) system. The human-in-the-loop simulation of the SARDA tool was conducted for east operations of Dallas-Ft. Worth International Airport (DFW) to evaluate performance of the SARDA tool and human factors, such as situational awareness and workload. The results indicates noticeable taxi delay reduction and fuel savings by using the SARDA tool. Reduction in controller workload were also observed throughout the scenario runs. The future plan includes modeling and simulation of the ramp operations of the Charlotte International Airport, and develop a decision support tool for the ramp controllers.

  15. REAL-TIME IDENTIFICATION AND CHARACTERIZATION OF ASBESTOS AND CONCRETE MATERIALS WITH RADIOACTIVE CONTAMINATION

    SciTech Connect

    XU, X. George; Zhang, X.C.

    2002-05-10

    Concrete and asbestos-containing materials were widely used in DOE building construction in the 1940s and 1950s. Over the years, many of these porous materials have been contaminated with radioactive sources, on and below the surface. To improve current practice in identifying hazardous materials and in characterizing radioactive contamination, an interdisciplinary team from Rensselaer has conducted research in two aspects: (1) to develop terahertz time-domain spectroscopy and imaging system that can be used to analyze environmental samples such as asbestos in the field, and (2) to develop algorithms for characterizing the radioactive contamination depth profiles in real-time in the field using gamma spectroscopy. The basic research focused on the following: (1) mechanism of generating of broadband pulsed radiation in terahertz region, (2) optimal free-space electro-optic sampling for asbestos, (3) absorption and transmission mechanisms of asbestos in THz region, (4) the role of asbestos sample conditions on the temporal and spectral distributions, (5) real-time identification and mapping of asbestos using THz imaging, (7) Monte Carlo modeling of distributed contamination from diffusion of radioactive materials into porous concrete and asbestos materials, (8) development of unfolding algorithms for gamma spectroscopy, and (9) portable and integrated spectroscopy systems for field testing in DOE. Final results of the project show that the combination of these innovative approaches has the potential to bring significant improvement in future risk reduction and cost/time saving in DOE's D and D activities.

  16. Reliable classification of moving waste materials with LIBS in concrete recycling.

    PubMed

    Xia, Han; Bakker, M C M

    2014-03-01

    Effective discrimination between different waste materials is of paramount importance for inline quality inspection of recycle concrete aggregates from demolished buildings. The moving targeted materials in the concrete waste stream are wood, PVC, gypsum block, glass, brick, steel rebar, aggregate and cement paste. For each material, up to three different types were considered, while thirty particles of each material were selected. Proposed is a reliable classification methodology based on integration of the LIBS spectral emissions in a fixed time window, starting from the deployment of the laser shot. PLS-DA (multi class) and the hybrid combination PCA-Adaboost (binary class) were investigated as efficient classifiers. In addition, mean centre and auto scaling approaches were compared for both classifiers. Using 72 training spectra and 18 test spectra per material, each averaged by ten shots, only PLS-DA achieved full discrimination, and the mean centre approach made it slightly more robust. Continuing with PLS-DA, the relation between data averaging and convergence to 0.3% average error was investigated using 9-fold cross-validations. Single-shot PLS-DA presented the highest challenge and most desirable methodology, which converged with 59 PC. The degree of success in practical testing will depend on the quality of the training set and the implications of the possibly remaining false positives.

  17. Wet runways. [aircraft landing and directional control

    NASA Technical Reports Server (NTRS)

    Horne, W. B.

    1975-01-01

    Aircraft stopping and directional control performance on wet runways is discussed. The major elements affecting tire/ground traction developed by jet transport aircraft are identified and described in terms of atmospheric, pavement, tire, aircraft system and pilot performance factors or parameters. Research results are summarized, and means for improving or restoring tire traction/aircraft performance on wet runways are discussed.

  18. Non-linear finite element-based material constitutive law for zero slump steel fiber reinforced concrete pipe structures

    NASA Astrophysics Data System (ADS)

    Mikhaylova, Alena

    This study presents a comprehensive investigation of performance and behavior of steel-fiber reinforced concrete pipes (SFRCP). The main goal of this study is to develop the material constitutive model for steel fiber reinforced concrete used in dry-cast application. To accomplish this goal a range of pipe sizes varying from 15 in. (400 mm) to 48 in. (1200 mm) in diameter and fiber content of 0.17%, 0.25%, 0.33%, 0.5%, 0.67% and 83% by volume were produced. The pipes were tested in three-edge bearing condition to obtain the load-deformation response and overall performance of the pipe. The pipes were also subjected to hydrostatic joint and joint shear tests to evaluate the performance of the fiber-pipe joints for water tightness and under differential displacements, respectively. In addition, testing on hardened concrete was performed to obtain the basic mechanical material properties. High variation in the test results for material testing was identified as a part of experimental investigation. A three-dimensional non-linear finite element model of the pipe under the three edge bearing condition was developed to identify the constitutive material relations of fiber-concrete composite. A constitutive model of concrete implementing the concrete plasticity and continuum fracture mechanics was considered for defining the complex non-linear behavior of fiber-concrete. Three main concrete damage algorithms were examined: concrete brittle cracking, concrete damaged plasticity with adaptive meshing technique and concrete damaged plasticity with visco-plastic regularization. The latter was identified as the most robust and efficient to model the post-cracking behavior of fiber reinforced concrete and was used in the subsequent studies. The tension stiffening material constitutive law for composite concrete was determined by converging the FEM solution of load-deformation response with the results of experimental testing. This was achieved by iteratively modifying the non

  19. Comparison of performance of partial prestressed beam-column subassemblages made of reactive powder concrete and normal concrete materials using finite element models

    NASA Astrophysics Data System (ADS)

    Nurjannah, S. A.; Budiono, B.; Imran, I.; Sugiri, S.

    2016-04-01

    Research on concrete material continues in several countries and had produced a concrete type of Ultra High Performance Concrete (UHPC) which has a better compressive strength, tensile strength, flexural strength, modulus of elasticity, and durability than normal concrete (NC) namely Reactive Powder Concrete (RPC). Researches on structures using RPC material showed that the RPC structures had a better performance than the NC structures in resisting gravity and lateral cyclic loads. In this study, an experiment was conducted to apply combination of constant axial and lateral cyclic loads to a prototype of RPC interior partial prestressed beam-column subassemblage (prototype of BCS-RPC) with a value of Partial Prestressed Ratio (PPR) of 31.72% on the beam. The test results were compared with finite element model of beam-column subassemblage made of RPC by PPR of 31.72% (BCS-RPC-31.72). Furthermore, there was BCS-RPC modeling with PPR of 21.39% (BCS-RPC-21.39) and beam-column subassemblages made of NC materials modeling with a value of PPR at 21.09% (BCS-NC-21.09) and 32.02% (BCS-NC-32.02). The purpose of this study was to determine the performance of the BCS-RPC models compared to the performance of the BCS-NC models with PPR values below and above 25%, which is the maximum limit of permitted PPR. The results showed that all models of BCS-RPC had a better performance than all models of BCS-NC and the BCS-RPC model with PPR above 25% still behaved ductile and was able to dissipate energy well.

  20. Epoxy asphalt concrete is a perspective material for the construction of roads

    NASA Astrophysics Data System (ADS)

    Vyrozhemskyi, Valerii; Kopynets, Ivan; Kischynskyi, Sergii; Bidnenko, Nataliia

    2017-09-01

    An effective way to increase the durability of asphalt concrete pavements that are subject to high traffic loads and adverse weather and climatic factors is the use of polymer additives which drastically improve the rheological and physical-mechanical properties of bitumen. The use of thermosetting polymers including epoxy resins for asphalt and bitumen modification is seen as a perspective solution for this issue. Conducted at DerzhdorNDI SE studies have proved high riding qualities of asphalt pavements that contain epoxy resins. When replacing 20-35% of bitumen with epoxy component, a significant improvement in strength characteristics of asphalt pavement is noted, especially at elevated temperatures. Specific feature of epoxy asphalt concrete is its ability to gain strength over a long-term operation. Thus, despite the increased cost of epoxy asphalt concrete, long service life of pavements on its basis (up to 30 years as predicted) ensures a high profitability of using this material, especially on the roads with heavy traffic and severe traffic conditions.

  1. Low frequency ultrasonic array imaging using signal post-processing for concrete material

    NASA Astrophysics Data System (ADS)

    Ozawa, Akio; Izumi, Hideki; Nakahata, Kazuyuki; Ohira, Katsumi; Ogawa, Kenzo

    2017-02-01

    The use of ultrasonic arrays to conduct nondestructive evaluation has significantly increased in recent years. A post-processing beam-forming technique that utilizes a complete set of signals of all combinations of transmission and reception el-ements was proposed as an array imaging technique. In this study, a delay-and-sum beam reconstruction method utilizing post-processing was applied to the imaging of internal voids and reinforced steel bars in concrete material. Due to the high attenuation of the ultrasonic wave in concrete, it is necessary to use an ultrasonic wave as the incident wave at low frequencies and high in-tensities. In this study, an array transducer with a total of 16 elements was designed on the basis of a multigaussian beam model. The center frequency of the transducer was 50 kHz, and low frequency imaging was achieved by performing computations using a graphics processing unit accelerators in the post-processing beam formation. The results indicated that the shapes of through holes and steel bars in a concrete specimen with 700 mm height were reconstructed with high resolution.

  2. Novel selective dyeing method for chrysotile asbestos detection in concrete materials.

    PubMed

    Oke, Yoshihiko; Yamasaki, Nakamichi; Amamoto, Go Y; Sasaki, Kazuhiro; Maeta, Naomi; Fujimaki, Hirokazu; Hashida, Toshiyuki

    2008-03-01

    There are a tremendous number of asbestos-containing buildings without any surveys on the presence of asbestos because of the difficulty to detect asbestos in building materials simply and quickly, although a great deal of worldwide effort was put into removing asbestos of which inhalation causes serious diseases. In this study, we newly developed a simple dyeing method to detect chrysotile asbestos, the most commonly used type of asbestos, in asbestos-cement composite materials using magnesium-chelating organic dyes. As an essential process for selective dyeing of chrysotile asbestos, special pretreatment with a calcium-chelating agent was developed to prevent the dyes from reacting with calcium, which is the major component of concrete materials. Our developed selective dyeing method was shown to possess sufficient sensitivity for detecting chrysotile asbestos in an amount greater than 0.1 mass% in concrete specimens, and there was an approximately linear relationship between the area fraction of dyed spots and the mass fraction of chrysotile asbestos. Our results may provide a basis for further development of a simple on-site detection method for chrysotile asbestos in building materials and may facilitate the progress of control and removal of asbestos in the environment.

  3. Comparison of Crack Initiation, Propagation and Coalescence Behavior of Concrete and Rock Materials

    NASA Astrophysics Data System (ADS)

    Zengin, Enes; Abiddin Erguler, Zeynal

    2017-04-01

    There are many previously studies carried out to identify crack initiation, propagation and coalescence behavior of different type of rocks. Most of these studies aimed to understand and predict the probable instabilities on different engineering structures such as mining galleries or tunnels. For this purpose, in these studies relatively smaller natural rock and synthetic rock-like models were prepared and then the required laboratory tests were performed to obtain their strength parameters. By using results provided from these models, researchers predicted the rock mass behavior under different conditions. However, in the most of these studies, rock materials and models were considered as contains none or very few discontinuities and structural flaws. It is well known that rock masses naturally are extremely complex with respect to their discontinuities conditions and thus it is sometimes very difficult to understand and model their physical and mechanical behavior. In addition, some vuggy rock materials such as basalts and limestones also contain voids and gaps having various geometric properties. Providing that the failure behavior of these type of rocks controlled by the crack initiation, propagation and coalescence formed from their natural voids and gaps, the effect of these voids and gaps over failure behavior of rocks should be investigated. Intact rocks are generally preferred due to relatively easy side of their homogeneous characteristics in numerical modelling phases. However, it is very hard to extract intact samples from vuggy rocks because of their complex pore sizes and distributions. In this study, the feasibility of concrete samples to model and mimic the failure behavior vuggy rocks was investigated. For this purpose, concrete samples were prepared at a mixture of %65 cement dust and %35 water and their physical and mechanical properties were determined by laboratory experiments. The obtained physical and mechanical properties were used to

  4. Novel dynamic thermal characterization of multifunctional concretes with microencapsulated phase change materials

    NASA Astrophysics Data System (ADS)

    Pisello, Anna Laura; Fabiani, Claudia; D'Alessandro, Antonella; Cabeza, Luisa F.; Ubertini, Filippo; Cotana, Franco

    2017-04-01

    Concrete is widely applied in the construction sector for its reliable mechanical performance, its easiness of use and low costs. It also appears promising for enhancing the thermal-energy behavior of buildings thanks to its capability to be doped with multifunctional fillers. In fact, key studies acknowledged the benefits of thermally insulated concretes for applications in ceilings and walls. At the same time, thermal capacity also represents a key property to be optimized, especially for lightweight constructions. In this view, Thermal-Energy Storage (TES) systems have been recently integrated into building envelopes for increasing thermal inertia. More in detail, numerical experimental investigations showed how Phase Change materials (PCMs), as an acknowledged passive TES strategy, can be effectively included in building envelope, with promising results in terms of thermal buffer potentiality. In particular, this work builds upon previous papers aimed at developing the new PCM-filled concretes for structural applications and optimized thermalenergy efficiency, and it is focused on the development of a new experimental method for testing such composite materials in thermal-energy dynamic conditions simulated in laboratory by exposing samples to environmentally controlled microclimate while measuring thermal conductivity and diffusivity by means of transient plane source techniques. The key findings show how the new composites are able to increasingly delay the thermal wave with increasing the PCM concentration and how the thermal conductivity varies during the course of the phase change, in both melting and solidification processes. The new analysis produces useful findings in proposing an effective method for testing composite materials with adaptive thermal performance, much needed by the scientific community willing to study building envelopes dynamics.

  5. Polymer concrete patching manual

    NASA Astrophysics Data System (ADS)

    Fontana, J. J.; Bartholomew, J.

    1982-06-01

    The practicality of using polymer concrete to repair deteriorated portland cement concrete bridge decks and pavements was demonstrated. This manual outlines the procedures for using polymer concrete as a rapid patching material to repair deteriorated concrete. The process technology, materials, equipment, and safety provisions used in manufacturing and placing polymer concrete are discussed. Potential users are informed of the various steps necessary to insure successful field applications of the material.

  6. Airborne FLIR sensors for runway incursion detection

    NASA Astrophysics Data System (ADS)

    Archer, Cynthia; White, Joseph; Neece, Robert

    2009-05-01

    Forward Looking Infrared (FLIR) sensors are potential components in hazard monitoring systems for general aviation aircraft. FLIR sensors can provide images of the runway area when normal visibility is reduced by meteorological conditions. We are investigating short wave infrared (SWIR) and long wave infrared (LWIR) cameras. Pre-recorded video taken from an aircraft on approach to landing provides raw data for our analysis. This video includes approaches under four conditions: clear morning, cloudy afternoon, clear evening, and clear night. We used automatic object detection techniques to quantify the ability of these sensors to alert the pilot to potential runway hazards. Our analysis is divided into three stages: locating the airport, tracking the runway, and detecting vehicle sized objects. The success or failure of locating the runway provides information on the ability of the sensors to provide situational awareness. Tracking the runway position from frame to frame provides information on the visibility of runway features, such as landing lights or runway edges, in the scene. Detecting small objects quantifies clutter and provides information on the ability of these sensors to image potential hazards. In this paper, we present results from our analysis of sample approach video.

  7. System Oriented Runway Management: A Research Update

    NASA Technical Reports Server (NTRS)

    Lohr, Gary W.; Brown, Sherilyn A.; Stough, Harry P., III; Eisenhawer, Steve; Atkins, Stephen; Long, Dou

    2011-01-01

    The runway configuration used by an airport has significant implications with respect to its capacity and ability to effectively manage surface and airborne traffic. Aircraft operators rely on runway configuration information because it can significantly affect an airline's operations and planning of their resources. Current practices in runway management are limited by a relatively short time horizon for reliable weather information and little assistance from automation. Wind velocity is the primary consideration when selecting a runway configuration; however when winds are below a defined threshold, discretion may be used to determine the configuration. Other considerations relevant to runway configuration selection include airport operator constraints, weather conditions (other than winds) traffic demand, user preferences, surface congestion, and navigational system outages. The future offers an increasingly complex landscape for the runway management process. Concepts and technologies that hold the potential for capacity and efficiency increases for both operations on the airport surface and in terminal and enroute airspace are currently under investigation. Complementary advances in runway management are required if capacity and efficiency increases in those areas are to be realized. The System Oriented Runway Management (SORM) concept has been developed to address this critical part of the traffic flow process. The SORM concept was developed to address all aspects of runway management for airports of varying sizes and to accommodate a myriad of traffic mixes. SORM, to date, addresses the single airport environment; however, the longer term vision is to incorporate capabilities for multiple airport (Metroplex) operations as well as to accommodate advances in capabilities resulting from ongoing research. This paper provides an update of research supporting the SORM concept including the following: a concept of overview, results of a TRCM simulation, single

  8. Development of a Tomography Technique for Assessment of the Material Condition of Concrete Using Optimized Elastic Wave Parameters

    PubMed Central

    Chai, Hwa Kian; Liu, Kit Fook; Behnia, Arash; Yoshikazu, Kobayashi; Shiotani, Tomoki

    2016-01-01

    Concrete is the most ubiquitous construction material. Apart from the fresh and early age properties of concrete material, its condition during the structure life span affects the overall structural performance. Therefore, development of techniques such as non-destructive testing which enable the investigation of the material condition, are in great demand. Tomography technique has become an increasingly popular non-destructive evaluation technique for civil engineers to assess the condition of concrete structures. In the present study, this technique is investigated by developing reconstruction procedures utilizing different parameters of elastic waves, namely the travel time, wave amplitude, wave frequency, and Q-value. In the development of algorithms, a ray tracing feature was adopted to take into account the actual non-linear propagation of elastic waves in concrete containing defects. Numerical simulation accompanied by experimental verifications of wave motion were conducted to obtain wave propagation profiles in concrete containing honeycomb as a defect and in assessing the tendon duct filling of pre-stressed concrete (PC) elements. The detection of defects by the developed tomography reconstruction procedures was evaluated and discussed. PMID:28773416

  9. Development of a Tomography Technique for Assessment of the Material Condition of Concrete Using Optimized Elastic Wave Parameters.

    PubMed

    Chai, Hwa Kian; Liu, Kit Fook; Behnia, Arash; Yoshikazu, Kobayashi; Shiotani, Tomoki

    2016-04-16

    Concrete is the most ubiquitous construction material. Apart from the fresh and early age properties of concrete material, its condition during the structure life span affects the overall structural performance. Therefore, development of techniques such as non-destructive testing which enable the investigation of the material condition, are in great demand. Tomography technique has become an increasingly popular non-destructive evaluation technique for civil engineers to assess the condition of concrete structures. In the present study, this technique is investigated by developing reconstruction procedures utilizing different parameters of elastic waves, namely the travel time, wave amplitude, wave frequency, and Q-value. In the development of algorithms, a ray tracing feature was adopted to take into account the actual non-linear propagation of elastic waves in concrete containing defects. Numerical simulation accompanied by experimental verifications of wave motion were conducted to obtain wave propagation profiles in concrete containing honeycomb as a defect and in assessing the tendon duct filling of pre-stressed concrete (PC) elements. The detection of defects by the developed tomography reconstruction procedures was evaluated and discussed.

  10. Runway Incursion Prevention for General Aviation Operations

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.; Prinzel, Lawrence J., III

    2006-01-01

    A Runway Incursion Prevention System (RIPS) and additional incursion detection algorithm were adapted for general aviation operations and evaluated in a simulation study at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) in the fall of 2005. RIPS has been designed to enhance surface situation awareness and provide cockpit alerts of potential runway conflicts in order to prevent runway incidents while also improving operational capability. The purpose of the study was to evaluate the airborne incursion detection algorithms and associated alerting and airport surface display concepts for general aviation operations. This paper gives an overview of the system, simulation study, and test results.

  11. Electronic System for Preventing Airport Runway Incursions

    NASA Technical Reports Server (NTRS)

    Dabney, Richard; Elrod, Susan

    2009-01-01

    A proposed system of portable illuminated signs, electronic monitoring equipment, and radio-communication equipment for preventing (or taking corrective action in response to) improper entry of aircraft, pedestrians, or ground vehicles onto active airport runways is described. The main overall functions of the proposed system would be to automatically monitor aircraft ground traffic on or approaching runways and to generate visible and/or audible warnings to affected pilots, ground-vehicle drivers, and control-tower personnel when runway incursions take place.

  12. Runway Safety Monitor Algorithm for Single and Crossing Runway Incursion Detection and Alerting

    NASA Technical Reports Server (NTRS)

    Green, David F., Jr.

    2006-01-01

    The Runway Safety Monitor (RSM) is an aircraft based algorithm for runway incursion detection and alerting that was developed in support of NASA's Runway Incursion Prevention System (RIPS) research conducted under the NASA Aviation Safety and Security Program's Synthetic Vision System project. The RSM algorithm provides warnings of runway incursions in sufficient time for pilots to take evasive action and avoid accidents during landings, takeoffs or when taxiing on the runway. The report documents the RSM software and describes in detail how RSM performs runway incursion detection and alerting functions for NASA RIPS. The report also describes the RIPS flight tests conducted at the Reno/Tahoe International Airport (RNO) and the Wallops Flight Facility (WAL) during July and August of 2004, and the RSM performance results and lessons learned from those flight tests.

  13. Nuclear Technology. Course 29: Civil/Structural Inspection. Module 29-6, Pre-Stressed Concrete Materials, Fabrication and Inspection.

    ERIC Educational Resources Information Center

    Groseclose, Richard

    This sixth in a series of six modules for a course titled Civil/Structural Inspection describes inspection activities associated with pre-stressed concrete such as reviewing material certifications and test reports, inspecting construction operations, performing materials testing, and preparing records and reports of inspection and testing…

  14. Nuclear Technology. Course 29: Civil/Structural Inspection. Module 29-6, Pre-Stressed Concrete Materials, Fabrication and Inspection.

    ERIC Educational Resources Information Center

    Groseclose, Richard

    This sixth in a series of six modules for a course titled Civil/Structural Inspection describes inspection activities associated with pre-stressed concrete such as reviewing material certifications and test reports, inspecting construction operations, performing materials testing, and preparing records and reports of inspection and testing…

  15. Real-Time Identification and Characterization of Asbestos and Concrete Materials with Radioactive Contamination

    SciTech Connect

    Xu, George; Zhang, Xi-Cheng

    1999-06-01

    Concrete and asbestos-containing materials were widely used in U.S. Department of Energy (DOE) building construction in the 1940s and 1950s. Over the years, many of these porous building materials have been contaminated with radioactive sources, on and below the surface. This intractable radioactive-and-hazardous- asbestos mixed-waste-stream has created a tremendous challenge to DOE decontamination and decommissioning (D&D) project managers. The current practice to identify asbestos and to characterize radioactive contamination depth profiles involve bore sampling, and is inefficient, costly, and unsafe. A three-year research project was started on 10/1/98 at Rensselaer with the following ultimate goals: (1) development of novel non-destructive methods for identifying the hazardous asbestos in real-time and in-situ, and (2) development of new algorithms and apparatus for characterizing the radioactive contamination depth profile in real-time and in-situ.

  16. Real-Time Identification and Characterization of Asbestos and Concrete Materials with Radioactive Contamination

    SciTech Connect

    Xu, George; Zhang, Xi-Cheng

    2000-06-01

    Concrete and asbestos-containing materials were widely used in U.S. Department of Energy (DOE) building construction in the 1940s and 1950s. Over the years, many of these porous building materials have been contaminated with radioactive sources, on and below the surface. This intractable radioactive-and-hazardous-asbestos mixed-waste stream has created a tremendous challenge to DOE decontamination and decommissioning (D&D) project managers. The current practice to identify asbestos and to characterize radioactive contamination depth profiles in based solely on bore sampling, which is inefficient, costly, and unsafe. A three-year research project was started 1998 at Rensselaer with the following ultimate goals: (1) development of novel non-destructive methods for identifying the hazardous asbestos in real-time and in-situ, and (2) development of new algorithms and apparatus for characterizing the radioactive contamination depth profile in real-time and in-situ.

  17. TRIZ Tool for Optimization of Airport Runway

    NASA Astrophysics Data System (ADS)

    Rao, K. Venkata; Selladurai, V.; Saravanan, R.

    TRIZ tool is used for conceptual design and layout of the novel ascending and descending runway model for the effective utilization of short length airports. Handling bigger aircrafts at smaller airports become the necessity for economic consideration and for the benefit of vast airliners and the aspiring air travelers of the region. The authors’ proposal of ascending and descending runway would enable the operational need of wide body aircrafts such as Boeing 747 and Airbus A380-800. Negotiating take-off and landing of bigger aircrafts at less than 10000 feet runway is an optimization solution. This conceptual model and the theoretical design with its layout is dealt in this paper as Part - I. The computer-aided design and analysis using MATLAB with Simulink tool box to confirm the adequacy of the runway length for the bigger aircrafts at smaller airports is however dealt in subsequent papers.

  18. Spot and Runway Departure Advisor (SARDA)

    NASA Technical Reports Server (NTRS)

    Jung, Yoon

    2016-01-01

    Spot and Runway Departure Advisor (SARDA) is a decision support tool to assist airline ramp controllers and ATC tower controllers to manage traffic on the airport surface to significantly improve efficiency and predictability in surface operations. The core function of the tool is the runway scheduler which generates an optimal solution for runway sequence and schedule of departure aircraft, which would minimize system delay and maximize runway throughput. The presentation also discusses the latest status of NASA's current surface research through a collaboration with an airline partner, where a tool is developed for airline ramp operators to assist departure pushback operations. The presentation describes the concept of the SARDA tool and results from human-in-the-loop simulations conducted in 2012 for Dallas-Ft. Worth International Airport and 2014 for Charlotte airport ramp tower.

  19. Effect of Uncertainty on Deterministic Runway Scheduling

    NASA Technical Reports Server (NTRS)

    Gupta, Gautam; Malik, Waqar; Jung, Yoon C.

    2012-01-01

    Active runway scheduling involves scheduling departures for takeoffs and arrivals for runway crossing subject to numerous constraints. This paper evaluates the effect of uncertainty on a deterministic runway scheduler. The evaluation is done against a first-come- first-serve scheme. In particular, the sequence from a deterministic scheduler is frozen and the times adjusted to satisfy all separation criteria; this approach is tested against FCFS. The comparison is done for both system performance (throughput and system delay) and predictability, and varying levels of congestion are considered. The modeling of uncertainty is done in two ways: as equal uncertainty in availability at the runway as for all aircraft, and as increasing uncertainty for later aircraft. Results indicate that the deterministic approach consistently performs better than first-come-first-serve in both system performance and predictability.

  20. STS-49 crew poses for group portrait on EAFB runway 22 after OV-105 landing

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-49 crewmembers pose for post flight group portrait on Edwards Air Force Base (EAFB) concrete runway 22 in front of Endeavour, Orbiter Vehicle (OV) 105. Crewmembers, wearing their launch and entry suits (LESs) and Endeavour caps, are (left to right) Mission Specialist (MS) Richard J. Hieb, Pilot Kevin P. Chilton, Commander Daniel C. Brandenstein, MS Thomas D. Akers, MS Pierre J. Thuot, MS Kathryn C. Thornton, and MS Bruce E. Melnick.

  1. Joint Winter Runway Friction Program Accomplishments

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.; Wambold, James C.; Henry, John J.; Andresen, Arild; Bastian, Matthew

    2002-01-01

    The major program objectives are: (1) harmonize ground vehicle friction measurements to report consistent friction value or index for similar contaminated runway conditions, for example, compacted snow, and (2) establish reliable correlation between ground vehicle friction measurements and aircraft braking performance. Accomplishing these objectives would give airport operators better procedures for evaluating runway friction and maintaining acceptable operating conditions, providing pilots information to base go/no go decisions, and would contribute to reducing traction-related aircraft accidents.

  2. Prevention of runway incursions due to closed runways or unsuitable runway choices by enhanced crew situational awareness and alerting

    NASA Astrophysics Data System (ADS)

    Vernaleken, Christoph; Urvoy, Carole; Klingauf, Uwe

    2007-04-01

    Of all incidents on the aerodrome surface, Runway Incursions, i.e. the incorrect presence of an aircraft on a runway, are the by far most safety-critical, resulting in many fatalities if they lead to an accident. A lack of flight crew situational awareness is almost always a causal factor in these occurrences, and like any Runway Incursion, the special case of choosing a closed or unsuitable runway - including mistaking a taxiway for a runway - may have catastrophic consequences, as the Singapore Airlines Flight SQ006 accident at Taipei in 2000 and, most recently, Comair Flight 5191, tragically show. In other incidents, such as UPS Flight 896 at Denver in 2001 departing from a closed runway or China Airlines Flight 11 taking off from a taxiway at Anchorage in 2002, a disaster was only avoided by mere luck. This paper describes how the concept for an onboard Surface Movement Awareness and Alerting System (SMAAS) can be applied to this special case and might help to prevent flight crews from taking off or landing on closed runways, unsuitable runways or taxiways, and presents initial evaluation results. An airport moving map based on an ED-99A/DO- 272A compliant Aerodrome Mapping Database (AMDB) is used to visualize runway closures and other applicable airport restrictions, based on NOTAM and D-ATIS data, to provide the crew with enhanced situational awareness in terms of position and operational environment. If this is not sufficient to prevent a hazardous situation, e.g. in case the crew is distracted, a tailored alerting concept consisting of both visual and aural alerts consistent with existing warning systems catches the crew's attention. For runway closures and restrictions, particularly those of temporary nature, the key issue for both extended situational awareness and alerting is how to get the corresponding data to the aircraft's avionics. Therefore, this paper also develops the concept of a machine-readable electronic Pre-flight Information Bulletin (e

  3. Runway Scheduling Using Generalized Dynamic Programming

    NASA Technical Reports Server (NTRS)

    Montoya, Justin; Wood, Zachary; Rathinam, Sivakumar

    2011-01-01

    A generalized dynamic programming method for finding a set of pareto optimal solutions for a runway scheduling problem is introduced. The algorithm generates a set of runway fight sequences that are optimal for both runway throughput and delay. Realistic time-based operational constraints are considered, including miles-in-trail separation, runway crossings, and wake vortex separation. The authors also model divergent runway takeoff operations to allow for reduced wake vortex separation. A modeled Dallas/Fort Worth International airport and three baseline heuristics are used to illustrate preliminary benefits of using the generalized dynamic programming method. Simulated traffic levels ranged from 10 aircraft to 30 aircraft with each test case spanning 15 minutes. The optimal solution shows a 40-70 percent decrease in the expected delay per aircraft over the baseline schedulers. Computational results suggest that the algorithm is promising for real-time application with an average computation time of 4.5 seconds. For even faster computation times, two heuristics are developed. As compared to the optimal, the heuristics are within 5% of the expected delay per aircraft and 1% of the expected number of runway operations per hour ad can be 100x faster.

  4. Terminal Area Procedures for Paired Runways

    NASA Technical Reports Server (NTRS)

    Lozito, Sandra; Verma, Savita Arora

    2011-01-01

    Parallel runway operations have been found to increase capacity within the National Airspace but poor visibility conditions reduce the use of these operations. The NextGen and SESAR Programs have identified the capacity benefits from increased use of closely-space parallel runway. Previous research examined the concepts and procedures related to parallel runways however, there has been no investigation of the procedures associated with the strategic and tactical pairing of aircraft for these operations. This simulation study developed and examined the pilot and controller procedures and information requirements for creating aircraft pairs for parallel runway operations. The goal was to achieve aircraft pairing with a temporal separation of 15s (+/- 10s error) at a coupling point that was about 12 nmi from the runway threshold. Two variables were explored for the pilot participants: two levels of flight deck automation (current-day flight deck automation and auto speed control future automation) as well as two flight deck displays that assisted in pilot conformance monitoring. The controllers were also provided with automation to help create and maintain aircraft pairs. Results show the operations in this study were acceptable and safe. Subjective workload, when using the pairing procedures and tools, was generally low for both controllers and pilots, and situation awareness was typically moderate to high. Pilot workload was influenced by display type and automation condition. Further research on pairing and off-nominal conditions is required however, this investigation identified promising findings about the feasibility of closely-spaced parallel runway operations.

  5. Impact resistance of sustainable construction material using light weight oil palm shells reinforced geogrid concrete slab

    NASA Astrophysics Data System (ADS)

    Muda, Z. C.; Malik, G.; Usman, F.; Beddu, S.; Alam, M. A.; Mustapha, K. N.; Birima, A. H.; Zarroq, O. S.; Sidek, L. M.; Rashid, M. A.

    2013-06-01

    This paper investigate the performance of lightweight oil palm shells (OPS) concrete slab with geogrid reinforcement of 300mm × 300mm size with 20mm, 30mm and 40 mm thick casted with different geogrid orientation and boundary conditions subjected to low impact projectile test. A self-fabricated drop-weight impact test rig with a steel ball weight of 1.2 kg drop at 1 m height has been used in this research work. The main variables for the study is to find the relationship of the impact resistance the slab thickness, boundary conditions and geogrid reinforcement orientation. Test results indicate that the used of the geogrid reinforcement increased the impact resistance under service (first) limit crack up to 5.9 times and at ultimate limit crack up to 20.1 times against the control sample (without geogrid). A good linear relationship has been established between first and ultimate crack resistance against the slab thickness. The orientation of the geogrid has minor significant to the crack resistance of the OPS concrete slab. OPS geogrid reinforced slab has a good crack resistance properties that can be utilized as a sustainable impact resistance construction materials.

  6. Space Shuttle Columbia hurtles down Runway 33

    NASA Technical Reports Server (NTRS)

    1997-01-01

    KENNEDY SPACE CENTER, FLA. -- With drag chute deployed, the Space Shuttle Columbia hurtles down Runway 33 at KSC''';s Shuttle Landing Facility to conclude the Microgravity Science Laboratory-1 (MSL- 1) mission. With main gear touchdown at 2:33:11 p.m. EDT, April 8, the STS-83 mission duration was 3 days, 23 hours, 12 minutes. The planned 16-day mission was cut short by a faulty fuel cell. This is only the third time in Shuttle program history that an orbiter was brought home early due to a mechanical problem. This was also the 36th KSC landing since the program began in 1981. Mission Commander James D. Halsell, Jr. flew Columbia to a perfect landing with help from Pilot Susan L. Still. Other crew members are Payload Commander Janice E. Voss; Mission Specialists Michael L.Gernhardt and Donald A. Thomas; and Payload Specialists Roger K. Crouch and Gregory T. Linteris. In spite of the abbreviated flight, the crew was able to perform MSL-1 experiments. The Spacelab-module-based experiments were used to test some of the hardware, facilities and procedures that are planned for use on the International Space Station and to conduct combustion, protein crystal growth and materials processing investigations.

  7. Space Shuttle Columbia hurtles down Runway 33

    NASA Technical Reports Server (NTRS)

    1997-01-01

    KENNEDY SPACE CENTER, FLA. -- With drag chute deployed, the Space Shuttle Columbia hurtles down Runway 33 at KSC''';s Shuttle Landing Facility to conclude the Microgravity Science Laboratory-1 (MSL- 1) mission. With main gear touchdown at 2:33:11 p.m. EDT, April 8, the STS-83 mission duration was 3 days, 23 hours, 12 minutes. The planned 16-day mission was cut short by a faulty fuel cell. This is only the third time in Shuttle program history that an orbiter was brought home early due to a mechanical problem. This was also the 36th KSC landing since the program began in 1981. Mission Commander James D. Halsell, Jr. flew Columbia to a perfect landing with help from Pilot Susan L. Still. Other crew members are Payload Commander Janice E. Voss; Mission Specialists Michael L.Gernhardt and Donald A. Thomas; and Payload Specialists Roger K. Crouch and Gregory T. Linteris. In spite of the abbreviated flight, the crew was able to perform MSL-1 experiments. The Spacelab-module-based experiments were used to test some of the hardware, facilities and procedures that are planned for use on the International Space Station and to conduct combustion, protein crystal growth and materials processing investigations.

  8. Materials for Emergency Repair of Runways.

    DTIC Science & Technology

    1984-04-30

    such as boric acid or borax , but only at the expense of the early strength develop- ment. (Figs. 4 and 5) Considering the shortness of the setting times...hint from the manufacturer of SET-45 is that boric acid is added which presumably have similar retarding effect as borax . In addition to the above...with water rapidly producing strength and heat. The hot weather formula also contains boric acid as a set retarder. The aluminum phosphate (ALP) mixture

  9. Materials for Emergency Repair of Runways.

    DTIC Science & Technology

    1985-03-20

    for the SET-45 cold mortar under identical conditions. This is attributed to the presence of borax ( boric acid ) in the hot mixture. Similar liquifying...Chemically active part of SET-45 mixtures consists of MgO grains and NH4H2 PO4 solid particles. Boric acid or borax may or may not be present. The...hot weather formula also contains boric acid as set retarder. pA, o - ~ ~ ~ - - -.-- 7~~ - . - Vi Mechanical Testing A major portion of the mechanical

  10. Development of polymer concrete for dike insulation at LNG facilities: Phase 4, Low cost materials

    SciTech Connect

    Kukacka, L.E.

    1991-01-01

    Earlier GRI-sponsored work at Brookhaven National Laboratory has resulted in the development and utilization of insulating polymer concrete composites (IPC) as a means of reducing the evaporation rate of liquified natural gas in the event of a spill into a containment dike, thereby improving the safety at these sites. Although all of the required properties can be attained with the IPC, it was estimated that a low-cost replacement for the expensive organic binder would be necessary before use of the material would be cost-effective. In the current program, several latex modified cement formulations were evaluated and the most promising one identified. A mixture of two carboxylated styrene-butadiene latexes was selected for use in detailed laboratory property characterizations and a subsequent field evaluation. When compared to the properties of IPC, the latex-modified insulating materials display somewhat higher thermal conductivities, greater permeability to water, and reduced strength. However, these properties still meet most of the performance criteria, and the unit cost of the material is less than one-fifth that of IPC made with epoxy binders. When installed as a 0.75-in. thick overlay, material costs are estimated to be $1.00/ft{sup 2}.

  11. Nano-modified cement composites and its applicability as concrete repair material

    NASA Astrophysics Data System (ADS)

    Manzur, Tanvir

    Nanotechnology or Nano-science, considered the forth industrial revolution, has received considerable attention in the past decade. The physical properties of a nano-scaled material are entirely different than that of bulk materials. With the emerging nanotechnology, one can build material block atom by atom. Therefore, through nanotechnology it is possible to enhance and control the physical properties of materials to a great extent. Composites such as concrete materials have very high strength and Young's modulus but relatively low toughness and ductility due to their covalent bonding between atoms and lacking of slip systems in the crystal structures. However, the strength and life of concrete structures are determined by the microstructure and mass transfer at nano scale. Cementitious composites are amenable to manipulation through nanotechnology due to the physical behavior and size of hydration products. Carbon nanotubes (CNT) are nearly ideal reinforcing agent due to extremely high aspect ratios and ultra high strengths. So there is a great potential to utilize CNT in producing new cement based composite materials. It is evident from the review of past literature that mechanical properties of nanotubes reinforced cementitious composites have been highly variable. Some researches yielded improvement in performance of CNT-cement composites as compared to plain cement samples, while other resulted in inconsequential changes in mechanical properties. Even in some cases considerable less strengths and modulus were obtained. Another major difficulty of producing CNT reinforced cementitious composites is the attainment of homogeneous dispersion of nanotubes into cement but no standard procedures to mix CNT within the cement is available. CNT attract more water to adhere to their surface due to their high aspect ratio which eventually results in less workability of the cement mix. Therefore, it is extremely important to develop a suitable mixing technique and an

  12. Rapid Runway Repair (RRR): An Optimization for Minimum Operating Strip (MOS) Selection

    DTIC Science & Technology

    2007-03-01

    panels, foldable FRP mats, precast concrete slabs, precast asphalt concrete block, magnesium phosphate, crushed rock, polyurethane cap, and AM-2... designs of concrete and asphaltic concrete have also been evaluated to be utilized as caps. The obstacle these capping materials have yet to...fiberglass-reinforced plastic (FRP) mats, bolt-together FRP panels, foldable FRP mats, precast concrete slabs, precast asphalt concrete block, magnesium

  13. Runway hazard detection in poor visibility conditions

    NASA Astrophysics Data System (ADS)

    Jiang, Bo; Rahman, Zia-ur

    2012-01-01

    More recently, research on enhancing the situational awareness of pilots, especially in poor visibility flight conditions, gains more and more interests. Since pilots may not be able to spot the runway clearly in poor visibility conditions, such as fog, smoke, haze or dim lighting conditions, aviation landing problem can occur due to the (unexpected) presence of objects on the runway. Complicated and trivial instruments, switches, bottoms, plus sudden happenings are enough for the pilots to take care of during landing approach. Therefore, an automatic hazard detection approach that combines non-linear Multi-scale Retinex (MSR) image enhancement, edge detection with basic edge pattern analysis, and image analysis is investigated. The effect of applying the enhancement method is to make the image of the runway almost independent from the poor atmospheric conditions. The following smart edge detection process extracts edge information, which can also reduce the storing space, the comparison and retrieval time, and the effect of sensor noise. After analyzing the features existing in the edge differences occurring in the runway area by digital image processing techniques, the existing potential hazard will be localized and labeled. Experimental results show that the proposed approach is effective in runway hazard detection in poor visibility conditions.

  14. Terminal Area Procedures for Paired Runways

    NASA Technical Reports Server (NTRS)

    Lozito, Sandy

    2011-01-01

    Parallel Runway operations have been found to increase capacity within the National Airspace (NAS) however, poor visibility conditions reduce this capacity [1]. Much research has been conducted to examine the concepts and procedures related to parallel runways however, there has been no investigation of the procedures associated with the strategic and tactical pairing of aircraft for these operations. This study developed and examined the pilot and controller procedures and information requirements for creating aircraft pairs for parallel runway operations. The goal was to achieve aircraft pairing with a temporal separation of 15s(+/- 10s error) at a coupling point that is about 12 nmi from the runway threshold. Two variables were explored for the pilot participants: Two levels of flight deck automation (current-day flight deck automation, and a prototype future automation) as well as two flight deck displays that assisted in pilot conformance monitoring. The controllers were also provided with automation to help create and maintain aircraft pairs. Data showed that the operations in this study were found to be acceptable and safe. Workload when using the pairing procedures and tools was generally low for both controllers and pilots, and situation awareness (SA) was typically moderate to high. There were some differences based upon the display and automation conditions for the pilots. Future research should consider the refinement of the concepts and tools for pilot and controller displays and automation for parallel runway concepts.

  15. Runway Incursion Prevention: A Technology Solution

    NASA Technical Reports Server (NTRS)

    Young, Steven D.; Jones, Denise R.

    2001-01-01

    A runway incursion occurs any time an airplane, vehicle, person or object on the ground creates a collision hazard with an airplane that is taking off or landing at an airport under the supervision of Air Traffic Control (ATC). Despite the best efforts of the Federal Aviation Administration (FAA), runway incursions continue to occur more frequently. The number of incursions reported in the U.S. rose from 186 in 1993 to 431 in 2000, an increase of 132 percent. Recently, the National Transportation Safety Board (NTSB) has made specific recommendations for reducing runway incursions including a recommendation that the FAA require, at all airports with scheduled passenger service, a ground movement safety system that will prevent runway incursions; the system should provide a direct warning capability to flight crews. To this end, NASA and its industry partners have developed an advanced surface movement guidance and control system (A-SMGCS) architecture and operational concept that are designed to prevent runway incursions while also improving operational capability. This operational concept and system design have been tested in both full-mission simulation and operational flight test experiments at major airport facilities. Anecdotal, qualitative, and specific quantitative results will be presented along with an assessment of technology readiness with respect to equipage.

  16. HIGH-COMPRESSIVE-STRENGTH CONCRETE.

    DTIC Science & Technology

    CONCRETE , COMPRESSIVE PROPERTIES), PERFORMANCE(ENGINEERING), AGING(MATERIALS), MANUFACTURING, STRUCTURES, THERMAL PROPERTIES, CREEP, DEFORMATION, REINFORCED CONCRETE , MATHEMATICAL ANALYSIS, STRESSES, MIXTURES, TENSILE PROPERTIES

  17. Review of factors affecting aircraft wet runway performance

    NASA Technical Reports Server (NTRS)

    Yager, T. J.

    1983-01-01

    Problems associated with aircraft operations on wet runways are discussed and major factors which influence tire/runway braking and cornering traction capability are identified including runway characteristics, tire hydroplaning, brake system anomalies, and pilot inputs. Research results from investigations conducted at the Langley Aircraft Landing Loads and Traction Facility and from tests with instrumented ground vehicles and aircraft are summarized to indicate the effects of different aircraft, tire, and runway parameters. Several promising means are described for improving tire/runway water drainage capability, brake system efficiency, and pilot training to help optimize aircraft traction performance on wet runways.

  18. Studying the effect of a hydrostatic stress/strain reduction factor on damage mechanics of concrete materials

    NASA Astrophysics Data System (ADS)

    Taqieddin, Ziad N.; Voyiadjis, George Z.

    2013-12-01

    In the non-linear finite element analysis (NFEA) of concrete materials, continuum damage mechanics (CDM) provides a powerful framework for the derivation of constitutive models capable of describing the mechanical behavior of such materials. The internal state variables of CDM can be introduced to the elastic analysis of concrete to form elastic-damage models (no inelastic strains), or to the elastic-plastic analysis in order to form coupled/uncoupled elastic-plastic-damage models. Experimental evidence that is well documented in literature shows that the susceptibility of concrete to damage and failure is distinguished under deviatoric loading from that corresponding to hydrostatic loading. A reduction factor is usually introduced into a CDM model to reduce the susceptibility of concrete to hydrostatic stresses/strains. In this work, the effect of a hydrostatic stress/strain reduction factor on the performances of two NFEA concrete models will be studied. These two (independently published) models did not provide any results showing such effect. One of these two models is an elastic-damage model, whereas the other is an uncoupled elastic-plastic-damage model. Simulations and comparisons are carried out between the performances of the two models under uniaxial tensile and compressive loading conditions. Simulations are also provided for the uncoupled elastic-plastic-damage model under the following additional loading conditions: biaxial tension and biaxial compression, uniaxial cyclic loading, and varying ratios of triaxial compressive loadings. These simulations clearly show the effect of the reduction factor on the numerically depicted behaviors of concrete materials. To have rational comparisons, the hydrostatic stress reduction factor applied to each model is chosen to be a function of the internal state variables common to both models. Therefore, once the two models are calibrated to simulate the experimental behaviors, their corresponding reduction factors

  19. Forward problem studies of electrical resistance tomography system on concrete materials

    NASA Astrophysics Data System (ADS)

    Ang, Vernoon; Rahiman, M. H. F.; Rahim, R. A.; Aw, S. R.; Wahab, Y. A.; Thomas W. K., T.; Siow, L. T.

    2017-03-01

    Electrical resistance tomography (ERT) is well known as non-invasive imaging technique, inexpensive, radiation free, visualization measurements of the multiphase flows and frequently applied in geophysical, medical and Industrial Process Tomography (IPT) applications. Application of ERT in concrete is a new exploration field, which can be used in monitoring and detecting the health and condition of concrete without destroying it. In this paper, ERT model under the condition of concrete is studied in which the sensitivity field model is produced and simulated by using COMSOL software. The affects brought by different current injection values with different concrete conductivity are studied in detail. This study able to provide the important direction for the further study of inverse problem in ERT system. Besides, the results of this technique hopefully can open a new exploration in inspection method of concrete structures in order to maintain the health of the concrete structure for civilian safety.

  20. Sequestering Lead in Paint by Utilizing Deconstructed Masonry Materials as Recycled Aggregate in Concrete. Revision 1

    DTIC Science & Technology

    2008-05-27

    process additive in foundry and scrap metal 3 operations before the toxic dust is collected in a bag house. Due to its high alkalinity, Bantox® can...assist in achieving concrete that does not have the toxicity characteristic for lead. Based on the information from available literature and industrial ...as percent (by weight) sodium oxide (Na2O). 3.2 Concrete Mixing and Curing A LWD Lancaster pan concrete mixer (Kercher Industries , Inc., Lebanon

  1. Requirements for Instrument Approaches to Converging Runways,

    DTIC Science & Technology

    1981-09-01

    PERSPECTIVE 2-1 2.1 Definition 2-1 2.2 Types of Converging Runways 2-1 2.2.1 Intersecting Approach Streams 2-3 2.2.2 Intersecting Runways 2-3 2.2.3...Therefore, a methodology to define and characterize ’e converging approaches is presented in this chapter. 2.1 Definition If two runways are not parallel...c nter of ARC, the positive X-direction is paralel to IA, and the positive Y-direction is parallel to TC,i C-1 *z / ,i// \\2D 2B0 C-2 FIUE w 4Z a!w wV

  2. Runway Incursion Prevention System Simulation Evaluation

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.

    2002-01-01

    A Runway Incursion Prevention System (RIPS) was evaluated in a full mission simulation study at the NASA Langley Research center in March 2002. RIPS integrates airborne and ground-based technologies to provide (1) enhanced surface situational awareness to avoid blunders and (2) alerts of runway conflicts in order to prevent runway incidents while also improving operational capability. A series of test runs was conducted in a high fidelity simulator. The purpose of the study was to evaluate the RIPS airborne incursion detection algorithms and associated alerting and airport surface display concepts. Eight commercial airline crews participated as test subjects completing 467 test runs. This paper gives an overview of the RIPS, simulation study, and test results.

  3. The Effect of Various Waste Materials' Contents on the Attenuation Level of Anti-Radiation Shielding Concrete.

    PubMed

    Azeez, Ali Basheer; Mohammed, Kahtan S; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Sandu, Andrei Victor; Razak, Rafiza Abdul

    2013-10-23

    Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised (137)Cs and ⁶⁰Co radioactive elements with photon energies of 0.662 MeV for (137)Cs and two energy levels of 1.17 and 1.33 MeV for the ⁶⁰Co. Likewise the mean free paths for the tested samples were obtained. The aim of this work is to investigate the effect of the waste loading rates and the particulate dispersive manner within the concrete matrix on the attenuation coefficients. The maximum linear attenuation coefficient (μ) was attained for concrete incorporates iron filling wastes of 30 wt %. They were of 1.12 ± 1.31×10(-3) for (137)Cs and 0.92 ± 1.57 × 10(-3) for ⁶⁰Co. Substantial improvement in attenuation performance by 20%-25% was achieved for concrete samples incorporate iron fillings as opposed to that of steel ball samples at different (5%-30%) loading rates. The steel balls and the steel slags gave much inferior values. The microstructure, concrete-metal composite density, the homogeneity and particulate dispersion were examined and evaluated using different metallographic, microscopic and measurement facilities.

  4. Probabilistic computer model of optimal runway turnoffs

    NASA Technical Reports Server (NTRS)

    Schoen, M. L.; Preston, O. W.; Summers, L. G.; Nelson, B. A.; Vanderlinden, L.; Mcreynolds, M. C.

    1985-01-01

    Landing delays are currently a problem at major air carrier airports and many forecasters agree that airport congestion will get worse by the end of the century. It is anticipated that some types of delays can be reduced by an efficient optimal runway exist system allowing increased approach volumes necessary at congested airports. A computerized Probabilistic Runway Turnoff Model which locates exits and defines path geometry for a selected maximum occupancy time appropriate for each TERPS aircraft category is defined. The model includes an algorithm for lateral ride comfort limits.

  5. NASA tire/runway friction projects

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1995-01-01

    The paper reviews several aspects of NASA Langley Research Center's tire/runway friction evaluations directed towards improving the safety and economy of aircraft ground operations. The facilities and test equipment used in implementing different aircraft tire friction studies and other related aircraft ground performance investigations are described together with recent workshop activities at NASA Wallops Flight Facility. An overview of the pending Joint NASA/Transport Canada/FM Winter Runway Friction Program is given. Other NASA ongoing studies and on-site field tests are discussed including tire wear performance and new surface treatments. The paper concludes with a description of future research plans.

  6. Investigation of Self Consolidating Concrete Containing High Volume of Supplementary Cementitious Materials and Recycled Asphalt Pavement Aggregates

    NASA Astrophysics Data System (ADS)

    Patibandla, Varun chowdary

    The use of sustainable technologies such as supplementary cementitiuous materials (SCMs), and/or recycled materials is expected to positively affect the performance of concrete mixtures. However, it is important to study and qualify such mixtures and check if the required specifications of their intended application are met before they can be implemented in practice. This study presents the results of a laboratory investigation of Self Consolidating concrete (SCC) containing sustainable technologies. A total of twelve concrete mixtures were prepared with various combinations of fly ash, slag, and recycled asphalt pavement (RAP). The mixtures were divided into three groups with constant water to cementitiuous materials ratio of 0.37, and based on the RAP content; 0, 25, and 50% of coarse aggregate replaced by RAP. All mixtures were prepared to achieve a target slump flow equal to or higher than 500 mm (24in). A control mixture for each group was prepared with 100% Portland cement whereas all other mixtures were designed to have up to 70% of portland cement replaced by a combination of supplementary cementitiuous materials (SCMs) such as class C fly ash and granulated blast furnace slag. The properties of fresh concrete investigated in this study include flowability, deformability; filling capacity, and resistance to segregation. In addition, the compressive strength at 3, 14, and 28 days, the tensile strength, and the unrestrained shrinkage up to 80 days was also investigated. As expected the inclusion of the sustainable technologies affected both fresh and hardened concrete properties. Analysis of the experimental data indicated that inclusion of RAP not only reduces the ultimate strength, but it also affected the compressive strength development rate. Moreover, several mixes satisfied compressive strength requirements for pavements and bridges; those mixes included relatively high percentages of SCMs and RAP. Based on the results obtained in this study, it is not

  7. Material and Structural Performance Evaluations of Hwangtoh Admixtures and Recycled PET Fiber-Added Eco-Friendly Concrete for CO2 Emission Reduction

    PubMed Central

    Koo, Bon-Min; Kim, Jang-Ho Jay; Kim, Sung-Bae; Mun, Sungho

    2014-01-01

    In order to reduce carbon dioxide (CO2) emissions and produce an eco-friendly construction material, a type of concrete that uses a minimal amount of cement, yet still retains equivalent properties to ordinary cement concrete, has been developed and studied all over the world. Hwangtoh, a type of red clay broadly deposited around the world, has traditionally been considered an eco-friendly construction material, with bonus advantages of having health and cost benefits. Presently, Hwangtoh is not commonly used as a modern construction material due to properties such as low strength and high rates of shrinkage cracking. Recent studies, however, have shown that Hwangtoh can be used as a mineral admixture to improve the strength of concrete. In addition, polyethylene terephthalate (PET) fibers recycled from PET bottle waste can be used to control shrinkage cracks in Hwangtoh concrete. Therefore, in this study, performance verification is conducted on newly developed Hwangtoh concrete mixed with short recycled PET fibers. The results show that Hwangtoh concrete has compressive strength, elastic modulus, and pH properties that are similar to these features in ordinary cement concrete. The properties of carbonation depth and creep strain of Hwangtoh concrete, however, are larger and smaller, respectively, than in ordinary cement concrete. According to flexural tests, reinforced concrete (RC) specimens cast with Hwangtoh admixtures (with and without PET fibers) possess similar or better capacities than ordinary RC specimens. The addition of PET fibers significantly improves the structural ductility of RC specimens under normal environmental conditions. However, the implementations of the concrete in aggressive environment must be carefully considered, since a previous study result indicates degradation of its durability performance in aggressive environments, such as seawater [1]. The results of this study validate the possibility of using eco-friendly Hwangtoh concrete

  8. Material and Structural Performance Evaluations of Hwangtoh Admixtures and Recycled PET Fiber-Added Eco-Friendly Concrete for CO₂ Emission Reduction.

    PubMed

    Koo, Bon-Min; Kim, Jang-Ho Jay; Kim, Sung-Bae; Mun, Sungho

    2014-08-19

    In order to reduce carbon dioxide (CO₂) emissions and produce an eco-friendly construction material, a type of concrete that uses a minimal amount of cement, yet still retains equivalent properties to ordinary cement concrete, has been developed and studied all over the world. Hwangtoh, a type of red clay broadly deposited around the world, has traditionally been considered an eco-friendly construction material, with bonus advantages of having health and cost benefits. Presently, Hwangtoh is not commonly used as a modern construction material due to properties such as low strength and high rates of shrinkage cracking. Recent studies, however, have shown that Hwangtoh can be used as a mineral admixture to improve the strength of concrete. In addition, polyethylene terephthalate (PET) fibers recycled from PET bottle waste can be used to control shrinkage cracks in Hwangtoh concrete. Therefore, in this study, performance verification is conducted on newly developed Hwangtoh concrete mixed with short recycled PET fibers. The results show that Hwangtoh concrete has compressive strength, elastic modulus, and pH properties that are similar to these features in ordinary cement concrete. The properties of carbonation depth and creep strain of Hwangtoh concrete, however, are larger and smaller, respectively, than in ordinary cement concrete. According to flexural tests, reinforced concrete (RC) specimens cast with Hwangtoh admixtures (with and without PET fibers) possess similar or better capacities than ordinary RC specimens. The addition of PET fibers significantly improves the structural ductility of RC specimens under normal environmental conditions. However, the implementations of the concrete in aggressive environment must be carefully considered, since a previous study result indicates degradation of its durability performance in aggressive environments, such as seawater [1]. The results of this study validate the possibility of using eco-friendly Hwangtoh concrete

  9. Construction Productivity Advancement Research (CPAR) Program. Investigation of Modified Sulfur Concrete as a Structural Material

    DTIC Science & Technology

    1993-07-01

    Industrial applications of modified sulfur concrete (MSC) have been extremely successful in areas of high corrosive activity such as load-bearing...The ductility of MSC in the postyield regime, however, has not been determined in these tests. Bond strength, Modified sulfur concrete , Strength

  10. 14 CFR 151.79 - Runway paving: Second runway; wind conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... economic factors of air traffic at the location, justify an additional runway for the airport; and (3) The... consideration to the airport noise factor, topography, soil conditions, and other pertinent factors affecting...

  11. 14 CFR 151.79 - Runway paving: Second runway; wind conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... economic factors of air traffic at the location, justify an additional runway for the airport; and (3) The... consideration to the airport noise factor, topography, soil conditions, and other pertinent factors affecting...

  12. Some effects of grooved runway configurations on aircraft tire braking traction under flooded runway conditions

    NASA Technical Reports Server (NTRS)

    Byrdsong, T. A.

    1973-01-01

    An experimental investigation was conducted to study the effect of grooved runway configurations on aircraft tire braking traction on flooded runway surfaces. The investigation was performed, utilizing size 49 x 17, type VII, aircraft tires with an inflation pressure of 170 lb per square inch at ground speeds up to approximately 120 knots. The results of this investigation indicate that when the runway is flooded, grooved surfaces provide better braking traction than an ungrooved surface and, in general, the level of braking traction was found to improve as the tire bearing pressure was increased because of an increase in the groove area of either the surface or the tire tread. Rounding the groove edges tended to degrade the tire braking capability from that developed on the same groove configuration with sharp edges. Results also indicate that braking friction coefficients for the test tires and runway surfaces decreased as ground speed was increased because of the hydroplaning effects.

  13. X-48C Flies Over Intersecting Runways

    NASA Image and Video Library

    2013-02-28

    The X-48C Hybrid Wing Body research aircraft flew over the intersection of several runways adjacent to the compass rose on Rogers Dry Lake at Edwards Air Force Base during one of the sub-scale aircraft's final test flights on Feb. 28, 2013.

  14. Machine vision for airport runway identification

    NASA Astrophysics Data System (ADS)

    Schubert, Matthew; Moore, Andrew J.; Dolph, Chester; Woodell, Glenn

    2015-03-01

    For rigid objects and fixed scenes, current machine vision technology is capable of identifying imagery rapidly and with specificity over a modest range of camera viewpoints and scene illumination. We applied that capability to the problem of runway identification using video of sixteen runway approaches at nine locations, subject to two simplifying assumptions. First, by using approach video from just one of the several possible seasonal variations (no snow cover and full foliage), we artificially removed one source of scene variation in this study. Secondly, by not using approach video at dawn and dusk, we limited the study to two illumination variants (day and night). We did allow scene variation due to atmospheric turbidity by using approach video from rainy and foggy days in some daytime approaches. With suitable ensemble statistics to account for temporal continuity in video, we observed high location specificity (<90% Bayesian posterior probability). We also tested repeatability, i.e., identification of a given runway across multiple videos, and observed robust repeatability only if illumination (day vs. night) was the same and approach visibility was good. Both specificity and repeatability degraded in poor weather conditions. The results of this simplified study show that geolocation via real-time comparison of cockpit image sensor video to a database of runway approach imagery is feasible, as long as the database contains imagery from about the same time of day (complete daylight and nighttime, excluding dawn and dusk) and the weather is clear at the time of the flight.

  15. Economic utilization of general aviation airport runways

    NASA Technical Reports Server (NTRS)

    Piper, R. R.

    1971-01-01

    The urban general aviation airport economics is studied in detail. The demand for airport services is discussed, and the different types of users are identified. The direct cost characteristics of the airport are summarized; costs to the airport owner are largely fixed, and, except at certain large airports, weight is not a significant factor in airport costs. The efficient use of an existing airport facility is explored, with the focus on the social cost of runway congestion as traffic density at the airport build up and queues form. The tradeoff between aircraft operating costs and airport costs is analyzed in terms of runway length. The transition from theory to practice is treated, and the policy of charging prices only on aircraft storage and fuel is felt likely to continue. Implications of the study from the standpoint of public policy include pricing that spreads traffic peaks to improve runway utilization, and pricing that discriminates against aircraft requiring long runways and causes owners to adopt V/STOL equipment.

  16. Evaluation of Scheduling Methods for Multiple Runways

    NASA Technical Reports Server (NTRS)

    Bolender, Michael A.; Slater, G. L.

    1996-01-01

    Several scheduling strategies are analyzed in order to determine the most efficient means of scheduling aircraft when multiple runways are operational and the airport is operating at different utilization rates. The study compares simulation data for two and three runway scenarios to results from queuing theory for an M/D/n queue. The direction taken, however, is not to do a steady-state, or equilibrium, analysis since this is not the case during a rush period at a typical airport. Instead, a transient analysis of the delay per aircraft is performed. It is shown that the scheduling strategy that reduces the delay depends upon the density of the arrival traffic. For light traffic, scheduling aircraft to their preferred runways is sufficient; however, as the arrival rate increases, it becomes more important to separate traffic by weight class. Significant delay reduction is realized when aircraft that belong to the heavy and small weight classes are sent to separate runways with large aircraft put into the 'best' landing slot.

  17. Evaluation of two transport aircraft and several ground test vehicle friction measurements obtained for various runway surface types and conditions. A summary of test results from joint FAA/NASA Runway Friction Program

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.; Vogler, William A.; Baldasare, Paul

    1990-01-01

    Tests with specially instrumented NASA Boeing 737 and 727 aircraft together with several different ground friction measuring devices were conducted for a variety of runway surface types and conditions. These tests are part of joint FAA/NASA Aircraft/Ground Vehicle Runway Friction Program aimed at obtaining a better understanding of aircraft ground handling performance under adverse weather conditions and defining relationships between aircraft and ground vehicle tire friction measurements. Aircraft braking performance on dry, wet, snow and ice-covered runway conditions is discussed as well as ground vehicle friction data obtained under similar runway conditions. For a given contaminated runway surface condition, the correlation between ground vehicles and aircraft friction data is identified. The influence of major test parameters on friction measurements such as speed, test tire characteristics, type and amount of surface contaminant, and ambient temperature are discussed. The effect of surface type on wet friction levels is also evaluated from comparative data collected on grooved and ungrooved concrete and asphalt surfaces.

  18. Perseus B Landing on Runway

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Perseus B high-altitude, remotely piloted research vehicle touches down on the runway at Edwards AFB, adjacent to NASA's Dryden Flight Research Center, after a test flight in September 1999. The Perseus B was the third version of the Perseus design developed by Aurora Flight Sciences under the Dryden-managed Environmental Research Aircraft and Sensor Technology (ERAST) program. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third

  19. Perseus B Landing on Runway

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Perseus B high-altitude, remotely piloted research vehicle touches down on the runway at Edwards AFB, adjacent to NASA's Dryden Flight Research Center, after a test flight in September 1999. The Perseus B was the third version of the Perseus design developed by Aurora Flight Sciences under the Dryden-managed Environmental Research Aircraft and Sensor Technology (ERAST) program. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third

  20. Design, Construction, Maintenance, and Evaluation of the McMurdo Sound (Antarctica) Sea Ice Runway for Heavy Wheeled Aircraft Operations

    DTIC Science & Technology

    2006-07-19

    adjacent to runway markers while the runway proper and the shoulders are being maintained to the 100 mm (4 in) standard in order to resume...mid-point markers . All markers should be made of durable, lightweight materials. Support posts must be frangible and present a tiny cross-section to...the wind to minimize snow drifting, which should be accomplished by a small diameter and a minimum number of posts; bamboo canes are currently used

  1. Feasibility and Practical Limits for the Use of Lightweight Prestressed Concrete (LWPC) as a Shipbuilding Material.

    DTIC Science & Technology

    1982-10-01

    concrete to be effective in resistinq botn in-plane shear and out-of-plane shear, whereas in a sti fened pl.te, the in-plane shear is resisted only by the...design load"ngs, the stress in the concrete oscillates with𔃻in the range of 0 to about 45% of the compressive strength, ’ith the stress being compression

  2. How Concrete Is Concrete?

    ERIC Educational Resources Information Center

    Gravemeijer, Koeno

    2011-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, "manipulatives", in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own,…

  3. Runway Operations Planning: A Two-Stage Solution Methodology

    NASA Technical Reports Server (NTRS)

    Anagnostakis, Ioannis; Clarke, John-Paul

    2003-01-01

    The airport runway is a scarce resource that must be shared by different runway operations (arrivals, departures and runway crossings). Given the possible sequences of runway events, careful Runway Operations Planning (ROP) is required if runway utilization is to be maximized. Thus, Runway Operations Planning (ROP) is a critical component of airport operations planning in general and surface operations planning in particular. From the perspective of departures, ROP solutions are aircraft departure schedules developed by optimally allocating runway time for departures given the time required for arrivals and crossings. In addition to the obvious objective of maximizing throughput, other objectives, such as guaranteeing fairness and minimizing environmental impact, may be incorporated into the ROP solution subject to constraints introduced by Air Traffic Control (ATC) procedures. Generating optimal runway operations plans was approached in with a 'one-stage' optimization routine that considered all the desired objectives and constraints, and the characteristics of each aircraft (weight class, destination, Air Traffic Control (ATC) constraints) at the same time. Since, however, at any given point in time, there is less uncertainty in the predicted demand for departure resources in terms of weight class than in terms of specific aircraft, the ROP problem can be parsed into two stages. In the context of the Departure Planner (OP) research project, this paper introduces Runway Operations Planning (ROP) as part of the wider Surface Operations Optimization (SOO) and describes a proposed 'two stage' heuristic algorithm for solving the Runway Operations Planning (ROP) problem. Focus is specifically given on including runway crossings in the planning process of runway operations. In the first stage, sequences of departure class slots and runwy crossings slots are generated and ranked based on departure runway throughput under stochastic conditions. In the second stage, the

  4. Diffusion and Leaching Behavior of Radionuclides in Category 3 Waste Encasement Concrete and Soil Fill Material – Summary Report

    SciTech Connect

    Mattigod, Shas V.; Wellman, Dawn M.; Bovaird, Chase C.; Parker, Kent E.; Clayton, Libby N.; Powers, Laura; Recknagle, Kurtis P.; Wood, Marcus I.

    2011-08-31

    One of the methods being considered for safely disposing of Category 3 low-level radioactive wastes is to encase the waste in concrete. Such concrete encasement would contain and isolate the waste packages from the hydrologic environment and would act as an intrusion barrier. The current plan for waste isolation consists of stacking low-level waste packages on a trench floor, surrounding the stacks with reinforced steel, and encasing these packages in concrete. These concrete-encased waste stacks are expected to vary in size with maximum dimensions of 6.4 m long, 2.7 m wide, and 4 m high. The waste stacks are expected to have a surrounding minimum thickness of 15 cm of concrete encasement. These concrete-encased waste packages are expected to withstand environmental exposure (solar radiation, temperature variations, and precipitation) until an interim soil cover or permanent closure cover is installed, and to remain largely intact thereafter. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages. The mobilized radionuclides may escape from the encased concrete by mass flow and/or diffusion and move into the surrounding subsurface environment. Therefore, it is necessary to assess the performance of the concrete encasement structure and the ability of the surrounding soil to retard radionuclide migration. The retardation factors for radionuclides contained in the waste packages can be determined from measurements of diffusion coefficients for these contaminants through concrete and fill material. Some of the mobilization scenarios include (1) potential leaching of waste form before permanent closure cover is installed; (2) after the cover installation, long-term diffusion of radionuclides from concrete waste form into surrounding fill material; (3) diffusion of radionuclides from contaminated soils into adjoining concrete encasement and clean fill material. Additionally, the rate of

  5. Corrosion-resistant sulfur concretes

    NASA Astrophysics Data System (ADS)

    McBee, W. C.; Sullivan, T. A.; Jong, B. W.

    1983-04-01

    Sulfur concretes have been developed by the Bureau of Mines as construction materials with physical and mechanical properties that suit them for use in acid and salt corrosive environments where conventional concretes fail. Mixture design methods were established for preparing sulfur concretes using different types of aggregates and recently developed mixed-modified sulfur cements. Bench-scale testing of the sulfur concretes has shown their potential value. Corrosion resistance, strength, and durability of sulfur concrete are superior to those of conventional materials. Field in situ evaluation tests of the sulfur concretes as replacement for conventional concrete materials are in progress in corrosive areas of 24 commercial chemical, fertilizer, and metallurgical plants.

  6. Optimum runway orientation relative to crosswinds

    NASA Technical Reports Server (NTRS)

    Falls, L. W.; Brown, S. C.

    1972-01-01

    Specific magnitudes of crosswinds may exist that could be constraints to the success of an aircraft mission such as the landing of the proposed space shuttle. A method is required to determine the orientation or azimuth of the proposed runway which will minimize the probability of certain critical crosswinds. Two procedures for obtaining the optimum runway orientation relative to minimizing a specified crosswind speed are described and illustrated with examples. The empirical procedure requires only hand calculations on an ordinary wind rose. The theoretical method utilizes wind statistics computed after the bivariate normal elliptical distribution is applied to a data sample of component winds. This method requires only the assumption that the wind components are bivariate normally distributed. This assumption seems to be reasonable. Studies are currently in progress for testing wind components for bivariate normality for various stations. The close agreement between the theoretical and empirical results for the example chosen substantiates the bivariate normal assumption.

  7. Feasibility Tests on Concrete with Very-High-Volume Supplementary Cementitious Materials

    PubMed Central

    Yang, Keun-Hyeok; Jeon, Yong-Su

    2014-01-01

    The objective of this study is to examine the compressive strength and durability of very high-volume SCM concrete. The prepared 36 concrete specimens were classified into two groups according to their designed 28-day compressive strength. For the high-volume SCM, the FA level was fixed at a weight ratio of 0.4 and the GGBS level varied between the weight ratio of 0.3 and 0.5, which resulted in 70–90% replacement of OPC. To enhance the compressive strength of very high-volume SCM concrete at an early age, the unit water content was controlled to be less than 150 kg/m3, and a specially modified polycarboxylate-based water-reducing agent was added. Test results showed that as SCM ratio (R SCM) increased, the strength gain ratio at an early age relative to the 28-day strength tended to decrease, whereas that at a long-term age increased up to R SCM of 0.8, beyond which it decreased. In addition, the beneficial effect of SCMs on the freezing-and-thawing and chloride resistances of the concrete decreased at R SCM of 0.9. Hence, it is recommended that R SCM needs to be restricted to less than 0.8–0.85 in order to obtain a consistent positive influence on the compressive strength and durability of SCM concrete. PMID:25162049

  8. Feasibility tests on concrete with very-high-volume supplementary cementitious materials.

    PubMed

    Yang, Keun-Hyeok; Jeon, Yong-Su

    2014-01-01

    The objective of this study is to examine the compressive strength and durability of very high-volume SCM concrete. The prepared 36 concrete specimens were classified into two groups according to their designed 28-day compressive strength. For the high-volume SCM, the FA level was fixed at a weight ratio of 0.4 and the GGBS level varied between the weight ratio of 0.3 and 0.5, which resulted in 70-90% replacement of OPC. To enhance the compressive strength of very high-volume SCM concrete at an early age, the unit water content was controlled to be less than 150 kg/m(3), and a specially modified polycarboxylate-based water-reducing agent was added. Test results showed that as SCM ratio (R SCM) increased, the strength gain ratio at an early age relative to the 28-day strength tended to decrease, whereas that at a long-term age increased up to R SCM of 0.8, beyond which it decreased. In addition, the beneficial effect of SCMs on the freezing-and-thawing and chloride resistances of the concrete decreased at R SCM of 0.9. Hence, it is recommended that R SCM needs to be restricted to less than 0.8-0.85 in order to obtain a consistent positive influence on the compressive strength and durability of SCM concrete.

  9. Formal Verification of the Runway Safety Monitor

    NASA Technical Reports Server (NTRS)

    Siminiceanu, Radu; Ciardo, Gianfranco

    2006-01-01

    The Runway Safety Monitor (RSM) designed by Lockheed Martin is part of NASA's effort to reduce runway accidents. We developed a Petri net model of the RSM protocol and used the model checking functions of our tool SMART to investigate a number of safety properties in RSM. To mitigate the impact of state-space explosion, we built a highly discretized model of the system, obtained by partitioning the monitored runway zone into a grid of smaller volumes and by considering scenarios involving only two aircraft. The model also assumes that there are no communication failures, such as bad input from radar or lack of incoming data, thus it relies on a consistent view of reality by all participants. In spite of these simplifications, we were able to expose potential problems in the RSM conceptual design. Our findings were forwarded to the design engineers, who undertook corrective action. Additionally, the results stress the efficiency attained by the new model checking algorithms implemented in SMART, and demonstrate their applicability to real-world systems.

  10. Runway Operations Planning: A Two-Stage Heuristic Algorithm

    NASA Technical Reports Server (NTRS)

    Anagnostakis, Ioannis; Clarke, John-Paul

    2003-01-01

    The airport runway is a scarce resource that must be shared by different runway operations (arrivals, departures and runway crossings). Given the possible sequences of runway events, careful Runway Operations Planning (ROP) is required if runway utilization is to be maximized. From the perspective of departures, ROP solutions are aircraft departure schedules developed by optimally allocating runway time for departures given the time required for arrivals and crossings. In addition to the obvious objective of maximizing throughput, other objectives, such as guaranteeing fairness and minimizing environmental impact, can also be incorporated into the ROP solution subject to constraints introduced by Air Traffic Control (ATC) procedures. This paper introduces a two stage heuristic algorithm for solving the Runway Operations Planning (ROP) problem. In the first stage, sequences of departure class slots and runway crossings slots are generated and ranked based on departure runway throughput under stochastic conditions. In the second stage, the departure class slots are populated with specific flights from the pool of available aircraft, by solving an integer program with a Branch & Bound algorithm implementation. Preliminary results from this implementation of the two-stage algorithm on real-world traffic data are presented.

  11. STS-30 crew poses with NASA administrators in front of OV-104 on EAFB runway

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-30 crewmembers pose with NASA administrators in front of Atlantis, Orbiter Vehicle (OV) 104, on concrete runway 22 at Edwards Air Force Base (EAFB), California. From left to right are Acting NASA Administrator Richard H. Truly, Commander David M. Walker, Mission Specialist (MS) Mark C. Lee, MS Mary L. Cleave, Pilot Ronald J. Grabe, MS Norman E. Thagard, and NASA Deputy Administrator Dale D. Myers. OV-104 is undergoing postlanding servicing following its successful landing at 12:44:33 pm (Pacific Daylight Time (PDT)).

  12. STS-30 crew poses with NASA administrators in front of OV-104 on EAFB runway

    NASA Technical Reports Server (NTRS)

    1989-01-01

    STS-30 crewmembers pose with NASA administrators in front of Atlantis, Orbiter Vehicle (OV) 104, on concrete runway 22 at Edwards Air Force Base (EAFB), California. From left to right are Acting NASA Administrator Richard H. Truly, Commander David M. Walker, Mission Specialist (MS) Mark C. Lee, MS Mary L. Cleave, Pilot Ronald J. Grabe, MS Norman E. Thagard, and NASA Deputy Administrator Dale D. Myers. Crewmembers have just egressed OV-104 via a mobile stairway after the successful landing at 12:44:33 pm (Pacific Daylight Time (PDT)).

  13. Nondestructive identification of material properties of fibre concrete: A time-harmonic electromagnetic field

    NASA Astrophysics Data System (ADS)

    Hobst, L.; Bílek, P.

    2016-06-01

    The magnetic approach to the identification of mechanical properties of fibre concrete, using permanent magnets, has its electromagnetic alternative, more suitable to the nondestructive detection of orientation of fibres, in addition to the evaluation of their volume fraction. This paper sketches related approaches to both experimental settings and computational simulations.

  14. Cockpit Technology for Prevention of General Aviation Runway Incursions

    NASA Technical Reports Server (NTRS)

    Prinzel, Lawrence J., III; Jones, Denise R.

    2007-01-01

    General aviation accounted for 74 percent of runway incursions but only 57 percent of the operations during the four-year period from fiscal year (FY) 2001 through FY2004. Elements of the NASA Runway Incursion Prevention System were adapted and tested for general aviation aircraft. Sixteen General Aviation pilots, of varying levels of certification and amount of experience, participated in a piloted simulation study to evaluate the system for prevention of general aviation runway incursions compared to existing moving map displays. Pilots flew numerous complex, high workload approaches under varying weather and visibility conditions. A rare-event runway incursion scenario was presented, unbeknownst to the pilots, which represented a typical runway incursion situation. The results validated the efficacy and safety need for a runway incursion prevention system for general aviation aircraft.

  15. Crack detection methods for concrete and steel using radio frequency identification and electrically conductive materials and its applications

    NASA Astrophysics Data System (ADS)

    Morita, Koichi; Noguchi, Kazuya

    2008-03-01

    Radio Frequency IDentification (RFID) tag is a promising device for the management of products at a very low cost. Huge number of such low-cost sensors can be installed to the structure beforehand, after a disaster we can access to these sensors wirelessly and very easily. In this system, an electrically conductive paint or printed sheet is applied to a part of structure in which crack will occur. Copper wire is connected to the attachment on the structure and a RFID tag. When a crack occurs, the paint or printed sheet is broken, resulting in an increase in resistance. Crack width can be estimated by the ability of an RFID transmitter to communicate with the tag. By bending tests of concrete specimens, the relationships between concrete crack width and conductivity of the materials are examined. It is shown that the level of concrete crack width can be related to the ability of the paint or printed sheet to conduct electricity or not. This printed sheet is also applied for steel crack. By fatigue test of steel specimen with a notch, very small steel crack can be detected by this sensor.

  16. Challenges in Strengthening of Concrete Elements with PBO-FRCM Materials

    NASA Astrophysics Data System (ADS)

    Trapko, T.; Urbańska, D.; Musiał, M.

    2017-06-01

    In the paper a technology of reinforced concrete elements strengthening with PBO mesh bonded with a mineral mortar was presented. The possibilities of application of this system in shear strengthening of reinforced concrete beams and compressed elements are in the range of interests of the authors. In the paper authors experiences in strengthening of such type elements with PBO mesh bonded with mineral mortar were described. Research has shown that destruction of elements strengthened with PBO-FRCM system is caused by a debonding of the fibres from the matrix layer or delamination at the final overlap of PBO mesh. In order to obtain the most efficient use of PBO fibres and prevent premature loosening of composite appropriate anchorage should be used.

  17. Quantitative linear and nonlinear resonance inspection techniques and analysis for material characterization: application to concrete thermal damage.

    PubMed

    Payan, C; Ulrich, T J; Le Bas, P Y; Saleh, T; Guimaraes, M

    2014-08-01

    Developed in the late 1980s, Nonlinear Resonant Ultrasound Spectroscopy (NRUS) has been widely employed in the field of material characterization. Most of the studies assume the measured amplitude to be proportional to the strain amplitude which drives nonlinear phenomena. In 1D resonant bar experiments, the configuration for which NRUS was initially developed, this assumption holds. However, it is not true for samples of general shape which exhibit several resonance mode shapes. This paper proposes a methodology based on linear resonant ultrasound spectroscopy, numerical simulations and nonlinear resonant ultrasound spectroscopy to provide quantitative values of nonlinear elastic moduli taking into account the 3D nature of the samples. In the context of license renewal in the field of nuclear energy, this study aims at providing some quantitative information related to the degree of micro-cracking of concrete and cement based materials in the presence of thermal damage. The resonance based method is validated as regard with concrete microstructure evolution during thermal exposure.

  18. Corrosion control of steel-reinforced concrete

    NASA Astrophysics Data System (ADS)

    Chung, D. D. L.

    2000-10-01

    The methods and materials for corrosion control of steel-reinforced concrete are reviewed. The methods are steel surface treatment, the use of admixtures in concrete, surface coating on concrete, and cathodic protection.

  19. 14 CFR 151.77 - Runway paving: General rules.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Runway paving: General rules. 151.77 Section 151.77 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.77 Runway paving: General...

  20. 14 CFR 151.77 - Runway paving: General rules.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Runway paving: General rules. 151.77 Section 151.77 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.77 Runway paving: General...

  1. 14 CFR 151.77 - Runway paving: General rules.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Runway paving: General rules. 151.77 Section 151.77 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.77 Runway paving: General...

  2. 14 CFR 151.77 - Runway paving: General rules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Runway paving: General rules. 151.77 Section 151.77 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.77 Runway paving: General...

  3. 14 CFR 151.77 - Runway paving: General rules.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Runway paving: General rules. 151.77 Section 151.77 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS Project Programming Standards § 151.77 Runway paving: General...

  4. 32 CFR 256.6 - Runway classification by aircraft type.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Runway classification by aircraft type. 256.6 Section 256.6 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS AIR INSTALLATIONS COMPATIBLE USE ZONES § 256.6 Runway classification by aircraft...

  5. E-Area Vault Concrete Material Property And Vault Durability/Degradation Projection Recommendations

    SciTech Connect

    Phifer, M. A.

    2014-03-11

    Subsequent to the 2008 E-Area Low-Level Waste Facility (ELLWF) Performance Assessment (PA) (WSRC 2008), two additional E-Area vault concrete property testing programs have been conducted (Dixon and Phifer 2010 and SIMCO 2011a) and two additional E-Area vault concrete durability modeling projections have been made (Langton 2009 and SIMCO 2012). All the information/data from these reports has been evaluated and consolidated herein by the Savannah River National Laboratory (SRNL) at the request of Solid Waste Management (SWM) to produce E-Area vault concrete hydraulic and physical property data and vault durability/degradation projection recommendations that are adequately justified for use within associated Special Analyses (SAs) and future PA updates. The Low Activity Waste (LAW) and Intermediate Level (IL) Vaults structural degradation predictions produced by Carey 2006 and Peregoy 2006, respectively, which were used as the basis for the 2008 ELLWF PA, remain valid based upon the results of the E-Area vault concrete durability simulations reported by Langton 2009 and those reported by SIMCO 2012. Therefore revised structural degradation predictions are not required so long as the mean thickness of the closure cap overlying the vaults is no greater than that assumed within Carey 2006 and Peregoy 2006. For the LAW Vault structural degradation prediction (Carey 2006), the mean thickness of the overlying closure cap was taken as nine feet. For the IL Vault structural degradation prediction (Peregoy 2006), the mean thickness of the overlying closure cap was taken as eight feet. The mean closure cap thicknesses as described here for both E-Area Vaults will be included as a key input and assumption (I&A) in the next revision to the closure plan for the ELLWF (Phifer et al. 2009). In addition, it has been identified as new input to the PA model to be assessed in the ongoing update to the new PA Information UDQE (Flach 2013). Once the UDQE is approved, the SWM Key I

  6. Monte Carlo modelling of single and multiple Compton scattering profiles in a concrete material

    NASA Astrophysics Data System (ADS)

    Akar Tarim, U.; Ozmutlu, E. N.; Gurler, O.; Yalcin, S.; Gundogdu, O.; Sharaf, J. M.; Bradley, D. A.

    2013-04-01

    A Monte Carlo simulation study has been conducted of 60Co photons Compton scattered in concrete, illustrating the degraded energy spectra of gamma-ray radiation. Results are produced representing a NaI(Tl) detector model. We were able to analyse energy distributions of photons that reach the detector system after suffering several successive Compton scatterings in the target. The predicted decrease in intensity of single- and multiple-scattering peaks with increase in thickness of the target medium are in good agreement with experimental observations and findings reported by others.

  7. Structural concretes with waste-based lightweight aggregates: from landfill to engineered materials.

    PubMed

    De'Gennaro, Roberto; Graziano, Sossio Fabio; Cappelletti, Piergiulio; Colella, Abner; Dondi, Michele; Langella, Alessio; De'Gennaro, Maurizio

    2009-09-15

    This research provides possible opportunities in the reuse of waste and particularly muds, coming from both ornamental stone (granite sludges from sawing and polishing operations) and ceramic production (porcelain stoneware tile polishing sludge), for the manufacture of lightweight aggregates. Lab simulation of the manufacturing cycle was performed by pelletizing and firing the waste mixes in a rotative furnace up to 1300 degrees C, and determining composition and physicomechanical properties of lightweight aggregates. The best formulation was used to produce and test lightweight structural concretes according to standard procedures. Both granite and porcelain stoneware polishing sludges exhibit a suitable firing behavior due to the occurrence of SiC (an abrasive component) which, by decomposing at high temperature with gas release, acts as a bloating promoter, resulting in aggregates with particle density < 1 Mg/m3. However, slight variations of mixture composition produce aggregates with rather different properties, going from values close to those of typical commercial expanded clays (particle density 0.68 Mg/m3; strength of particle 1.2 MPa) to products with high mechanical features (particle density 1.25 Mg/m3; strength of particle 6.9 MPa). The best formulation (50 wt.% porcelain stoneware polishing sludge +50 wt.% granite sawing sludge) was used to successfully manufacture lightweight structural concretes with suitable properties (compressive strength 28 days > 20 MPa, bulk density 1.4-2.0 Mg/m3).

  8. Field site leaching from recycled concrete aggregates applied as sub-base material in road construction.

    PubMed

    Engelsen, Christian J; Wibetoe, Grethe; van der Sloot, Hans A; Lund, Walter; Petkovic, Gordana

    2012-06-15

    The release of major and trace elements from recycled concrete aggregates used in an asphalt covered road sub-base has been monitored for more than 4 years. A similar test field without an asphalt cover, directly exposed to air and rain, and an asphalt covered reference field with natural aggregates in the sub-base were also included in the study. It was found that the pH of the infiltration water from the road sub-base with asphalt covered concrete aggregates decreased from 12.6 to below pH 10 after 2.5 years of exposure, whereas this pH was reached within only one year for the uncovered field. Vertical temperature profiles established for the sub-base, could explain the measured infiltration during parts of the winter season. When the release of major and trace elements as function of field pH was compared with pH dependent release data measured in the laboratory, some similar pH trends were found. The field concentrations of Cd, Ni, Pb and Zn were found to be low throughout the monitoring period. During two of the winter seasons, a concentration increase of Cr and Mo was observed, possibly due to the use of de-icing salt. The concentrations of the trace constituents did not exceed Norwegian acceptance criteria for ground water and surface water Class II.

  9. Material Evaluation of an Elastomer, Epoxy and Lightweight Concrete Rail Attachment System for Direct Fixation Light Rail Applications

    NASA Astrophysics Data System (ADS)

    Swarner, Benjamin R.

    Sound Transit plans to extend its current light rail system, which runs along the I-5 corridor in Seattle, Washington, across the I-90 Homer Hadley floating bridge as part of a project to connect the major city centers in the region. But, no light rail has ever crossed a floating bridge due to several unique engineering challenges. One of these challenges is attaching the rails to the existing bridge deck without drilling into the bridge pontoons. This research program was developed to test and analyze a direct fixation method that uses lightweight concrete plinths and an elastomer-epoxy system to attach the rails to the bridge deck. The elastomer used was a two-part, pourable elastomer with cork particles intermixed to alter the mechanical properties of the material. A lightweight concrete mixture was analyzed for use in the plinths, and system tests investigated the system response under tensile, compressive and shear loading. The shear response of the system was examined further under varying loading conditions including different surface preparations, elastomer thicknesses, strain-rates and after freeze-thaw conditioning. Experimental data was examined for trends based on these parameters to best characterize the system, and the elastomer was evaluated in the context of modern elastomer research.

  10. ELWIRA "Plants, wood, steel, concrete - a lifecycle as construction materials": University meets school - science meets high school education

    NASA Astrophysics Data System (ADS)

    Strauss-Sieberth, Alexandra; Strauss, Alfred; Kalny, Gerda; Rauch, Hans Peter; Loiskandl, Willibald

    2016-04-01

    The research project "Plants, wood, steel, concrete - a lifecycle as construction materials" (ELWIRA) is in the framework of the Sparkling Science programme performed by the University of Natural Resources and Life Sciences together with the Billroth Gymnasium in Vienna. The targets of a Sparkling Science project are twofold (a) research and scientific activities should already be transferred in the education methods of schools in order to fascinate high school students for scientific methods and to spark young people's interest in research, and (b) exciting research questions not solved and innovative findings should be addressed. The high school students work together with the scientists on their existing research questions improve the school's profile and the high school student knowledge in the investigated Sparkling Science topic and can lead to a more diverse viewing by the involvement of the high school students. In the project ELWIRA scientists collaborate with the school to quantify and evaluate the properties of classical building materials like concrete and natural materials like plants and woodlogs in terms of their life cycle through the use of different laboratory and field methods. The collaboration with the high school students is structured in workshops, laboratory work and fieldworks. For an efficient coordination/communication, learning and research progress new advanced electronic media like "Moodle classes/courses" have been used and utilized by the high school students with great interest. The Moodle classes are of high importance in the knowledge transfer in the dialogue with the high school students. The research project is structured into four main areas associated with the efficiencies of building materials: (a) the aesthetic feeling of people in terms of the appearance of materials and associated structures will be evaluated by means of jointly developed and collected questionnaires. The analysis, interpretation and evaluation are carried

  11. Transient creep effects and the lubricating power of water in materials ranging from paper to concrete and Kevlar

    NASA Astrophysics Data System (ADS)

    Vlahinić, Ivan; Thomas, Jeffrey J.; Jennings, Hamlin M.; Andrade, José E.

    2012-07-01

    A diverse class of viscous materials, which includes familiar materials such concrete, wood, and Kevlar, exhibit surprising, counterintutive properties under internal moisture content fluctuations. In test after test over the past 50 years, the viscosity of these materials is observed to decrease, often dramatically, during wetting and drying. The key characteristics of the observed viscous softening are: the decrease in viscosity is temporary, and depending on the specimen size can be greatly delayed with respect to the associated change in weight; the decrease in viscosity is absent under steady state flow. Based on recent research on the properties of water and other polar fluids confined by hydrophilic surfaces, we provide a physical explanation and propose a constitutive law. The resulting model accurately captures the interplay between the pore fluid movement and macroscopic constitutive properties in totality. The model is verified against published data for the creep of paper sheets exposed to cyclic moisture conditions. Experimental data of different materials under similar boundary conditions are compared using a new metric, the creep rate factor. The results further reinforce the idea that nanoscale movement of water enhances the internal 'lubrication' of the studied materials, interpreted as loosening of the hydrogen bonds.

  12. Some considerations in the evaluation of concrete as a structural material for alternative LLW (low-level radioactive waste) disposal technologies

    SciTech Connect

    MacKenzie, D.R.; Siskind, B.; Bowerman, B.S.; Piciulo, P.L.

    1987-01-01

    The objective of this study was to develop information needed to evaluate the long-term performance of concrete and reinforced concrete as a structural material for alternative LLW disposal methods. The capability to carry out such an evaluation is required for licensing a site which employs one of these alternative methods. The basis for achieving the study objective was the review and analysis of the literature on concrete and its properties, particularly its durability. In carrying out this program characteristics of concrete useful in evaluating its performance and factors that can affect its performance were identified. The factors are both intrinsic, i.e., associated with composition of the concrete (and thus controllable), and extrinsic, i.e., due to external environmental forces such as climatic conditions and aggressive chemicals in the soil. The testing of concrete, using both accelerated tests and long-term non-accelerated tests, is discussed with special reference to its application to modeling of long-term performance prediction. On the basis of the study's results, conditions for acceptance are recommended as an aid in the licensing of disposal sites which make use of alternative methods.

  13. Throughput Benefit Assessment for Tactical Runway Configuration Management (TRCM)

    NASA Technical Reports Server (NTRS)

    Phojanamongkolkij, Nipa; Oseguera-Lohr, Rosa M.; Lohr, Gary W.; Fenbert, James W.

    2014-01-01

    The System-Oriented Runway Management (SORM) concept is a collection of needed capabilities focused on a more efficient use of runways while considering all of the factors that affect runway use. Tactical Runway Configuration Management (TRCM), one of the SORM capabilities, provides runway configuration and runway usage recommendations, monitoring the active runway configuration for suitability given existing factors, based on a 90 minute planning horizon. This study evaluates the throughput benefits using a representative sample of today's traffic volumes at three airports: Memphis International Airport (MEM), Dallas-Fort Worth International Airport (DFW), and John F. Kennedy International Airport (JFK). Based on this initial assessment, there are statistical throughput benefits for both arrivals and departures at MEM with an average of 4% for arrivals, and 6% for departures. For DFW, there is a statistical benefit for arrivals with an average of 3%. Although there is an average of 1% benefit observed for departures, it is not statistically significant. For JFK, there is a 12% benefit for arrivals, but a 2% penalty for departures. The results obtained are for current traffic volumes and should show greater benefit for increased future demand. This paper also proposes some potential TRCM algorithm improvements for future research. A continued research plan is being worked to implement these improvements and to re-assess the throughput benefit for today and future projected traffic volumes.

  14. Repair and rehabilitation with polymer concrete

    SciTech Connect

    Kukacka, L.E.

    1988-09-01

    As a result of their fast setting characteristics and excellent mechanical and physical properties, polymer concretes (PC) are finding ever increasing useage for the repair of deteriorated portland cement concrete structures. Applications include the repair of highway pavements and bridge decks, airport runways, hydrotechnical structures, tunnels, and industrial flooring. The most commonly used resins and monomer systems for these applications are epoxies, polyesters and methylmethacrylate. Furfuryl alcohol has been used experimentally, and shows promise for use in making emergency repairs under adverse moisture or extreme temperature conditions. In the paper, repair procedures will be discussed and several case histories given. 6 refs.

  15. Analysis of Physical Properties and Mineralogical of Pyrolysis Tires Rubber Ash Compared Natural Sand in Concrete material

    NASA Astrophysics Data System (ADS)

    Syamir Senin, Mohamad; Shahidan, Shahiron; Syazani Leman, Alif; Izzati Raihan Ramzi Hannan, Nurul

    2016-11-01

    Waste tires pose significant health and environmental concerns if not recycled or discarded properly. At the same time, natural sand is becoming scarcer and costlier due to its non-availability. Waste tires as fine aggregate can be an economical and sustainable alternative to the natural sand. Recent years, the interest on recycling waste tires into civil engineering applications by the researchers has increased. In this research, the chemical and physical properties of the tires rubber ash and the natural sand have been analysed. The densities of the rubber ash are lower than the natural sand. Rubber ash had finer particle size compared to the natural sand. Almost all chemical in the natural sand had in rubber ash with the additional sulphur trioxide and zinc oxide in the rubber ash, made the rubber ash better than natural sand. Rubber ash seems to be a suitable material to use in concrete as sand replacement.

  16. Runway Incursion Prevention System for General Aviation Operations

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.; Prinzel III, Lawrence J.

    2006-01-01

    A Runway Incursion Prevention System (RIPS) and additional incursion detection algorithm were adapted for general aviation operations and evaluated in a simulation study at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) in the fall of 2005. RIPS has been designed to enhance surface situation awareness and provide cockpit alerts of potential runway conflicts in order to prevent runway incidents while also improving operational capability. The purpose of the study was to evaluate the airborne incursion detection algorithms and associated alerting and airport surface display concepts for general aviation operations. This paper gives an overview of the system, simulation study, and test results.

  17. Improved Acrylic Systems for Rapid Runway Repair.

    DTIC Science & Technology

    1983-05-01

    Concrete * Fast-Setting Concrete N Acrylic Polymer Research * 1 k UST mACV lC@ea. ON -- -0 - OW. 00....Y d*Ip OF 40 domb) The objectives of this...available to the general public, including foreign nationals. This technical report has been reviewed and is approved for publication. DANIEL J. PIERRE, Capt...resins. The aggregate and resin might be premixed for placement or (as in the research reported herein) the cap might be formed by percolation of liquid

  18. Process for impregnating a concrete or cement body with a polymeric material

    DOEpatents

    Mattus, A.J.; Spence, R.D.

    1988-05-04

    A process for impregnating cementitious solids with polymeric materials by blending polymeric materials in a grout, allowing the grout to cure, and contacting the resulting solidified grout containing the polymeric materials with an organic mixture containing a monomer, a cross-linking agent and a catalyst. The mixture dissolves the polymerized particles and forms a channel for distributing the monomer throughout the network formed by the polymeric particles. The organic components are then cured to form a substantially water-impermeable mass.

  19. Process for impregnating a concrete or cement body with a polymeric material

    DOEpatents

    Mattus, Alfred J.; Spence, Roger D.

    1989-01-01

    A process for impregnating cementitious solids with polymeric materials by blending polymeric materials in a grout, allowing the grout to cure, and contacting the resulting solidified grout containing the polymeric materials with an organic mixture containing a monomer, a cross-linking agent and a catalyst. The mixture dissolves the polymerized particles and forms a channel for distributing the monomer throughout the network formed by the polymeric particles. The organic components are then cured to form a substantially water-impermeable mass.

  20. Determination of some radionucluides and heavy elements concentrations in concrete raw materials

    NASA Astrophysics Data System (ADS)

    ElFaham, Mohamed M.; Khalil, Osama M.; Elhassan, Asmaa; Salama, S.

    2015-08-01

    The presence of natural radionuclides in raw materials used in cement manufacturing was determined by using analytical methods. The used Raw materials are limestone, clay, slag, and gypsum, which be used with different concentrations in cement production. Different analytical techniques such as Laser Induced Breakdown Spectroscopy (LIBS) technique, Gamma spectroscopy, Inductively Coupled Plasma (ICP) spectroscopy, X-ray fluorescence spectroscopy (XRF), in addition to X-Ray Diffraction (XRD) for phase identification of a crystalline material. The obtained data show that there is no significant radiological hazards arising from using the present cement components in the different applications. XRD data shows that there is no crystalline structures in the raw materials.

  1. The Impact of Coal Combustion Fly Ash Used as a Supplemental Cementitious Material on the Leaching of Constituents from Cements and Concretes

    EPA Science Inventory

    The objective of this report is to compare the leaching of portland cement-based materials that have been prepared with and without coal combustion fly ash to illustrate whether there is evidence that the use of fly ash in cement and concrete products may result in increased leac...

  2. The Impact of Coal Combustion Fly Ash Used as a Supplemental Cementitious Material on the Leaching of Constituents from Cements and Concretes

    EPA Science Inventory

    The objective of this report is to compare the leaching of portland cement-based materials that have been prepared with and without coal combustion fly ash to illustrate whether there is evidence that the use of fly ash in cement and concrete products may result in increased leac...

  3. Runway Incursion Prevention System Testing at the Wallops Flight Facility

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.

    2005-01-01

    A Runway Incursion Prevention System (RIPS) integrated with a Synthetic Vision System concept (SVS) was tested at the Reno/Tahoe International Airport (RNO) and Wallops Flight Facility (WAL) in the summer of 2004. RIPS provides enhanced surface situational awareness and alerts of runway conflicts in order to prevent runway incidents while also improving operational capability. A series of test runs was conducted using a Gulfstream-V (G-V) aircraft as the test platform and a NASA test aircraft and a NASA test van as incurring traffic. The purpose of the study, from the RIPS perspective, was to evaluate the RIPS airborne incursion detection algorithms and associated alerting and airport surface display concepts, focusing on crossing runway incursion scenarios. This paper gives an overview of the RIPS, WAL flight test activities, and WAL test results.

  4. Evaluation of a tritium runway-lighting system. Technical note

    SciTech Connect

    Katz, E.S.

    1992-04-01

    A tritium powered runway lighting system was installed and evaluated at the Federal Aviation Administration (FAA) Technical Center. The purpose of this evaluation was to determine if the tritium runway lighting system would safely support Federal Aviation Regulations (FAR) Part 135 commercial operations, during nighttime visual flight rules (VFR) conditions at remote airports. Subject pilots having flight experience levels appropriate for pilots conducting FAR Part 135 air taxi operations were afforded the opportunity of flight testing the system. Results of the evaluation indicate that the tritium runway lighting system does not meet all of the minimum criteria necessary for FAA approval and, therefore, would not guarantee an acceptable level of safety. Tritium Runway Lighting System, Remote Airports.

  5. Review Study on Runway Capacity Parameters and Improvement

    NASA Astrophysics Data System (ADS)

    Safrilah; Putra, J. C. P.

    2017-06-01

    The demand of air travel continues to increase over time, due to its short travel time, reliability and safety. Problems then arise when airport capacity, especially airside (mainly runway) capacity cannot cope with the demand. Some airports build the expensive additional infrastructure, while some others believe that manage on system is more efficient and effective. The study gathering information from various source about parameters related to runway capacity so that the improvement made in the future will solve right on target. To accommodate wide number of factors, the study classify the parameters into five categories in which operation/procedure related parameters play an important role (52%). To facilitate future research on runway capacity, the study also tabulates methods used by various scholars to improve runway capacity

  6. Nondestructive evaluation of frost heave effects on a runway

    NASA Astrophysics Data System (ADS)

    Lenngren, Carl A.

    1998-03-01

    An Airport located inland central Sweden is susceptible to frost heave. The runway is uneven especially at the end of each winter. The Swedish Road and Transportation Institute Laser Profiler was brought to the site in the spring of 1997 in order to study this seasonal effect. Several longitudinal profiles were sampled along the entire length of the runway. The test was then repeated in the fall when the runway had settled. The profiles were then investigated to see if certain criteria were fulfilled, like the International Civil Aviation Organization straightedge guideline. Several different wavelength intervals of unevenness were also examined. It was found that the frost heave affected certain wavelength bands more than others. It was also possible to determine exactly where the most troublesome spots were located and if they would adversely interfere with an expansion of the runway. Data from the profile could also serve as help in preparing guidelines for safety rules related to roughness.

  7. 13. Looking northwest from the 1937 main section runway toward ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Looking northwest from the 1937 main section runway toward cattle pens (first floor) and the catwalk (second floor) - Ewing Livestock Market, South side of First Avenue North, 500 feet west of Route 724, Ewing, Lee County, VA

  8. Lateral runway approach guidance using Loran-C

    NASA Technical Reports Server (NTRS)

    Simpson, R. W.

    1983-01-01

    The design and flight test of a lateral guidance system for flying approaches to a runway by general aviation aircraft are examined. The issue is whether or not good dynamic response can be obtained by exploiting the repeatable accuracy of Loran-C position data and combining it with heading rate data. The pilot needs cross pointer displays so he can keep the aircraft within approx. 75 feet of the runway centerline at approach speeds typical of general aviation aircraft.

  9. Establishment and Discontinuance Criteria for Runway Visual Range (RVR) at Category I Precision Landing System Runway

    DTIC Science & Technology

    1987-01-01

    System 1W, . . . .7 11-2 Default Runw.a . . ...... 7 III-i Marginal Life. Category I PrEr 12 Tv-i RVR Reporting -. 13 IV-2 Comparison of Values ... 15 ...System at the first two Category I precision instrumented runways at an airport over an economic life-cycle of 15 years. Based on this analysis...is an important variable for most benefits and costs. Benefits and costs are computed for each of 15 years, discounted to present value at the 10

  10. Monte carlo simulation of innovative neutron and photon shielding material composing of high density concrete, waste rubber, lead and boron carbide

    NASA Astrophysics Data System (ADS)

    Aim-O, P.; Wongsawaeng, D.; Phruksarojanakun, P.; Tancharakorn, S.

    2017-06-01

    High-density concrete exhibits high strength and can perform an important role of gamma ray attenuation. In order to upgrade this material’s radiation-shielding performance, hydrogen-rich material can be incorporated. Waste rubber from vehicles has high hydrogen content which is the prominent characteristic to attenuate neutron. The objective of this work was to evaluate the radiation-shielding properties of this composite material against neutron and photon radiations. Monte Carlo transport simulation was conducted to simulate radiation through the composite material. Am-241/Be was utilized for neutron source and Co-60 for photon source. Parameters of the study included volume percentages of waste rubber, lead and boron carbide and thickness of the shielding material. These designs were also fabricated and the radiation shielding properties were experimentally evaluated. The best neutron and gamma ray shielding material was determined to be high-density concrete mixed with 5 vol% crumb rubber and 5 vol% lead powder. This shielding material increased the neutron attenuation by 64% and photon attenuation by 68% compared to ordinary concrete. Also, increasing the waste rubber content to greater than 5% resulted in a decrease in the radiation attenuation. This innovative composite radiation shielding material not only benefits nuclear science and engineering applications, but also helps solve the environmental issue of waste rubber.

  11. STS-70 Discovery approaches Runway 33

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Space Shuttle orbiter Discovery approaches KSC's Runway 33, with the Vehicle Assembly Building in the background, marking a successful conclusion to the STS-70 mission. Discovery landed on orbit 143, during the second opportunity of the day. Main gear touchdown was unofficially listed at 8:02 a.m. EDT on July 22, 1995. The orbiter traveled some 3.7 million statute miles during the nearly nine-day flight, which included a one-day extension because of fog and low visibility conditions at the KSC Shuttle Landing Facility. STS-70 was the 24th Shuttle landing at KSC and the 70th Space Shuttle mission. The five-member crew deployed the NASA Tracking and Data Relay Satellite-G (TDRS-G). Crew members were Commander Terence 'Tom' Henricks, Pilot Kevin R. Kregel, and Mission Specialists Nancy Jane Currie, Donald A. Thomas and Mary Ellen Weber. STS-70 also was the maiden flight of the new Block 1 orbiter main engine, which flew in the number one position. The other two engines were of the existing Phase II design.

  12. Developing an Innovative Field Expedient Fracture Toughness Testing Protocol for Concrete Materials

    SciTech Connect

    Wang, Jy-An John; Liu, Ken C; Naus, Dan J

    2008-09-01

    The Spiral Notch Torsion Fracture Toughness Test (SNTT) was developed recently to determine the intrinsic fracture toughness (KIC) of structural materials. The SNTT system operates by applying pure torsion to uniform cylindrical specimens with a notch line that spirals around the specimen at a 45 pitch. KIC values are obtained with the aid of a three-dimensional finite-element computer code, TOR3D-KIC. The SNTT method is uniquely suitable for testing a wide variety of materials used extensively in pressure vessel and piping structural components and weldments. Application of the method to metallic, ceramic, and graphite materials has been demonstrated. One important characteristic of SNTT is that neither a fatigue precrack or a deep notch are required for the evaluation of brittle materials, which significantly reduces the sample size requirement. In this paper we report results for a Portland cement-based mortar to demonstrate applicability of the SNTT method to cementitious materials. The estimated KIC of the tested mortar samples with compressive strength of 34.45 MPa was found to be 0.19 MPa m.

  13. Tungsten - Tungsten Trioxide Electrodes for the Long-term Monitoring of Corrosion Processes in Highly Alkaline Media and Concrete-based Materials.

    PubMed

    Kolar, Mitja; Doliška, Aleš; Svegl, Franc; Kalcher, Kurt

    2010-12-01

    The determination of pH in highly alkaline solutions and concrete materials is extremely important for monitoring or predicting the corrosion processes of reinforced concrete structures and to follow the hydration process of Portland cement, fly-ash, micro silica and other materials used in concrete manufacturing. The corrosion of reinforced concrete structures and the hydration of pozzolanic materials are long-term processes, which means, that appropriate durable, and resilient pH electrodes are needed, for direct implantation regarding solid concrete bodies. The purpose of this work was to characterise the potentiometric and surface properties of tungsten electrodes after exposure to extreme alkaline solutions. The tungsten wire surface was activated at 800 °C for 30 min within an oxygen flow. The formation of homogenous and compact multiple layers of WO3 crystals was observed using X-ray diffraction and scanning electron microscopy. X-ray diffraction of those tungsten electrodes exposed to saturated calcium hydroxide solution or the pore-water of cement-based materials during 10 months, indicated partly dissolved WO3. Two new compounds appeared on the electrodes surfaces; pure tungsten and CaWO4. The presence of tungsten was affecting any potentiometric response in acidic pH region (2-5) but in pH 5-12 region the response still remained linear with a slope of 42 ± 2 mV/pH unit. The W/WO3 electrode was suitable for the long-term monitoring of corrosion processes in concrete-based materials according to the pH changes as it has stable and repeatable responses to alkaline solutions (pH > 12). All the tested interferring ions had no significant influence on electrode potential. The W/WO3 electrode is simple, robust, inexpensive, and temperature resistant and can be applied in potentiometric titrations as well as in batch and flow-injection analysis. The prepared electrode is a highly promising pH sensor for the monitoring of pH changes in highly alkaline capillary

  14. Innovative hyperspectral imaging (HSI) based techniques applied to end-of-life concrete drill core characterization for optimal dismantling and materials recovery

    NASA Astrophysics Data System (ADS)

    Bonifazi, Giuseppe; Picone, Nicoletta; Serranti, Silvia

    2015-02-01

    The reduction of EOL concrete disposal in landfills, together with a lower exploitation of primary raw materials, generates a strong interest to develop, set-up and apply innovative technologies to maximize Construction and Demolition Waste (C&DW) conversion into useful secondary raw materials. Such a goal can be reached starting from a punctual in-situ efficient characterization of the objects to dismantle in order to develop demolition actions aimed to set up innovative mechanical-physical processes to recover the different materials and products to recycle. In this paper an innovative recycling-oriented characterization strategy based on HyperSpectral Imaging (HSI) is described in order to identify aggregates and mortar in drill core samples from end-of-life concrete. To reach this goal, concrete drill cores from a demolition site were systematically investigated by HSI in the short wave infrared field (1000-2500 nm). Results obtained by the adoption of the HSI approach showed as this technology can be successfully applied to analyze quality and characteristics of C&DW before dismantling and as final product to reutilise after demolition-milling-classification actions. The proposed technique and the related recognition logics, through the spectral signature detection of finite physical domains (i.e. concrete slice and/or particle) of different nature and composition, allows; i) to develop characterization procedures able to quantitatively assess end-of-life concrete compositional/textural characteristics and ii) to set up innovative sorting strategies to qualify the different materials constituting drill core samples.

  15. Aircraft and ground vehicle friction correlation test results obtained under winter runway conditions during joint FAA/NASA Runway Friction Program

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.; Vogler, William A.; Baldasare, Paul

    1988-01-01

    Aircraft and ground vehicle friction data collected during the Joint FAA/NASA Runway Friction Program under winter runway conditions are discussed and test results are summarized. The relationship between the different ground vehicle friction measurements obtained on compacted snow- and ice-covered conditions is defined together with the correlation to aircraft tire friction performance under similar runway conditions.

  16. Space Shuttle Columbia touches down on Runway 33

    NASA Technical Reports Server (NTRS)

    1997-01-01

    KENNEDY SPACE CENTER, FLA. -- The Space Shuttle Columbia touches down on Runway 33 at KSC''';s Shuttle Landing Facility at 2:33:11 p.m. EDT, April 8, to conclude the Microgravity Science Laboratory-1 (MSL-1) mission. At main gear touchdown, the STS-83 mission duration was 3 days, 23 hours, 12 minutes. The planned 16-day mission was cut short by a faulty fuel cell. This is only the third time in Shuttle program history that an orbiter was brought home early due to mechanical problems. This was also the 36th KSC landing since the program began in 1981. Mission Commander James D. Halsell, Jr. flew Columbia to a perfect landing with help from Pilot Susan L. Still. Other crew members are Payload Commander Janice E. Voss; Mission Specialists Michael L. Gernhardt and Donald A. Thomas; and Payload Specialists Roger K. Crouch and Gregory T. Linteris. In spite of the abbreviated flight, the crew was able to perform MSL-1 experiments. The Spacelab-module-based experiments were used to test some of the hardware, facilities and procedures that are planned for use on the International Space Station and to conduct combustion, protein crystal growth and materials processing investigations.

  17. Space Shuttle Columbia prepares to touch down on Runway 33

    NASA Technical Reports Server (NTRS)

    1997-01-01

    KENNEDY SPACE CENTER, FLA. -- The Space Shuttle Columbia prepares to touch down on Runway 33 at KSC''';s Shuttle Landing Facility at approximately 2:33 p.m. EDT, April 8, to conclude the Microgravity Science Laboratory-1 (MSL-1) mission. At main gear touchdown, the STS-83 mission duration will be just under four days. The planned 16-day mission was cut short by a faulty fuel cell. This is only the third time in Shuttle program history that an orbiter was brought home early due to mechanical problems. This was also the 36th KSC landing since the program began in 1981. Mission Commander James D. Halsell, Jr. flew Columbia to a perfect landing with help from Pilot Susan L. Still. Other crew members are Payload Commander Janice E. Voss; Mission Specialists Michael L.Gernhardt and Donald A. Thomas; and Payload Specialists Roger K. Crouch and Gregory T. Linteris. In spite of the abbreviated flight, the crew was able to perform MSL-1 experiments. The Spacelab-module-based experiments were used to test some of the hardware, facilities and procedures that are planned for use on the International Space Station and to conduct combustion, protein crystal growth and materials processing investigations.

  18. Space Shuttle Columbia touches down on Runway 33

    NASA Technical Reports Server (NTRS)

    1997-01-01

    KENNEDY SPACE CENTER, FLA. -- The Space Shuttle Columbia touches down on Runway 33 at KSC''';s Shuttle Landing Facility at 2:33:11 p.m. EDT, April 8, to conclude the Microgravity Science Laboratory-1 (MSL-1) mission. At main gear touchdown, the STS-83 mission duration was 3 days, 23 hours, 12 minutes. The planned 16-day mission was cut short by a faulty fuel cell. This is only the third time in Shuttle program history that an orbiter was brought home early due to mechanical problems. This was also the 36th KSC landing since the program began in 1981. Mission Commander James D. Halsell, Jr. flew Columbia to a perfect landing with help from Pilot Susan L. Still. Other crew members are Payload Commander Janice E. Voss; Mission Specialists Michael L. Gernhardt and Donald A. Thomas; and Payload Specialists Roger K. Crouch and Gregory T. Linteris. In spite of the abbreviated flight, the crew was able to perform MSL-1 experiments. The Spacelab-module-based experiments were used to test some of the hardware, facilities and procedures that are planned for use on the International Space Station and to conduct combustion, protein crystal growth and materials processing investigations.

  19. STS-94 Columbia Landing at KSC (South Runway)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Space Shuttle orbiter Columbia touches down on Runway 33 at KSCs Shuttle Landing Facility at 6:46:34 a.m. EDT with Mission Commander James D. Halsell Jr. and Pilot Susan L. Still at the controls to complete the STS-94 mission. Also on board are Mission Specialist Donald A. Thomas, Mission Specialist Michael L. Gernhardt, Payload Commander Janice Voss, and Payload Specialists Roger K. Crouch and Gregory T. Linteris. During the Microgravity Science Laboratory-1 (MSL-1) mission, the Spacelab module was used to test some of the hardware, facilities and procedures that are planned for use on the International Space Station while the flight crew conducted combustion, protein crystal growth and materials processing experiments. This mission was a reflight of the STS-83 mission that lifted off from KSC in April of this year. That space flight was cut short due to indications of a faulty fuel cell. This was Columbias 11th landing at KSC and the 38th landing at the space center in the history of the Shuttle program.

  20. Space Shuttle Columbia prepares to touch down on Runway 33

    NASA Technical Reports Server (NTRS)

    1997-01-01

    KENNEDY SPACE CENTER, FLA. -- The Space Shuttle Columbia prepares to touch down on Runway 33 at KSC''';s Shuttle Landing Facility at approximately 2:33 p.m. EDT, April 8, to conclude the Microgravity Science Laboratory-1 (MSL-1) mission. At main gear touchdown, the STS-83 mission duration will be just under four days. The planned 16-day mission was cut short by a faulty fuel cell. This is only the third time in Shuttle program history that an orbiter was brought home early due to mechanical problems. This was also the 36th KSC landing since the program began in 1981. Mission Commander James D. Halsell, Jr. flew Columbia to a perfect landing with help from Pilot Susan L. Still. Other crew members are Payload Commander Janice E. Voss; Mission Specialists Michael L.Gernhardt and Donald A. Thomas; and Payload Specialists Roger K. Crouch and Gregory T. Linteris. In spite of the abbreviated flight, the crew was able to perform MSL-1 experiments. The Spacelab-module-based experiments were used to test some of the hardware, facilities and procedures that are planned for use on the International Space Station and to conduct combustion, protein crystal growth and materials processing investigations.

  1. STS-94 Columbia Landing at KSC (South Runway)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Space Shuttle orbiter Columbia touches down on Runway 33 at KSCs Shuttle Landing Facility at 6:46:34 a.m. EDT with Mission Commander James D. Halsell Jr. and Pilot Susan L. Still at the controls to complete the STS-94 mission. Also on board are Mission Specialist Donald A. Thomas, Mission Specialist Michael L. Gernhardt, Payload Commander Janice Voss, and Payload Specialists Roger K. Crouch and Gregory T. Linteris. During the Microgravity Science Laboratory-1 (MSL-1) mission, the Spacelab module was used to test some of the hardware, facilities and procedures that are planned for use on the International Space Station while the flight crew conducted combustion, protein crystal growth and materials processing experiments. This mission was a reflight of the STS-83 mission that lifted off from KSC in April of this year. That space flight was cut short due to indications of a faulty fuel cell. This was Columbias 11th landing at KSC and the 38th landing at the space center in the history of the Shuttle program.

  2. The Concrete and Pavement Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

  3. The Concrete and Pavement Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

  4. Concrete density estimation by rebound hammer method

    NASA Astrophysics Data System (ADS)

    Ismail, Mohamad Pauzi bin; Jefri, Muhamad Hafizie Bin; Abdullah, Mahadzir Bin; Masenwat, Noor Azreen bin; Sani, Suhairy bin; Mohd, Shukri; Isa, Nasharuddin bin; Mahmud, Mohamad Haniza bin

    2016-01-01

    Concrete is the most common and cheap material for radiation shielding. Compressive strength is the main parameter checked for determining concrete quality. However, for shielding purposes density is the parameter that needs to be considered. X- and -gamma radiations are effectively absorbed by a material with high atomic number and high density such as concrete. The high strength normally implies to higher density in concrete but this is not always true. This paper explains and discusses the correlation between rebound hammer testing and density for concrete containing hematite aggregates. A comparison is also made with normal concrete i.e. concrete containing crushed granite.

  5. Concrete density estimation by rebound hammer method

    SciTech Connect

    Ismail, Mohamad Pauzi bin Masenwat, Noor Azreen bin; Sani, Suhairy bin; Mohd, Shukri; Jefri, Muhamad Hafizie Bin; Abdullah, Mahadzir Bin; Isa, Nasharuddin bin; Mahmud, Mohamad Haniza bin

    2016-01-22

    Concrete is the most common and cheap material for radiation shielding. Compressive strength is the main parameter checked for determining concrete quality. However, for shielding purposes density is the parameter that needs to be considered. X- and -gamma radiations are effectively absorbed by a material with high atomic number and high density such as concrete. The high strength normally implies to higher density in concrete but this is not always true. This paper explains and discusses the correlation between rebound hammer testing and density for concrete containing hematite aggregates. A comparison is also made with normal concrete i.e. concrete containing crushed granite.

  6. Environmental impact of highway construction and repair materials on surface and ground waters. Case study: crumb rubber asphalt concrete.

    PubMed

    Azizian, Mohammad F; Nelson, Peter O; Thayumanavan, Pugazhendhi; Williamson, Kenneth J

    2003-01-01

    The practice of incorporating certain waste products into highway construction and repair materials (CRMs) has become more popular. These practices have prompted the National Academy of Science, National Cooperative Highway Research Program (NCHRP) to research the possible impacts of these CRMs on the quality of surface and ground waters. State department of transportations (DOTs) are currently experimenting with use of ground tire rubber ( crumb rubber) in bituminous construction and as a crack sealer. Crumb rubber asphalt concrete (CR-AC) leachates contain a mixture of organic and metallic contaminants. Benzothiazole and 2(3H)-benzothiazolone (organic compounds used in tire rubber manufacturing) and the metals mercury and aluminum were leached in potentially harmful concentrations (exceeding toxic concentrations for aquatic toxicity tests). CR-AC leachate exhibited moderate to high toxicity for algae ( Selenastrum capriconutum) and moderate toxicity for water fleas ( Daphnia magna). Benzothiazole was readily removed from CR-AC leachate by the environmental processes of soil sorption, volatilization, and biodegradation. Metals, which do not volatilize or photochemically or biologically degrade, were removed from the leachate by soil sorption. Contaminants from CR-AC leachates are thus degraded or retarded in their transport through nearby soils and ground waters.

  7. PIXE/RBS as a tool to study cementitious materials: Application to the dynamic leaching of concrete

    NASA Astrophysics Data System (ADS)

    Llorente, I.; Castellote, M.; Gonzalez-Arrabal, R.; Ynsa, M. D.; Muñoz-Martin, A.; de Viedma, P. G.; Castillo, A.; Martínez, I.; Andrade, C.; Zuloaga, P.; Ordoñez, M.

    2009-12-01

    The suitability of the application of Ion Beam Analysis (IBA) techniques such as Particle Induced X-ray Emission spectrometry (PIXE) and Rutherford Backscattering Spectrometry (RBS) to elemental depth profiling in concrete is analysed, studying hardened samples of concrete prior to and after a dynamic leaching test. A calibration of the data has been done by comparing the results obtained by IBA techniques with those obtained by Chemical and Thermogravimetric Analysis (TG/DTA). From PIXE and RBS data relevant information about the migration of minor elements, within the concrete matrix after leaching is obtained.

  8. Human risk factors associated with pilots in runway excursions.

    PubMed

    Chang, Yu-Hern; Yang, Hui-Hua; Hsiao, Yu-Jung

    2016-09-01

    A breakdown analysis of civil aviation accidents worldwide indicates that the occurrence of runway excursions represents the largest portion among all aviation occurrence categories. This study examines the human risk factors associated with pilots in runway excursions, by applying a SHELLO model to categorize the human risk factors and to evaluate the importance based on the opinions of 145 airline pilots. This study integrates aviation management level expert opinions on relative weighting and improvement-achievability in order to develop four kinds of priority risk management strategies for airline pilots to reduce runway excursions. The empirical study based on experts' evaluation suggests that the most important dimension is the liveware/pilot's core ability. From the perspective of front-line pilots, the most important risk factors are the environment, wet/containment runways, and weather issues like rain/thunderstorms. Finally, this study develops practical strategies for helping management authorities to improve major operational and managerial weaknesses so as to reduce the human risks related to runway excursions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Performance of Waterless Concrete

    NASA Technical Reports Server (NTRS)

    Toutanji, Houssam; Evans, Steve; Grugel, Richard N.

    2010-01-01

    The development of permanent lunar bases is constrained by performance of construction materials and availability of in-situ resources. Concrete seems a suitable construction material for the lunar environment, but water, one of its major components, is an extremely scarce resource on the Moon. This study explores an alternative to hydraulic concrete by replacing the binding mix of concrete (cement and water) with sulfur. Sulfur is a volatile element on the lunar surface that can be extracted from lunar soils by heating. Sulfur concrete mixes were prepared to investigate the effect of extreme environmental conditions on the properties of sulfur concrete. A hypervelocity impact test was conducted, having as its target a 5-cm cubic sample of sulfur concrete. This item consisted of JSC-1 lunar regolith simulant (65%) and sulfur (35%). The sample was placed in the MSFC Impact Test Facility s Micro Light Gas Gun target chamber, and was struck by a 1-mm diameter (1.4e-03 g) aluminum projectile at 5.85 km/s. In addition, HZTERN code, provided by NASA was used to study the effectiveness of sulfur concrete when subjected to space radiation.

  10. Refractory concretes

    DOEpatents

    Holcombe, Jr., Cressie E.

    1979-01-01

    Novel concrete compositions comprise particles of aggregate material embedded in a cement matrix, said cement matrix produced by contacting an oxide selected from the group of Y.sub.2 O.sub.3, La.sub.2 O.sub.3, Nd.sub.2 O.sub.3, Sm.sub.2 O.sub.3, Eu.sub.2 O.sub.3 and Gd.sub.2 O.sub.3 with an aqueous solution of a salt selected from the group of NH.sub.4 NO.sub.3, NH.sub.4 Cl, YCl.sub.3 and Mg(NO.sub.3).sub.2 to form a fluid mixture; and allowing the fluid mixture to harden.

  11. Measurement of tritium penetration through concrete material covered by various paints coating

    SciTech Connect

    Edao, Y.; Kawamura, Y.; Kurata, R.; Hayashi, T.; Yamanishi, T.; Fukada, S.; Takeishi, T.

    2015-03-15

    The present study aims at obtaining fundamental data on tritium migration in porous materials, which include soaking effect, interaction between tritium and cement paste coated with paints and transient tritium sorption in porous cement. The amounts of tritium penetrated into or released from cement paste with epoxy and urethane paint coatings were measured. The tritium penetration amounts were increased with the HTO (tritiated water) exposure time. Time to achieve a saturated value of tritium sorption was more than 60 days for cement paste coated with epoxy paint and with urethane paint, while that for cement paste without any paint coating took 2 days to achieve it. The effect of tritium permeation reduction by the epoxy paint was higher than that of the urethane. Although their paint coatings were effective for reduction of tritium penetration through the cement paste which was exposed to HTO for a short period, it was found that the amount of tritium trapped in the paints became large for a long period. Tritium penetration rates were estimated by an analysis of one-dimensional diffusion in the axial direction of a thickness of a sample. Obtained data were helpful for evaluation of tritium contamination and decontamination. (authors)

  12. Lightweight polymer concrete composites

    SciTech Connect

    Fontana, J.J.; Steinberg, M.; Reams, W.

    1985-08-01

    Lightweight polymer concrete composites have been developed with excellent insulating properties. The composites consist of lightweight aggregates such as expanded perlites, multicellular glass nodules, or hollow alumina silicate microspheres bound together with unsaturated polyester or epoxy resins. These composites, known as Insulating Polymer Concrete (IPC), have thermal conductivites from 0.09 to 0.19 Btu/h-ft-/sup 0/F. Compressive strengths, dependent upon the aggregates used, range from 1000 to 6000 psi. These materials can be precast or cast-in-place on concrete substrates. Recently, it has been demonstrated that these materials can also be sprayed onto concrete and other substrates. An overlay application of IPC is currently under way as dike insulation at an LNG storage tank facility. The composites have numerous potentials in the construction industry such as insulating building blocks or prefabricated insulating wall panels.

  13. Effect of different runway sizes on pilot performance during simulated night landing approaches.

    PubMed

    Mertens, H W; Lewis, M F

    1982-05-01

    Both anecdotal reports from pilots and theories of visual cues would predict lower approaches to narrow or long runways than to wide and short runways. Similar, practice approaches made by pilots to a particular width of runway should lead to an increase in subsequent approach angles flown to wider runways and a decrease in approach angles flown to narrower runways. Two experiments with instrument-rated pilots made quantitative tests and these predictions. In Experiment I, three pilots flew simulated approaches and landings in a fixed-base simulator with a computer-generated image visual display. Practice approaches were flown with an 8,000-ft long runway that was either 75, 150, or 300 ft wide; test approaches were to runways with widths or 75, 100, 150, 200, and 300 ft. In Experiment II, 40 pilots controlled the slant of a moving model runway during simulated night visual approaches. Five different models simulated runways from 100 to 300 ft wide and 3,000 to 9,000 ft long. As predicted, training on a wide runway in Experiment I lowered approach angle in approaches to narrower runways; a narrow practice runway also raised approach angles to wider runways. The magnitude of these practice effects increased as distance from runway threshold decreased. There was also a general tendency for approach angles to decrease as runway width decreased. The latter effect was corroborated in Experiment II; in addition, generated approach angles decreased with increasing runway length. Giving half the pilots information about runway size prior to each approach had no effect on responses. These findings add to the quantitative evidence of danger in night visual approaches due to visual illusions and large variability in the visual perception of approach angle.

  14. Aircraft and Ground Vehicle Winter Runway Friction Assessment

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1999-01-01

    Some background information is given together with the scope and objectives of a 5-year, Joint Winter Runway Friction Measurement Program between the National Aeronautics & Space Administration (NASA), Transport Canada (TC), and the Federal Aviation Administration (FAA). The primary objective of this effort is to perform instrumented aircraft and ground vehicle tests aimed at identifying a common number that all the different ground vehicle devices would report. This number, denoted the International Runway Friction Index (IRFI), will be related to all types of aircraft stopping performance. The range of test equipment, the test sites, test results and accomplishments, the extent of the substantial friction database compiled, and future test plans will be described. Several related studies have also been implemented including the effects of contaminant type on aircraft impingement drag, and the effectiveness of various runway and aircraft de-icing chemical types, and application rates.

  15. A Runway Surface Monitor using Internet of Things

    NASA Astrophysics Data System (ADS)

    Troiano, Amedeo; Pasero, Eros

    2014-05-01

    The monitoring of runway surfaces, for the detection of ice formation or presence of water, is an important issue for reducing maintenance costs and improving traffic safety. An innovative sensor was developed to detect the presence of ice or water on its surface, and its repeatability, stability and reliability were assessed in different simulations and experiments, performed both in laboratory and in the field. Three sensors were embedded in the runway of the Turin-Caselle airport, in the north-west of Italy, to check the state of its surface. Each sensor was connected to a GPRS modem to send the collected data to a common database. The entire system was installed about three years ago, and up to now it shows correct work and automatic reactivation after malfunctions without any external help. The state of the runway surface is virtual represented in an internet website, using the Internet of Things features and opening new scenarios.

  16. Marking and Lighting of Unpaved Runways - Inservice Testing,

    DTIC Science & Technology

    1984-03-01

    I Cessna 150 3 Cessna 172 2 Piper PA28 2 Homebuilt 2 Twin engine, fixed gear: Islander 1 Question 8. Is your aircraft based at this field? Responses A...Runwav Aignmen *Go-Aroirnd Markers (Yellow and a If aircraft is no firmly on runway at this point I (1/3 of runway),. Right Hand Pattern pilot should...territory, with obstacles, it’s really great to have a visual indication for a safe glide. 2. Do not feel POMOLA is necessary with small aircraft

  17. Aluminum runway surface as possible aid to aircraft braking

    NASA Technical Reports Server (NTRS)

    Miller, C. D.; Pinkel, I. I.

    1973-01-01

    Several concepts are described for use singly or in combination to improve aircraft braking. All involve a thin layer of aluminum covering all or part of the runway. Advantage would derive from faster heat conduction from the tire-runway interface. Heating of tread surface with consequent softening and loss of friction coefficient should be reduced. Equations are developed indicating that at least 99 percent of friction heat should flow into the aluminum. Preliminary test results indicate a coefficient of sliding friction of 1.4, with predictably slight heating of tread. Elimination of conventional brakes is at least a remote possibility.

  18. Black Box Testing: Experiments with Runway Incursion Advisory Alerting System

    NASA Technical Reports Server (NTRS)

    Mukkamala, Ravi

    2005-01-01

    This report summarizes our research findings on the Black box testing of Runway Incursion Advisory Alerting System (RIAAS) and Runway Safety Monitor (RSM) system. Developing automated testing software for such systems has been a problem because of the extensive information that has to be processed. Customized software solutions have been proposed. However, they are time consuming to develop. Here, we present a less expensive, and a more general test platform that is capable of performing complete black box testing. The technique is based on the classification of the anomalies that arise during Monte Carlo simulations. In addition, we also discuss a generalized testing tool (prototype) that we have developed.

  19. Runway width effects in the visual approach to landing.

    PubMed

    Galanis, G; Jennings, A; Beckett, P

    2001-01-01

    The effect of changes in runway width on the perception of glide-slope has been the subject of extensive investigations. Despite considerable research, an explanation of this effect has been elusive. A mathematical model for glide-slope perception was published recently based on the premise that a desirable goal of perception is to form a perception with minimal uncertainty. One of the qualitative predictions of that model was that changes in the aspect ratio of the runway would affect the perceived glide-slope. In this article, the predictions of the model are quantified and are shown to be in close agreement with experimental results in the literature.

  20. The effect of shoe material on the kinetics and kinematics of foot slip at impact on concrete.

    PubMed

    Pardoe, C H; McGuigan, M P; Rogers, K M; Rowe, L L; Wilson, A M

    2001-04-01

    Previous studies on shoeing have demonstrated that shoe material alters the time taken from foot impact to the foot stopping sliding (slip time) and the distance slid. These are assumed to reflect differences in the craniocaudal ground reaction force (GRF) between the shoe and the ground during foot slip. This study tested the hypothesis that the slip time and distance are reflected in the resistance to slippage of the foot after impact. The forefeet of 8 horses were shod in horseshoes constructed of steel, plastic and rubber. Each horse was trotted for 8 placements per forefoot in each shoe type over a concrete topped forceplate and simultaneous kinematic data recorded at 240 Hz. Slip distance and slip time were calculated from the kinematic data and craniocaudal (Fy), and vertical (Fz) GRFs determined during slip the averaged for each shoe type. The slip time and distance were variable between runs in all 3 shoe types, and there was no significant difference between the mean values for the 3 shoe types. Fy reached a value of 0.98 +/- 0.17 N/kg during slip in the plastic shoes which was significantly lower than the rubber shoes, at 1.13 +/- 0.17 N/kg, P = 0.02. The Fy/Fz ratio (a measure of dynamic friction) was significantly lower in the plastic shoes, 0.34 +/- 0.08, compared to the steel shoes, 0.46 +/- 0.04, P = 0.003. This study is being extended to investigate effects of shoe slippage at the end of the stance phase and the energy dissipation during foot slip in the different shoe types. Future investigations should aim to identify the optimum slip characteristics to modulate loading (magnitude and rate) during impact, with the aim of reducing the risk of injury.

  1. Changes in the Albedo of the Pegasus and Phoenix Runways, 2000-2017

    DTIC Science & Technology

    2017-07-18

    of the snow and ice layers that composed the runway, lead- ing to extended shutdowns. In addition, during short warming trends that caused temporary...was slightly colder and stronger. Longer warming trends led to the presence of liquid water on the runway surface, which significantly lowered the...fraction of pixel n that overlaps the runway; and p = the subset of pixels for each individual runway that are cloud - free, high-quality data. Data

  2. Material Performance and Animal Clinical Studies on Performance-Optimized Hwangtoh Mixed Mortar and Concrete to Evaluate Their Mechanical Properties and Health Benefits.

    PubMed

    Koo, Bon-Min; Kim, Jang-Ho Jay; Kim, Tae-Kyun; Kim, Byung-Yun

    2015-09-17

    In this study, the amount of cement used in a concrete mix is minimized to reduce the toxic effects on users by adjusting the concrete mixture contents. The reduction of cement is achieved by using various admixtures (ground granulated blast-furnace slag, flyash, ordinary Portland cement, and activated Hwangtoh powder). To apply the mix to construction, material property tests such as compressive strength, slump, and pH are performed. Preliminary experimental results showed that the Hwangtoh concrete could be used as a healthy construction material. Also, the health issues and effects of Hwangtoh mortar are quantitatively evaluated through an animal clinical test. Mice are placed in Hwangtoh mortar and cement mortar cages to record their activity. For the test, five cages are made with Hwangtoh and ordinary Portland cement mortar floors, using Hwangtoh powder replacement ratios of 20%, 40%, 60%, and 80% of the normal cement mortar mixing ratio, and two cages are made with Hwangtoh mortar living quarters. The activity parameter measurements included weight, food intake, water intake, residential space selection, breeding activity, and aggression. The study results can be used to evaluate the benefits of using Hwangtoh as a cement replacing admixture for lifestyle, health and sustainability.

  3. Material Performance and Animal Clinical Studies on Performance-Optimized Hwangtoh Mixed Mortar and Concrete to Evaluate Their Mechanical Properties and Health Benefits

    PubMed Central

    Koo, Bon-Min; Kim, Jang-Ho Jay; Kim, Tae-Kyun; Kim, Byung-Yun

    2015-01-01

    In this study, the amount of cement used in a concrete mix is minimized to reduce the toxic effects on users by adjusting the concrete mixture contents. The reduction of cement is achieved by using various admixtures (ground granulated blast-furnace slag, flyash, ordinary Portland cement, and activated Hwangtoh powder). To apply the mix to construction, material property tests such as compressive strength, slump, and pH are performed. Preliminary experimental results showed that the Hwangtoh concrete could be used as a healthy construction material. Also, the health issues and effects of Hwangtoh mortar are quantitatively evaluated through an animal clinical test. Mice are placed in Hwangtoh mortar and cement mortar cages to record their activity. For the test, five cages are made with Hwangtoh and ordinary Portland cement mortar floors, using Hwangtoh powder replacement ratios of 20%, 40%, 60%, and 80% of the normal cement mortar mixing ratio, and two cages are made with Hwangtoh mortar living quarters. The activity parameter measurements included weight, food intake, water intake, residential space selection, breeding activity, and aggression. The study results can be used to evaluate the benefits of using Hwangtoh as a cement replacing admixture for lifestyle, health and sustainability. PMID:28793563

  4. Shuttle Challenger landing on Runway 17 at Edwards at end of 51-B mission

    NASA Image and Video Library

    1985-05-06

    Shuttle Challenger lands on Runway 17 at Edwards at end of 51-B mission. The photo is a rear view of the shuttle landing gear touching the runway, with clouds of dirt trailing behind it. The nose gear is still in the air (071); Side view of the Challenger landing gear touching the runway (072).

  5. Shuttle Challenger landing on Runway 17 at Edwards at end of 51-B mission

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Shuttle Challenger lands on Runway 17 at Edwards at end of 51-B mission. The photo is a rear view of the shuttle landing gear touching the runway, with clouds of dirt trailing behind it. The nose gear is still in the air (071); Side view of the Challenger landing gear touching the runway (072).

  6. Measures to increase airfield capacity by changing aircraft runway occupancy characteristics

    NASA Technical Reports Server (NTRS)

    Gosling, G. D.; Kanafani, A.; Rockaday, S. L. M.

    1981-01-01

    Airfield capacity and aircraft runway occupancy characteristics were studied. Factors that caused runway congestion and airfield crowding were identified. Several innovations designed to alleviate the congestion are discussed. Integrated landing management, the concept that the operation of the final approach and runway should be considered in concert, was identified as underlying all of the innovations.

  7. 76 FR 67018 - Notice to Manufacturers of Airport In-Pavement Stationary Runway Weather Information Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... Federal Aviation Administration Notice to Manufacturers of Airport In-Pavement Stationary Runway Weather... of In-Pavement Stationary Runway Weather Information Systems. SUMMARY: Projects funded under the... Active or Passive In- Pavement Stationary Runway Weather Information Systems that meet the requirements...

  8. Parallel runway requirement analysis study. Volume 2: Simulation manual

    NASA Technical Reports Server (NTRS)

    Ebrahimi, Yaghoob S.; Chun, Ken S.

    1993-01-01

    This document is a user manual for operating the PLAND_BLUNDER (PLB) simulation program. This simulation is based on two aircraft approaching parallel runways independently and using parallel Instrument Landing System (ILS) equipment during Instrument Meteorological Conditions (IMC). If an aircraft should deviate from its assigned localizer course toward the opposite runway, this constitutes a blunder which could endanger the aircraft on the adjacent path. The worst case scenario would be if the blundering aircraft were unable to recover and continue toward the adjacent runway. PLAND_BLUNDER is a Monte Carlo-type simulation which employs the events and aircraft positioning during such a blunder situation. The model simulates two aircraft performing parallel ILS approaches using Instrument Flight Rules (IFR) or visual procedures. PLB uses a simple movement model and control law in three dimensions (X, Y, Z). The parameters of the simulation inputs and outputs are defined in this document along with a sample of the statistical analysis. This document is the second volume of a two volume set. Volume 1 is a description of the application of the PLB to the analysis of close parallel runway operations.

  9. General view of runway 33 at the Kennedy Space Center ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of runway 33 at the Kennedy Space Center looking at the ground support equipment and the aft and starboard side of the Orbiter Discovery as the orbiter is undergoing post flight processing and preparations to be towed to the Orbiter Processing Facility. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  10. General view of runway 33 at the Kennedy Space Center ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of runway 33 at the Kennedy Space Center looking at the ground support equipment and the port side of the Orbiter Discovery as the orbiter is undergoing post flight processing and preparations to be towed to the Orbiter Processing Facility. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  11. General view of the Orbiter Discovery on runway 33 at ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of the Orbiter Discovery on runway 33 at Kennedy Space Center shortly after landing. The orbiter is processed and prepared for being towed to the Orbiter Processing Facility for continued post flight processing and pre flight preparations for its next mission. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  12. General view of runway 33 at the Kennedy Space Center ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of runway 33 at the Kennedy Space Center looking at the ground support equipment and the aft and port side of the Orbiter Discovery as the orbiter is undergoing post flight processing and preparations to be towed to the Orbiter Processing Facility. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  13. Airport runway detection in satellite images by Adaboost learning

    NASA Astrophysics Data System (ADS)

    Zongur, Ugur; Halici, Ugur; Aytekin, Orsan; Ulusoy, Ilkay

    2009-09-01

    Advances in hardware and pattern recognition techniques, along with the widespread utilization of remote sensing satellites, have urged the development of automatic target detection systems in satellite images. Automatic detection of airports is particularly essential, due to the strategic importance of these targets. In this paper, a runway detection method using a segmentation process based on textural properties is proposed for the detection of airport runways, which is the most distinguishing element of an airport. Several local textural features are extracted including not only low level features such as mean, standard deviation of image intensity and gradient, but also Zernike Moments, Circular-Mellin Features, Haralick Features, as well as features involving Gabor Filters, Wavelets and Fourier Power Spectrum Analysis. Since the subset of the mentioned features, which have a role in the discrimination of airport runways from other structures and landforms, cannot be predicted trivially, Adaboost learning algorithm is employed for both classification and determining the feature subset, due to its feature selector nature. By means of the features chosen in this way, a coarse representation of possible runway locations is obtained. Promising experimental results are achieved and given.

  14. Perseus B Heads for Landing on Edwards AFB Runway

    NASA Image and Video Library

    1998-04-30

    The Perseus B remotely piloted aircraft approaches the runway at Edwards Air Force Base, Calif. at the conclusion of a development flight at NASA's Dryden flight Research Center in April 1998. The Perseus B is the latest of three versions of the Perseus design developed by Aurora Flight Sciences under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program.

  15. Study of Asphaltic Concrete Produced in Dryer Drum Mixers for Airport Pavements.

    DTIC Science & Technology

    1976-10-01

    STWDARDS-163- w S 4 -- , ,a, i I Report No-c FAA-RD-76-165 STUDY OF ASPHALTIC CONCRETE PRODUCED IN DRYER DRUM MIXERS FOR AIRPORT PAVEMENTS 0 E. T...PREFACE This study was supported by the Systems Research and Development Service of the Federal Aviation Administration. This is a final report presenting...the asphaltic concrete . In September, 1976 the Alaskan Region of FAA reported that the runway pavement had transverse thermal cracks approximately 200

  16. System-Oriented Runway Management Concept of Operations

    NASA Technical Reports Server (NTRS)

    Lohr, Gary W.; Atkins, Stephen

    2015-01-01

    This document describes a concept for runway management that maximizes the overall efficiency of arrival and departure operations at an airport or group of airports. Specifically, by planning airport runway configurations/usage, it focuses on the efficiency with which arrival flights reach their parking gates from their arrival fixes and departure flights exit the terminal airspace from their parking gates. In the future, the concept could be expanded to include the management of other limited airport resources. While most easily described in the context of a single airport, the concept applies equally well to a group of airports that comprise a metroplex (i.e., airports in close proximity that share resources such that operations at the airports are at least partially dependent) by including the coordination of runway usage decisions between the airports. In fact, the potential benefit of the concept is expected to be larger in future metroplex environments due to the increasing need to coordinate the operations at proximate airports to more efficiently share limited airspace resources. This concept, called System-Oriented Runway Management (SORM), is further broken down into a set of airport traffic management functions that share the principle that operational performance must be measured over the complete surface and airborne trajectories of the airport's arrivals and departures. The "system-oriented" term derives from the belief that the traffic management objective must consider the efficiency of operations over a wide range of aircraft movements and National Airspace System (NAS) dynamics. The SORM concept is comprised of three primary elements: strategic airport capacity planning, airport configuration management, and combined arrival/departure runway planning. Some aspects of the SORM concept, such as using airport configuration management1 as a mechanism for improving aircraft efficiency, are novel. Other elements (e.g., runway scheduling, which is a part

  17. Uncertainty Analysis for the Evaluation of a Passive Runway Arresting System

    NASA Technical Reports Server (NTRS)

    Deloach, Richard; Marlowe, Jill M.; Yager, Thomas J.

    2009-01-01

    This paper considers the stopping distance of an aircraft involved in a runway overrun incident when the runway has been provided with an extension comprised of a material engineered to induce high levels of rolling friction and drag. A formula for stopping distance is derived that is shown to be the product of a known formula for the case of friction without drag, and a dimensionless constant between 0 and 1 that quantifies the further reduction in stopping distance when drag is introduced. This additional quantity, identified as the Drag Reduction Factor, D, is shown to depend on the ratio of drag force to friction force experienced by the aircraft as it enters the overrun area. The specific functional form of D is shown to depend on how drag varies with speed. A detailed uncertainty analysis is presented which reveals how the uncertainty in estimates of stopping distance are influenced by experimental error in the force measurements that are acquired in a typical evaluation experiment conducted to assess candidate overrun materials.

  18. Performance of "Waterless Concrete"

    NASA Technical Reports Server (NTRS)

    Toutanji, H. A.; Grugel, R. N.

    2009-01-01

    Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in a lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and, by oxidation of the soil, iron and sulfur can be produced. Sulfur concrete specimens were cycled between liquid nitrogen (approx.]91 C) and room temperature (^21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (^21 C) and ^-101 C. Test results showed that due to temperature cycling, the compressive strength of cycled specimens was 20% of those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibres. The lunar regolith simulant was melted in a 25 cc Pt- Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to i hour. Glass fibres and small rods were pulled from the melt. The glass fibres were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Beams strengthened with glass fibres showed to exhibit an increase in the flexural strength by as much as 45%.

  19. Fiber reinforced concrete solar collector

    SciTech Connect

    Slemmons, A. J.; Newgard, P. J.

    1985-05-07

    A solar collector is disclosed comprising a glass member having a solar selective coating thereon, and a molded, glass-reinforced concrete member bonded to the glass member and shaped to provide a series of passageways between the glass member and the fiber-reinforced concrete member capable of carrying heat exchanging fluid therethrough. The fiber-reinforced concrete member may be formed by spraying a thin layer of concrete and chopped fibers such as chopped glass fibers onto a mold to provide an inexpensive and lightweight, thin-walled member. The fiber-reinforced concrete member may have a lightweight cellular concrete backing thereon for insulation purposes. The collector is further characterized by the use of materials which have substantially matching thermal coefficients of expansion over the temperature range normally encountered in the use of solar collectors.

  20. Electrical resistance of carbon-nanofiber concrete

    NASA Astrophysics Data System (ADS)

    Gao, Di; Sturm, Mariel; Mo, Y. L.

    2009-09-01

    Concrete is the most widely used construction material, and carbon nanofibers have many advantages in both mechanical and electrical properties such as high strength, high Young's modulus and high conductivity. In this paper, the mechanical and electrical properties of concrete containing carbon nanofibers (CNF) are experimentally studied. The test results indicate that the compressive strength and per cent reduction in electrical resistance while loading concrete containing CNF are much greater than those of plain concrete. Finally, a reasonable concentration of CNF is obtained for use in concrete which not only enhances compressive strength, but also improves the electrical properties required for strain monitoring, damage evaluation and self-health monitoring of concrete.

  1. Impact resistance performance of green construction material using light weight oil palm shells reinforced bamboo concrete slab

    NASA Astrophysics Data System (ADS)

    Muda, Z. C.; Usman, F.; Beddu, S.; Alam, M. A.; Thiruchelvam, S.; Sidek, L. M.; Basri, H.; Saadi, S.

    2013-06-01

    This paper investigate the performance of lightweight oil palm shells (OPS) concrete with varied bamboo reinforcement content for the concrete slab of 300mm x 300mm size reinforced with different thickness subjected to low impact projectile test. A self-fabricated drop-weight impact test rig with a steel ball weight of 1.2 kg drop at 1 m height has been used in this research work. The main variables for the study is to find the relationship of the impact resistance against the amount of bamboo reinforcement and slab thickness. A linear relationship has been established between first and ultimate crack resistance against bamboo diameters and slab thickness by the experiment. The linear relationship has also been established between the service (first) crack and ultimate crack resistance against the bamboo reinforcement diameter for a constant spacing for various slab thickness using 0.45 OPS and 0.6 OPS bamboo reinforced concrete. The increment in bamboo diameter has more effect on the first crack resistance than the ultimate crack resistance. The linear relationship has also been established between the service (first) crack and ultimate crack resistance against the various slab thickness. Increment in slab thickness of the slab has more effect on the crack resistance as compare to the increment in the diameter of the bamboo reinforcement.

  2. Utilization of Electric Arc Furnace Dust as raw material for the production of ceramic and concrete building products.

    PubMed

    Sikalidis, Constantine; Mitrakas, Manassis

    2006-01-01

    The up to 20 wt% addition of the Electric Arc Furnace Dust (EAFD) hazardous waste on the properties of extruded clay-based ceramic building products fired at various temperatures (850 to 1050 degrees C), as well as of dolomite-concrete products was investigated. Chemical, mineralogical and particle size distribution analyses were performed in order to characterize the used EAFD. The results showed that the ceramic specimens prepared had water absorption, firing shrinkage, apparent density, mechanical strength, colour and leaching behaviour within accepted limits. Addition of 7.5 to 15 wt% EAFD presented improved properties, while 20 wt% seems to be the upper limit. Dolomite-concrete specimens were prepared by vibration and press-forming of mixtures containing cement, sand, dolomite, EAFD and water. Modulus of rupture values were significantly increased by the addition of EAFD. The leaching tests showed stabilization of all toxic metals within the sintered ceramic structure, while the leaching behaviour of lead in dolomite-concrete products needs further detailed study.

  3. A Concept for Rapid Repair of Bomb-Damaged Runways Using Regulated-Set Cement

    DTIC Science & Technology

    1975-07-01

    that exerted by aggregate which restrains the amount of shrinkage that can actually be realized (Reference 27). The ratio of shrinkage of concrete...or mortar), S , to shrinkage of neat paste, So , depends on the aggregate content, g , in the concrete (Reference 28) and is expressed as bo (1...capping material must include aggregate of some type to reduce the problem of drying shrinkage at later dates. Joint boards should be included in the

  4. NASA Research For Instrument Approaches To Closely Spaced Parallel Runways

    NASA Technical Reports Server (NTRS)

    Elliott, Dawn M.; Perry, R. Brad

    2000-01-01

    Within the NASA Aviation Systems Capacity Program, the Terminal Area Productivity (TAP) Project is addressing airport capacity enhancements during instrument meteorological condition (IMC). The Airborne Information for Lateral Spacing (AILS) research within TAP has focused on an airborne centered approach for independent instrument approaches to closely spaced parallel runways using Differential Global Positioning System (DGPS) and Automatic Dependent Surveillance-Broadcast (ADS-B) technologies. NASA Langley Research Center (LaRC), working in partnership with Honeywell, Inc., completed in AILS simulation study, flight test, and demonstration in 1999 examining normal approaches and potential collision scenarios to runways with separation distances of 3,400 and 2,500 feet. The results of the flight test and demonstration validate the simulation study.

  5. Development of a Bayesian Belief Network Runway Incursion Model

    NASA Technical Reports Server (NTRS)

    Green, Lawrence L.

    2014-01-01

    In a previous paper, a statistical analysis of runway incursion (RI) events was conducted to ascertain their relevance to the top ten Technical Challenges (TC) of the National Aeronautics and Space Administration (NASA) Aviation Safety Program (AvSP). The study revealed connections to perhaps several of the AvSP top ten TC. That data also identified several primary causes and contributing factors for RI events that served as the basis for developing a system-level Bayesian Belief Network (BBN) model for RI events. The system-level BBN model will allow NASA to generically model the causes of RI events and to assess the effectiveness of technology products being developed under NASA funding. These products are intended to reduce the frequency of RI events in particular, and to improve runway safety in general. The development, structure and assessment of that BBN for RI events by a Subject Matter Expert panel are documented in this paper.

  6. PREPACKED CONCRETE.

    DTIC Science & Technology

    Twenty four hardened plain concrete wallettes , each 31 in. high by 25 in. wide by 6 in. thick, were sawed into various rectangular parallelepipeds...The wallettes represented three groups of prepacked concrete: reference aggregate intruded with fresh-water grout, coral aggregate with fresh-water...prismatic test specimens were involved in the program for determining the effectsof: type of mixing water, type of wiremesh cover atop the wallette form

  7. The noise impact of proposed runway alternatives at Craig Airport

    NASA Technical Reports Server (NTRS)

    Deloach, R.

    1982-01-01

    Four proposed runway expansion alternatives at Craig Airport in Jacksonville, Florida have been assessed with respect to their forecasted noise impact in the year 2005. The assessment accounts for population distributions around the airport and human subjective response to noise, as well as the distribution of noise levels in the surrounding community (footprints). The impact analysis was performed using the Airport-noise Levels and Annoyance Model (ALAMO), an airport community response model recently developd at Langley Research Center.

  8. Runway Detection From Map, Video and Aircraft Navigational Data

    DTIC Science & Technology

    2016-03-01

    FROM MAP, VIDEO AND AIRCRAFT NAVIGATIONAL DATA by Jose R. Espinosa Gloria March 2016 Thesis Advisor: Roberto Cristi Co-Advisor: Oleg...COVERED Master’s thesis 4. TITLE AND SUBTITLE RUNWAY DETECTION FROM MAP, VIDEO AND AIRCRAFT NAVIGATIONAL DATA 5. FUNDING NUMBERS 6. AUTHOR...Mexican Navy, unmanned aerial vehicles (UAV) have been equipped with daylight and infrared cameras. Processing the video information obtained from these

  9. Benefits Assessment for Tactical Runway Configuration Management Tool

    NASA Technical Reports Server (NTRS)

    Oseguera-Lohr, Rosa; Phojanamongkolkij, Nipa; Lohr, Gary; Fenbert, James W.

    2013-01-01

    The Tactical Runway Configuration Management (TRCM) software tool was developed to provide air traffic flow managers and supervisors with recommendations for airport configuration changes and runway usage. The objective for this study is to conduct a benefits assessment at Memphis (MEM), Dallas Fort-Worth (DFW) and New York's John F. Kennedy (JFK) airports using the TRCM tool. Results from simulations using the TRCM-generated runway configuration schedule are compared with results using historical schedules. For the 12 days of data used in this analysis, the transit time (arrival fix to spot on airport movement area for arrivals, or spot to departure fix for departures) for MEM departures is greater (7%) than for arrivals (3%); for JFK, there is a benefit for arrivals (9%) but not for departures (-2%); for DFW, arrivals show a slight benefit (1%), but this is offset by departures (-2%). Departure queue length benefits show fewer aircraft in queue for JFK (29%) and MEM (11%), but not for DFW (-13%). Fuel savings for surface operations at MEM are seen for both arrivals and departures. At JFK there are fuel savings for arrivals, but these are offset by increased fuel use for departures. In this study, no surface fuel benefits resulted for DFW. Results suggest that the TRCM algorithm requires modifications for complex surface traffic operations that can cause taxi delays. For all three airports, the average number of changes in flow direction (runway configuration) recommended by TRCM was many times greater than the historical data; TRCM would need to be adapted to a particular airport's needs, to limit the number of changes to acceptable levels. The results from this analysis indicate the TRCM tool can provide benefits at some high-capacity airports. The magnitude of these benefits depends on many airport-specific factors and would require adaptation of the TRCM tool; a detailed assessment is needed prior to determining suitability for a particular airport.

  10. Runway Exit Designs for Capacity Improvement Demonstrations. Phase 1: Algorithm Development

    NASA Technical Reports Server (NTRS)

    Trani, A. A.; Hobeika, A. G.; Sherali, H.; Kim, B. J.; Sadam, C. K.

    1990-01-01

    A description and results are presented of a study to locate and design rapid runway exits under realistic airport conditions. The study developed a PC-based computer simulation-optimization program called REDIM (runway exit design interactive model) to help future airport designers and planners to locate optimal exits under various airport conditions. The model addresses three sets of problems typically arising during runway exit design evaluations. These are the evaluations of existing runway configurations, addition of new rapid runway turnoffs, and the design of new runway facilities. The model is highly interactive and allows a quick estimation of the expected value of runway occupancy time. Aircraft populations and airport environmental conditions are among the multiple inputs to the model to execute a viable runway location and geometric design solution. The results presented suggest that possible reductions on runway occupancy time (ROT) can be achieved with the use of optimally tailored rapid runway designs for a given aircraft population. Reductions of up to 9 to 6 seconds are possible with the implementation of 30 m/sec variable geometry exits.

  11. FOD Cover Analysis for Rapid Runway Repair.

    DTIC Science & Technology

    1980-10-30

    tested as shown in Figure 7. The plastic sheet was much thinner and weaker than the T17 POD cover material, but nevertheless acts as a mem- brane and...Analysis Based on the preliminary analysis of the POD cover and the simple thin plastic sheet tests, it was agreed that a minimum of 7 1 5 35 87 -65...c.hange -h rt.: the analysis. c. Jet Blast Analyses The main objectives of this portion of the POD o,.,r ,rn~’>,:’ are to explore the advantages gained by

  12. Concrete Mixing Methods and Concrete Mixers: State of the Art.

    PubMed

    Ferraris, C F

    2001-01-01

    As for all materials, the performance of concrete is determined by its microstructure. Its microstructure is determined by its composition, its curing conditions, and also by the mixing method and mixer conditions used to process the concrete. This paper gives an overview of the various types of mixing methods and concrete mixers commercially available used by the concrete industry. There are two main types of mixers used: batch mixers and continuous mixers. Batch mixers are the most common. To determine the mixing method best suited for a specific application, factors to be considered include: location of the construction site (distance from the batching plant), the amount of concrete needed, the construction schedule (volume of concrete needed per hour), and the cost. Ultimately, the quality of the concrete produced determines its performance after placement. An important measure of the quality is the homogeneity of the material after mixing. This paper will review mixing methods in regards to the quality of the concrete produced. Some procedures used to determine the effectiveness of the mixing will be examined.

  13. Concrete Mixing Methods and Concrete Mixers: State of the Art

    PubMed Central

    Ferraris, Chiara F.

    2001-01-01

    As for all materials, the performance of concrete is determined by its microstructure. Its microstructure is determined by its composition, its curing conditions, and also by the mixing method and mixer conditions used to process the concrete. This paper gives an overview of the various types of mixing methods and concrete mixers commercially available used by the concrete industry. There are two main types of mixers used: batch mixers and continuous mixers. Batch mixers are the most common. To determine the mixing method best suited for a specific application, factors to be considered include: location of the construction site (distance from the batching plant), the amount of concrete needed, the construction schedule (volume of concrete needed per hour), and the cost. Ultimately, the quality of the concrete produced determines its performance after placement. An important measure of the quality is the homogeneity of the material after mixing. This paper will review mixing methods in regards to the quality of the concrete produced. Some procedures used to determine the effectiveness of the mixing will be examined. PMID:27500029

  14. Parallel runway requirement analysis study. Volume 1: The analysis

    NASA Technical Reports Server (NTRS)

    Ebrahimi, Yaghoob S.

    1993-01-01

    The correlation of increased flight delays with the level of aviation activity is well recognized. A main contributor to these flight delays has been the capacity of airports. Though new airport and runway construction would significantly increase airport capacity, few programs of this type are currently underway, let alone planned, because of the high cost associated with such endeavors. Therefore, it is necessary to achieve the most efficient and cost effective use of existing fixed airport resources through better planning and control of traffic flows. In fact, during the past few years the FAA has initiated such an airport capacity program designed to provide additional capacity at existing airports. Some of the improvements that that program has generated thus far have been based on new Air Traffic Control procedures, terminal automation, additional Instrument Landing Systems, improved controller display aids, and improved utilization of multiple runways/Instrument Meteorological Conditions (IMC) approach procedures. A useful element to understanding potential operational capacity enhancements at high demand airports has been the development and use of an analysis tool called The PLAND_BLUNDER (PLB) Simulation Model. The objective for building this simulation was to develop a parametric model that could be used for analysis in determining the minimum safety level of parallel runway operations for various parameters representing the airplane, navigation, surveillance, and ATC system performance. This simulation is useful as: a quick and economical evaluation of existing environments that are experiencing IMC delays, an efficient way to study and validate proposed procedure modifications, an aid in evaluating requirements for new airports or new runways in old airports, a simple, parametric investigation of a wide range of issues and approaches, an ability to tradeoff air and ground technology and procedures contributions, and a way of considering probable

  15. Craters in concrete slabs due to detonation - drawbacks of material models with a Mohr-Coulomb yield surface

    NASA Astrophysics Data System (ADS)

    Conrad, Markus

    2015-09-01

    Numerical simulations have been performed with a commercial distributed explicit FE-solver and the results have been compared with experiments. High explosive was placed in front of different concrete slabs with the dimension 100 × 100 × 16 cm. Some of the results of the simulations, in particular the profile of the craters, are not in agreement with the test results. Therefore the key characteristics of the constitutive equation based on Mohr-Coulomb yield surfaces and a damage evolution linked to the plastic strain has been reviewed.

  16. FREEZING AND THAWING RESISTANCE OF CONCRETE WITH INITIAL CRACK

    NASA Astrophysics Data System (ADS)

    Naito, Hideki; Hayashi, Hiroshi; Saiki, Yusuke; Sando, Koichi; Koga, Hideyuki; Suzuki, Motoyuki

    Freezing and thawing resistance of concrete with an initial crack was investigated. The specimens were classified into plane concrete, fiber reinforced concrete, and reinforced concrete. In the tests of plane concrete with an initial crack, the crack grows seriously by the frozen expansion pressure of the water infiltrated into the crack, though the concrete material had high resistance to freezing and thawing. In the experimental results of fiber reinforced concrete, the long polypropylene fiber was useful to prevent the spalling of concrete cover, though the crack growth was not prevented. Moreover, in the experimental results of reinforced concrfete, it was shown that the crack growth was effectively prevented by steel reinforcing bar.

  17. STS-41 Discovery, OV-103, glides over concrete runway 22 at EAFB, California

    NASA Image and Video Library

    1990-10-10

    STS041-S-093 (10 Oct 1990) --- Discovery is only moments away from touchdown at Edwards Air Force Base to end a four-day mission in space for its five-man crew. The vehicle landed at 6:57 a.m. PDT, Oct. 10, 1990. Onboard the spacecraft were Astronauts Richard N. Richards, Robert D. Cabana, William M. Shepherd, Bruce E. Melnick and Thomas D. Akers.

  18. Engineering properties of cement mortar with pond ash in South Korea as construction materials: from waste to concrete

    NASA Astrophysics Data System (ADS)

    Jung, Sang; Kwon, Seung-Jun

    2013-09-01

    Among the wastes from coal combustion product, only fly ash is widely used for mineral mixture in concrete for its various advantages. However the other wastes including bottom ash, so called PA (pond ash) are limitedly reused for reclamation. In this paper, the engineering properties of domestic pond ash which has been used for reclamation are experimentally studied. For this, two reclamation sites (DH and TA) in South Korea are selected, and two domestic PAs are obtained. Cement mortar with two different w/c (water to cement) ratios and 3 different replacement ratios (0%, 30%, and 60%) of sand are prepared for the tests. For workability and physical properties of PA cement mortar, several tests like flow, setting time, and compressive strength are evaluated. Several durability tests including porosity measuring, freezing and thawing, chloride migration, and accelerated carbonation are also performed. Through the tests, PA (especially from DH area) in surface saturated condition is evaluated to have internal curing action which leads to reasonable strength development and durability performances. The results show a potential applicability of PA to concrete aggregate, which can reduce consuming natural resources and lead to active reutilization of coal product waste.

  19. Use of Very Weak Radiation Sources to Determine Aircraft Runway Position

    NASA Technical Reports Server (NTRS)

    Drinkwater, Fred J., III; Kibort, Bernard R.

    1965-01-01

    Various methods of providing runway information in the cockpit during the take-off and landing roll have been proposed. The most reliable method has been to use runway distance markers when visible. Flight tests were used to evaluate the feasibility of using weak radio-active sources to trigger a runway distance counter in the cockpit. The results of these tests indicate that a weak radioactive source would provide a reliable signal by which this indicator could be operated.

  20. STS-31 on Runway 22 at Edwards with Recovery Personnel

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Personnel and equipment converge on the orbiter Discovery to begin servicing the spacecraft following its landing April 29, 1990, at NASA's then Ames-Dryden Flight Research Facility, Edwards, California. Post-landing servicing by the recovery convoy is carried out after each Space Shuttle landing and includes safety checks for flammable and toxic gases escaping from systems aboard the orbiters, hooking up engine fuel purge and equipment coolant lines, and inspecting the brakes before the vehicle is towed from the runway to the shuttle facility at Dryden where it is prepared for the ferry flight back to the Kennedy Space Center in Florida. Up to 24 vehicles and scores of personnel make up the landing recovery convoys at Dryden. Space Shuttles are the main element of America's Space Transportation System and are used for space research and other space applications. The shuttles are the first vehicles capable of being launched into space and returning to Earth on a routine basis. Space Shuttles are used as orbiting laboratories in which scientists and mission specialists conduct a wide variety of scientific experiments. Crews aboard shuttles place satellites in orbit, rendezvous with satellites to carry out repair missions and return them to space, and retrieve satellites and return them to Earth for refurbishment and reuse. Space Shuttles are true aerospace vehicles. They leave Earth and its atmosphere under rocket power provided by three liquid-propellant main engines with two solid-propellant boosters attached plus an external liquid-fuel tank. After their orbital missions, they streak back through the atmosphere and land like airplanes. The returning shuttles, however, land like gliders, without power and on runways. Other rockets can place heavy payloads into orbit, but, they can only be used once. Space Shuttles are designed to be continually reused. When Space Shuttles are used to transport complete scientific laboratories into space, the laboratories remain

  1. STS-36 on Edwards Runway with Recovery Personnel

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Personnel and equipment converge on the orbiter Atlantis to begin servicing the spacecraft following its landing 4 March 1990, at NASA's then Ames-Dryden Flight Research Facility, Edwards, California. Mission elapsed time for the Department of Defense mission was 4 days, 10 hours, 19 minutes and 15 seconds. Actual landing time was 10:08 a.m. Post-landing servicing by the recovery convoy is carried out after each Space Shuttle landing and includes safety checks for flammable and toxic gases escaping from systems aboard the orbiters, hooking up engine fuel purge and equipment coolant lines, and inspecting the brakes before the vehicle is towed from the runway to the shuttle facility at Dryden where it is prepared for the ferry flight back to the Kennedy Space Center in Florida. Up to 24 vehicles and scores of personnel make up the landing recovery convoys at Dryden. Space Shuttles are the main element of America's Space Transportation System and are used for space research and other space applications. The shuttles are the first vehicles capable of being launched into space and returning to Earth on a routine basis. Space Shuttles are used as orbiting laboratories in which scientists and mission specialists conduct a wide variety of scientific experiments. Crews aboard shuttles place satellites in orbit, rendezvous with satellites to carry out repair missions and return them to space, and retrieve satellites and return them to Earth for refurbishment and reuse. Space Shuttles are true aerospace vehicles. They leave Earth and its atmosphere under rocket power provided by three liquid-propellant main engines with two solid-propellant boosters attached plus an external liquid-fuel tank. After their orbital missions, they streak back through the atmosphere and land like airplanes. The returning shuttles, however, land like gliders, without power and on runways. Other rockets can place heavy payloads into orbit, but, they can only be used once. Space Shuttles are designed

  2. STS-31 on Runway 22 at Edwards with Recovery Personnel

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Personnel and equipment converge on the orbiter Discovery to begin servicing the spacecraft following its landing April 29, 1990, at NASA's then Ames-Dryden Flight Research Facility, Edwards, California. Post-landing servicing by the recovery convoy is carried out after each Space Shuttle landing and includes safety checks for flammable and toxic gases escaping from systems aboard the orbiters, hooking up engine fuel purge and equipment coolant lines, and inspecting the brakes before the vehicle is towed from the runway to the shuttle facility at Dryden where it is prepared for the ferry flight back to the Kennedy Space Center in Florida. Up to 24 vehicles and scores of personnel make up the landing recovery convoys at Dryden. Space Shuttles are the main element of America's Space Transportation System and are used for space research and other space applications. The shuttles are the first vehicles capable of being launched into space and returning to Earth on a routine basis. Space Shuttles are used as orbiting laboratories in which scientists and mission specialists conduct a wide variety of scientific experiments. Crews aboard shuttles place satellites in orbit, rendezvous with satellites to carry out repair missions and return them to space, and retrieve satellites and return them to Earth for refurbishment and reuse. Space Shuttles are true aerospace vehicles. They leave Earth and its atmosphere under rocket power provided by three liquid-propellant main engines with two solid-propellant boosters attached plus an external liquid-fuel tank. After their orbital missions, they streak back through the atmosphere and land like airplanes. The returning shuttles, however, land like gliders, without power and on runways. Other rockets can place heavy payloads into orbit, but, they can only be used once. Space Shuttles are designed to be continually reused. When Space Shuttles are used to transport complete scientific laboratories into space, the laboratories remain

  3. STS-36 on Edwards Runway with Recovery Personnel

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Personnel and equipment converge on the orbiter Atlantis to begin servicing the spacecraft following its landing 4 March 1990, at NASA's then Ames-Dryden Flight Research Facility, Edwards, California. Mission elapsed time for the Department of Defense mission was 4 days, 10 hours, 19 minutes and 15 seconds. Actual landing time was 10:08 a.m. Post-landing servicing by the recovery convoy is carried out after each Space Shuttle landing and includes safety checks for flammable and toxic gases escaping from systems aboard the orbiters, hooking up engine fuel purge and equipment coolant lines, and inspecting the brakes before the vehicle is towed from the runway to the shuttle facility at Dryden where it is prepared for the ferry flight back to the Kennedy Space Center in Florida. Up to 24 vehicles and scores of personnel make up the landing recovery convoys at Dryden. Space Shuttles are the main element of America's Space Transportation System and are used for space research and other space applications. The shuttles are the first vehicles capable of being launched into space and returning to Earth on a routine basis. Space Shuttles are used as orbiting laboratories in which scientists and mission specialists conduct a wide variety of scientific experiments. Crews aboard shuttles place satellites in orbit, rendezvous with satellites to carry out repair missions and return them to space, and retrieve satellites and return them to Earth for refurbishment and reuse. Space Shuttles are true aerospace vehicles. They leave Earth and its atmosphere under rocket power provided by three liquid-propellant main engines with two solid-propellant boosters attached plus an external liquid-fuel tank. After their orbital missions, they streak back through the atmosphere and land like airplanes. The returning shuttles, however, land like gliders, without power and on runways. Other rockets can place heavy payloads into orbit, but, they can only be used once. Space Shuttles are designed

  4. Benefit Assessment for Metroplex Tactical Runway Configuration Management (mTRCM) in a Simulated Environment

    NASA Technical Reports Server (NTRS)

    Phojanamongkolkij, Nipa; Oseguera-Lohr, Rosa M.; Lohr, Gary W.; Robbins, Steven W.; Fenbert, James W.; Hartman, Christopher L.

    2015-01-01

    The System-Oriented Runway Management (SORM) concept is a collection of capabilities focused on a more efficient use of runways while considering all of the factors that affect runway use. Tactical Runway Configuration Management (TRCM), one of the SORM capabilities, provides runway configuration and runway usage recommendations, and monitoring the active runway configuration for suitability given existing factors. This report focuses on the metroplex environment, with two or more proximate airports having arrival and departure operations that are highly interdependent. The myriad of factors that affect metroplex opeations require consideration in arriving at runway configurations that collectively best serve the system as a whole. To assess the metroplex TRCM (mTRCM) benefit, the performance metrics must be compared with the actual historical operations. The historical configuration schedules can be viewed as the schedules produced by subject matter experts (SMEs), and therefore are referred to as the SMEs' schedules. These schedules were obtained from the FAA's Aviation System Performance Metrics (ASPM) database; this is the most representative information regarding runway configuration selection by SMEs. This report focused on a benefit assessment of total delay, transit time, and throughput efficiency (TE) benefits using the mTRCM algorithm at representative volumes for today's traffic at the New York metroplex (N90).

  5. Physical properties of core-concrete systems: Al2O3-ZrO2 molten materials measured by aerodynamic levitation

    NASA Astrophysics Data System (ADS)

    Ohishi, Yuji; Kargl, F.; Nakamori, F.; Muta, Hiroaki; Kurosaki, Ken; Yamanaka, Shinsuke

    2017-04-01

    During a molten core-concrete interaction, molten oxides consisting of molten core materials (UO2 and ZrO2) and concrete (Al2O3, SiO2, CaO) are formed. Reliable data on the physical properties of the molten oxides will allow us to accurately predict the progression of a nuclear reactor core meltdown accident. In this study, the viscosities and densities of molten (ZrO2)x(Al2O3)1-x (x = 0.356 and 0.172) were measured using an aerodynamic levitation technique. The densities of two small samples were estimated from their masses and their volumes (calculated from recorded images of the molten samples). The droplets were forced to oscillate using speakers, and their viscosities were evaluated from the damping behaviors of their oscillations. The results showed that the viscosity of molten (ZrO2)x(Al2O3)1-x compared to that of pure molten Al2O3 is 25% lower for x = 0.172, while it is unexpectedly 20% higher for x = 0.356.

  6. Factors that determine depth perception of trapezoids, windsurfers, runways

    PubMed Central

    Tseng, Chia-Huei; Gobell, Joetta L.; Sperling, George

    2015-01-01

    We report here a windsurfer1 illusion, a naturally occurring trapezoidal illusion in which the small end of the sail viewed at a distance appears to be pointed away from the observer even when it is closer. This naturally occurring illusion is so compelling that observers are unaware of their gross perceptual misinterpretation of the scene. Four laboratory experiment of this kind of trapezoidal illusion investigated the joint effects of retinal orientation, head position, relative motion, and the relative direction of gravity on automatic depth perception. Observers viewed two adjacent white trapezoids outlined on a black background rotating back and forth ± 20° on a vertical axis much like the sails of two adjacent windsurfers. Observers reported which side of the trapezoids (long or short) appeared to be closer to them (i.e., in front). The longer edge of the trapezoid was reported in front 76 ± 2% of trials (“windsurfer effect”) whether it was on the left or on the right. When the display was rotated 90°to produce a runway configuration, there was a striking asymmetry: the long edge was perceived to be in front 97% when it was on the bottom but only 43% when it was on top (“runway effect”). The runway effect persisted when the head was tilted 90° or when displays on the ceiling were viewed from the floor. Ninety-five percent of the variance of the variance in the strikingly different 3D perceptions produced by the same 2D trapezoid image was quantitatively explained by a model that assumes there are just three additive bias factors that account for perceiving an edge as closer: Implicit linear perspective, lower position on the retina (based on an automatic assumption of viewing from above), and being lower in world coordinates. PMID:26029073

  7. Concrete waterproofing in nuclear industry.

    PubMed

    Scherbyna, Alexander N; Urusov, Sergei V

    2005-01-01

    One of the main points of aggregate safety during the transportation and storage of radioactive materials is to supply waterproofing for all constructions having direct contact with radiating substances and providing strength, seismic shielding etc. This is the problem with all waterside structures in nuclear industry and concrete installations in the treatment and storage of radioactive materials. In this connection, the problem of developing efficient techniques both for the repair of operating constructions and the waterproofing of new objects of the specified assignment is genuine. Various techniques of concrete waterproofing are widely applied in the world today. However, in conditions of radiation many of these techniques can bring not a profit but irreparable damage of durability and reliability of a concrete construction; for instance, when waterproofing materials contain organic constituents, polymers etc. Application of new technology or materials in basic construction elements requires in-depth analysis and thorough testing. The price of an error might be very large. A comparative analysis shows that one of the most promising types of waterproofing materials for radiation loaded concrete constructions is "integral capillary systems" (ICS). The tests on radiation, thermal and strength stability of ICS and ICS-treated concrete samples were initiated and fulfilled in RFNC-VNIITF. The main result is--ICS applying is increasing of waterproofing and strength properties of concrete in conditions of readiation The paper is devoted to describing the research strategy, the tests and their results and also to planning of new tests.

  8. The Joint Winter Runway Friction Measurement Program: NASA Perspective

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1996-01-01

    Some background information is given together with the scope and objectives of the 5-year, Joint National Aeronautics & Space Administration (NASA)/Transport Canada (TC)/Federal Aviation Administration (FAA) Winter Runway Friction Measurement Program. The range of the test equipment, the selected test sites and a tentative test program schedule are described. NASA considers the success of this program critical in terms of insuring adequate ground handling performance capability in adverse weather conditions for future aircraft being designed and developed as well as improving the safety of current aircraft ground operations.

  9. Space shuttle Discovery STS-120 touches down on Runway 33

    NASA Image and Video Library

    2007-11-07

    The drag chute deployed behind space shuttle Discovery helps slow its smooth landing on Runway 33 of the Shuttle Landing Facility at NASA's Kennedy Space Center, completing the 15-day mission STS-120. Main gear touchdown was 1:01:16 p.m. Wheel stop was at 1:02:07 p.m. Mission elapsed time was 15 days, 2 hours, 24 minutes and 2 seconds. The STS-120 crew continued the construction of the station with the installation of the Harmony Node 2 module and the relocation of the P6 truss.

  10. 32 CFR 256.6 - Runway classification by aircraft type.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... Class B runways A-1, A-3, A-4, A-5, A-6, F-106, F-5, F-15, F-18, S-3, C-121, EC-121, WC-121, C-123, C..., F-14, F-4, F-8, F-111, T-2, T-38, B-52, B-57, B-57F, C-124, EC-130E, HC-130, C-135, VC-137, YF-12, SR-71, F-100, F-101, F-102, B-66, C-9, C-54, C-97, C-118, C-141, KC-135, EC-135, RC-135, U-2,...

  11. Development of polymer concrete for dike insulation at LNG facilities: Phase 4, Low cost materials. Final report, September 1, 1987--April 30, 1990

    SciTech Connect

    Kukacka, L.E.

    1991-01-01

    Earlier GRI-sponsored work at Brookhaven National Laboratory has resulted in the development and utilization of insulating polymer concrete composites (IPC) as a means of reducing the evaporation rate of liquified natural gas in the event of a spill into a containment dike, thereby improving the safety at these sites. Although all of the required properties can be attained with the IPC, it was estimated that a low-cost replacement for the expensive organic binder would be necessary before use of the material would be cost-effective. In the current program, several latex modified cement formulations were evaluated and the most promising one identified. A mixture of two carboxylated styrene-butadiene latexes was selected for use in detailed laboratory property characterizations and a subsequent field evaluation. When compared to the properties of IPC, the latex-modified insulating materials display somewhat higher thermal conductivities, greater permeability to water, and reduced strength. However, these properties still meet most of the performance criteria, and the unit cost of the material is less than one-fifth that of IPC made with epoxy binders. When installed as a 0.75-in. thick overlay, material costs are estimated to be $1.00/ft{sup 2}.

  12. Nuclear Power Plant Concrete Structures

    SciTech Connect

    Basu, Prabir; Labbe, Pierre; Naus, Dan

    2013-01-01

    A nuclear power plant (NPP) involves complex engineering structures that are significant items of the structures, systems and components (SSC) important to the safe and reliable operation of the NPP. Concrete is the commonly used civil engineering construction material in the nuclear industry because of a number of advantageous properties. The NPP concrete structures underwent a great degree of evolution, since the commissioning of first NPP in early 1960. The increasing concern with time related to safety of the public and environment, and degradation of concrete structures due to ageing related phenomena are the driving forces for such evolution. The concrete technology underwent rapid development with the advent of chemical admixtures of plasticizer/super plasticizer category as well as viscosity modifiers and mineral admixtures like fly ash and silica fume. Application of high performance concrete (HPC) developed with chemical and mineral admixtures has been witnessed in the construction of NPP structures. Along with the beneficial effect, the use of admixtures in concrete has posed a number of challenges as well in design and construction. This along with the prospect of continuing operation beyond design life, especially after 60 years, the impact of extreme natural events ( as in the case of Fukushima NPP accident) and human induced events (e.g. commercial aircraft crash like the event of September 11th 2001) has led to further development in the area of NPP concrete structures. The present paper aims at providing an account of evolution of NPP concrete structures in last two decades by summarizing the development in the areas of concrete technology, design methodology and construction techniques, maintenance and ageing management of concrete structures.

  13. Graphical User Interface Development and Design to Support Airport Runway Configuration Management

    NASA Technical Reports Server (NTRS)

    Jones, Debra G.; Lenox, Michelle; Onal, Emrah; Latorella, Kara A.; Lohr, Gary W.; Le Vie, Lisa

    2015-01-01

    The objective of this effort was to develop a graphical user interface (GUI) for the National Aeronautics and Space Administration's (NASA) System Oriented Runway Management (SORM) decision support tool to support runway management. This tool is expected to be used by traffic flow managers and supervisors in the Airport Traffic Control Tower (ATCT) and Terminal Radar Approach Control (TRACON) facilities.

  14. Comparison of Procedures for Dual and Triple Closely Spaced Parallel Runways

    NASA Technical Reports Server (NTRS)

    Verma, Savita; Ballinger, Deborah; Subramanian Shobana; Kozon, Thomas

    2012-01-01

    A human-in-the-loop high fidelity flight simulation experiment was conducted, which investigated and compared breakout procedures for Very Closely Spaced Parallel Approaches (VCSPA) with two and three runways. To understand the feasibility, usability and human factors of two and three runway VCSPA, data were collected and analyzed on the dependent variables of breakout cross track error and pilot workload. Independent variables included number of runways, cause of breakout and location of breakout. Results indicated larger cross track error and higher workload using three runways as compared to 2-runway operations. Significant interaction effects involving breakout cause and breakout location were also observed. Across all conditions, cross track error values showed high levels of breakout trajectory accuracy and pilot workload remained manageable. Results suggest possible avenues of future adaptation for adopting these procedures (e.g., pilot training), while also showing potential promise of the concept.

  15. Concrete Durability: A Multibillion-Dollar Opportunity

    DTIC Science & Technology

    1987-01-01

    Fum -Containing Products 79 MDF Materials 85 Fiber-Reinforced Materials 85 Modified - Sulfur Concretes 87 References 88 APPENDIX: BIOGRAPHICAL SKETCHES...construction. MODIFIED - SULFUR CONCRETES Molten sulfur-sand grouts have been used for many years in the constructLin of acid vats because of their

  16. Penetration analysis of projectile with inclined concrete target

    NASA Astrophysics Data System (ADS)

    Kim, S. B.; Kim, H. W.; Yoo, Y. H.

    2015-09-01

    This paper presents numerical analysis result of projectile penetration with concrete target. We applied dynamic material properties of 4340 steels, aluminium and explosive for projectile body. Dynamic material properties were measured with static tensile testing machine and Hopkinson pressure bar tests. Moreover, we used three concrete damage models included in LS-DYNA 3D, such as SOIL_CONCRETE, CSCM (cap model with smooth interaction) and CONCRETE_DAMAGE (K&C concrete) models. Strain rate effect for concrete material is important to predict the fracture deformation and shape of concrete, and penetration depth for projectiles. CONCRETE_DAMAGE model with strain rate effect also applied to penetration analysis. Analysis result with CSCM model shows good agreement with penetration experimental data. The projectile trace and fracture shapes of concrete target were compared with experimental data.

  17. Investigating the Impact of Temperature Changes, Material Aging, and Service Load on the Strain of a Reinforced Concrete Construction

    NASA Astrophysics Data System (ADS)

    Kanciruk, Adam

    2014-12-01

    Intensive exploitation of coal beds in the Upper Silesia Coal Basin led to the degradation of the Katowice-Muchowiec civilian/military airport. As a result, it became necessary to adapt the Pyrzowice military airport for use as a public transport facility. This involved reconstruction of a hangar located at the airport. As part of this process, a new hangar slab was constructed, designed in such a way as to bear the load of passenger aircraft. In the area of the greatest wheel load to the slab, three strain rosettes were installed for the purpose of monitoring the slab strain. The mointoring process - which has been automatically conducted for almost three years now - revealed deformations resulting from service load, the aging of reinforced concrete, and changes of its temperature. Intensywna eksploatacja górnośląskich złóż węgla doprowadziła do degradacji cywilno-wojskowego lotniska Katowice-Muchowiec. W związku z tym, wynikła konieczność przystosowania do celów komunikacyjnych lotniska wojskowego w Pyrzowicach, w tym przebudowy znajdującego się na jego terenie hangaru. W ramach przebudowy wykonano nową posadzkę, zdolną przenosić ciężar samolotów pasażerskich. W posadzce tej, w rejonie występowania największych nacisków zainstalowano 3 rozety tensometryczne w celu monitorowania jej odkształceń. Monitorowanie to, prowadzone w sposób automatyczny już niemal 3 lata, wykazało występowanie odkształceń będących skutkiem obciążeń eksploatacyjnych, starzenia się żelbetu oraz zmian jego temperatury.

  18. Long-term leaching from recycled concrete aggregates applied as sub-base material in road construction.

    PubMed

    Engelsen, Christian J; van der Sloot, Hans A; Petkovic, Gordana

    2017-06-01

    In the present study, the metal leaching from recycled concrete aggregates (RCA) used in road sub-base is presented after >10years of exposure. The released levels of inorganic constituents, the effect of small variation of pH and the use of de-icing salt during winter season were studied. In addition, speciation modelling for the major elements has been provided. The pH varied from 7.5 to 8.5 for the sub-base constructed with RCA whereas the pH of around 8 was obtained for the test section not affected by the traffic and de-icing salts. Despite a small variation in pH, the leachability of Al, Ca and Mg was found to be strongly dependent on pH and fair agreement between the measured and predicted concentrations was obtained. The speciation modelling indicated that gibbsite, calcite and magnesite controlled the solubility of Al, Ca and Mg, respectively, which was in agreement with the expected carbonation products. Due to the larger pH fluctuations in the test sections exposed to the road traffic, increased concentrations were observed for the oxyanions. The same effect was not seen for the trace metal cations Cd, Cu, Ni, Pb and Zn. The distinct pH dependent leaching profile (solubility maximum in the mildly basic pH region) for vanadium could be seen after 10years of exposure. The simplified risk assessment showed that the released quantities did not exceed the chosen acceptance criteria for groundwater and fresh water. The results obtained for the test section not influenced by road dust and de-icing salts, complied with these criteria even without considering any dilution effects caused by the mixing of pore water with groundwater.

  19. Exploration of the Theoretical Physical Capacity of the John F. Kennedy International Airport Runway System

    NASA Technical Reports Server (NTRS)

    Neitzke, Kurt W.; Guerreiro, Nelson M.

    2014-01-01

    A design study was completed to explore the theoretical physical capacity (TPC) of the John F. Kennedy International Airport (KJFK) runway system for a northflow configuration assuming impedance-free (to throughput) air traffic control functionality. Individual runways were modeled using an agent-based, airspace simulation tool, the Airspace Concept Evaluation System (ACES), with all runways conducting both departures and arrivals on a first-come first-served (FCFS) scheduling basis. A realistic future flight schedule was expanded to 3.5 times the traffic level of a selected baseline day, September 26, 2006, to provide a steady overdemand state for KJFK runways. Rules constraining departure and arrival operations were defined to reflect physical limits beyond which safe operations could no longer be assumed. Safety buffers to account for all sources of operational variability were not included in the TPC estimate. Visual approaches were assumed for all arrivals to minimize inter-arrival spacing. Parallel runway operations were assumed to be independent based on lateral spacing distances. Resulting time intervals between successive airport operations were primarily constrained by same-runway and then by intersecting-runway spacing requirements. The resulting physical runway capacity approximates a theoretical limit that cannot be exceeded without modifying runway interaction assumptions. Comparison with current KJFK operational limits for a north-flow runway configuration indicates a substantial throughput gap of approximately 48%. This gap may be further analyzed to determine which part may be feasibly bridged through the deployment of advanced systems and procedures, and which part cannot, because it is either impossible or not cost-effective to control. Advanced systems for bridging the throughput gap may be conceptualized and simulated using this same experimental setup to estimate the level of gap closure achieved.

  20. Environmental durability of polymer concrete

    SciTech Connect

    Palmese, G.R.; Chawalwala, A.J.

    1996-12-31

    Over the past two decades, polymer concrete has increasingly been used for a number of applications including piping, machine bases, chemically resistant flooring, and bridge overlays. Currently, the use of polymer concrete as a wear surface for polymeric composite bridge decks is being investigated. Polymer concrete is a particulate composite comprised of mineral aggregate bound by a polymeric matrix. Such materials possess significantly higher mechanical properties than Portland cement concrete. However, the mechanical characteristics and environmental durability of polymer concrete are influenced by a number of factors. Among these are the selection of aggregate and resin, surface treatment, and cure conditions. In this work the influence of matrix selection and cure history on the environmental durability of polymer concrete was investigated. Particular attention was given to the effects of water on composite properties and to the mechanisms by which degradation occurs. The basalt-based polymer concrete systems investigated were susceptible to attack by water. Furthermore, results suggest that property loss associated with water exposure was primarily a result of interfacial weakening.

  1. Cement and Concrete Nanoscience and Nanotechnology

    PubMed Central

    Raki, Laila; Beaudoin, James; Alizadeh, Rouhollah; Makar, Jon; Sato, Taijiro

    2010-01-01

    Concrete science is a multidisciplinary area of research where nanotechnology potentially offers the opportunity to enhance the understanding of concrete behavior, to engineer its properties and to lower production and ecological cost of construction materials. Recent work at the National Research Council Canada in the area of concrete materials research has shown the potential of improving concrete properties by modifying the structure of cement hydrates, addition of nanoparticles and nanotubes and controlling the delivery of admixtures. This article will focus on a review of these innovative achievements.

  2. Introduction to Concrete Finishing. Instructor Edition. Introduction to Construction Series.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This instructor's guide contains the materials required to teach a competency-based introductory course in concrete finishing to students who have chosen to explore careers in construction. The following topics are covered in the course's three instructional units: concrete materials, concrete tools, and applied skills. Each unit contains some or…

  3. KSC off-runway contingency operation - Mode 7

    NASA Technical Reports Server (NTRS)

    Maples, Arthur; Doerr, Donald

    1991-01-01

    The possibility of a mishap during a space shuttle landing at Kennedy Space Center (KSC) dictates the need for plans to rescue astronauts from areas other than the Shuttle Landing Facility (SLF). All shuttle landings are unpowered, gliding flight maneuvers, and a deviation from the planned flight profile could result in a shuttle landing or crashing somewhere other than the SLF runway. The geography of the Kennedy Space Center makes helicopter airlifting the only universal means of transportation for the rescue crew. This rescue crew is composed of KSC contractor fire-rescuemen who would ride to the crash scene on USAF HH-3 helicopters. These crews are provided with personal protective suits and training in shallow water, swamp, and dry land rescues. They aid the egress of the crew to a safe area for helicopter pickup and subsequent triage and medevac.

  4. KSC off-runway contingency operation - Mode 7

    NASA Technical Reports Server (NTRS)

    Maples, Arthur; Doerr, Donald

    1991-01-01

    The possibility of a mishap during a space shuttle landing at Kennedy Space Center (KSC) dictates the need for plans to rescue astronauts from areas other than the Shuttle Landing Facility (SLF). All shuttle landings are unpowered, gliding flight maneuvers, and a deviation from the planned flight profile could result in a shuttle landing or crashing somewhere other than the SLF runway. The geography of the Kennedy Space Center makes helicopter airlifting the only universal means of transportation for the rescue crew. This rescue crew is composed of KSC contractor fire-rescuemen who would ride to the crash scene on USAF HH-3 helicopters. These crews are provided with personal protective suits and training in shallow water, swamp, and dry land rescues. They aid the egress of the crew to a safe area for helicopter pickup and subsequent triage and medevac.

  5. Incorporating Active Runway Crossings in Airport Departure Scheduling

    NASA Technical Reports Server (NTRS)

    Gupta, Gautam; Malik, Waqar; Jung, Yoon C.

    2010-01-01

    A mixed integer linear program is presented for deterministically scheduling departure and ar rival aircraft at airport runways. This method addresses different schemes of managing the departure queuing area by treating it as first-in-first-out queues or as a simple par king area where any available aircraft can take-off ir respective of its relative sequence with others. In addition, this method explicitly considers separation criteria between successive aircraft and also incorporates an optional prioritization scheme using time windows. Multiple objectives pertaining to throughput and system delay are used independently. Results indicate improvement over a basic first-come-first-serve rule in both system delay and throughput. Minimizing system delay results in small deviations from optimal throughput, whereas minimizing throughput results in large deviations in system delay. Enhancements for computational efficiency are also presented in the form of reformulating certain constraints and defining additional inequalities for better bounds.

  6. Penetration of concrete targets

    SciTech Connect

    Forrestal, M.J.; Cargile, J.D.; Tzou, R.D.Y.

    1993-08-01

    We developed penetration equations for ogive-nosed projectiles that penetrated concrete targets after normal impact. Our penetration equations predict axial force on the projectile nose, rigid-body motion, and final penetration depth. For target constitutive models, we conducted triaxial material experiments to confining pressures of 600 MPa and curve-fit these data with a linear pressure-volumetric strain relation and with a linear Mohr-Coulomb, shear strength-pressure relation. To verify our penetration equations, we conducted eleven penetration experiments with 0.90 kg, 26.9-mm-diameter, ogive-nosed projectiles into 1.37-m-diameter concrete targets with unconfined compressive strengths between 32-40 MPa. Predictions from our penetration equation are compared with final penetration depth measurements for striking velocities between 280--800 m/s.

  7. Micro Environmental Concrete

    NASA Astrophysics Data System (ADS)

    Lanez, M.; Oudjit, M. N.; Zenati, A.; Arroudj, K.; Bali, A.

    Reactive powder concretes (RPC) are characterized by a particle diameter not exceeding 600 μm and having very high compressive and tensile strengths. This paper describes a new generation of micro concrete, which has an initial as well as a final high physicomechanical performance. To achieve this, 15% by weight of the Portland cement have been substituted by materials rich in Silica (Slag and Dune Sand). The results obtained from the tests carried out on the RPC show that compressive and tensile strengths increase when incorporating the addition, thus improving the compactness of mixtures through filler and pozzolanic effects. With a reduction in the aggregate phase in the RPC and the abundance of the dune sand (southern of Algeria) and slag (industrial by-product of the blast furnace), the use of the RPC will allow Algeria to fulfil economical as well as ecological requirements.

  8. STS-68 on Runway with 747 SCA - Columbia Ferry Flyby

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The space shuttle Endeavour receives a high-flying salute from its sister shuttle, Columbia, atop NASA's Shuttle Carrier Aircraft, shortly after Endeavor's landing 12 October 1994, at Edwards, California, to complete mission STS-68. Columbia was being ferried from the Kennedy Space Center, Florida, to Air Force Plant 42, Palmdale, California, where it will undergo six months of inspections, modifications, and systems upgrades. The STS-68 11-day mission was devoted to radar imaging of Earth's geological features with the Space Radar Laboratory. The orbiter is surrounded by equipment and personnel that make up the ground support convoy that services the space vehicles as soon as they land. Space Shuttles are the main element of America's Space Transportation System and are used for space research and other space applications. The shuttles are the first vehicles capable of being launched into space and returning to Earth on a routine basis. Space Shuttles are used as orbiting laboratories in which scientists and mission specialists conduct a wide variety of scientific experiments. Crews aboard shuttles place satellites in orbit, rendezvous with satellites to carry out repair missions and return them to space, and retrieve satellites and return them to Earth for refurbishment and reuse. Space Shuttles are true aerospace vehicles. They leave Earth and its atmosphere under rocket power provided by three liquid-propellant main engines with two solid-propellant boosters attached plus an external liquid-fuel tank. After their orbital missions, they streak back through the atmosphere and land like airplanes. The returning shuttles, however, land like gliders, without power and on runways. Other rockets can place heavy payloads into orbit, but, they can only be used once. Space Shuttles are designed to be continually reused. When Space Shuttles are used to transport complete scientific laboratories into space, the laboratories remain inside the payload bay throughout the

  9. STS-68 on Runway with 747 SCA - Columbia Ferry Flyby

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The space shuttle Endeavour receives a high-flying salute from its sister shuttle, Columbia, atop NASA's Shuttle Carrier Aircraft, shortly after Endeavor's landing 12 October 1994, at Edwards, California, to complete mission STS-68. Columbia was being ferried from the Kennedy Space Center, Florida, to Air Force Plant 42, Palmdale, California, where it will undergo six months of inspections, modifications, and systems upgrades. The STS-68 11-day mission was devoted to radar imaging of Earth's geological features with the Space Radar Laboratory. The orbiter is surrounded by equipment and personnel that make up the ground support convoy that services the space vehicles as soon as they land. Space Shuttles are the main element of America's Space Transportation System and are used for space research and other space applications. The shuttles are the first vehicles capable of being launched into space and returning to Earth on a routine basis. Space Shuttles are used as orbiting laboratories in which scientists and mission specialists conduct a wide variety of scientific experiments. Crews aboard shuttles place satellites in orbit, rendezvous with satellites to carry out repair missions and return them to space, and retrieve satellites and return them to Earth for refurbishment and reuse. Space Shuttles are true aerospace vehicles. They leave Earth and its atmosphere under rocket power provided by three liquid-propellant main engines with two solid-propellant boosters attached plus an external liquid-fuel tank. After their orbital missions, they streak back through the atmosphere and land like airplanes. The returning shuttles, however, land like gliders, without power and on runways. Other rockets can place heavy payloads into orbit, but, they can only be used once. Space Shuttles are designed to be continually reused. When Space Shuttles are used to transport complete scientific laboratories into space, the laboratories remain inside the payload bay throughout the

  10. NASA Runway Incursion Prevention System (RIPS) Dallas-Fort Worth Demonstration Performance Analysis

    NASA Technical Reports Server (NTRS)

    Cassell, Rick; Evers, Carl; Esche, Jeff; Sleep, Benjamin; Jones, Denise R. (Technical Monitor)

    2002-01-01

    NASA's Aviation Safety Program Synthetic Vision System project conducted a Runway Incursion Prevention System (RIPS) flight test at the Dallas-Fort Worth International Airport in October 2000. The RIPS research system includes advanced displays, airport surveillance system, data links, positioning system, and alerting algorithms to provide pilots with enhanced situational awareness, supplemental guidance cues, a real-time display of traffic information, and warnings of runway incursions. This report describes the aircraft and ground based runway incursion alerting systems and traffic positioning systems (Automatic Dependent Surveillance - Broadcast (ADS-B) and Traffic Information Service - Broadcast (TIS-B)). A performance analysis of these systems is also presented.

  11. Wake Encounter Analysis for a Closely Spaced Parallel Runway Paired Approach Simulation

    NASA Technical Reports Server (NTRS)

    Mckissick,Burnell T.; Rico-Cusi, Fernando J.; Murdoch, Jennifer; Oseguera-Lohr, Rosa M.; Stough, Harry P, III; O'Connor, Cornelius J.; Syed, Hazari I.

    2009-01-01

    A Monte Carlo simulation of simultaneous approaches performed by two transport category aircraft from the final approach fix to a pair of closely spaced parallel runways was conducted to explore the aft boundary of the safe zone in which separation assurance and wake avoidance are provided. The simulation included variations in runway centerline separation, initial longitudinal spacing of the aircraft, crosswind speed, and aircraft speed during the approach. The data from the simulation showed that the majority of the wake encounters occurred near or over the runway and the aft boundaries of the safe zones were identified for all simulation conditions.

  12. Construction, Maintenance, and Operation of a Glacial Runway, McMurdo Station, Antarctica

    DTIC Science & Technology

    1998-03-01

    Station ""-"- \\ /4 Amundsen - Scott ItS~~ South Pole Station t 01, ",,0 Marble Pt. • "",McMurdo •.•o/j... Scott South Pole Station , Concepts for such runways include "blue-ice"t and Palmer Station on the Antarctic Peninsula runways on glacier ice and runways...February. Numerous LC-130 flights (on wheels) were operated in supplying South Pole station , and a C-130 was operated between Christchurch and

  13. Mechanical behavior of concrete and related porous materials under partial saturation: The effective stress and the viscous softening due to movement of nanometer-scale pore fluid

    NASA Astrophysics Data System (ADS)

    Vlahinic, Ivan

    becomes necessary to describe the fluid flow in a double porosity medium, i.e. a medium containing both macro- and nano-scale porosity. We show that the proposed model can quantitatively capture the key observations that have thus far evaded a simple mechanical description. The materials more closely examined in this work enjoy a wide variety of practical uses. Wood and concrete are used as a basis for infrastructure the world over; porous glass with engineered nanometer-sized openings is used for its sorptive and filtering abilities; KevlarRTM and similar synthetic polymers are used for their high strength-to-weight ratio in creating body armor, ropes, and even sails.

  14. Effects of runway shift and stay rules on rats' serial pattern learning in the T-maze.

    PubMed

    Cohen, Jerome; Westlake, Kimberly; Szelest, Izabela

    2004-11-01

    Rats received three-trial series on a T-maze consisting of extended visually distinct left-black and right-striped side runways. During the first phase of training, when allowed to select baited runways within these series, they predominantly alternated their choices. During the second phase, rats received forced-choice serial pattern training of series consisting of two rewarded (R) trials and one nonrewarded (N) trial in two fixed orders, RRN and RNR. In Experiment 1, the rats in the runway shift rule group always received the second R trial when forced down a runway opposite that on the preceding trial in the series and the N trial when forced down the same runway. The rats in the runway stay rule group always received the second R trial when forced down the same runway and the N trial when forced down the opposite runway. In Experiment 2, each rat was conditionally trained with both runway outcome rules as determined by the central alley lighting and the type of food in the side alleys. The rats took longer to reduce their running speed on the N trial within each sequence under the runway stay rule than under the runway shift rule. They also took longer to acquire serial pattern responding for the RNR than for the RRN series only under the runway stay rule condition. When subsequently reexposed to series of free-choice trials on the final phase, rats maintained spontaneous alternating choice patterns under the runway shift rule conditions but either seldom alternated their choices (Experiment 1) or greatly reduced choice alternations (Experiment 2) under the runway stay rule condition. We discussed these effects in terms of rats' natural foraging strategies and as a factor that interacts with other within- and between-series variables that affect serial pattern behavior.

  15. Experimental needs of high temperature concrete

    SciTech Connect

    Chern, J.C.; Marchertas, A.H.

    1985-01-01

    The needs of experimental data on concrete structures under high temperature, ranging up to about 370/sup 0/C for operating reactor conditions and to about 900/sup 0/C and beyond for hypothetical accident conditions, are described. This information is required to supplement analytical methods which are being implemented into the finite element code TEMP-STRESS to treat reinforced concrete structures. Recommended research ranges from material properties of reinforced/prestressed concrete, direct testing of analytical models used in the computer codes, to investigations of certain aspects of concrete behavior, the phenomenology of which is not well understood. 10 refs.

  16. Design and fabrication of polymer concrete pipe

    SciTech Connect

    Schroeder, J.E.; Abdelgawad, A.T.

    1982-10-08

    Polymer concrete is a composite material which has strength and durability characteristics greatly superior to those of portland cement concrete and better durability in hot brine than steel. polymer concrete has been successfully tested in brine and steam at temperatures up to 260 C. Exposures were as long as 960 days. Glass filament wound polymer concrete pipe was developed with excellent strength, low weight, and a cost comparable to or less than schedule 40 steel. Connections can be made with slip joints for low pressure applications and flanged joints for high pressure applications.

  17. Effects of various runway lighting parameters upon the relation between runway visual range and visual range of centerline and edge lights in fog

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1973-01-01

    Thirty six students and 54 commercial airline pilots were tested in the fog chamber to determine the effect of runway edge and centerline light intensity and spacing, fog density, ambient luminance level, and lateral and vertical offset distance of the subject from the runway's centerline upon horizontal visual range. These data were obtained to evaluate the adequacy of a balanced lighting system to provide maximum visual range in fog viewing both centerline and runway edge lights. The daytime system was compared against two other candidate lighting systems; the nighttime system was compared against other candidate lighting systems. The second objective was to determine if visual range is affected by lights between the subject and the farthestmost light visible through the fog. The third objective was to determine if college student subjects differ from commercial airline pilots in their horizontal visual range through fog. Two studies were conducted.

  18. Construction Cluster Volume IV: [Concrete Work].

    ERIC Educational Resources Information Center

    Pennsylvania State Dept. of Justice, Harrisburg. Bureau of Correction.

    The document is the fourth of a series, to be integrated with a G.E.D. program, containing instructional materials for the construction cluster. The volume focuses on concrete work and consists of 20 instructional units which require a month of study. The units include: (1) uses of concrete and occupational information; (2) soils, drainage, and…

  19. Using Concrete Manipulatives in Mathematical Instruction

    ERIC Educational Resources Information Center

    Jones, Julie P.; Tiller, Margaret

    2017-01-01

    Concrete, Representational, Abstract (CRA) instruction is a process for teaching and learning mathematical concepts. Starting with manipulation of concrete materials (counters, beans, Unifix cubes), the process moves students to the representational level (tallies, dots, stamps), and peaks at the abstract level, at which numbers and symbols are…

  20. Three-track runway and taxiway profiles measured at International Airports E and F

    NASA Technical Reports Server (NTRS)

    Hall, A. W.

    1971-01-01

    Three-track runway and taxiway profiles are presented for use in studies of airplane response to ground roughness. This report presents the tabulated and plotted data for two international airports (designed airports E and F).

  1. Three-track runway and taxiway profiles measured at international airports G and H

    NASA Technical Reports Server (NTRS)

    Hall, A. W.

    1972-01-01

    Three-track runway and taxiway profiles are presented for use in studies of airplane response to ground roughness. This report presents the tabulated and plotted data for two international airports (designated airports G and H).

  2. White Sands Space Harbor Area 1, Runway 17/35, Extending 35,000 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    White Sands Space Harbor Area 1, Runway 17/35, Extending 35,000 feet north from Range Road 10, beginning approximately 4.2 miles northeast of intersection with Range Road 7, White Sands, Dona Ana County, NM

  3. Three-track runway and taxiway profiles measured at international airports I and J

    NASA Technical Reports Server (NTRS)

    Hall, A. W.

    1972-01-01

    Three-track runway and taxiway profiles are presented for use in studies of airplane response to ground roughness. Tabulated and plotted data for two international airports, (designated I and J), are included.

  4. Development and Execution of the RUNSAFE Runway Safety Bayesian Belief Network Model

    NASA Technical Reports Server (NTRS)

    Green, Lawrence L.

    2015-01-01

    One focus area of the National Aeronautics and Space Administration (NASA) is to improve aviation safety. Runway safety is one such thrust of investigation and research. The two primary components of this runway safety research are in runway incursion (RI) and runway excursion (RE) events. These are adverse ground-based aviation incidents that endanger crew, passengers, aircraft and perhaps other nearby people or property. A runway incursion is the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and take-off of aircraft; one class of RI events simultaneously involves two aircraft, such as one aircraft incorrectly landing on a runway while another aircraft is taking off from the same runway. A runway excursion is an incident involving only a single aircraft defined as a veer-off or overrun off the runway surface. Within the scope of this effort at NASA Langley Research Center (LaRC), generic RI, RE and combined (RI plus RE, or RUNSAFE) event models have each been developed and implemented as a Bayesian Belief Network (BBN). Descriptions of runway safety issues from the literature searches have been used to develop the BBN models. Numerous considerations surrounding the process of developing the event models have been documented in this report. The event models were then thoroughly reviewed by a Subject Matter Expert (SME) panel through multiple knowledge elicitation sessions. Numerous improvements to the model structure (definitions, node names, node states and the connecting link topology) were made by the SME panel. Sample executions of the final RUNSAFE model have been presented herein for baseline and worst-case scenarios. Finally, a parameter sensitivity analysis for a given scenario was performed to show the risk drivers. The NASA and LaRC research in runway safety event modeling through the use of BBN technology is important for several reasons. These include: 1) providing a means to clearly

  5. Numerical simulation of steel-concrete composite Virender beam

    NASA Astrophysics Data System (ADS)

    Wu, Qinggui; Cao, Xinming; Luo, Quanrui

    2017-08-01

    In this paper, a new type of steel-concrete composite Vierendeel beam is proposed. The finite element analysis of the new type of steel-concrete composite Vierendeel beam is carried out by using ABAQUS. To compare the mechanical properties with traditional beam, the normal reinforced concrete beam with the same section size is also analyzed by using ABAQUS. The simulation results show that the material strength of the new type steel-concrete composite Vierendeel beam is fully utilized, and the flexural capacity and deformation performance of the new type of steel-concrete composite Vierendeel beam are greatly improved compared with normal reinforced concrete beam.

  6. STS-38 Atlantis, Orbiter Vehicle (OV) 104, lands on runway 33 at KSC SLF

    NASA Image and Video Library

    1990-11-20

    STS038-S-041 (20 Nov 1990) --- STS-38 Atlantis, Orbiter Vehicle (OV) 104, lands on runway 33 at Kennedy Space Center (KSC) Shuttle Landing Facility (SLF). The main landing gear (MLG) has just touched down on the runway surface as the nose landing gear (NLG) glides above it. The Department of Defense (DOD)-devoted mission came to an end (with complete wheel stop) at 4:43:37 pm (Eastern Standard Time (EST)).

  7. STS-34 Atlantis, OV-104, touches down on runway 23 at EAFB, California

    NASA Image and Video Library

    1989-10-23

    STS-34 Atlantis, Orbiter Vehicle (OV) 104, main landing gear (MLG) touches down on Runway 23 dry lake bed at Edwards Air Force Base (EAFB), California. The nose landing gear rides above runway before touchdown as the MLG wheels produce a cloud of dust. OV-104's port side profile is captured as it glides by at a speed of approximately 195 knots (224 miles per hour). The tail section with deployed speedbrake/rudder and space shuttle main engines (SSMEs) are visible.

  8. Evaluation of Winter Operational Runway Friction Measurement Equipment, Procedures, and Research

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This document produced by the FAA/Industry Winter Runway Friction Measurement and Reporting Working Group, is designed to provide an overview of current information on the present guidance, practices, and procedures for reporting runway pavement surface conditions during winter operations at airports. It contains recommendations on the desirability of providing the best procedural consistency and standardization and discusses the available means to implement the guidance that will result in improved aviation safety at airports during hazardous winter conditions.

  9. Bond characteristics of reinforcing steel embedded in geopolymer concrete

    NASA Astrophysics Data System (ADS)

    Kathirvel, Parthiban; Thangavelu, Manju; Gopalan, Rashmi; Raja Mohan Kaliyaperumal, Saravana

    2017-07-01

    The force transferring between reinforcing steel and the surrounding concrete in reinforced concrete is influenced by several factors. Whereas, the study on bond behaviour of geopolymer concrete (GPC) is lagging. In this paper, an experimental attempt has been made to evaluate the geopolymer concrete bond with reinforcing steel of different diameter and embedded length using standard pull out test. The geopolymer concrete is made of ground granulated blast furnace slag (GGBFS) as geopolymer source material (GSM). The tests were conducted to evaluate the development of bond between steel and concrete of grade M40 and M50 with 12 and 16 mm diameter reinforcing steel for geopolymer and cement concrete mixes and to develop a relation between bond strength and compressive strength. From the experimental results, it has been observed that the bond strength of the geopolymer concrete mixes was more compared to the cement concrete mixes and increases with the reduction in the diameter of the bar.

  10. Effect of Iron and Carbonation of the Diffusion of Iodine and Rhenium in Waste Encasement Concrete and Soil Fill Material under Hydraulically Unsaturated Conditions

    SciTech Connect

    Wellman, Dawn M.; Parker, Kent E.; Powers, Laura; Whyatt, Greg A.; Clayton, Libby N.; Mattigod, Shas V.; Wood, Marcus I.

    2008-07-31

    Assessing long-term performance of Category 3 cement wasteforms and accurate prediction for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e. sorption or precipitation). A set of sediment-concrete half-cell diffusion experiments was conducted under unsaturated conditions (4% and 7% by weight moisture content) using carbonated and non-carbonated concrete-soil half-cells. Results indicate the behavior of rhenium and iodine release was comparable within a given half-cell test. Diffusivity in soil is a function of moisture content; a 3% increase in moisture content affords a one to two order of magnitude increase in diffusivity. Release of iodine and rhenium was 1 to 3 orders of magnitude less from non-carbonated, relative to carbonated, concrete monoliths. Inclusion of iron in non-carbonate monoliths resulted in the lowest concrete diffusivity values for both iodine and rhenium. This suggests that in the presence of iron, iodine and rhenium are converted to reduced species, which are less soluble and better retained within the concrete monolith. The release of iodine and rhenium was greatest from iron-bearing, carbonated concrete monoliths, suggesting carbonation negates the effect of iron on the retention of iodine and rhenium within concrete monoliths. This is likely due to enhanced formation of microcracks in the presence of iron, which provide preferential paths for contaminant migration. Although the release of iodine and rhenium were greatest from carbonated concrete monoliths containing iron, the migration of iodine and rhenium within a given half-cell is dependent on the moisture content, soil diffusivity, and diffusing species.

  11. The Apparent Thermal Conductivity of Pozzolana Concrete

    NASA Astrophysics Data System (ADS)

    Bessenouci, M. Z.; Triki, N. E. Bibi; Khelladi, S.; Draoui, B.; Abene, A.

    The recent development of some lightweight construction materials, such as light concrete, can play an important role as an insulator, while maintaining sufficient levels of mechanical performance. The quality of insulation to provide depends on the climate, the exposure of the walls and also the materials used in the construction. The choice of a material to be used as an insulator, obviously, depends on its availability and its cost. This is a study of natural pozzolanas as basic components in building materials. It is intended to highlight their thermal advantage. It is economically advantageous to use pozzolana in substitution for a portion of the clinker as hydraulically active additions, as well as in compositions of lightweight concretes in the form of pozzolanic aggregate mixtures, which provide mechanical strengths that comply with current standards. A theoretical study is conducted on the apparent thermal conductivity of building materials, namely concrete containing pozzolana. Thermal modeling, apparent to that commonly used for porous materials, has been applied to pozzolana concrete. Experimental results on measurements of the apparent thermal conductivity of pozzolana concrete are reported in this study, using an approach that considers that concrete is composed of two solid ingredients, a binding matrix (hydrated cement paste) and all aggregates. A second comparative theoretical approach is used for the case where concrete consists of a solid phase and a fluid phase (air).

  12. Self-cleaning geopolymer concrete - A review

    NASA Astrophysics Data System (ADS)

    Norsaffirah Zailan, Siti; Mahmed, Norsuria; Bakri Abdullah, Mohd Mustafa Al; Sandu, Andrei Victor

    2016-06-01

    Concrete is the most widely used construction materials for building technology. However, cement production releases high amounts of carbon dioxide (CO2) to the atmosphere that leads to increasing the global warming. Thus, an alternative, environmental friendly construction material such as geopolymer concrete has been developed. Geopolymer concrete applies greener alternative binder, which is an innovative construction material that replaces the Portland cement. This technology introduced nano-particles such as nanoclay into the cement paste in order to improve their mechanical properties. The concrete materials also have been developed to be functioned as self-cleaning construction materials. The self-cleaning properties of the concrete are induced by introducing the photocatalytic materials such as titania (TiO2) and zinc oxide (ZnO). Self-cleaning concrete that contains those photocatalysts will be energized by ultraviolet (UV) radiation and accelerates the decomposition of organic particulates. Thus, the cleanliness of the building surfaces can be maintained and the air surrounding air pollution can be reduced. This paper briefly reviews about self-cleaning concrete.

  13. Benefits of continuous deflection profile analysis: a case study of runway 17R-35L at Dallas/Fort Worth International Airport using the rolling dynamic deflectometer

    NASA Astrophysics Data System (ADS)

    Turen, Tracy A.; Dossey, Terry; McCullough, B. F.

    1998-03-01

    A research project was undertaken by the The University of Texas at Austin's Center for Transportation Research to assess the condition and remaining life of a large section of Runway (RW) 17R-35L and taxiway L at Dallas/Fort Worth International Airport. Concrete fatigue was determined from fatigue testing of RW core samples and from deflection data obtained from an experimental testing device called the Rolling Dynamic Deflectometer (RDD). The RDD is a truck-mounted device that measures continuous deflection profiles of pavements. The RDD appears to be a very promising device for use in pavement performance analysis. The RDD gives much more comprehensive deflection data than devices currently in use such as the Falling Weight Deflectometer and the Dynaflect and the data collection procedure is quicker and more efficient. Additionally, continuous deflection profiles provide more ways of assessing the in-place structural adequacy of pavements. For this research, RDD data from one section approximately 305 m (1000 ft.) was selected to illustrate several possible ways to analyze the data. Due to the large amount of data collected by sampling every 152 mm (6 in.) on a runway over a mile in length, a program called RDD3 was developed to perform the analysis. Results of this analysis are presented here.

  14. An assessment of predominant causal factors of pilot deviations that contribute to runway incursions

    NASA Astrophysics Data System (ADS)

    Campbell, Denado M.

    The aim of this study was to identify predominant causal factors of pilot deviations in runway incursions over a two-year period. Runway incursion reports were obtained from NASA's Aviation Safety Reporting System (ASRS), and a qualitative method was used by classifying and coding each report to a specific causal factor(s). The causal factors that were used were substantiated by research from the Aircraft Owner's and Pilot's Association that found that these causal factors were the most common in runway incursion incidents and accidents. An additional causal factor was also utilized to determine the significance of pilot training in relation to runway incursions. From the reports examined, it was found that miscommunication and situational awareness have the greatest impact on pilots and are most often the major causes of runway incursions. This data can be used to assist airports, airlines, and the FAA to understand trends in pilot deviations, and to find solutions for specific problem areas in runway incursion incidents.

  15. A method for determining landing runway length for a STOL aircraft

    NASA Technical Reports Server (NTRS)

    Watson, D. M.; Hardy, G. H.; Moran, J. F.; Warner, D. N., Jr.

    1981-01-01

    Based on data obtained from flight tests of the augmentor wing jet STOL research aircraft, a method is proposed for determining the length of the landing runway for powered-lift STOL aircraft. The suggested method determines runway landing length by summing three segments: the touchdown-dispersion distance, the transition distance from touchdown to application of brakes, and the stopping distance after brakes are applied. It is shown how the landing field length can be reduced either through improved autoland system design or by providing the pilot with appropriate information to allow him to identify a "low probability" long or short landing and to execute a go-around. The proposed method appears to determine a safe runway landing length for the STOL application and offers the potential for reducing runway length if great emphasis is placed on a short-runway capability. FAR Parts 25 and 121 appear conservative and suitable for the situation where no great emphasis is placed on reducing the runway length requirement.

  16. An airport runway centerline location method for one-off aerial imaging system

    NASA Astrophysics Data System (ADS)

    Ge, Shule; Xu, Tingfa; Ni, Guoqiang; Shao, Xiaoguang

    2010-11-01

    An airport runway centerline location method is proposed for extracting airport runway in images from one-off aerial imaging system. One-off aerial imaging system captures image at an altitude about one kilometer or below, thus detailed feature of the scenery reveals itself clearly. The proposed method relies on this precondition to detect and locate centerline of airport runway. This method has four steps: edge detection, dominating line orientation extraction, distance histogram building and centerline location. A salient edge detection method is developed with Sobel detector, which could detect edges of runway strips at the disturbance of edges features from surrounding objects. Then, a traditional Hough transform is performed to build a Hough map, within which the dominating line orientation is extracted. After getting the dominating line orientation, a reference straight line is chosen for building distance histogram. This distance histogram is a one-dimensional one, built up with the distance of all edge pixels in the edge map to the reference line. Airport centerline has a three-peak pattern in the one-dimensional distance histogram, and the center peak is corresponding to the centerline of airport runway. Experiments with simulated images show this method could location airport runway centerline effectively.

  17. Hydroelastic response of a floating runway to cnoidal waves

    SciTech Connect

    Ertekin, R. C.; Xia, Dingwu

    2014-02-15

    The hydroelastic response of mat-type Very Large Floating Structures (VLFSs) to severe sea conditions, such as tsunamis and hurricanes, must be assessed for safety and survivability. An efficient and robust nonlinear hydroelastic model is required to predict accurately the motion of and the dynamic loads on a VLFS due to such large waves. We develop a nonlinear theory to predict the hydroelastic response of a VLFS in the presence of cnoidal waves and compare the predictions with the linear theory that is also developed here. This hydroelastic problem is formulated by directly coupling the structure with the fluid, by use of the Level I Green-Naghdi theory for the fluid motion and the Kirchhoff thin plate theory for the runway. The coupled fluid structure system, together with the appropriate jump conditions are solved in two-dimensions by the finite-difference method. The numerical model is used to study the nonlinear response of a VLFS to storm waves which are modeled by use of the cnoidal-wave theory. Parametric studies show that the nonlinearity of the waves is very important in accurately predicting the dynamic bending moment and wave run-up on a VLFS in high seas.

  18. Runway Independent Aircraft Extremely Short Takeoff and Landing

    NASA Technical Reports Server (NTRS)

    Hall, David W.; Pasman, Renee

    2004-01-01

    This report Summarizes the work done is support of NASA/Ames Runway Independent Aircraft Research during the summer of 2003. This work centered on the tasks laid out by the Statement of Work, which was to: Identify and assess operational scenarios including airport air and ground operations and how RIA operations would interface; 2) Identify critical technologies and create a list of technologies that might be pushed to provide a quantum jump in operating economy, reliability, and safety should sufficient finding be available; 3) Create public domain powered high lift methodologies; and 4) Identify and assess vehicle concepts that provide innovative approaches to RIA operations. All these tasks were accomplished, with certain areas needing additional exploration in future grant work. Three designs were analyzed to provide strawman configurations for the RIA operations. All three aircraft carried 60 passengers, with a stage length of 1,000 nautical miles. They were capable of operating with a balanced field length of 2000 feet or less. Three different technology approaches were explored. The first, the Model 115, was a mid-wing USB design, developed as a near-term, low risk concept. The second aircraft, the EMAX, used a directed thrust system, was a far-term, high-risk approach. The third configuration was the Model 114, whose development began in summer 2002. In addition, further research was conducted on issues related to STOL operations, such as noise concerns, SNI operations, and other areas of interest.

  19. Fuel dispersal modeling for aircraft-runway impact scenarios

    SciTech Connect

    Tieszen, S.R.

    1995-11-01

    A fuel dispersal model for C-141 transport accidents was developed for the Defense Nuclear Agency`s Fuel Fire Technology Base Program to support Weapon System Safety Assessments. The spectrum of accidents resulting from aircraft impact on a runway was divided into three fuel dispersal regimes: low, intermediate, and high-velocity impact. Sufficient data existed in the accident, crash test, and fuel-filled bomb literature to support development of a qualitative framework for dispersal models, but not quantitative models for all regimes. Therefore, a test series at intermediate scale was conducted to generate data on which to base the model for the high-velocity regime. Tests were conducted over an impact velocity range from 12 m/s to 91 m/s and angles of impact from 22.5{degrees} to 67.5{degrees}. Dependent variables were area covered by dispersed fuel, amount of mass in that area, and location of the area relative to the impact line. Test results showed that no liquid pooling occurred for impact velocities greater than 61 m/s, independent of the angle of impact. Some pooling did occur at lower velocities, but in no test was the liquid-layer thickness greater than 5.25 mm.

  20. Determination of optimal trajectories for an aircraft returning to the runway following a complete loss of thrust after takeoff

    NASA Astrophysics Data System (ADS)

    Gordon, Craig A.

    This thesis examines the ability of a small, single-engine airplane to return to the runway following an engine failure shortly after takeoff. Two sets of trajectories are examined. One set of trajectories has the airplane fly a straight climb on the runway heading until engine failure. The other set of trajectories has the airplane perform a 90° turn at an altitude of 500 feet and continue until engine failure. Various combinations of wind speed, wind direction, and engine failure times are examined. The runway length required to complete the entire flight from the beginning of the takeoff roll to wheels stop following the return to the runway after engine failure is calculated for each case. The optimal trajectories following engine failure consist of three distinct segments: a turn back toward the runway using a large bank angle and angle of attack; a straight glide; and a reversal turn to align the airplane with the runway. The 90° turn results in much shorter required runway lengths at lower headwind speeds. At higher headwind speeds, both sets of trajectories are limited by the length of runway required for the landing rollout, but the straight climb cases generally require a lower angle of attack to complete the flight. The glide back to the runway is performed at an airspeed below the best glide speed of the airplane due to the need to conserve potential energy after the completion of the turn back toward the runway. The results are highly dependent on the rate of climb of the airplane during powered flight. The results of this study can aid the pilot in determining whether or not a return to the runway could be performed in the event of an engine failure given the specific wind conditions and runway length at the time of takeoff. The results can also guide the pilot in determining the takeoff profile that would offer the greatest advantage in returning to the runway.

  1. 8. Photocopied August 1978. BREAKING CONCRETE BARS, JULY 1898. TESTING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Photocopied August 1978. BREAKING CONCRETE BARS, JULY 1898. TESTING MACHINE USED BY VON SCHON IN EXPERIMENTS ON METHODS OF MIXING CONCRETE AND ON CONCRETE AGGREGATES WHICH USED LOCAL MATERIALS. (4) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  2. 7 CFR 3201.36 - Concrete and asphalt release fluids.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Concrete and asphalt release fluids. 3201.36 Section... PROCUREMENT Designated Items § 3201.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete...

  3. 7 CFR 2902.36 - Concrete and asphalt release fluids.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Concrete and asphalt release fluids. 2902.36 Section... PROCUREMENT Designated Items § 2902.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete...

  4. 7 CFR 3201.36 - Concrete and asphalt release fluids.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Concrete and asphalt release fluids. 3201.36 Section... PROCUREMENT Designated Items § 3201.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete...

  5. 7 CFR 2902.36 - Concrete and asphalt release fluids.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Concrete and asphalt release fluids. 2902.36 Section... PROCUREMENT Designated Items § 2902.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete...

  6. 7 CFR 3201.36 - Concrete and asphalt release fluids.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Concrete and asphalt release fluids. 3201.36 Section... PROCUREMENT Designated Items § 3201.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete...

  7. Patio Stone Project Gives Students a Concrete Learning Experience

    ERIC Educational Resources Information Center

    Fitzgerald, Mike

    2005-01-01

    In this article, the author presents an overview of concrete as a building material and as an example of a particle composite, and discusses the origins of concrete in ancient Rome. He then describes an activity in which students can cast a concrete patio stone. Students can apply the technological design process, as well as the elements of…

  8. Patio Stone Project Gives Students a Concrete Learning Experience

    ERIC Educational Resources Information Center

    Fitzgerald, Mike

    2005-01-01

    In this article, the author presents an overview of concrete as a building material and as an example of a particle composite, and discusses the origins of concrete in ancient Rome. He then describes an activity in which students can cast a concrete patio stone. Students can apply the technological design process, as well as the elements of…

  9. Life Cycle Assessment of Completely Recyclable Concrete

    PubMed Central

    De Schepper, Mieke; Van den Heede, Philip; Van Driessche, Isabel; De Belie, Nele

    2014-01-01

    Since the construction sector uses 50% of the Earth’s raw materials and produces 50% of its waste, the development of more durable and sustainable building materials is crucial. Today, Construction and Demolition Waste (CDW) is mainly used in low level applications, namely as unbound material for foundations, e.g., in road construction. Mineral demolition waste can be recycled as crushed aggregates for concrete, but these reduce the compressive strength and affect the workability due to higher values of water absorption. To advance the use of concrete rubble, Completely Recyclable Concrete (CRC) is designed for reincarnation within the cement production, following the Cradle-to-Cradle (C2C) principle. By the design, CRC becomes a resource for cement production because the chemical composition of CRC will be similar to that of cement raw materials. If CRC is used on a regular basis, a closed concrete-cement-concrete material cycle will arise, which is completely different from the current life cycle of traditional concrete. Within the research towards this CRC it is important to quantify the benefit for the environment and Life Cycle Assessment (LCA) needs to be performed, of which the results are presented in a this paper. It was observed that CRC could significantly reduce the global warming potential of concrete. PMID:28788174

  10. Life Cycle Assessment of Completely Recyclable Concrete.

    PubMed

    De Schepper, Mieke; Van den Heede, Philip; Van Driessche, Isabel; De Belie, Nele

    2014-08-21

    Since the construction sector uses 50% of the Earth's raw materials and produces 50% of its waste, the development of more durable and sustainable building materials is crucial. Today, Construction and Demolition Waste (CDW) is mainly used in low level applications, namely as unbound material for foundations, e.g., in road construction. Mineral demolition waste can be recycled as crushed aggregates for concrete, but these reduce the compressive strength and affect the workability due to higher values of water absorption. To advance the use of concrete rubble, Completely Recyclable Concrete (CRC) is designed for reincarnation within the cement production, following the Cradle-to-Cradle (C2C) principle. By the design, CRC becomes a resource for cement production because the chemical composition of CRC will be similar to that of cement raw materials. If CRC is used on a regular basis, a closed concrete-cement-concrete material cycle will arise, which is completely different from the current life cycle of traditional concrete. Within the research towards this CRC it is important to quantify the benefit for the environment and Life Cycle Assessment (LCA) needs to be performed, of which the results are presented in a this paper. It was observed that CRC could significantly reduce the global warming potential of concrete.

  11. Workability of Mass Concrete. Report 2. Supplemental Proportioning Parameters.

    DTIC Science & Technology

    1996-09-01

    proportions for mass concrete with assurance that the concrete will have adequate workability. The initial phase of this study was to obtain information...Corps of Engineers (HQUSACE), as a part of Civil Works Investigation Studies Work Unit 32768, "Workability of Mass Concrete ." The study was conducted...Paul F. Mlakar, Chief, Concrete and Materials Division (CMD), and Mr. Edward F. O’Neil, Acting Chief, Engineering Mechanics Branch (EMB), CMD. Dr

  12. Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 2. Toxicity of aircraft and runway deicer

    USGS Publications Warehouse

    Corsi, Steven; Hall, David W.; Geis, Steven W.

    2001-01-01

    Streams receiving runoff from General Mitchell International Airport (GMIA), Milwaukee, Wisconsin, USA, were studied to assess toxic impacts of aircraft and runway deicers. Elevated levels of constituents related to deicing (propylene glycol, ethylene glycol, and ammonia) were observed in stream samples. The LC50s of type I deicer for Ceriodaphnia dubia, Pimephelas promelas, Hyalela azteca, and Chironimus tentans and the EC50 for Microtox® were less than 5,000 mg/L of propylene glycol. Concentrations up to 39,000 mg/L were observed at airport outfall sites in samples collected during deicing events. The IC25s of type I deicer for C. dubia and P. promelas were less than 1,500 mg/L of propylene glycol. Concentrations up to 960 mg/L were observed in low-flow samples at an airport outfall site. Measured toxicity of stream water was greatest during winter storms when deicers were applied. Chronic toxicity was observed at airport outfall samples from low-flow periods in the winter and the summer, with the greater toxic impacts from the winter sample. All forms of toxicity in stream-water samples decreased as downstream flows increased.

  13. Retrofitting of Reinforced Concrete Beams using Reactive Powder Concrete (RPC)

    NASA Astrophysics Data System (ADS)

    Karthik, S.; Sundaravadivelu, Karthik

    2017-07-01

    Strengthening of existing damaged structures is one of the leading studies in civil engineering. The purpose of retrofitting is to structurally treat the member with an aim to restore the structure to its original strength. The focus of this project is to study the behaviour of damaged Reinforced Concrete beam retrofitted with Reactive Powder Concrete (RPC) Overlay. Reinforced concrete beams of length 1200 mm, width 100 mm and depth 200 mm were casted with M30 grade of concrete in the laboratory and cured for 28 days. One beam is taken as control and are tested under two point loading to find out ultimate load. Remaining beams are subjected to 90 % ultimate load of control beams. The partially damaged beams are retrofitted with Reactive Powder Concrete Overlay at the full tension face of the beam and side overlay depends upon the respectable retrofitting techniques with 10 mm and 20 mm thick layer to find optimum. Materials like steel fibres are added to enhance the ductility by eliminating coarse particle for homogeneity of the structure. Finally, the modes of failure for retrofitted beams are analysed experimentally under two point loading & compared the results with Control beam.

  14. From Runway to Orbit: Reflections of a NASA Engineer

    NASA Technical Reports Server (NTRS)

    Iliff, Kenneth W.; Peebles, Curtis L.

    2004-01-01

    In his remarkable memoir Runway to Orbit, Dr. Kenneth W. Iliff - the recently retired Chief Scientist of the NASA Dryden Flight Research Center- tells a highly personal, yet a highly persuasive account of the last forty years of American aeronautical research. His interpretation of events commands respect, because over these years he has played pivotal roles in many of the most important American aeronautics and spaceflight endeavors. Moreover, his narrative covers much of the second half of the first 100 years of flight, a centennial anniversary being celebrated this year. aerospace knowledge. He arrived at the then NASA Flight Research Center in 1962 as a young aeronautical engineer and quickly became involved in two of the seminal projects of modern flight, the X-15 and the lifting bodies. In the process, he pioneered (with Lawrence Taylor) the application of digital computing to the reduction of flight data, arriving at a method known as parameter estimation, now applied the world over. Parameter estimation not only enabled researchers to acquire stability and control derivatives from limited flight data, but in time allowed them to obtain a wide range of aerodynamic effects. Although subsequently involved in dozens of important projects, Dr. Iliff devoted much of his time and energy to hypersonic flight, embodied in the Shuttle orbiter (or as he refers to it, the world s fastest airplane). To him, each Shuttle flight, instrumented to obtain a variety of data, represents a research treasure trove, one that he has mined for years. This book, then, represents the story of Dr. Ken Iliff s passion for flight, his work, and his long and astoundingly productive career. It can be read with profit not just by scientists and engineers, but equally by policy makers, historians, and journalists wishing to better comprehend advancements in flight during the second half of the twentieth century. Dr. Iliff's story is one of immense contributions to the nation s repository of

  15. Nanogranular origin of concrete creep.

    PubMed

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-06-30

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium-silicate-hydrates (C-S-H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C-S-H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C-S-H forms: low density, high density, ultra-high density. We demonstrate that the creep rate ( approximately 1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years.

  16. Nanogranular origin of concrete creep

    PubMed Central

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-01-01

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium–silicate–hydrates (C–S–H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C–S–H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C–S–H forms: low density, high density, ultra-high density. We demonstrate that the creep rate (≈1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years. PMID:19541652

  17. Diffusion and Leaching of Selected Radionuclides (Iodine-129, Technetium-99, and Uranium) Through Category 3 Waste Encasement Concrete and Soil Fill Material

    SciTech Connect

    Mattigod, Shas V.; Whyatt, Greg A.; Serne, R. Jeffrey; Martin, P. F.; Schwab, Kristen E.; Wood, Marcus I.

    2001-09-24

    An assessment of long-term performance of Category 3 waste-enclosing cement grouts requires data about the leachability/diffusion of radionuclide species (iodine-129, technetium-99, and uranium) when the waste forms come in contact with groundwater. Leachability data were collected by conducting dynamic (ANS-16.1) and static leach tests on radionuclide-containing cement specimens. The diffusivity of radionuclides in soil and concrete media was collected by conducting soil-soil and concrete-soil half-cell experiments.

  18. Benefits Assessment for Single-Airport Tactical Runway Configuration Management Tool (TRCM)

    NASA Technical Reports Server (NTRS)

    Oseguera-Lohr, Rosa; Phojanamonogkolkij, Nipa; Lohr, Gary W.

    2015-01-01

    The System-Oriented Runway Management (SORM) concept was developed as part of the Airspace Systems Program (ASP) Concepts and Technology Development (CTD) Project, and is composed of two basic capabilities: Runway Configuration Management (RCM), and Combined Arrival/Departure Runway Scheduling (CADRS). RCM is the process of designating active runways, monitoring the active runway configuration for suitability given existing factors, and predicting future configuration changes; CADRS is the process of distributing arrivals and departures across active runways based on local airport and National Airspace System (NAS) goals. The central component in the SORM concept is a tool for taking into account all the various factors and producing a recommendation for what would be the optimal runway configuration, runway use strategy, and aircraft sequence, considering as many of the relevant factors required in making this type of decision, and user preferences, if feasible. Three separate tools were initially envisioned for this research area, corresponding to the time scale in which they would operate: Strategic RCM (SRCM), with a planning horizon on the order of several hours, Tactical RCM (TRCM), with a planning horizon on the order of 90 minutes, and CADRS, with a planning horizon on the order of 15-30 minutes[1]. Algorithm development was initiated in all three of these areas, but the most fully developed to date is the TRCM algorithm. Earlier studies took a high-level approach to benefits, estimating aggregate benefits across most of the major airports in the National Airspace Systems (NAS), for both RCM and CADRS [2]. Other studies estimated the benefit of RCM and CADRS using various methods of re-sequencing arrivals to reduce delays3,4, or better balancing of arrival fixes5,6. Additional studies looked at different methods for performing the optimization involved in selecting the best Runway Configuration Plan (RCP) to use7-10. Most of these previous studies were high

  19. Controllers and Pilots Play a Key Role in Runway Safety Initiatives Through Real-Time Simulation

    NASA Technical Reports Server (NTRS)

    Madson, Mike; Bender, Kim

    2004-01-01

    A new and innovative way to evaluate runway safety initiatives for airports is through the use of interactive real-time simulation. The National Aeronautics and Space Administration (NASA) operates an integrated suite of simulators that can give both pilots and tower controllers the ability to simultaneously "try out" ideas in the safety of virtual reality. In February of 2003, the FAA conducted a demonstration in the NASA facilities for Dallas/Fort Worth International Airport (DFW) of a concept to reduce runway crossings and enhance the efficiency of the airport. Currently DFW experiences about 1,700 runway crossings per day, which contribute to arrival and departure delays and the potential for runway incursions. The proposed concept included the addition of new perimeter taxiways on the East and West sides of the airport. Through use of NASA's unique simulation capabilities, DFW controllers and commercial pilots provided expert feedback on the safety and operational implications by directly experiencing the proposed changes. Overall, the data collected from the participants and the simulators demonstrated that the concept would improve operations at DFW, if implemented. Improvements were observed in many areas including departure rates, taxi duration, runway crossings, and controller and pilot communications.

  20. Study on the Configuration and Capacity of the Lateral Runway Based on the Airport Green Operation

    NASA Astrophysics Data System (ADS)

    Li, Xiong; Li, Feng; Chen, Xiaoqing

    2017-05-01

    Airport as an important transportation infrastructure, its efficient operation, energy saving and emission reduction are of great significance for the sustainable development of the city. The planning of the lateral runway is gradually being applied in the construction of large airports. First, the different utilization modes of the lateral runway and adjacent parallel runway were analyzed. After which four operational correlations and intervals were discussed, i.e.: independent operation, take-off & take-off dependent operation, take-off & landing dependent operation and fully dependent operation. Taking Chengdu new airport as an example, the airfield simulation models were established to evaluate the efficiency of the lateral runway. The simulation result suggests: A group of longitudinal and transverse runways can meet the hourly take-off and landing movements of about 75-77 in the case of independent operation. The take-off & landing dependent operation has relatively large impact on capacity. Under the conditions of fully dependent operation, the hourly movements are only 65, lower by about 16%, 10% and 6% compared with other three modes.

  1. Controllers and Pilots Play a Key Role in Runway Safety Initiatives Through Real-Time Simulation

    NASA Technical Reports Server (NTRS)

    Madson, Mike; Bender, Kim

    2004-01-01

    A new and innovative way to evaluate runway safety initiatives for airports is through the use of interactive real-time simulation. The National Aeronautics and Space Administration (NASA) operates an integrated suite of simulators that can give both pilots and tower controllers the ability to simultaneously "try out" ideas in the safety of virtual reality. In February of 2003, the FAA conducted a demonstration in the NASA facilities for Dallas/Fort Worth International Airport (DFW) of a concept to reduce runway crossings and enhance the efficiency of the airport. Currently DFW experiences about 1,700 runway crossings per day, which contribute to arrival and departure delays and the potential for runway incursions. The proposed concept included the addition of new perimeter taxiways on the East and West sides of the airport. Through use of NASA's unique simulation capabilities, DFW controllers and commercial pilots provided expert feedback on the safety and operational implications by directly experiencing the proposed changes. Overall, the data collected from the participants and the simulators demonstrated that the concept would improve operations at DFW, if implemented. Improvements were observed in many areas including departure rates, taxi duration, runway crossings, and controller and pilot communications.

  2. Flow conditions of fresh mortar and concrete in different pipes

    SciTech Connect

    Jacobsen, Stefan; Haugan, Lars; Hammer, Tor Arne; Kalogiannidis, Evangelos

    2009-11-15

    The variation in fresh concrete flow rate over the pipe cross section was investigated on differently coloured and highly flowable concrete mixes flowing through pipes of different materials (rubber, steel, acryl). First, uncoloured (gray) concrete was poured through the pipe and the pipe blocked. Similar but coloured (black) concrete was then poured into the pipe filled with gray concrete, flowing after the gray concrete for a while before being blocked and hardened. The advance of the colouring along the pipe wall (showing boundary flow rate) was observed on the moulded concrete surface appearing after removing the pipe from the hardened concrete. The shapes of the interfaces between uncoloured and coloured concrete (showing variation of flow rate over the pipe cross section) were observed on sawn surfaces of concrete half cylinders cut along the length axes of the concrete-filled pipe. Flow profiles over the pipe cross section were clearly seen with maximum flow rates near the centre of the pipe and low flow rate at the pipe wall (typically rubber pipe with reference concrete without silica fume and/or stabilizers). More plug-shaped profiles, with long slip layers and less variation of flow rate over the cross section, were also seen (typically in smooth acrylic pipes). Flow rate, amount of concrete sticking to the wall after flow and SEM-images of pipe surface roughness were observed, illustrating the problem of testing full scale pumping.

  3. Studies on recycled aggregates-based concrete.

    PubMed

    Rakshvir, Major; Barai, Sudhirkumar V

    2006-06-01

    Reduced extraction of raw materials, reduced transportation cost, improved profits, reduced environmental impact and fast-depleting reserves of conventional natural aggregates has necessitated the use of recycling, in order to be able to conserve conventional natural aggregate. In this study various physical and mechanical properties of recycled concrete aggregates were examined. Recycled concrete aggregates are different from natural aggregates and concrete made from them has specific properties. The percentages of recycled concrete aggregates were varied and it was observed that properties such as compressive strength showed a decrease of up to 10% as the percentage of recycled concrete aggregates increased. Water absorption of recycled aggregates was found to be greater than natural aggregates, and this needs to be compensated during mix design.

  4. Lunar concrete for construction

    NASA Technical Reports Server (NTRS)

    Cullingford, Hatice S.; Keller, M. Dean

    1992-01-01

    Feasibility of using concrete for lunar base construction was discussed recently without relevant data for the effects of vacuum on concrete. Our experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the Moon are provided in this paper, along with specific conclusions from the existing database.

  5. Lunar concrete for construction

    NASA Technical Reports Server (NTRS)

    Cullingford, Hatice S.; Keller, M. Dean

    1988-01-01

    Feasibility of using concrete for lunar-base construction has been discussed recently without relevant data for the effects of vacuum on concrete. Experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the moon are provided in this paper along with specific conclusions from the existing data base.

  6. Lunar concrete for construction

    SciTech Connect

    Cullingford, H.S.; Keller, M.D.

    1988-01-01

    Feasibility of using concrete for lunar-base construction has been discussed recently without relevant data for the effects of vacuum on concrete. Our experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the moon are provided in this paper along with specific conclusions from the existing data base. 10 refs., 3 figs., 2 tabs.

  7. Application of concrete in marine structures

    SciTech Connect

    Rashid, A.; Nygaard, C.

    1997-07-01

    The use of concrete in marine environment has gained tremendous popularity in the past decade and is continued to be a very popular material for marine industry in the world today. It has a very diversified use from large offshore platforms and floating structures in the North Sea, Canada and South America to offshore loading terminals and junction platforms in shallow waters in the marshes of southern Louisiana in the Gulf of Mexico. Also, precast concrete sections are extensively used all over the world in the construction of marine structures. Because of their large variety of shapes and sizes, they can be tailored to fit multiple applications in marine environment. The added quality control in the fabrication yard and the ease of installation by lifting makes them a very attractive option. The use of precast concrete sections is gaining a lot of popularity in South America. A lot of fabrication yards are manufacturing these sections locally. There are hundreds of offshore concrete platforms utilizing these sections in Lake Maracaibo, Venezuela. The paper discusses the use of concrete for offshore structures including floaters. It describes some general concepts and advantages to be gained by the use of concrete (precast and cast-in-place) in marine environment. It also discusses some general design considerations required for the use of different types of precast concrete sections that can be utilized for oil and gas platforms and loading terminals. Lastly the paper describes some typical examples of concrete platforms built out of concrete piles, precast concrete girders and beam sections and concrete decking.

  8. Radiation Damage In Reactor Cavity Concrete

    SciTech Connect

    Field, Kevin G; Le Pape, Yann; Naus, Dan J; Remec, Igor; Busby, Jeremy T; Rosseel, Thomas M; Wall, Dr. James Joseph

    2015-01-01

    License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has established a renewed focus on long-term aging of nuclear generating stations materials, and recently, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete. The Expanded Materials Degradation Analysis (EMDA), jointly performed by the Department of Energy, the Nuclear Regulatory Commission and Industry, identified the urgent need to develop a consistent knowledge base on irradiation effects in concrete. Much of the historical mechanical performance data of irradiated concrete does not accurately reflect typical radiation conditions in NPPs or conditions out to 60 or 80 years of radiation exposure. To address these potential gaps in the knowledge base, The Electric Power Research Institute and Oak Ridge National Laboratory are working to disposition radiation damage as a degradation mechanism. This paper outlines the research program within this pathway including: (i) defining the upper bound of the neutron and gamma dose levels expected in the biological shield concrete for extended operation (80 years of operation and beyond), (ii) determining the effects of neutron and gamma irradiation as well as extended time at temperature on concrete, (iii) evaluating opportunities to irradiate prototypical concrete under accelerated neutron and gamma dose levels to establish a conservative bound and share data obtained from different flux, temperature, and fluence levels, (iv) evaluating opportunities to harvest and test irradiated concrete from international NPPs, (v) developing cooperative test programs to improve confidence in the results from the various concretes and research reactors, (vi) furthering the understanding of the effects of radiation on concrete (see companion paper) and (vii) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge.

  9. A comparison of the lattice discrete particle method to the finite-element method and the K&C material model for simulating the static and dynamic response of concrete.

    SciTech Connect

    Smith, Jovanca J.; Bishop, Joseph E.

    2013-11-01

    This report summarizes the work performed by the graduate student Jovanca Smith during a summer internship in the summer of 2012 with the aid of mentor Joe Bishop. The projects were a two-part endeavor that focused on the use of the numerical model called the Lattice Discrete Particle Model (LDPM). The LDPM is a discrete meso-scale model currently used at Northwestern University and the ERDC to model the heterogeneous quasi-brittle material, concrete. In the first part of the project, LDPM was compared to the Karagozian and Case Concrete Model (K&C) used in Presto, an explicit dynamics finite-element code, developed at Sandia National Laboratories. In order to make this comparison, a series of quasi-static numerical experiments were performed, namely unconfined uniaxial compression tests on four varied cube specimen sizes, three-point bending notched experiments on three proportional specimen sizes, and six triaxial compression tests on a cylindrical specimen. The second part of this project focused on the application of LDPM to simulate projectile perforation on an ultra high performance concrete called CORTUF. This application illustrates the strengths of LDPM over traditional continuum models.

  10. Runway exit designs for capacity improvement demonstrations. Phase 2: Computer model development

    NASA Technical Reports Server (NTRS)

    Trani, A. A.; Hobeika, A. G.; Kim, B. J.; Nunna, V.; Zhong, C.

    1992-01-01

    The development is described of a computer simulation/optimization model to: (1) estimate the optimal locations of existing and proposed runway turnoffs; and (2) estimate the geometric design requirements associated with newly developed high speed turnoffs. The model described, named REDIM 2.0, represents a stand alone application to be used by airport planners, designers, and researchers alike to estimate optimal turnoff locations. The main procedures are described in detail which are implemented in the software package and possible applications are illustrated when using 6 major runway scenarios. The main output of the computer program is the estimation of the weighted average runway occupancy time for a user defined aircraft population. Also, the location and geometric characteristics of each turnoff are provided to the user.

  11. Action-specific effects in aviation: what determines judged runway size?

    PubMed

    Gray, Rob; Navia, José Antonio; Allsop, Jonathan

    2014-01-01

    Several recent studies have shown that the performance of a skill that involves acting on a goal object can influence one's judgment of the size of that object. The present study investigated this effect in an aviation context. Novice pilots were asked to perform a series of visual approach and landing manoeuvres in a flight simulator. After each landing, participants next performed a task in which runway size was judged for different simulated altitudes. Gaze behaviour and control stick kinematics were also analyzed. There were significant relationships between judged runway size and multiple action-related variables including touchdown velocity, time fixating the runway, and the magnitude and frequency of control inputs. These findings suggest that relationship between the perception of a target object and action is not solely determined by performance success or failure but rather involves a relationship between multiple variables that reflect the actor's ability.

  12. Simulator Evaluation of Runway Incursion Prevention Technology for General Aviation Operations

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.; Prinzel, Lawrence J., III

    2011-01-01

    A Runway Incursion Prevention System (RIPS) has been designed under previous research to enhance airport surface operations situation awareness and provide cockpit alerts of potential runway conflict, during transport aircraft category operations, in order to prevent runway incidents while also improving operations capability. This study investigated an adaptation of RIPS for low-end general aviation operations using a fixed-based simulator at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC). The purpose of the study was to evaluate modified RIPS aircraft-based incursion detection algorithms and associated alerting and airport surface display concepts for low-end general aviation operations. This paper gives an overview of the system, simulation study, and test results.

  13. Method and device for landing aircraft dependent on runway occupancy time

    NASA Technical Reports Server (NTRS)

    Ghalebsaz Jeddi, Babak (Inventor)

    2012-01-01

    A technique for landing aircraft using an aircraft landing accident avoidance device is disclosed. The technique includes determining at least two probability distribution functions; determining a safe lower limit on a separation between a lead aircraft and a trail aircraft on a glide slope to the runway; determining a maximum sustainable safe attempt-to-land rate on the runway based on the safe lower limit and the probability distribution functions; directing the trail aircraft to enter the glide slope with a target separation from the lead aircraft corresponding to the maximum sustainable safe attempt-to-land rate; while the trail aircraft is in the glide slope, determining an actual separation between the lead aircraft and the trail aircraft; and directing the trail aircraft to execute a go-around maneuver if the actual separation approaches the safe lower limit. Probability distribution functions include runway occupancy time, and landing time interval and/or inter-arrival distance.

  14. Non-airborne conflicts: The causes and effects of runway transgressions

    NASA Technical Reports Server (NTRS)

    Tarrel, Richard J.

    1985-01-01

    The 1210 ASRS runway transgression reports are studied and expanded to yield descriptive statistics. Additionally, a one of three subset was studied in detail for purposes of evaluating the causes, risks, and consequences behind trangression events. Occurrences are subdivided by enabling factor and flight phase designations. It is concluded that a larger risk of collision is associated with controller enabled departure transgressions over all other categories. The influence of this type is especially evident during the period following the air traffic controllers' strike of 1981. Causal analysis indicates that, coincidentally, controller enabled departure transgressions also, show the strongest correlations between causal factors. It shows that departure errors occur more often when visibility is reduced, and when multiple takeoff runways or intersection takeoffs are employed. In general, runway transgressions attributable to both pilot and controller errors arise from three problem areas: information transfer, awareness, and spatial judgement. Enhanced awareness by controllers will probably reduce controller enabled incidents.

  15. Runway Incursion Prevention System: Demonstration and Testing at the Dallas/Fort Worth International Airport

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.; Quach, Cuong C.; Young, Steven D.

    2007-01-01

    A Runway Incursion Prevention System (RIPS) was tested at the Dallas-Ft. Worth International Airport (DFW) in October 2000. The system integrated airborne and ground components to provide both pilots and controllers with enhanced situational awareness, supplemental guidance cues, a real-time display of traffic information, and warning of runway incursions in order to prevent runway incidents while also improving operational capability. A series of test runs was conducted using NASA s Boeing 757 research aircraft and a test van equipped to emulate an incurring aircraft. The system was also demonstrated to over 100 visitors from the aviation community. This paper gives an overview of the RIPS, DFW flight test activities, and quantitative and qualitative results of the testing.

  16. Application of Artificial Neural Network to Predict the use of Runway at Juanda International Airport

    NASA Astrophysics Data System (ADS)

    Putra, J. C. P.; Safrilah

    2017-06-01

    Artificial neural network approaches are useful to solve many complicated problems. It solves a number of problems in various areas such as engineering, medicine, business, manufacturing, etc. This paper presents an application of artificial neural network to predict a runway capacity at Juanda International Airport. An artificial neural network model of backpropagation and multi-layer perceptron is adopted to this research to learning process of runway capacity at Juanda International Airport. The results indicate that the training data is successfully recognizing the certain pattern of runway use at Juanda International Airport. Whereas, testing data indicate vice versa. Finally, it can be concluded that the approach of uniformity data and network architecture is the critical part to determine the accuracy of prediction results.

  17. A fresh look at runway incursions: onboard surface movement awareness and alerting system based on SVS

    NASA Astrophysics Data System (ADS)

    Vernaleken, Christoph; Mihalic, Lamir; Güttler, Mathias; Klingauf, Uwe

    2006-05-01

    Increasing traffic density on the aerodrome surface due to the continuous worldwide growth in the number of flight operations does not only cause capacity and efficiency problems, but also increases the risk of serious incidents and accidents on the airport movement area. Of these, Runway Incursions are the by far most safety-critical. In fact, the worst-ever accident in civil aviation, the collision of two Boeing B747s on Tenerife in 1977 with 583 fatalities, was caused by a Runway Incursion. Therefore, various Runway Safety programs have recently been initiated around the globe, often focusing on ground-based measures such as improved surveillance. However, as a lack of flight crew situational awareness is a key causal factor in many Runway Incursion incidents and accidents, there is a strong need for an onboard solution, which should be capable of interacting cooperatively with ground-based ATM systems, such as A-SMGCS where available. This paper defines the concept of preventive and reactive Runway Incursion avoidance and describes a Surface Movement Awareness & Alerting System (SMAAS) designed to alert the flight crew if they are at risk of infringing a runway. Both the SVS flight deck displays and the corresponding alerting algorithms utilize an ED 99A/RTCA DO-272A compliant aerodrome database, as well as airport operational, traffic and clearance data received via ADS-B or other data links, respectively. The displays provide the crew with enhanced positional, operational, clearance and traffic awareness, and they are used to visualize alerts. A future enhancement of the system will provide intelligent alerting for conflicts caused by surrounding traffic.

  18. Interval Management with Spacing to Parallel Dependent Runways (IMSPIDR) Experiment and Results

    NASA Technical Reports Server (NTRS)

    Baxley, Brian T.; Swieringa, Kurt A.; Capron, William R.

    2012-01-01

    An area in aviation operations that may offer an increase in efficiency is the use of continuous descent arrivals (CDA), especially during dependent parallel runway operations. However, variations in aircraft descent angle and speed can cause inaccuracies in estimated time of arrival calculations, requiring an increase in the size of the buffer between aircraft. This in turn reduces airport throughput and limits the use of CDAs during high-density operations, particularly to dependent parallel runways. The Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR) concept uses a trajectory-based spacing tool onboard the aircraft to achieve by the runway an air traffic control assigned spacing interval behind the previous aircraft. This paper describes the first ever experiment and results of this concept at NASA Langley. Pilots flew CDAs to the Dallas Fort-Worth airport using airspeed calculations from the spacing tool to achieve either a Required Time of Arrival (RTA) or Interval Management (IM) spacing interval at the runway threshold. Results indicate flight crews were able to land aircraft on the runway with a mean of 2 seconds and less than 4 seconds standard deviation of the air traffic control assigned time, even in the presence of forecast wind error and large time delay. Statistically significant differences in delivery precision and number of speed changes as a function of stream position were observed, however, there was no trend to the difference and the error did not increase during the operation. Two areas the flight crew indicated as not acceptable included the additional number of speed changes required during the wind shear event, and issuing an IM clearance via data link while at low altitude. A number of refinements and future spacing algorithm capabilities were also identified.

  19. Reliability Modeling Methodology for Independent Approaches on Parallel Runways Safety Analysis

    NASA Technical Reports Server (NTRS)

    Babcock, P.; Schor, A.; Rosch, G.

    1998-01-01

    This document is an adjunct to the final report An Integrated Safety Analysis Methodology for Emerging Air Transport Technologies. That report presents the results of our analysis of the problem of simultaneous but independent, approaches of two aircraft on parallel runways (independent approaches on parallel runways, or IAPR). This introductory chapter presents a brief overview and perspective of approaches and methodologies for performing safety analyses for complex systems. Ensuing chapter provide the technical details that underlie the approach that we have taken in performing the safety analysis for the IAPR concept.

  20. Texture Modification of the Shuttle Landing Facility Runway at the NASA Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Daugherty, Robert H.; Yager, Thomas J.

    1996-01-01

    This paper describes the test procedures and the selection criteria used in selecting the best runway surface texture modification at the Kennedy Space Center (KSC) Shuttle Landing Facility (SLF) to reduce Orbiter tire wear. The new runway surface may ultimately result in an increase of allowable crosswinds for launch and landing operations. The modification allows launch and landing operations in 20-kt crosswinds if desired. This 5-kt increase over the previous 15-kt limit drastically increases landing safety and the ability to make on-time launches to support missions where space station rendezvous is planned.

  1. Air Traffic and Operational Data on Selected US Airports with Parallel Runways

    NASA Technical Reports Server (NTRS)

    Doyle, Thomas M.; McGee, Frank G.

    1998-01-01

    This report presents information on a number of airports in the country with parallel runways and focuses on those that have at least one pair of parallel runways closer than 4300 ft. Information contained in the report describes the airport's current operational activity as obtained through contact with the facility and from FAA air traffic tower activity data for FY 1997. The primary reason for this document is to provide a single source of information for research to determine airports where Airborne Information for Lateral Spacing (AILS) technology may be applicable.

  2. Model experiments to evaluate vortex dissipation devices proposed for installation on or near aircraft runways

    NASA Technical Reports Server (NTRS)

    Kohl, R. E.

    1973-01-01

    The effectiveness of various vortex dissipation devices proposed for installation on or near aircraft runways is evaluated on basis of results of experiments conducted with a 0.03-scale model of a Boeing 747 transport aircraft in conjunction with a simulated runway. The test variables included type of vortex dissipation device, mode of operation of the powered devices, and altitude, lift coefficient and speed of the generating aircraft. A total of fifteen devices was investigated. The evaluation is based on time sequence photographs taken in the vertical and horizontal planes during each run.

  3. Expansion of flight simulator capability for study and solution of aircraft directional control problems on runways

    NASA Technical Reports Server (NTRS)

    Kibbee, G. W.

    1978-01-01

    The development, evaluation, and evaluation results of a DC-9-10 runway directional control simulator are described. An existing wide bodied flight simulator was modified to this aircraft configuration. The simulator was structured to use either two of antiskid simulations; (1) an analog mechanization that used aircraft hardware; or (2) a digital software simulation. After the simulation was developed it was evaluated by 14 pilots who made 818 simulated flights. These evaluations involved landings, rejected takeoffs, and various ground maneuvers. Qualitatively most pilots evaluated the simulator as realistic with good potential especially for pilot training for adverse runway conditions.

  4. Runway Exit Designs for Capacity Improvement Demonstrations. Phase 2. Computer Model Development

    DTIC Science & Technology

    1992-01-15

    same aircraft mix. RGURE 6.4 Schematic of Washington National Airport. 15 i18 Runway 18-36 J 2094 (6,870’) x 46 (150’) Runway 15-33 Remote 1582 ...Mass (In.) Base (m.) Gem (Kg.) Saab 340-2 SAAB-340 12,020 7194 21.44 7.14 90.88 British Aeios. 31 BAE-31 6,600 4,131 15.05 4.60 87.18 Embraer 120 EMB

  5. Nondestructive evaluation of thick concrete structures

    NASA Astrophysics Data System (ADS)

    Clayton, Dwight A.

    2015-03-01

    Concrete has been used in the construction of nuclear power plants (NPPs) due to three primary properties: its low cost, structural strength, and ability to shield radiation. Examples of concrete structures important to the safety of Light Water Reactor (LWR) plants include the containment building, spent fuel pool, and cooling towers. Use in these structures has made concrete's long-term performance crucial for the safe operation of commercial NPPs. Extending LWR operating period to 60 years and beyond will likely increase susceptibility and severity of known forms of degradation. New mechanisms of materials degradation are also possible. This creates the need to be able to nondestructively evaluate the current subsurface concrete condition of aging concrete material in NPP structures. The size and complexity of NPP containment structures and heterogeneity of Portland cement concrete make characterization of the degradation extent a difficult task. Specially designed and fabricated test specimens can provide realistic flaws that are similar to actual flaws in terms of how they interact with a particular nondestructive evaluation (NDE) technique. Artificial test blocks allow the isolation of certain testing problems as well as the variation of certain parameters. Representative large heavily reinforced concrete specimens would allow for comparative testing to evaluate the state-of-the-art NDE in this area and to identify additional developments necessary to address the challenges potentially found in NPPs.

  6. Moisture Transport Through Sprayed Concrete Tunnel Linings

    NASA Astrophysics Data System (ADS)

    Holter, Karl Gunnar; Geving, Stig

    2016-01-01

    Waterproofing of permanent sprayed concrete tunnel linings with sprayed membranes in a continuous sandwich structure has been attempted since 2000 and has seen increased use in some countries. The main function of a sprayed membrane from a waterproofing perspective is to provide crack bridging and hence prevent flow of liquid water into the tunnel through cracks and imperfections in the concrete material. However, moisture can migrate through the concrete and EVA-based membrane materials by capillary and vapor diffusion mechanisms. These moisture transport mechanisms can have an influence on the degree of saturation, and may influence the pore pressures in the concrete material as well as risk of freeze-thaw damage of the concrete and membrane. The paper describes a detailed study of moisture transport material parameters, moisture condition in tunnel linings and climatic conditions tunnels in hard rock in Norway. These data have been included in a hygrothermal simulation model in the software WUFI for moisture transport to substantiate moisture transport and long-term effects on saturation of the concrete and membrane material. The findings suggest that EVA-based membranes exhibit significant water absorption and vapor transport properties although they are impermeable to liquid water flow. State-of-the-art sprayed concrete material applied with the wet mix method exhibits very low hydraulic conductivities, lower than 10-14 m/s, thus saturated conductive water flow is a very unlikely dominant transport mechanism. Moisture transport through the lining structure by capillary flow and vapor diffusion are calculated to approximately 3 cm3/m2 per day for lining thicknesses in the range of 25-35 cm and seasonal Nordic climate variations. The calculated moisture contents in the tunnel linings from the hygrothermal simulations are largely in agreement with the measured moisture contents in the tunnel linings. The findings also indicate that the concrete material exhibits

  7. Final Environmental Assessment for the Runway Extension and New Parking Apron at Tyndall Air Force Base, Florida

    DTIC Science & Technology

    2004-01-01

    SO 2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (03), and lead ( Pb ). Although the ozone standards are being reduced significantly with... lead ( Pb ). Response: Similar statement modification inserted. Final Environmental Assessment for the Runway Extension and New Parking Apron 29 Final Environmental Assessment for the Runway Extension and New Parking Apron 30

  8. Ultrasonic testing of reactive powder concrete.

    PubMed

    Washer, Glenn; Fuchs, Paul; Graybeal, Benjamin A; Hartmann, Joseph Lawrence

    2004-02-01

    Concrete is a critical material for the construction of infrastructure facilities throughout the world. Traditional concretes consist of cement paste and aggregates ranging in size from 6 to 25 mm that form a heterogeneous material with substantial compressive strength and a very low tensile strength. Steel reinforcement is used to provide tensile strength for reinforced concrete structures and as a composite the material is useful for structural applications. A new material known as reactive powder concrete (RPC) is becoming available. It differs significantly from traditional concrete; RPC has no large aggregates, and contains small steel fibers that provide additional strength and, in some cases, can replace traditional steel reinforcement. Due to its high density and lack of aggregates, ultrasonic inspections at frequencies 10 to 20 times that of traditional concrete inspections are possible. This paper reports on the initial findings of research conducted to determine the applicability of ultrasonic testing techniques for the condition assessment of RPC. Pulse velocities for shear and longitudinal waves and ultrasonic measurement of the modulus of elasticity for RPC are reported. Ultrasonic crack detection for RPC also is investigated.

  9. Comparative testing of nondestructive examination techniques for concrete structures

    NASA Astrophysics Data System (ADS)

    Clayton, Dwight A.; Smith, Cyrus M.

    2014-03-01

    A multitude of concrete-based structures are typically part of a light water reactor (LWR) plant to provide foundation, support, shielding, and containment functions. Concrete has been used in the construction of nuclear power plants (NPPs) because of three primary properties, its inexpensiveness, its structural strength, and its ability to shield radiation. Examples of concrete structures important to the safety of LWR plants include containment building, spent fuel pool, and cooling towers. Comparative testing of the various NDE concrete measurement techniques requires concrete samples with known material properties, voids, internal microstructure flaws, and reinforcement locations. These samples can be artificially created under laboratory conditions where the various properties can be controlled. Other than NPPs, there are not many applications where critical concrete structures are as thick and reinforced. Therefore, there are not many industries other than the nuclear power plant or power plant industry that are interested in performing NDE on thick and reinforced concrete structures. This leads to the lack of readily available samples of thick and heavily reinforced concrete for performing NDE evaluations, research, and training. The industry that typically performs the most NDE on concrete structures is the bridge and roadway industry. While bridge and roadway structures are thinner and less reinforced, they have a good base of NDE research to support their field NDE programs to detect, identify, and repair concrete failures. This paper will summarize the initial comparative testing of two concrete samples with an emphasis on how these techniques could perform on NPP concrete structures.

  10. New Concept Study for Repair of Bomb-Damaged Runways. Volume I. Concept Identification.

    DTIC Science & Technology

    1979-09-01

    to be considered during the project. These assumptions were as follows: 1. Types of Pavements to be Repaired - Portland cement concrete, asphaltic ...concrete, or portland cement concrete with asphalt overlay were the types of pavements to be repaired. The portland cement concrete will not be...an excellent bond with old concrete or asphalt . There are several inorganic and organic cements that have these characteristics. In operation, the

  11. Sequestration of CO2 by concrete carbonation.

    PubMed

    Galan, Isabel; Andrade, Carmen; Mora, Pedro; Sanjuan, Miguel A

    2010-04-15

    Carbonation of reinforced concrete is one of the causes of corrosion, but it is also a way to sequester CO2. The characteristics of the concrete cover should ensure alkaline protection for the steel bars but should also be able to combine CO2 to a certain depth. This work attempts to advance the knowledge of the carbon footprint of cement. As it is one of the most commonly used materials worldwide, it is very important to assess its impact on the environment. In order to quantify the capacity of cement based materials to combine CO2 by means of the reaction with hydrated phases to produce calcium carbonate, Thermogravimetry and the phenolphthalein indicator have been used to characterize several cement pastes and concretes exposed to different environments. The combined effect of the main variables involved in this process is discussed. The moisture content of the concrete seems to be the most influential parameter.

  12. Dryden B-52 Launch Aircraft on Edwards AFB Runway

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA's venerable workhorse, the B-52 mothership, rolls out on the Edwards AFB runway after a test flight in 1996. Over the course of more than 40 years, the B-52 launched numerous experimental aircraft, ranging from the X-15 to the X-38, and was also used as a flying testbed for a variety of other research projects. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft supported the development of parachute recovery systems used to recover the space shuttle solid rocket

  13. Modeling of concrete response at high temperature

    SciTech Connect

    Pfeiffer, P.; Marchertas, A.

    1984-01-01

    A rate-type creep law is implemented into the computer code TEMP-STRESS for high temperature concrete analysis. The disposition of temperature, pore pressure and moisture for the particular structure in question is provided as input for the thermo-mechanical code. The loss of moisture from concrete also induces material shrinkage which is accounted for in the analytical model. Examples are given to illustrate the numerical results.

  14. Evaluation and Repair of Concrete Slabs

    DTIC Science & Technology

    1992-01-01

    is duce a readily flowable concrete that is capable of listed in Table 1. completely filling the formed area. For large surface areas, it may be...Poor compaction, irregular surfaces, expansive soils , and the presence of mud or soft organic material can all result in a yielding subgrade. Again... fill all the spaces around the coarse aggregate. It is easily recognized by voids in the surface where the concrete appears as coarse aggregate

  15. Behavior of reinforced concrete at elevated temperatures

    SciTech Connect

    Freskakis, G.N.

    1984-09-01

    A study is presented concerning the behavior of reinforced concrete sections at elevated temperatures. Material properties of concrete and reinforcing steel are discussed. Behavior studies are made by means of moment-curvature-axial force relationships. Particular attention is given to the load carrying capacity, thermal forces and moments, and deformation capacity. The effects on these properties of variations in the strength properties, the temperature level and distribution, the amount of reinforcing steel, and limiting values of strains are considered.

  16. Properties of Concrete partially replaced with Coconut Shell as Coarse aggregate and Steel fibres in addition to its Concrete volume

    NASA Astrophysics Data System (ADS)

    Kalyana Chakravarthy, P. R.; Janani, R.; Ilango, T.; Dharani, K.

    2017-03-01

    Cement is a binder material with various composition of Concrete but instantly it posses low tensile strength. The study deals with mechanical properties of that optimized fiber in comparison with conventional and coconut shell concrete. The accumulation of fibers arbitrarily dispersed in the composition increases the resistance to cracking, deflection and other serviceability conditions substantially. The steel fiber in extra is one of the revision in coconut shell concrete and the outcome of steel fiber in coconut shell concrete was to investigate and compare with the conventional concrete. For the given range of steel fibe from 0.5 to 2.0%, 12 beams and 36 cylindrical specimens were cast and tested to find the mechanical properties like flexural strength, split tensile, impact resistance and the modulus of elasticity of both conventional and coconut shell concrete has been studied and the test consequences are compared with the control concrete and coconut shell concrete for M25 Grade. It is fulfilled that, the steel fibers used in this venture has shown significant development in all the properties of conventional and coconut shell concrete while compared to controlled conventional and coconut shell concrete like, Flexural strength by 6.67 % for 1.0 % of steel fiber in conventional concrete and by 5.87 % for 1.5 % of steel fiber in coconut shell concrete.

  17. High-performance concretes: A state-of-the-art report

    SciTech Connect

    Zia, P.; Leming, M.L.; Ahmad, S.H.

    1991-01-01

    The state-of-the-art report summarizes the results of an extensive search and review of available literature on the mechanical properties of concrete, with particular reference to the highway application of high performance concrete (HPC). The authors define high performance concrete in terms of minimum requirements for strength and durability, as well as potential to reduce construction time. The report discusses in detail the selection of materials and the manufacture of high performance concrete; the behavior of plastic and hardened concrete, including strength and deformation characteristics; the behavior of fiber-reinforced concrete; and the applications of high performance concretes.

  18. Concreteness Fading in Mathematics and Science Instruction: A Systematic Review

    ERIC Educational Resources Information Center

    Fyfe, Emily R.; McNeil, Nicole M.; Son, Ji Y.; Goldstone, Robert L.

    2014-01-01

    A longstanding debate concerns the use of concrete versus abstract instructional materials, particularly in domains such as mathematics and science. Although decades of research have focused on the advantages and disadvantages of concrete and abstract materials considered independently, we argue for an approach that moves beyond this dichotomy and…

  19. Concreteness Fading in Mathematics and Science Instruction: A Systematic Review

    ERIC Educational Resources Information Center

    Fyfe, Emily R.; McNeil, Nicole M.; Son, Ji Y.; Goldstone, Robert L.

    2014-01-01

    A longstanding debate concerns the use of concrete versus abstract instructional materials, particularly in domains such as mathematics and science. Although decades of research have focused on the advantages and disadvantages of concrete and abstract materials considered independently, we argue for an approach that moves beyond this dichotomy and…

  20. Environmental Assessment Addressing FTFA07-1174, Repair Approach Lighting System at the North End of Runway 01/19 at Eglin AFB, Florida

    DTIC Science & Technology

    2013-05-01

    The USAF proposes to repair the approach lighting system at the north end of Runway 01/19 on Eglin AFB, Florida. Based on the age and condition of...the existing runway approach lighting structures, repairing the approach lighting system at the north end of Runway 01/19 is required to provide a safe

  1. Laser ablation studies of concrete

    SciTech Connect

    Savina, M.; Xu, Z.; Wang, Y.; Reed, C.; Pellin, M.

    1999-10-20

    Laser ablation was studied as a means of removing radioactive contaminants from the surface and near-surface regions of concrete. The authors present the results of ablation tests on cement and concrete samples using a 1.6 kW pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied using cement and high density concrete as targets. Ablation efficiency and material removal rates were determined as functions of irradiance and pulse overlap. Doped samples were also ablated to determine the efficiency with which surface contaminants were removed and captured in the effluent. The results show that the cement phase of the material melts and vaporizes, but the aggregate portion (sand and rock) fragments. The effluent consists of both micron-size aerosol particles and chunks of fragmented aggregate material. Laser-induced optical emission spectroscopy was used to analyze the surface during ablation. Analysis of the effluent showed that contaminants such as cesium and strontium were strongly segregated into different regions of the particle size distribution of the aerosol.

  2. Monte Carlo simulations for optimization of neutron shielding concrete

    NASA Astrophysics Data System (ADS)

    Piotrowski, Tomasz; Tefelski, Dariusz B.; Polański, Aleksander; Skubalski, Janusz

    2012-06-01

    Concrete is one of the main materials used for gamma and neutron shielding. While in case of gamma rays an increase in density is usually efficient enough, protection against neutrons is more complex. The aim of this paper is to show the possibility of using the Monte Carlo codes for evaluation and optimization of concrete mix to reach better neutron shielding. Two codes (MCNPX and SPOT — written by authors) were used to simulate neutron transport through a wall made of different concretes. It is showed that concrete of higher compressive strength attenuates neutrons more effectively. The advantage of heavyweight concrete (with barite aggregate), usually used for gamma shielding, over the ordinary concrete was not so clear. Neutron shielding depends on many factors e.g. neutron energy, barrier thickness and atomic composition. All this makes a proper design of concrete as a very important issue for nuclear power plant safety assurance.

  3. Monte Carlo simulations for optimization of neutron shielding concrete

    NASA Astrophysics Data System (ADS)

    Piotrowski, Tomasz; Tefelski, Dariusz; Polański, Aleksander; Skubalski, Janusz

    2012-06-01

    Concrete is one of the main materials used for gamma and neutron shielding. While in case of gamma rays an increase in density is usually efficient enough, protection against neutrons is more complex. The aim of this paper is to show the possibility of using the Monte Carlo codes for evaluation and optimization of concrete mix to reach better neutron shielding. Two codes (MCNPX and SPOT — written by authors) were used to simulate neutron transport through a wall made of different concretes. It is showed that concrete of higher compressive strength attenuates neutrons more effectively. The advantage of heavyweight concrete (with barite aggregate), usually used for gamma shielding, over the ordinary concrete was not so clear. Neutron shielding depends on many factors e.g. neutron energy, barrier thickness and atomic composition. All this makes a proper design of concrete as a very important issue for nuclear power plant safety assurance.

  4. Relating Fresh Concrete Viscosity Measurements from Different Rheometers.

    PubMed

    Ferraris, Chiara F; Martys, Nicos S

    2003-01-01

    Concrete rheological properties need to be properly measured and predicted in order to characterize the workability of fresh concrete, including special concretes such as self-consolidating concrete (SCC). It was shown by a round-robin test held in 2000 [1,2] that different rheometer designs gave different values of viscosity for the same concrete. While empirical correlation between different rheometers was possible, for a procedure that is supposed to "scientifically" improve on the empirical slump tests, this situation is unsatisfactory. To remedy this situation, a new interpretation of the data was developed. In this paper, it is shown that all instruments tested could be directly and quantitatively compared in terms of relative plastic viscosity instead of the plastic viscosity alone. This should eventually allow the measurements from various rheometer designs to be directly calibrated against known standards of plastic viscosity, putting concrete rheometry and concrete workability on a sounder materials science basis.

  5. Relating Fresh Concrete Viscosity Measurements from Different Rheometers

    PubMed Central

    Ferraris, Chiara F.; Martys, Nicos S.

    2003-01-01

    Concrete rheological properties need to be properly measured and predicted in order to characterize the workability of fresh concrete, including special concretes such as self-consolidating concrete (SCC). It was shown by a round-robin test held in 2000 [1,2] that different rheometer designs gave different values of viscosity for the same concrete. While empirical correlation between different rheometers was possible, for a procedure that is supposed to “scientifically” improve on the empirical slump tests, this situation is unsatisfactory. To remedy this situation, a new interpretation of the data was developed. In this paper, it is shown that all instruments tested could be directly and quantitatively compared in terms of relative plastic viscosity instead of the plastic viscosity alone. This should eventually allow the measurements from various rheometer designs to be directly calibrated against known standards of plastic viscosity, putting concrete rheometry and concrete workability on a sounder materials science basis. PMID:27413607

  6. Field Evaluation of Ultra-High Pressure Water Systems for Runway Rubber Removal

    DTIC Science & Technology

    2014-04-01

    collected in a Trackjet vacuum chamber. ................................................................... 70 Figure 74. SH8000R removing rubber on Runway...regulations in a given area, this process may also include vacuuming the residue for disposal offsite. This process is also referred to as...to 6 ft. The process involves a system that vacuums the debris, separates the abrasive particles for recycling, and stores the resultant debris

  7. Down-to-the-runway enhanced flight vision system (EFVS) approach test results

    NASA Astrophysics Data System (ADS)

    McKinley, John B.; Heidhausen, Eric; Cramer, James A.; Krone, Norris J., Jr.

    2008-04-01

    Flight tests where conducted at Cambridge-Dorchester Airport (KCGE) and Easton Municipal Airport / Newnam Field (KESN) in a Cessna 402B aircraft using a head-up display (HUD) and a Kollsman Enhanced Vision System (EVS-I) infrared camera. These tests were sponsored by the MITRE Corporation's Center for Advanced Aviation System Development (CAASD) and the Federal Aviation Administration. Imagery of the EVS-I infrared camera, HUD guidance cues, and out-the-window video were each separately recorded at an engineering workstation for each approach, roll-out, and taxi operation. The EVS-I imagery was displayed on the HUD with guidance cues generated by the mission computer. Also separately recorded was the inertial flight path data. Enhanced Flight Vision System (EFVS) approaches were conducted from the final approach fix to runway flare, touchdown, roll-out and taxi using the HUD and EVS-I sensor as the only visual reference. Flight conditions included two-pilot crew, day, night, non-precision course offset approaches, ILS approach, crosswind approaches, and missed approaches. Results confirmed the feasibility for safe conduct of down-to-the-runway precision approaches in low visibility to runways with and without precision approach systems, when consideration is given to proper aircraft instrumentation, pilot training, and acceptable procedures. Operational benefits include improved runway occupancy rates, and reduced delays and diversions.

  8. Design and development of a modified runway model of mouse drug self-administration.

    PubMed

    Pandy, Vijayapandi; Khan, Yasmin

    2016-02-23

    The present study established a novel mouse model of a runway drug self-administration in our laboratory. The operant runway apparatus consisted of three long runways arranged in a zig-zag manner. The methodology consisted of six distinct phases: habituation, preconditioning, conditioning, post-conditioning, extinction and reinstatement. The effects of saline were compared with escalating doses of either ethanol (0.5-4.0 g/kg, i.p), heroin (5-40 mg/kg, i.p), or nicotine (0.1-0.5mg/kg, i.p) administered in the goal box during the conditioning phase (day 1 to day 5). A significant decrease in the time of trained (conditioned) mice to reach the goal box confirmed the subjects' motivation to seek those drugs on day 6 (expression). The mice were then subjected to non-rewarded extinction trials for 5 days over which run times were significantly increased. After 5 days of abstinence, a priming dose of ethanol or heroin (1/5th of maximum dose used in conditioning) significantly reinstated the drug-seeking behavior. These results suggest that the modified runway model can serve as a powerful behavioral tool for the study of the behavioral and neurobiological bases of drug self-administration and, as such, is appropriate simple but powerful tool for investigating the drug-seeking behavior of laboratory mice.

  9. Aircraft and avionic related research required to develop an effective high-speed runway exit system

    NASA Technical Reports Server (NTRS)

    Schoen, M. L.; Hosford, J. E.; Graham, J. M., Jr.; Preston, O. W.; Frankel, R. S.; Erickson, J. B.

    1979-01-01

    Research was conducted to increase airport capacity by studying the feasibility of the longitudinal separation between aircraft sequences on final approach. The multidisciplinary factors which include the utility of high speed exits for efficient runway operations were described along with recommendations and highlights of these studies.

  10. STS-111 commander, Ken Cockrell, greets dignitaries and recovery technicians on the runway at Edward

    NASA Technical Reports Server (NTRS)

    2002-01-01

    STS-111 commander Ken Cockrell greets dignitaries and recovery technicians on the runway at Edwards Air Force Base following the landing of the space shuttle Endeavour on June 19, 2002. Behind Cockrell are (from left) mission specialists Philippe Perrin and Franklin Chang-Diaz and Shuttle pilot Paul Lockhart.

  11. Development of a Bayesian Belief Network Runway Incursion and Excursion Model

    NASA Technical Reports Server (NTRS)

    Green, Lawrence L.

    2014-01-01

    In a previous work, a statistical analysis of runway incursion (RI) event data was conducted to ascertain the relevance of this data to the top ten Technical Challenges (TC) of the National Aeronautics and Space Administration (NASA) Aviation Safety Program (AvSP). The study revealed connections to several of the AvSP top ten TC and identified numerous primary causes and contributing factors of RI events. The statistical analysis served as the basis for developing a system-level Bayesian Belief Network (BBN) model for RI events, also previously reported. Through literature searches and data analysis, this RI event network has now been extended to also model runway excursion (RE) events. These RI and RE event networks have been further modified and vetted by a Subject Matter Expert (SME) panel. The combined system-level BBN model will allow NASA to generically model the causes of RI and RE events and to assess the effectiveness of technology products being developed under NASA funding. These products are intended to reduce the frequency of runway safety incidents/accidents, and to improve runway safety in general. The development and structure of the BBN for both RI and RE events are documented in this paper.

  12. Effect of multiple path approach procedures on runway landing capacity. [under ILS and MLS conditions

    NASA Technical Reports Server (NTRS)

    Tosic, V.; Horonjeff, R.

    1976-01-01

    When using the Instrument Landing System (ILS) all aircraft must follow a straight line approach path before landing. The Microwave Landing System (MLS) will allow use of differing curved approach paths. The objective of this research is to find out whether the introduction of MLS and consequently multiple approach paths can bring an increase in runway landing capacity. A model is developed which is capable of computing the expected ultimate landing runway capacity, under ILS and MLS conditions, when aircraft population characteristics and Air Traffic Control separation rules are given. This model can be applied in situations when only a horizontal separation between aircraft approaching a runway is allowed, as well as when both vertical and horizontal separations are possible. Results suggest that an increase in runway landing capacity, caused by introducing the MLS-described multiple approach paths, is to be expected only when an aircraft population consists of aircraft with significantly differing approach velocities and particularly in situations when a vertical separation can be applied.

  13. Comprehensive and Highly Accurate Measurements of Crane Runways, Profiles and Fastenings.

    PubMed

    Dennig, Dirk; Bureick, Johannes; Link, Johannes; Diener, Dmitri; Hesse, Christian; Neumann, Ingo

    2017-05-13

    The process of surveying crane runways has been continually refined due to the competitive situation, modern surveying instruments, additional sensors, accessories and evaluation procedures. Guidelines, such as the International Organization for Standardization (ISO) 12488-1, define target values that must be determined by survey. For a crane runway these are for example the span, the position and height of the rails. The process has to be objective and reproducible. However, common processes of surveying crane runways do not meet these requirements sufficiently. The evaluation of the protocols, ideally by an expert, requires many years of experience. Additionally, the recording of crucial parameters, e.g., the wear of the rail, or the condition of the rail fastening and rail joints, is not regulated and for that reason are often not considered during the measurement. To solve this deficit the Advanced Rail Track Inspection System (ARTIS) was developed. ARTIS is used to measure the 3D position of crane rails, the cross-section of the crane rails, joints and, for the first time, the (crane-rail) fastenings. The system consists of a monitoring vehicle and an external tracking sensor. It makes kinematic observations with the tracking sensor from outside the rail run, e.g., the floor of an overhead crane runway, possible. In this paper we present stages of the development process of ARTIS, new target values, calibration of sensors and results of a test measurement.

  14. Sensitivity of Runway Occupancy Time (ROT) to Various Rollout and Turnoff (ROTO) Factors. Volume 1

    NASA Technical Reports Server (NTRS)

    Goldthorpe, S. H.

    1997-01-01

    The Terminal Area Productivity (TAP) research program was initiated by NASA to increase the airport capacity for transport aircraft operations. One element of the research program is called Low Visibility Landing and Surface Operations (LVLASO). A goal of the LVLASO research is to develop transport aircraft technologies which reduce Runway Occupancy Time (ROT) so that it does not become the limiting factor in the terminal area operations that determine the capacity of a runway. Under LVLASO, the objective of this study was to determine the sensitivity of ROT to various factors associated with the Rollout and Turnoff (ROTO) operation for transport aircraft. The following operational factors were studied and are listed in the order of decreasing ROT sensitivity: ice/flood runway surface condition, exit entrance ground speed, number of exits, high-speed exit locations and spacing, aircraft type, touchdown ground speed standard deviation, reverse thrust and braking method, accurate exit prediction capability, maximum reverse thrust availability, spiral-arc vs. circle-arc exit geometry, dry/slush/wet/snow runway surface condition, maximum allowed deceleration, auto asymmetric braking on exit, do not stow reverse thrust before the exit, touchdown longitudinal location standard deviation, flap setting, anti-skid efficiency, crosswind conditions, stopping on the exit and touchdown lateral offset.

  15. Comprehensive and Highly Accurate Measurements of Crane Runways, Profiles and Fastenings

    PubMed Central

    Dennig, Dirk; Bureick, Johannes; Link, Johannes; Diener, Dmitri; Hesse, Christian; Neumann, Ingo

    2017-01-01

    The process of surveying crane runways has been continually refined due to the competitive situation, modern surveying instruments, additional sensors, accessories and evaluation procedures. Guidelines, such as the International Organization for Standardization (ISO) 12488-1, define target values that must be determined by survey. For a crane runway these are for example the span, the position and height of the rails. The process has to be objective and reproducible. However, common processes of surveying crane runways do not meet these requirements sufficiently. The evaluation of the protocols, ideally by an expert, requires many years of experience. Additionally, the recording of crucial parameters, e.g., the wear of the rail, or the condition of the rail fastening and rail joints, is not regulated and for that reason are often not considered during the measurement. To solve this deficit the Advanced Rail Track Inspection System (ARTIS) was developed. ARTIS is used to measure the 3D position of crane rails, the cross-section of the crane rails, joints and, for the first time, the (crane-rail) fastenings. The system consists of a monitoring vehicle and an external tracking sensor. It makes kinematic observations with the tracking sensor from outside the rail run, e.g., the floor of an overhead crane runway, possible. In this paper we present stages of the development process of ARTIS, new target values, calibration of sensors and results of a test measurement. PMID:28505076

  16. 14 CFR 151.15 - Federal-aid Airport Program: Policy affecting runway or taxiway remarking.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Federal-aid Airport Program: Policy... § 151.15 Federal-aid Airport Program: Policy affecting runway or taxiway remarking. No project for... remarking if the present marking is obliterated by construction, alteration or repair work included in...

  17. 14 CFR 151.15 - Federal-aid Airport Program: Policy affecting runway or taxiway remarking.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Federal-aid Airport Program: Policy... § 151.15 Federal-aid Airport Program: Policy affecting runway or taxiway remarking. No project for... remarking if the present marking is obliterated by construction, alteration or repair work included in...

  18. 14 CFR 151.15 - Federal-aid Airport Program: Policy affecting runway or taxiway remarking.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Federal-aid Airport Program: Policy... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS General Requirements § 151.15 Federal-aid Airport Program: Policy affecting runway or taxiway remarking. No project for...

  19. 14 CFR 151.15 - Federal-aid Airport Program: Policy affecting runway or taxiway remarking.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Federal-aid Airport Program: Policy... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRPORTS FEDERAL AID TO AIRPORTS General Requirements § 151.15 Federal-aid Airport Program: Policy affecting runway or taxiway remarking. No project for...

  20. Development of the Runway Incursion Advisory and Alerting System (RIAAS): Research Summary

    NASA Technical Reports Server (NTRS)

    Jones, Denise R. (Technical Monitor); Cassell, Rick

    2005-01-01

    This report summarizes research conducted on an aircraft based Runway Incursion Advisory and Alerting System (RIAAS) developed under a cooperative agreement between Rannoch Corporation and the NASA Langley Research Center. A summary of RIAAS is presented along with results from simulation and flight testing, safety benefits, and key technical issues.

  1. STS-26 Discovery, OV-103, with landing gear deployed glides above EAFB runway

    NASA Image and Video Library

    1988-10-03

    STS-26 Discovery, Orbiter Vehicle (OV) 103, with nose landing gear (NLG) and main landing gear (MLG) deployed glides above dry lakebed runway 17 at Edwards Air Force Base (EAFB), California. This profile view shows OV-103's port side just before MLG touchdown.

  2. Design and development of a modified runway model of mouse drug self-administration

    PubMed Central

    Pandy, Vijayapandi; Khan, Yasmin

    2016-01-01

    The present study established a novel mouse model of a runway drug self-administration in our laboratory. The operant runway apparatus consisted of three long runways arranged in a zig-zag manner. The methodology consisted of six distinct phases: habituation, preconditioning, conditioning, post-conditioning, extinction and reinstatement. The effects of saline were compared with escalating doses of either ethanol (0.5–4.0 g/kg, i.p), heroin (5–40 mg/kg, i.p), or nicotine (0.1–0.5mg/kg, i.p) administered in the goal box during the conditioning phase (day 1 to day 5). A significant decrease in the time of trained (conditioned) mice to reach the goal box confirmed the subjects’ motivation to seek those drugs on day 6 (expression). The mice were then subjected to non-rewarded extinction trials for 5 days over which run times were significantly increased. After 5 days of abstinence, a priming dose of ethanol or heroin (1/5th of maximum dose used in conditioning) significantly reinstated the drug-seeking behavior. These results suggest that the modified runway model can serve as a powerful behavioral tool for the study of the behavioral and neurobiological bases of drug self-administration and, as such, is appropriate simple but powerful tool for investigating the drug-seeking behavior of laboratory mice. PMID:26902717

  3. Preliminary Human-in-the-Loop Assessment of Procedures for Very-Closely-Spaced Parallel Runways

    NASA Technical Reports Server (NTRS)

    Verma, Savita; Lozito, Sandra C.; Ballinger, Deborah S.; Trot, Greg; Hardy, Gordon H.; Panda, Ramesh C.; Lehmer, Ronald D.; Kozon, Thomas E.

    2010-01-01

    Demand in the future air transportation system concept is expected to double or triple by 2025 [1]. Increasing airport arrival rates will help meet the growing demand that could be met with additional runways but the expansion airports is met with environmental challenges for the surrounding communities when using current standards and procedures. Therefore, changes to airport operations can improve airport capacity without adding runways. Building additional runways between current ones, or moving them closer, is a potential solution to meeting the increasing demand, as addressed by the Terminal Area Capacity Enhancing Concept (TACEC). TACEC requires robust technologies and procedures that need to be tested such that operations are not compromised under instrument meteorological conditions. The reduction of runway spacing for independent simultaneous operations dramatically exacerbates the criticality of wake vortex incursion and the calculation of a safe and proper breakout maneuver. The study presented here developed guidelines for such operations by performing a real-time, human-in-the-loop simulation using precision navigation, autopilot-flown approaches, with the pilot monitoring aircraft spacing and the wake vortex safe zone during the approach.

  4. Response of a WB-47E Airplane to Runway Roughness at Eielson AFB, Alaska, September 1964

    NASA Technical Reports Server (NTRS)

    Morris, Garland J.; Hall, Albert W.

    1965-01-01

    An investigation has been conducted to measure the response of a WB-47E airplane to the roughness of the runway at Eielson AFB, Alaska. The acceleration level in the pilot's compartment and the pitching oscillation of the airplane were found to be sufficiently high to possibly cause pilot discomfort and have an adverse effect on the precision of take-off.

  5. Functional Analysis for an Integrated Capability of Arrival/Departure/Surface Management with Tactical Runway Management

    NASA Technical Reports Server (NTRS)

    Phojanamongkolkij, Nipa; Okuniek, Nikolai; Lohr, Gary W.; Schaper, Meilin; Christoffels, Lothar; Latorella, Kara A.

    2014-01-01

    The runway is a critical resource of any air transport system. It is used for arrivals, departures, and for taxiing aircraft and is universally acknowledged as a constraining factor to capacity for both surface and airspace operations. It follows that investigation of the effective use of runways, both in terms of selection and assignment as well as the timing and sequencing of the traffic is paramount to the efficient traffic flows. Both the German Aerospace Center (DLR) and NASA have developed concepts and tools to improve atomic aspects of coordinated arrival/departure/surface management operations and runway configuration management. In December 2012, NASA entered into a Collaborative Agreement with DLR. Four collaborative work areas were identified, one of which is called "Runway Management." As part of collaborative research in the "Runway Management" area, which is conducted with the DLR Institute of Flight Guidance, located in Braunschweig, the goal is to develop an integrated system comprised of the three DLR tools - arrival, departure, and surface management (collectively referred to as A/D/S-MAN) - and NASA's tactical runway configuration management (TRCM) tool. To achieve this goal, it is critical to prepare a concept of operations (ConOps) detailing how the NASA runway management and DLR arrival, departure, and surface management tools will function together to the benefit of each. To assist with the preparation of the ConOps, the integrated NASA and DLR tools are assessed through a functional analysis method described in this report. The report first provides the highlevel operational environments for air traffic management (ATM) in Germany and in the U.S., and the descriptions of the DLR's A/D/S-MAN and NASA's TRCM tools at the level of details necessary to compliment the purpose of the study. Functional analyses of each tool and a completed functional analysis of an integrated system design are presented next in the report. Future efforts to fully

  6. Microbially influenced degradation of concrete structures

    NASA Astrophysics Data System (ADS)

    Rogers, Robert D.; Hamilton, Melinda A.; Nelson, Lee O.

    1998-03-01

    Steel reinforced concrete is the most widely used construction material in the world. The economic costs of repair or replacement of environmentally damaged concrete structures is astronomical. For example, half of the concrete bridges in the Federal Department of Transportation highway system are in need of major repairs. Microbially influenced degradation of concrete (MID) is one of the recognized degradative processes known to adversely affect concrete integrity. It is not possible to assign a specific percent of effect to any of these processes. However, MID has been shown to be as aggressive as any of the physical/chemical phenomena. In addition, the possibility exists that there is a synergism which results in cumulative effects from all the processes. Three groups of bacteria are known to promote MID. Of these, sulfur-oxidizing bacteria (SOB) are the most aggressive. Much is known about the nutritional needs of these bacteria. However, there has not been a biological linkage established between the presence of environmental, polluting sulfur sources and the degradation of concrete structures. It has been shown that the environmental pollutants sulfur dioxide and sulfite can be utilized by active SOB for the biological production of sulfuric acid. Therefore, it is not a reach of reality to assume that SOB exposed to these pollutants could have a major impact on the degradation of concrete structures. But, until the environment sulfur loop is closed it will not be possible to calculate how important SOB activity is in initiating and promoting damage.

  7. Microstructure of high-strength foam concrete

    SciTech Connect

    Just, A.; Middendorf, B.

    2009-07-15

    Foam concretes are divided into two groups: on the one hand the physically foamed concrete is mixed in fast rotating pug mill mixers by using foaming agents. This concrete cures under atmospheric conditions. On the other hand the autoclaved aerated concrete is chemically foamed by adding aluminium powder. Afterwards it is cured in a saturated steam atmosphere. New alternatives for the application of foam concretes arise from the combination of chemical foaming and air curing in manufacturing processes. These foam concretes are new and innovative building materials with interesting properties: low mass density and high strength. Responsible for these properties are the macro-, meso- and microporosity. Macropores are created by adding aluminium powder in different volumes and with different particle size distributions. However, the microstructure of the cement matrix is affected by meso- and micropores. In addition, the matrix of the hardened cement paste can be optimized by the specific use of chemical additives for concrete. The influence of aluminium powder and chemical additives on the properties of the microstructure of the hardened cement matrices were investigated by using petrographic microscopy as well as scanning electron microscopy.

  8. Pilot perception of light emitting diodes versus incandescent elevated runway guard lights

    NASA Astrophysics Data System (ADS)

    Stevens, Hilary

    Pilots must understand and be aware of the purpose of each airport sign, light and marking, for there are numerous. The Federal Aviation Administration (FAA) is planning on replacing the current incandescent lighting with far more economical LED airport lighting. In preparation for this change, two experiments were conducted for this thesis. Experiment 1 attempted to determine what pilots know about the meaning of the signs, markings and lights on the taxiways and runways through a questionnaire that was developed with the FAA. Experiment 2 evaluated pilot perception of LED lighting compared to current incandescent elevated runway guard lights. The meaning of airfield lights is not often stressed in pilot training and many pilots are unsure as to the intended purpose of specific lighting. Experiment 1 attempted to evaluate the uncertainty of these caution lights. In experiment 1, a knowledge survey about runway lighting and markings was created. The survey was developed by a flight instructor and approved by the Federal Aviation Administration. The surveys were given to about 150 pilots with varying flight ratings and experience levels. Experiment 1 results determined that there is a need for more intensive or remedial training on some airport signals. Results also showed that some runway signals need to have greater cue salience. Experiment 2 was designed to replace the existing elevated runway guard lights at a local airport from incandescent lights to light emitting diodes. Permission to cross onto the runways from a taxiway at airports must be given by the air traffic (ground) controller. The demarcation between taxiway and runway is indicated by the elevated runway guard light (ERGL), which signals to the taxiing pilot to hold short at the border of the runway until permission to cross the intersection is obtained. Incandescent lights are currently installed in the ERGLs. Experiment 2 of this thesis was designed to evaluate pilot's perceptions of the elevated

  9. Reinforced Concrete Modeling

    DTIC Science & Technology

    1982-07-01

    AFWL-TR-82-9 AFWL-TR-82-9 REINFORCED CONCRETE MODELING H. L. Schreyer J. W. Jeter, Jr. New Mexico Engineering Reseprch Institute University of New...Subtitle) S. TYPE OF REPORT & PERIOD COVERED REINFORCED CONCRETE MODELING Final Report 6. PERFORMING OtG. REPORT NUMBER NMERI TA8-9 7. AUTHORg) S...loading were identified and used to evaluate current concrete models . Since the endochronic and viscoplastic models provide satisfactory descriptions

  10. Some engineering properties of heavy concrete added silica fume

    NASA Astrophysics Data System (ADS)

    Akkaş, Ayşe; Başyiǧit, Celalettin; Esen, Serap

    2013-12-01

    Many different types of building materials have been used in building construction for years. Heavy concretes can be used as a building material for critical building as it can contain a mixture of many heavy elements. The barite itself for radiation shielding can be used and also in concrete to produce the workable concrete with a maximum density and adequate structural strength. In this study, some engineering properties like compressive strength, elasticity modules and flexure strength of heavy concretes' added Silica fume have been investigated.

  11. Use of recycled plastics in concrete: A critical review.

    PubMed

    Gu, Lei; Ozbakkaloglu, Togay

    2016-05-01

    Plastics have become an essential part of our modern lifestyle, and the global plastic production has increased immensely during the past 50years. This has contributed greatly to the production of plastic-related waste. Reuse of waste and recycled plastic materials in concrete mix as an environmental friendly construction material has drawn attention of researchers in recent times, and a large number of studies reporting the behavior of concrete containing waste and recycled plastic materials have been published. This paper summarizes the current published literature until 2015, discussing the material properties and recycling methods of plastic and the influence of plastic materials on the properties of concrete. To provide a comprehensive review, a total of 84 studies were considered, and they were classified into sub categories based on whether they dealt with concrete containing plastic aggregates or plastic fibers. Furthermore, the morphology of concrete containing plastic materials is described in this paper to explain the influence of plastic aggregates and plastic fibers on the properties of concrete. The properties of concretes containing virgin plastic materials were also reviewed to establish their similarities and differences with concrete containing recycled plastics.

  12. Effects of forced-choice runway variations on rats' T-maze serial pattern learning.

    PubMed

    Szelest, Izabela; Cohen, Jerome

    2006-05-01

    Rats learned an ordered RNR/RNN serial pattern task in a T-maze where they were shifted to a different runway on Trial 3 only in the RNR series (shift-win/stay-lose group) or only in the RNN series (stay-win/shift-lose group). The shift-win/stay-lose group developed faster speeds on Trial 3 of the RNR than on Trial 3 of the RNN series more easily than the stay-win/shift-lose group. This difference occurred whether all rats were forced onto the same runway on the first two trials (Experiment 1) or onto a different runway on Trial 2 from that on Trial 1 in each series (Experiment 2). Posttraining probe tests revealed that the shift-win/stay-lose group in each experiment relied on the runway shift event in Trial 3 or on the series position to anticipate the second reward within a series. Such reward expectancies were greater when the runway shift occurred in the same series position as during training. These probe tests revealed that the stay-win/shift-lose group relied only on the series position in Experiment 2. Our findings do not support predictions based on an associative predictive validity model. Rather, they reflect rats' predisposition to spontaneously alternate choices in the T-maze, a tendency corresponding to their inherent win-shift foraging strategy. Rats in each group also reduced their speeds less on the nonrewarded Trial 2 when it preceded a rewarded rather than a nonrewarded Trial 3. This effect suggests that rats were able to determine which series contained a second rewarded trial. We discuss the theoretical implications of this Trial 2 speed effect in terms of rats' uncertainty about where this second rewarded trial might occur in the RNR series.

  13. Perseus B Heads for Landing on Edwards AFB Runway

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Perseus B remotely piloted aircraft approaches the runway at Edwards Air Force Base, Calif. at the conclusion of a development flight at NASA's Dryden flight Research Center in April 1998. The Perseus B is the latest of three versions of the Perseus design developed by Aurora Flight Sciences under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation

  14. Perseus B Heads for Landing on Edwards AFB Runway

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Perseus B remotely piloted aircraft approaches the runway at Edwards Air Force Base, Calif. at the conclusion of a development flight at NASA's Dryden flight Research Center in April 1998. The Perseus B is the latest of three versions of the Perseus design developed by Aurora Flight Sciences under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation

  15. 78 FR 37236 - Prestressed Concrete Steel Rail Tie Wire From China, Mexico, and Thailand

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-20

    ... COMMISSION Prestressed Concrete Steel Rail Tie Wire From China, Mexico, and Thailand Determinations On the... injured by reason of imports from China, Mexico, and Thailand of prestressed concrete steel rail tie wire... materially injured or threatened with material injury by reason of LTFV imports of prestressed concrete...

  16. Rollout and Turnoff (ROTO) Guidance and Information Displays: Effect on Runway Occupancy Time in Simulated Low-Visibility Landings

    NASA Technical Reports Server (NTRS)

    Hueschen, Richard M.; Hankins, Walter W., III; Barker, L. Keith

    2001-01-01

    This report examines a rollout and turnoff (ROTO) system for reducing the runway occupancy time for transport aircraft in low-visibility weather. Simulator runs were made to evaluate the system that includes a head-up display (HUD) to show the pilot a graphical overlay of the runway along with guidance and steering information to a chosen exit. Fourteen pilots (airline, corporate jet, and research pilots) collectively flew a total of 560 rollout and turnoff runs using all eight runways at Hartsfield Atlanta International Airport. The runs consisted of 280 runs for each of two runway visual ranges (RVRs) (300 and 1200 ft). For each visual range, half the runs were conducted with the HUD information and half without. For the runs conducted with the HUD information, the runway occupancy times were lower and more consistent. The effect was more pronounced as visibility decreased. For the 1200-ft visibility, the runway occupancy times were 13% lower with HUD information (46.1 versus 52.8 sec). Similarly, for the 300-ft visibility, the times were 28% lower (45.4 versus 63.0 sec). Also, for the runs with HUD information, 78% (RVR 1200) and 75% (RVR 300) had runway occupancy times less than 50 sec, versus 41 and 20%, respectively, without HUD information.

  17. Hydrothermal alteration of concrete: Yucca Mountain repository analogues

    SciTech Connect

    Myers, K.B.; Meike, A.

    1997-10-01

    Concrete could comprise a major share of construction materials present in the potential Yucca Mountain high-level radioactive waste repository. Concrete and shotcrete would be used as mechanical support (precast concrete liners), or road bed (invert) in repository emplacement drifts. These drifts could reach at least 150 to 200{degrees}C for extended periods of time, possibly in the presence of fluids. This study characterizes chemical and structural transformations in concrete that may occur as a result of a repository hydrothermal cycle. The specific concrete formulation to be used in the potential Yucca Mountain repository had not been determined at the time of the experiment. Invert and Fibercrete{sup TM} materials from the Exploratory Studies Facility (ESF) were chosen for these experiments as representatives of standard construction concrete used in this setting.

  18. Laboratory constitutive characterization of cellular concrete.

    SciTech Connect

    Hardy, Robert Douglas; Lee, Moo Yul; Bronowski, David R.

    2004-03-01

    To establish mechanical material properties of cellular concrete mixes, a series of quasi-static, compression and tension tests have been completed. This report summarizes the test methods, set-up, relevant observations, and results from the constitutive experimental efforts. Results from the uniaxial and triaxial compression tests established failure criteria for the cellular concrete in terms of stress invariants I{sub 1} and J{sub 2}. {radical}J{sub 2} (MPa) = 297.2 - 278.7 exp{sup -0.000455 I}{sub 1}{sup (MPa)} for the 90-pcf concrete {radical}J{sub 2} (MPa) = 211.4 - 204.2 exp {sup -0.000628 I}{sub 1}{sup (MPa)} for the 60-pcf concrete

  19. 51. DETAIL VIEW OF VIVIANNA ERA CONCRETE HOUSE WITH CONCRETE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. DETAIL VIEW OF VIVIANNA ERA CONCRETE HOUSE WITH CONCRETE PATIO SLAB LOOKING SOUTHWEST. NOTICE MINE WORKINGS BACKGROUND LEFT. - Mariscal Quicksilver Mine & Reduction Works, Terlingua, Brewster County, TX

  20. Mechanical Model for Dynamic Behavior of Concrete Under Impact Loading

    NASA Astrophysics Data System (ADS)

    Sun, Yuanxiang

    Concrete is a geo-material which is used substantively in the civil building and military safeguard. One coupled model of damage and plasticity to describe the complex behavior of concrete subjected to impact loading is proposed in this research work. The concrete is assumed as homogeneous continuum with pre-existing micro-cracks and micro-voids. Damage to concrete is caused due to micro-crack nucleation, growth and coalescence, and defined as the probability of fracture at a given crack density. It induces a decrease of strength and stiffness of concrete. Compaction of concrete is physically a collapse of the material voids. It produces the plastic strain in the concrete and, at the same time, an increase of the bulk modulus. In terms of crack growth model, micro-cracks are activated, and begin to propagate gradually. When crack density reaches a critical value, concrete takes place the smashing destroy. The model parameters for mortar are determined using plate impact experiment with uni-axial strain state. Comparison with the test results shows that the proposed model can give consistent prediction of the impact behavior of concrete. The proposed model may be used to design and analysis of concrete structures under impact and shock loading. This work is supported by State Key Laboratory of Explosion science and Technology, Beijing Institute of Technology (YBKT14-02).