Void parameters of 24 cores of concrete removed from a consolidation test study section of I-64.

DOT National Transportation Integrated Search

1972-01-01

During the construction of I-64 near Charlottesville, Virginia, the Ballenger Paving Company chose to set up a limited experiment to investigate various factors affecting the consolidation of concrete by vibration. The test design varied the speed of...

Cold Weather Admixture Systems Demonstration at Fort Wainwright, Alaska

DTIC Science & Technology

2010-08-01

3, and 5, the remaining two test sec- tions (Test Sections 2 and 4) were readied for concrete . The interior formwork was removed, and the rebar was...Washington, DC 20314-1000 ERDC/CRREL TR-10-6 ii Abstract: Cold Weather Admixture Systems (CWAS) is a new approach to cold weather concreting that...incorporates suites of commercially avail- able chemical admixtures in concrete mixes. When used in combination, these admixtures depress the freezing

Seismic performance of interior precast concrete beam-column connections with T-section steel inserts under cyclic loading

NASA Astrophysics Data System (ADS)

Ketiyot, Rattapon; Hansapinyo, Chayanon

2018-04-01

An experimental investigation was conducted to study the performance of precast beam-column concrete connections using T-section steel inserts into the concrete beam and joint core, under reversed cyclic loading. Six 2/3-scale interior beam-column subassemblies, one monolithic concrete specimen and five precast concrete specimens were tested. One precast specimen was a simple connection for a gravity load resistant design. Other precast specimens were developed with different attributes to improve their seismic performance. The test results showed that the performance of the monolithic specimen M1 represented ductile seismic behavior. Failure of columns and joints could be prevented, and the failure of the frame occurred at the flexural plastic hinge formation at the beam ends, close to the column faces. For the precast specimens, the splitting crack along the longitudinal lapped splice was a major failure. The precast P5 specimen with double steel T-section inserts showed better seismic performance compared to the other precast models. However, the dowel bars connected to the steel inserts were too short to develop a bond. The design of the precast concrete beams with lap splice is needed for longer lap lengths and should be done at the beam mid span or at the low flexural stress region.

Analysis and design of on-grade reinforced concrete track support structures

NASA Technical Reports Server (NTRS)

Mclean, F. G.; Williams, R. D.; Greening, L. R.

1972-01-01

For the improvement of rail service, the Department of Transportation, Federal Rail Administration, is sponsoring a test track on the Atchison, Topeka, and Santa Fe Railway. The test track will contain nine separate rail support structures, including one conventional section for control and three reinforced concrete structures on grade, one slab and two beam sections. The analysis and design of these latter structures was accomplished by means of the finite element method, NASTRAN, and is presented.

Performance of concrete members subjected to large hydrocarbon pool fires

DOE PAGES

Zwiers, Renata I.; Morgan, Bruce J.

1989-01-01

The authors discuss an investigation to determine analytically if the performance of concrete beams and columns in a hydrocarbon pool test fire would differ significantly from their performance in a standard test fire. The investigation consisted of a finite element analysis to obtain temperature distributions in typical cross sections, a comparison of the resulting temperature distribution in the cross section, and a strength analysis of a beam based on temperature distribution data. Results of the investigation are reported.

Constitutive Behavior and Finite Element Analysis of FRP Composite and Concrete Members.

PubMed

Ann, Ki Yong; Cho, Chang-Geun

2013-09-10

The present study concerns compressive and flexural constitutive models incorporated into an isoparametric beam finite element scheme for fiber reinforced polymer (FRP) and concrete composites, using their multi-axial constitutive behavior. The constitutive behavior of concrete was treated in triaxial stress states as an orthotropic hypoelasticity-based formulation to determine the confinement effect of concrete from a three-dimensional failure surface in triaxial stress states. The constitutive behavior of the FRP composite was formulated from the two-dimensional classical lamination theory. To predict the flexural behavior of circular cross-section with FRP sheet and concrete composite, a layered discretization of cross-sections was incorporated into nonlinear isoparametric beam finite elements. The predicted constitutive behavior was validated by a comparison to available experimental results in the compressive and flexural beam loading test.

Asphaltic concrete overlays of rigid and flexible pavements : final report.

DOT National Transportation Integrated Search

1980-10-01

This study evaluated the effect of a given thickness of asphaltic concrete overlay in rehabilitating 53 test sections conforming to the experiment design. This factorial design specified various levels of traffic intensity and overlay thickness for b...

Retardation of reflective cracking using additive 5990.

DOT National Transportation Integrated Search

1987-01-01

Research was conducted in 1980 using Additive 5990 to prevent : reflective cracking in asphalt cement concrete when placed over : portland cement concrete. Test sections were placed with 08, 3%, : 68, and 9% Additive 5990 by weight of asphalt cement ...

Wear resistant pavement study.

DOT National Transportation Integrated Search

2009-01-01

This report documents the construction of three special pavement test sections on I-90 east of Spokane, Washington. The test sections included ultra-thin and thin whitetopping, Modified Class D open graded asphalt concrete, and micro/macro surfacing ...

Asphaltic concrete overlays of rigid and flexible pavements : interim report No. 1.

DOT National Transportation Integrated Search

1977-09-01

This study evaluated the effect of a given thickness of asphaltic concrete overlay in rehabilitating 53 test sections conforming to the experiment design. This factorial design specified various levels of traffic intensity and overlay thickness for b...

Effect of antistripping additives on the compaction of bituminous concrete.

DOT National Transportation Integrated Search

1981-01-01

The objective of this investigation was to determine the effect of antistripping additives on the compaction of bituminous concrete. To do this, the densities obtained on test sections with and without additive were compared. Comparisons of nuclear d...

Constitutive Behavior and Finite Element Analysis of FRP Composite and Concrete Members

PubMed Central

Ann, Ki Yong; Cho, Chang-Geun

2013-01-01

The present study concerns compressive and flexural constitutive models incorporated into an isoparametric beam finite element scheme for fiber reinforced polymer (FRP) and concrete composites, using their multi-axial constitutive behavior. The constitutive behavior of concrete was treated in triaxial stress states as an orthotropic hypoelasticity-based formulation to determine the confinement effect of concrete from a three-dimensional failure surface in triaxial stress states. The constitutive behavior of the FRP composite was formulated from the two-dimensional classical lamination theory. To predict the flexural behavior of circular cross-section with FRP sheet and concrete composite, a layered discretization of cross-sections was incorporated into nonlinear isoparametric beam finite elements. The predicted constitutive behavior was validated by a comparison to available experimental results in the compressive and flexural beam loading test. PMID:28788312

Evaluation of nondestructive evaluation methods for application in early detection Of deterioration in concrete pavements

DOT National Transportation Integrated Search

2000-01-01

Three nondestructive evaluation (NDE) methods for concrete pavements - surface ultrasonic pulse velocity measurements (UPV), the impact-echo (IE) method, and the use of a seismic pavement analyzer (SPA) - were tested on six sections of two continuous...

Steel slag in hot mix asphalt concrete : final report

DOT National Transportation Integrated Search

2000-04-01

In September 1994, steel slag test and control sections were constructed in Oregon to evaluate the use of steel slag in hot mix asphalt concrete (HMAC). This report covers the construction and five-year performance of a pavement constructed with 30% ...

Time dependent variation of carrying capacity of prestressed precast beam

NASA Astrophysics Data System (ADS)

Le, Tuan D.; Konečný, Petr; Matečková, Pavlína

2018-04-01

The article deals with the evaluation of the precast concrete element time dependent carrying capacity. The variation of the resistance is inherited property of laboratory as well as in-situ members. Thus the specification of highest, yet possible, laboratory sample resistance is important with respect to evaluation of laboratory experiments based on the test machine loading capabilities. The ultimate capacity is evaluated through the bending moment resistance of a simply supported prestressed concrete beam. The probabilistic assessment is applied. Scatter of random variables of compressive strength of concrete and effective height of the cross section is considered. Monte Carlo simulation technique is used to investigate the performance of the cross section of the beam with changes of tendons’ positions and compressive strength of concrete.

IET. Coupling station (TAN620), plans and sections. Concrete shielding walls ...

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

IET. Coupling station (TAN-620), plans and sections. Concrete shielding walls and boron surface treatment. Elevation shows two floor levels, position of periscopes, and stairways. Ralph M. Parsons 902-4-ANP-602-A 325. Date: February 1954. Approved by INEEL Classification Office for public release. INEEL index code no. 035-0620-00-693-106910 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Testing Notched Ends of Prestressed Concrete Box Beams: Final Letter Report on Projects 1479 and 1340

DOT National Transportation Integrated Search

1994-12-01

Prestressed concrete box beams incorporated in a bridge project under construction in the Houston District encountered cracking in the notched (dapped) ends during fabrication. Because the members in question are trapezoidal in section and have inter...

Use of carbon black in bituminous concrete in Virginia.

DOT National Transportation Integrated Search

1981-01-01

In an attempt to verify the claim that the addition of carbon black to bituminous concrete increases its stability and performance, a test section placed on a deformed bridge deck surface near Altavista and one on Route 360 near Richmond are being ev...

Installation and early performance of a field test section of asphalt rubber concrete.

DOT National Transportation Integrated Search

1991-01-01

Asphalt rubber, which is produced by reacting asphalt cement and crumb rubber, is claimed to increase fatigue life and reduce rutting of asphalt concrete; however, the service life must be increased significantly to offset the additional coast of add...

11. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

11. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. OC12-50-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/15, Rev. E. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, Rev. E; Date: 21 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

13. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

13. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. OC12-50-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/18, Rev. D. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, Rev. D, no change; Date: 18 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

9. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

9. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. ENG 04-35350-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/13. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, no change; Date: 17 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

10. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

10. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. OC12-50-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/14, Rev. B. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, Rev. B; Date: 21 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

12. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

12. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. OC12-50-10; Drawing No. 60-09-06; no sheet number within title block. D.O. SERIES 1109/16, Rev. E. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, Rev. E; Date: 26 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

OECD MCCI 2-D Core Concrete Interaction (CCI) tests : CCI-2 test data report-thermalhydraulic results, Rev. 0 October 15, 2004.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farmer, M. T.; Lomperski, S.; Kilsdonk, D. J.

The Melt Attack and Coolability Experiments (MACE) program addressed the issue of the ability of water to cool and thermally stabilize a molten core-concrete interaction when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. As a follow-on program to MACE, The Melt Coolability and Concrete Interaction Experiments (MCCI) project is conducting reactor material experiments and associated analysis to achieve the following objectives: (1)more » resolve the ex-vessel debris coolability issue through a program that focuses on providing both confirmatory evidence and test data for the coolability mechanisms identified in MACE integral effects tests, and (2) address remaining uncertainties related to long-term two-dimensional molten core-concrete interactions under both wet and dry cavity conditions. Achievement of these two program objectives will demonstrate the efficacy of severe accident management guidelines for existing plants, and provide the technical basis for better containment designs for future plants. In terms of satisfying these objectives, the Management Board (MB) approved the conduct of two long-term 2-D Core-Concrete Interaction (CCI) experiments designed to provide information in several areas, including: (i) lateral vs. axial power split during dry core-concrete interaction, (ii) integral debris coolability data following late phase flooding, and (iii) data regarding the nature and extent of the cooling transient following breach of the crust formed at the melt-water interface. This data report provides thermal hydraulic test results from the CCI-2 experiment, which was conducted on August 24, 2004. Test specifications for CCI-2 are provided in Table 1-1. This experiment investigated the interaction of a fully oxidized 400 kg PWR core melt, initially containing 8 wt % Limestone/Common Sand (LCS) concrete, with a specially designed two-dimensional LCS concrete test section with an initial cross-sectional area of 50 cm x 50 cm. The report begins by providing a summary description of the CCI-2 test apparatus and operating procedures, followed by presentation of the thermal-hydraulic results. Detailed posttest debris examination results will be provided in a subsequent publication. Observations drawn within this report regarding the overall cavity erosion behavior may be subject to revision once the posttest examinations are completed, since these examinations will fully reveal the final cavity shape.« less

Analysis of Stress in Steel and Concrete in Cfst Push-Out Test Samples

NASA Astrophysics Data System (ADS)

Grzeszykowski, Bartosz; Szadkowska, Magdalena; Szmigiera, Elżbieta

2017-09-01

The paper presents the analysis of stress in steel and concrete in CFST composite elements subjected to push-out tests. Two analytical models of stress distribution are presented. The bond at the interface between steel and concrete in the initial phase of the push-out test is provided by the adhesion. Until the force reach a certain value, the slip between both materials does not occur or it is negligibly small, what ensures full composite action of the specimen. In the first analytical model the full bond between both materials was assumed. This model allows to estimate value of the force for which the local loss of adhesion in given cross section begins. In the second model it was assumed that the bond stress distribution is constant along the shear transfer length of the specimen. Based on that the formulas for triangle distribution of stress in steel and concrete for the maximum push-out force were derived and compared with the experimental results. Both models can be used to better understand the mechanisms of interaction between steel and concrete in composite steel-concrete columns.

Evaluation of long-term pavement performance and noise characteristics of the next generation concrete surface : final report.

DOT National Transportation Integrated Search

2014-01-01

This report documents the performance of the first Next Generation Concrete Surface (NGCS) built by the : Washington State Department of Transportation (WSDOT). A 1,500 foot test section was installed on the : eastbound lanes of I-82 near Sunnyside, ...

Evaluation of long-term pavement performance and noise characteristics of the next generation concrete surface.

DOT National Transportation Integrated Search

2011-04-01

This report documents the construction of the first Next Generation Concrete Surface (NGCS) by the Washington State Department of Transportation (WSDOT). A 1,500 foot test section was installed on the eastbound lanes of I-82 near Sunnyside, WA in Oct...

OECD MCCI project 2-D Core Concrete Interaction (CCI) tests : CCI-3 test data report-thermalhydraulic results. Rev. 0 October 15, 2005.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farmer, M. T.; Lomperski, S.; Kilsdonk, D. J.

The Melt Attack and Coolability Experiments (MACE) program addressed the issue of the ability of water to cool and thermally stabilize a molten core-concrete interaction when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. As a follow-on program to MACE, The Melt Coolability and Concrete Interaction Experiments (MCCI) project is conducting reactor material experiments and associated analysis to achieve the following objectives: (1)more » resolve the ex-vessel debris coolability issue through a program that focuses on providing both confirmatory evidence and test data for the coolability mechanisms identified in MACE integral effects tests, and (2) address remaining uncertainties related to long-term two-dimensional molten core-concrete interactions under both wet and dry cavity conditions. Achievement of these two program objectives will demonstrate the efficacy of severe accident management guidelines for existing plants, and provide the technical basis for better containment designs for future plants. In terms of satisfying these objectives, the Management Board (MB) approved the conduct of a third long-term 2-D Core-Concrete Interaction (CCI) experiment designed to provide information in several areas, including: (i) lateral vs. axial power split during dry core-concrete interaction, (ii) integral debris coolability data following late phase flooding, and (iii) data regarding the nature and extent of the cooling transient following breach of the crust formed at the melt-water interface. This data report provides thermal hydraulic test results from the CCI-3 experiment, which was conducted on September 22, 2005. Test specifications for CCI-3 are provided in Table 1-1. This experiment investigated the interaction of a fully oxidized 375 kg PWR core melt, initially containing 15 wt% siliceous concrete, with a specially designed two-dimensional siliceous concrete test section with an initial cross-sectional area of 50 cm x 50 cm. The sand and aggregate constituents for this particular siliceous concrete were provided by CEA as an in-kind contribution to the program. The report begins by providing a summary description of the CCI-3 test apparatus and operating procedures, followed by presentation of the thermal-hydraulic results. Detailed posttest debris examination results will be provided in a subsequent publication. Observations drawn within this report regarding the overall cavity erosion behavior may be subject to revision once the posttest examinations are completed, since these examinations will fully reveal the final cavity shape.« less

Thick Concrete Specimen Construction, Testing, and Preliminary Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clayton, Dwight A.; Hoegh, Kyle; Khazanovich, Lev

The purpose of the U.S. Department of Energy Office of Nuclear Energy’s Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the variousmore » nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations. A preliminary report detailed some of the challenges associated with thick reinforced concrete sections and prioritized conceptual designs of specimens that could be fabricated to represent NPP concrete structures for using in NDE evaluation comparisons. This led to the construction of the concrete specimen presented in this report, which has sufficient reinforcement density and cross-sectional size to represent an NPP containment wall. Details on how a suitably thick concrete specimen was constructed are presented, including the construction materials, final nominal design schematic, as well as formwork and rigging required to safely meet the desired dimensions of the concrete structure. The report also details the type and methods of forming the concrete specimen as well as information on how the rebar and simulated defects were embedded. Details on how the resulting specimen was transported, safely anchored, and marked to allow access for systematic comparative NDE testing of defects in a representative NPP containment wall concrete specimen are also given. Data collection using the MIRA Ultrasonic NDE equipment and initial results are also presented along with a discussion of the preliminary findings. Comparative NDE of various defects in reinforced concrete specimens is a key component in identifying the most promising techniques and directing the research and development efforts needed to characterize concrete degradation in commercial NPPs. This requires access to the specimens for data collection using state-of-the-art technology. The construction of the specimen detailed in this report allows for an evaluation of how different NDE techniques may interact with the size and complexities of NPP concrete structures. These factors were taken into account when determining specimen size and features to ensure a realistic design. The lateral dimensions of the specimen were also chosen to mitigate unrealistic boundary effects that would not affect the results of field NPP concrete testing. Preliminary results show that, while the current methods are able to identify some of the deeper defects, improvements in data processing or hardware are necessary to be able to achieve the precision and reliability achieved in evaluating thinner and less heavily reinforced concrete structures.« less

Bulb-T beams with self-consolidating concrete on the Route 33 bridge over the Pamunkey River in Virginia.

DOT National Transportation Integrated Search

2008-01-01

This study evaluated the bulb-T beams made with self-consolidating concrete (SCC) used in the Route 33 Bridge over the Pamunkey River at West Point, Virginia. Before the construction of the bridge, two test beams with SCC similar in cross section to ...

Acoustic inspection of concrete bridge decks

NASA Astrophysics Data System (ADS)

Henderson, Mark E.; Dion, Gary N.; Costley, R. Daniel

1999-02-01

The determination of concrete integrity, especially in concrete bridge decks, is of extreme importance. Current systems for testing concrete structures are expensive, slow, or tedious. State of the art systems use ground penetrating radar, but they have inherent problems especially with ghosting and signal signature overlap. The older method of locating delaminations in bridge decks involves either tapping on the surface with a hammer or metal rod, or dragging a chain-bar across the bridge deck. Both methods require a `calibrated' ear to determine the difference between good sections and bad sections of concrete. As a consequence, the method is highly subjective, different from person to person and even day to day for a given person. In addition, archival of such data is impractical, or at least improbable, in most situations. The Diagnostic Instrumentation and Analysis Laboratory has constructed an instrument that implements the chain-drag method of concrete inspection. The system is capable of real-time analysis of recorded signals, archival of processed data, and high-speed data acquisition so that post-processing of the data is possible for either research purposes or for listening to the recorded signals.

Seismic Behaviour of Composite Steel Fibre Reinforced Concrete Shear Walls

NASA Astrophysics Data System (ADS)

Boita, Ioana-Emanuela; Dan, Daniel; Stoian, Valeriu

2017-10-01

In this paper is presented an experimental study conducted at the “Politehnica” University of Timisoara, Romania. This study provides results from a comprehensive experimental investigation on the behaviour of composite steel fibre reinforced concrete shear walls (CSFRCW) with partially or totally encased profiles. Two experimental composite steel fibre reinforced concrete walls (CSFRCW) and, as a reference specimen, a typical reinforced concrete shear wall (RCW), (without structural reinforcement), were fabricated and tested under constant vertical load and quasi-static reversed cyclic lateral loads, in displacement control. The tests were performed until failure. The tested specimens were designed as 1:3 scale steel-concrete composite elements, representing a three storeys and one bay element from the base of a lateral resisting system made by shear walls. Configuration/arrangement of steel profiles in cross section were varied within the specimens. The main objective of this research consisted in identifying innovative solutions for composite steel-concrete shear walls with enhanced performance, as steel fibre reinforced concrete which was used in order to replace traditional reinforced concrete. A first conclusion was that replacing traditional reinforcement with steel fibre changes the failure mode of the elements, as from a flexural mode, in case of element RCW, to a shear failure mode for CSFRCW. The maximum lateral force had almost similar values but test results indicated an improvement in cracking response, and a decrease in ductility. The addition of steel fibres in the concrete mixture can lead to an increase of the initial cracking force, and can change the sudden opening of a crack in a more stable process.

Improved Sectional Image Analysis Technique for Evaluating Fiber Orientations in Fiber-Reinforced Cement-Based Materials.

PubMed

Lee, Bang Yeon; Kang, Su-Tae; Yun, Hae-Bum; Kim, Yun Yong

2016-01-12

The distribution of fiber orientation is an important factor in determining the mechanical properties of fiber-reinforced concrete. This study proposes a new image analysis technique for improving the evaluation accuracy of fiber orientation distribution in the sectional image of fiber-reinforced concrete. A series of tests on the accuracy of fiber detection and the estimation performance of fiber orientation was performed on artificial fiber images to assess the validity of the proposed technique. The validation test results showed that the proposed technique estimates the distribution of fiber orientation more accurately than the direct measurement of fiber orientation by image analysis.

Improved Sectional Image Analysis Technique for Evaluating Fiber Orientations in Fiber-Reinforced Cement-Based Materials

PubMed Central

Lee, Bang Yeon; Kang, Su-Tae; Yun, Hae-Bum; Kim, Yun Yong

2016-01-01

The distribution of fiber orientation is an important factor in determining the mechanical properties of fiber-reinforced concrete. This study proposes a new image analysis technique for improving the evaluation accuracy of fiber orientation distribution in the sectional image of fiber-reinforced concrete. A series of tests on the accuracy of fiber detection and the estimation performance of fiber orientation was performed on artificial fiber images to assess the validity of the proposed technique. The validation test results showed that the proposed technique estimates the distribution of fiber orientation more accurately than the direct measurement of fiber orientation by image analysis. PMID:28787839

OECD MMCI 2-D Core Concrete Interaction (CCI) tests : CCCI-1 test data report-thermalhydraulic results. Rev 0 January 31, 2004.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farmer, M. T.; Lomperski, S.; Aeschlimann, R. W.

The Melt Attack and Coolability Experiments (MACE) program addressed the issue of the ability of water to cool and thermally stabilize a molten core-concrete interaction when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. As a follow-on program to MACE, The Melt Coolability and Concrete Interaction Experiments (MCCI) project is conducting reactor material experiments and associated analysis to achieve the following objectives: (1)more » resolve the ex-vessel debris coolability issue through a program that focuses on providing both confirmatory evidence and test data for the coolability mechanisms identified in MACE integral effects tests, and (2) address remaining uncertainties related to long-term two-dimensional molten coreconcrete interactions under both wet and dry cavity conditions. Achievement of these two program objectives will demonstrate the efficacy of severe accident management guidelines for existing plants, and provide the technical basis for better containment designs for future plants. In terms of satisfying these objectives, the Management Board (MB) approved the conduct of two long-term 2-D Core-Concrete Interaction (CCI) experiments designed to provide information in several areas, including: (i) lateral vs. axial power split during dry core-concrete interaction, (ii) integral debris coolability data following late phase flooding, and (iii) data regarding the nature and extent of the cooling transient following breach of the crust formed at the melt-water interface. This data report provides thermal hydraulic test results from the CCI-1 experiment, which was conducted on December 19, 2003. Test specifications for CCI-1 are provided in Table 1-1. This experiment investigated the interaction of a fully oxidized 400 kg PWR core melt, initially containing 8 wt % calcined siliceous concrete, with a specially designed two-dimensional siliceous concrete test section with an initial cross-sectional area of 50 cm x 50 cm. The report begins by providing a summary description of the CCI-1 test apparatus and operating procedures, followed by presentation of the thermal-hydraulic results. The posttest debris examination results will be provided in a subsequent publication. Observations drawn within this report regarding the overall cavity erosion behavior may be subject to revision once the posttest examinations are completed, since these examinations will fully reveal the final cavity shape.« less

Parametric Study of Fire Performance of Concrete Filled Hollow Steel Section Columns with Circular and Square Cross-Section

NASA Astrophysics Data System (ADS)

Nurfaidhi Rizalman, Ahmad; Tahir, Ng Seong Yap Mahmood Md; Mohammad, Shahrin

2018-03-01

Concrete filled hollow steel section column have been widely accepted by structural engineers and designers for high rise construction due to the benefits of combining steel and concrete. The advantages of concrete filled hollow steel section column include higher strength, ductility, energy absorption capacity, and good structural fire resistance. In this paper, comparison on the fire performance between circular and square concrete filled hollow steel section column is established. A three-dimensional finite element package, ABAQUS, was used to develop the numerical model to study the temperature development, critical temperature, and fire resistance time of the selected composite columns. Based on the analysis and comparison of typical parameters, the effect of equal cross-sectional size for both steel and concrete, concrete types, and thickness of external protection on temperature distribution and structural fire behaviour of the columns are discussed. The result showed that concrete filled hollow steel section column with circular cross-section generally has higher fire resistance than the square section.

The use of hydrated lime as an antistripping additive : addendum to final report.

DOT National Transportation Integrated Search

1990-01-01

The subject report describes a follow-up evaluation of test sections that were installed in 1982 and 1983 and reported on in 1987. Each test section contained three asphalt concretes: (1) with no additive, (2) with hydrated lime, and (3) with one or ...

Application of Hydrophilic Silanol-Based Chemical Grout for Strengthening Damaged Reinforced Concrete Flexural Members

PubMed Central

Ju, Hyunjin; Lee, Deuck Hang; Cho, Hae-Chang; Kim, Kang Su; Yoon, Seyoon; Seo, Soo-Yeon

2014-01-01

In this study, hydrophilic chemical grout using silanol (HCGS) was adopted to overcome the performance limitations of epoxy materials used for strengthening existing buildings and civil engineering structures. The enhanced material performances of HCGS were introduced, and applied to the section enlargement method, which is one of the typical structural strengthening methods used in practice. To evaluate the excellent structural strengthening performance of the HCGS, structural tests were conducted on reinforced concrete beams, and analyses on the flexural behaviors of test specimens were performed by modified partial interaction theory (PIT). In particular, to improve the constructability of the section enlargement method, an advanced strengthening method was proposed, in which the precast panel was directly attached to the bottom of the damaged structural member by HCGS, and the degree of connection of the test specimens, strengthened by the section enlargement method, were quantitatively evaluated by PIT-based analysis. PMID:28788708

Application of Hydrophilic Silanol-Based Chemical Grout for Strengthening Damaged Reinforced Concrete Flexural Members.

PubMed

Ju, Hyunjin; Lee, Deuck Hang; Cho, Hae-Chang; Kim, Kang Su; Yoon, Seyoon; Seo, Soo-Yeon

2014-06-23

In this study, hydrophilic chemical grout using silanol (HCGS) was adopted to overcome the performance limitations of epoxy materials used for strengthening existing buildings and civil engineering structures. The enhanced material performances of HCGS were introduced, and applied to the section enlargement method, which is one of the typical structural strengthening methods used in practice. To evaluate the excellent structural strengthening performance of the HCGS, structural tests were conducted on reinforced concrete beams, and analyses on the flexural behaviors of test specimens were performed by modified partial interaction theory (PIT). In particular, to improve the constructability of the section enlargement method, an advanced strengthening method was proposed, in which the precast panel was directly attached to the bottom of the damaged structural member by HCGS, and the degree of connection of the test specimens, strengthened by the section enlargement method, were quantitatively evaluated by PIT-based analysis.

Electrokinetic Strength Enhancement of Concrete

NASA Technical Reports Server (NTRS)

Cardenas, Henry E. (Inventor)

2016-01-01

A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

Electrokenitic Corrosion Treatment of Concrete

NASA Technical Reports Server (NTRS)

Cardenas, Henry E (Inventor)

2015-01-01

A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

Evaluation of Minimum Asphalt Concrete Thickness Criteria

DTIC Science & Technology

2008-10-01

9 Figure 6. Dry density versus moisture content for CH material... density measurements. ............................ 24 Figure 18. EPC installation in a crushed gravel base course layer...Construction Materials Materials Characterization Laboratory Testing Field Testing Test Section Construction Hydrometer, Modified Proctor , Specific

Experimental Research on Seismic Performance of Four-Element Variable Cross-Sectional Concrete Filled Steel Tubular Laced Columns

NASA Astrophysics Data System (ADS)

Ou, Zhijing; Lin, Jianmao; Chen, Shengfu; Lin, Wen

2017-10-01

A total of 7 experimental tests were conducted to investigate seismic performance of four element variable cross-sectional Concrete Filled Steel Tubular (CFST) laced columns. The experimental parameters are longitudinal slope and arrangement type of lacing tubes. The rules on hysteresis loop, ductility, energy expenditure, and stiffness degradation of specimens are researched. Test results indicate that all specimens have good seismic performance; their hysteresis loops are full without obvious shrinkage. With the increase of longitudinal slope, the horizontal carrying capacity increases, energy dissipation capacity improve, and there is slightly increase in stiffness degradation. The influence of arrangement type of lacing tubes on displacement ductility of specimens is big.

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.

Final Report: Self Consolidating Concrete Construction for Modular Units

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gentry, Russell; Kahn, Lawrence; Kurtis, Kimberly

This report outlines the development of a self-consolidating concrete (also termed “self-compacting concrete” or SCC) so that concrete placement can be made into steel plate composite (SC) modular structures without the need for continuous concrete placement. As part of the research, SCC mixtures were developed and validated to ensure sufficient shear capacity across cold-joints, while minimizing shrinkage and temperature increase during curing to enhance concrete bonding with the steel plate construction found in modular units. The self-roughening concrete produced as part of this research was assessed in SC structures at three scales: small-scale shear-friction specimens, mid-scale beams tested in in-planemore » and out-of-plane bending, and a full-scale validation test using an SC module produced by Westinghouse as part of the Plant Vogtle expansion. The experiments show that the self-roughening concrete can produce a cold-joint surface of 0.25 inches (6 mm) without external vibration during concrete placement. The experiments and subsequent analysis show that the shear friction provisions of ACI 318-14, Section 22.9 can be used to assess the shear capacity of the cold-joints in SC modular construction, and that friction coefficient of 1.35 is appropriate for use with these provisions.« less

Study on Effects of Different Replacement Rate on Bending Behavior of Big Recycled Aggregate Self Compacting Concrete

NASA Astrophysics Data System (ADS)

Li, Jing; Guo, Tiantian; Gao, Shuai; Jiang, Lin; Zhao, Zhijun; Wang, Yalin

2018-03-01

Big recycled aggregate self compacting concrete is a new type of recycled concrete, which has the advantages of low hydration heat and green environmental protection, but its bending behavior can be affected by different replacement rate. Therefor, in this paper, the research status of big Recycled aggregate self compacting concrete was systematically introduced, and the effect of different replacement rate of big recycled aggregate on failure mode, crack distribution and bending strength of the beam were studied through the bending behavior test of 4 big recycled aggregate self compacting concrete beams. The results show that: The crack distribution of the beam can be affected by the replacement rate; The failure modes of big recycled aggregate beams are the same as those of ordinary concrete; The plane section assumption is applicable to the big recycled aggregate self compacting concrete beam; The higher the replacement rate, the lower the bending strength of big recycled aggregate self compacting concrete beams.

Predicting moisture-induced damage to asphaltic concrete : field evaluation : final report.

DOT National Transportation Integrated Search

1981-01-01

Virginia was one of seven agencies that participated in the evaluation of a stripping test developed under National Cooperative Highway Research Program Project 4-8(3). The test was used to predict stripping of a field test section and the test resul...

Study on evaluation of corrosion condition of reinforcing bar embedded concrete using infrared thermal imaging camera

NASA Astrophysics Data System (ADS)

Ruiko, Watanabe; Toshiaki, Mizobuchi

2017-04-01

Rapid aging of many concrete structures, which have been developed during rapid economic growth period in Japan, has become a serious problem for us these days. And thus, there is an urgent need to prolong their service life expectancies. For this purpose, the deterioration of reinforcing bars in the concrete structures should be detected quickly and correctly at the early stages. Nevertheless, conventional testing methods such as destructive and nondestructive testing have disadvantages: partial damages on concrete structures; difficulty with quantitative evaluation, etc. Many preceding studies have examined to estimate the deterioration of reinforcing bars based on the temperature of the concrete specimen surfaces. According to those papers, the differences in corrosion degree of reinforcing bars have a certain effect on the temperature of concrete specimen surfaces. In this study, firstly, the quantitative evaluation of the corrosion degree was conducted with 3D scanner which could measure the volume, coverage area and cross-sectional area. Secondly, the surface of the concrete specimen was cooled down with liquid nitrogen, and thirdly, thermographic change was observed up until the air temperature. Finally, the surface of the concrete specimen was detected clearly by the thermal images. As a result, this study shows that the corrosion thickness tends to get bigger, following the uprising temperature of the concrete specimen surfaces. The same kind of tendency can be observed by the thermal images, too.

A&M. TAN607. Southern sections added in expansion project of 1957. ...

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

A&M. TAN-607. Southern sections added in expansion project of 1957. Camera facing northwest. Concrete decontamination section on left end. Photographer: Jack L. Anderson. Date: October 23, 1957. INEEL negative no. 57-5337 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Comparative study on the mechanical mechanism of confined concrete supporting arches in underground engineering.

PubMed

Lv, Zhijin; Qin, Qian; Jiang, Bei; Luan, Yingcheng; Yu, Hengchang

2018-01-01

In order to solve the supporting problem in underground engineering with high stress, square steel confined concrete (SQCC) supporting method is adopted to enhance the control on surrounding rocks, and the control effect is remarkable. The commonly used cross section shapes of confined concrete arch are square and circular. At present, designers have no consensus on which kind is more proper. To search for the answer, this paper makes an analysis on the mechanical properties of the two shapes of the cross-sections. A full-scale indoor comparative test was carried out on the commonly used straight-wall semi-circular SQCC arch and circular steel confined concrete arch (CCC arch). This test is based on self-developed full-scale test system for confined concrete arch. Our research, combining with the numerical analysis, shows: (1) SQCC arch is consistent with CCC arch in the deformation and failure mode. The largest damages parts are at the legs of both of them. (2) The SQCC arch's bearing capability is 1286.9 kN, and the CCC arch's ultimate bearing capability is 1072.4kN. Thus, the SQCC arch's bearing capability is 1.2 times that of the CCC arch. (3) The arches are subjected to combined compression and bending, bending moment is the main reason for the arch failure. The section moment of inertia of SQCC arch is 1.26 times of that of CCC arch, and the former is better than the latter in bending performance. The ultimate bearing capacity is positively correlated with the size of the moment of inertia. Based on the above research, the engineering suggestions are as follows: (1) To improve the bearing capacity of the arch, the cross-sectional shape of the chamber should be optimized and the arch bearing mode changed accordingly. (2) The key damaged positions, such as the arch leg, should be reinforced, optimizing the state of force on the arch. SQCC arches should be used for supporting in underground engineering, which is under stronger influence of the bending moment and non-uniform load on the supporting arches. The research results could provide a theoretical basis for the design of confined concrete support in underground engineering.

Comparative study on the mechanical mechanism of confined concrete supporting arches in underground engineering

PubMed Central

Qin, Qian; Jiang, Bei; Luan, Yingcheng; Yu, Hengchang

2018-01-01

In order to solve the supporting problem in underground engineering with high stress, square steel confined concrete (SQCC) supporting method is adopted to enhance the control on surrounding rocks, and the control effect is remarkable. The commonly used cross section shapes of confined concrete arch are square and circular. At present, designers have no consensus on which kind is more proper. To search for the answer, this paper makes an analysis on the mechanical properties of the two shapes of the cross-sections. A full-scale indoor comparative test was carried out on the commonly used straight-wall semi-circular SQCC arch and circular steel confined concrete arch (CCC arch). This test is based on self-developed full-scale test system for confined concrete arch. Our research, combining with the numerical analysis, shows: (1) SQCC arch is consistent with CCC arch in the deformation and failure mode. The largest damages parts are at the legs of both of them. (2) The SQCC arch’s bearing capability is 1286.9 kN, and the CCC arch’s ultimate bearing capability is 1072.4kN. Thus, the SQCC arch’s bearing capability is 1.2 times that of the CCC arch. (3) The arches are subjected to combined compression and bending, bending moment is the main reason for the arch failure. The section moment of inertia of SQCC arch is 1.26 times of that of CCC arch, and the former is better than the latter in bending performance. The ultimate bearing capacity is positively correlated with the size of the moment of inertia. Based on the above research, the engineering suggestions are as follows: (1) To improve the bearing capacity of the arch, the cross-sectional shape of the chamber should be optimized and the arch bearing mode changed accordingly. (2) The key damaged positions, such as the arch leg, should be reinforced, optimizing the state of force on the arch. SQCC arches should be used for supporting in underground engineering, which is under stronger influence of the bending moment and non-uniform load on the supporting arches. The research results could provide a theoretical basis for the design of confined concrete support in underground engineering. PMID:29447187

Critical factors in displacement ductility assessment of high-strength concrete columns

NASA Astrophysics Data System (ADS)

Taheri, Ali; Moghadam, Abdolreza S.; Tasnimi, Abass Ali

2017-12-01

Ductility of high-strength concrete (HSC) columns with rectangular sections was assessed in this study by reviewing experimental data from the available literature. Up to 112 normal weights concrete columns with strength in the range of 50-130 MPa were considered and presented as a database. The data included the results of column testes under axial and reversed lateral loading. Displacement ductility of HSC columns was evaluated in terms of their concrete and reinforcement strengths, bar arrangement, volumetric ratio of transverse reinforcement, and axial loading. The results indicated that the confinement requirements and displacement ductility in HSC columns are more sensitive than those in normal strength concrete columns. Moreover, ductility is descended by increasing concrete strength. However, it was possible to obtain ductile behavior in HSC columns through proper confinement. Furthermore, this study casts doubt about capability of P/ A g f c' ratio that being inversely proportional to displacement ductility of HSC columns.

Shear transfer in concrete reinforced with carbon fibers

NASA Astrophysics Data System (ADS)

El-Mokadem, Khaled Mounir

2001-10-01

Scope and method of study. The research started with preliminary tests and studies on the behavior and effect of carbon fibers in different water solutions and mortar/concrete mixes. The research work investigated the use of CF in the production of concrete pipes and prestressed concrete double-tee sections. The research then focused on studying the effect of using carbon fibers on the direct shear transfer of sand-lightweight reinforced concrete push-off specimens. Findings and conclusions. In general, adding carbon fibers to concrete improved its tensile characteristics but decreased its compressive strength. The decrease in compressive strength was due to the decrease in concrete density as fibers act as three-dimensional mesh that entrapped air. The decrease in compressive strength was also due to the increase in the total surface area of non-cementitious material in the concrete. Sand-lightweight reinforced concrete push-off specimens with carbon fibers had lower shear carrying capacity than those without carbon fibers for the same cement content in the concrete. Current building codes and specifications estimate the shear strength of concrete as a ratio of the compressive strength. If applying the same principals then the ratio of shear strength to compressive strength for concrete reinforced with carbon fibers is higher than that for concrete without carbon fibers.

Application of Non-pressure Reinforced Concrete Pipes in Modern Construction and Reconstruction of Highways

NASA Astrophysics Data System (ADS)

Rakitin, B. A.; Pogorelov, S. N.; Kolmogorova, A. O.

2017-11-01

Modern highway construction technologies provide for the quality water discharge systems to increase facilities’ service life. Pipeline operating conditions require the use of durable and reliable materials and structures. The experience in using reinforced concrete pipes for these purposes shows their utilization efficiency. The present paper considers the experience in the use of non-pressure reinforced concrete pipes manufactured by the German company SCHLOSSER-PFEIFFER under the Ural region geological and climatic conditions. The authors analyzed the actual operation of underground pipelines and effective loads upon them. A detailed study of the mechanical properties of reinforced concrete pipes is necessary to improve their production technology and to enhance their serviceability. The use of software-based methods helped to develop a mathematical model and to estimate the strength and crack resistance of reinforced concrete pipes at different laying depths. The authors carried out their complex research of the strain-stress behaviour of reinforced concrete pipes and identified the most hazardous sections in the structure. The calculations performed were confirmed by the results of laboratory tests completed in the construction materials, goods, and structures test center. Based on the completed research, the authors formulated their recommendations to improve the design and technology of non-pressure reinforced concrete pipes.

Study of Strain-Stress Behavior of Non-Pressure Reinforced Concrete Pipes Used in Road Building

NASA Astrophysics Data System (ADS)

Rakitin, B. A.; Pogorelov, S. N.; Kolmogorova, A. O.

2017-11-01

The article contains the results of the full-scale tests performed for special road products - large-diameter non-pressure concrete pipes reinforced with a single space cylindrical frame manufactured with the technology of high-frequency vertical vibration molding with an immediate demolding. The authors studied the change in the strain-stress behavior of reinforced concrete pipes for underground pipeline laying depending on their laying depth in the trench and the transport load considering the properties of the surrounding ground mass. The strain-stress behavior of the reinforced concrete pipes was evaluated using the strain-gauge method based on the application of active resistance strain gauges. Based on the completed research, the authors made a conclusion on the applicability of a single space frame for reinforcement of large-diameter non-pressure concrete pipes instead of a double frame which allows one to significantly reduce the metal consumption for the production of one item. As a result of the full-scale tests of reinforced concrete pipes manufactured by vertical vibration molding, the authors obtained new data on the deformation of a pipeline cross-section depending on the placement of the transport load with regard to the axis.

Cyclic behavior, development, and characteristics of a ductile hybrid fiber-reinforced polymer (DHFRP) for reinforced concrete members

NASA Astrophysics Data System (ADS)

Hampton, Francis Patrick

Reinforced concrete (R/C) structures especially pavements and bridge decks that constitute vital elements of the infrastructure of all industrialized societies are deteriorating prematurely. Structural repair and upgrading of these structural elements have become a more economical option for constructed facilities especially in the United States and Canada. One method of retrofitting concrete structures is the use of advanced materials. Fiber reinforced polymer (FRP) composite materials typically are in the form of fabric sheets or reinforcing bars. While the strength and stiffness of the FRP is high, composites are inherently brittle, with limited or no ductility. Conventional FRP systems cannot currently meet ductility demand, and therefore, may fail in a catastrophic failure mode. The primary goal of this research was to develop an optimized prototype 10-mm diameter DHFRP bar. The behavior of the bar under full load reversals to failure was investigated. However, this bar first needed to be designed and manufactured in the Fibrous Materials Research at Drexel University. Material properties were determined through testing to categorize the strength properties of the DHFRP. Similitude was used to demonstrate the scaling of properties from the original model bars. The four most important properties of the DHFRP bars are sufficient strength and stiffness, significant ductility for plasticity to develop in the R/C section, and sufficient bond strength for the R/C section to develop its full strength. Once these properties were determined the behavior of reinforced concrete members was investigated. This included the testing of prototype-size beams under monotonic loading and model and prototype beam-columns under reverse cyclic loading. These tests confirmed the large ductility exhibited by the DHFRP. Also the energy absorption capacity of the bar was demonstrated by the hysteretic behavior of the beam-columns. Displacement ductility factors in the range of 3--6 were achieved for all concrete elements tested. To study the long-term behavior of DHFRP, the creep-rupture strength of 5-mm bars was tested. This was conducted first on individual bar specimens and is important in the life-cycle design and performance of DHFRP reinforced concrete.

HOT CELL BUILDING, TRA632. FIRST FLOOR FOUNDATION PLAN SHOWS SECTIONALIZED ...

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

HOT CELL BUILDING, TRA-632. FIRST FLOOR FOUNDATION PLAN SHOWS SECTIONALIZED FLOOR LOADINGS AND CONCRETE SLAB THICKNESSES, A TYPICAL FEATURE OF NUCLEAR ARCHITECTURE. IDAHO OPERATIONS OFFICE MTR-632-IDO-2, 11/1952. INL INDEX NO. 531-0632-62-396-110561, REV. 1. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

EVALUATION OF BURIED CONDUITS AS PERSONNEL SHELTERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albright, G.H.; LeDoux, J.C.; Mitchell, R.A.

1960-07-14

Supersedes ITR-1421. Twelve large-diameter buried conduit sections of various shapes were tested in the 60- to l49-psi overpressure region of Burst Priscilla to make an empirical determination of the degree of personnel protection afforded by commercially available steel and concrete conduits at depths of burial of 5, 7.5, and 10 feet below grade. Essentially, it was desired to assure that Repartment of Defense Class I, 100psi and comparable radiations, and Class II, 50-psi and comparable radiations, protection is afforded by use of such conduits of various configurations. Measurements were made of free-field overpressure at the ground surface above the structure;more » pressure inside the structures; acceleration of each structure; deflection of each structure; dust inside each structure; fragmentary missiles inside the concrete structures; and gamma and neutron radiation dose inside each structure. All buried conduit sections tested provided adequate Class I protection for the conditions under which the conduits were tested. Standard 8-foot concrete sewer pipe withstood 126-psi overpressure without significant damage, minor tension cracks observed; standard 10-gage corrugated-steel 8-foot circular conduit sections withstood 126- psi overpressure without significant damage; and standard 10-gage corrugated- steel cattle-pass conduits withstood 149-psi overpressure without significant damage. Durations of positive pressure were from 206 to 333 milliseconds. (auth)« less

The use of hydrated lime as an antistripping additive : final report.

DOT National Transportation Integrated Search

1987-01-01

The purpose of this investigation was to evaluate the performance of six test sections of asphalt concrete that contained no additive, hydrated lime, and a chemical additive. Tests were also conducted on pavement samples taken periodically to determi...

Radiation Damage In Reactor Cavity Concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Field, Kevin G; Le Pape, Yann; Naus, Dan J

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 tomore » 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.« less

Extracting concrete thermal characteristics from temperature time history of RC column exposed to standard fire.

PubMed

Kim, Jung J; Youm, Kwang-Soo; Reda Taha, Mahmoud M

2014-01-01

A numerical method to identify thermal conductivity from time history of one-dimensional temperature variations in thermal unsteady-state is proposed. The numerical method considers the change of specific heat and thermal conductivity with respect to temperature. Fire test of reinforced concrete (RC) columns was conducted using a standard fire to obtain time history of temperature variations in the column section. A thermal equilibrium model in unsteady-state condition was developed. The thermal conductivity of concrete was then determined by optimizing the numerical solution of the model to meet the observed time history of temperature variations. The determined thermal conductivity with respect to temperature was then verified against standard thermal conductivity measurements of concrete bricks. It is concluded that the proposed method can be used to conservatively estimate thermal conductivity of concrete for design purpose. Finally, the thermal radiation properties of concrete for the RC column were estimated from the thermal equilibrium at the surface of the column. The radiant heat transfer ratio of concrete representing absorptivity to emissivity ratio of concrete during fire was evaluated and is suggested as a concrete criterion that can be used in fire safety assessment.

Extracting Concrete Thermal Characteristics from Temperature Time History of RC Column Exposed to Standard Fire

PubMed Central

2014-01-01

A numerical method to identify thermal conductivity from time history of one-dimensional temperature variations in thermal unsteady-state is proposed. The numerical method considers the change of specific heat and thermal conductivity with respect to temperature. Fire test of reinforced concrete (RC) columns was conducted using a standard fire to obtain time history of temperature variations in the column section. A thermal equilibrium model in unsteady-state condition was developed. The thermal conductivity of concrete was then determined by optimizing the numerical solution of the model to meet the observed time history of temperature variations. The determined thermal conductivity with respect to temperature was then verified against standard thermal conductivity measurements of concrete bricks. It is concluded that the proposed method can be used to conservatively estimate thermal conductivity of concrete for design purpose. Finally, the thermal radiation properties of concrete for the RC column were estimated from the thermal equilibrium at the surface of the column. The radiant heat transfer ratio of concrete representing absorptivity to emissivity ratio of concrete during fire was evaluated and is suggested as a concrete criterion that can be used in fire safety assessment. PMID:25180197

Flexural strength of self compacting fiber reinforced concrete beams using polypropylene fiber: An experimental study

NASA Astrophysics Data System (ADS)

Lisantono, Ade; Praja, Baskoro Abdi; Hermawan, Billy Nouwen

2017-11-01

One of the methods to increase the tensile strength of concrete is adding a fiber material into the concrete. While to reduce a noise in a construction project, a self compacting concrete was a good choices in the project. This paper presents an experimental study of flexural behavior and strength of self compacting fiber reinforced concrete (RC) beams using polypropylene fiber. The micro monofilament polypropylene fibers with the proportion 0.9 kg/m3 of concrete weight were used in this study. Four beam specimens were cast and tested in this study. Two beams were cast of self compacting reinforced concrete without fiber, and two beams were cast of self compacting fiber reinforced concrete using polypropylene. The beams specimen had the section of (180×260) mm and the length was 2000 mm. The beams had simple supported with the span of 1800 mm. The longitudinal reinforcements were using diameter of 10 mm. Two reinforcements of Ø10 mm were put for compressive reinforcement and three reinforcements of Ø10 mm were put for tensile reinforcement. The shear reinforcement was using diameter of 8 mm. The shear reinforcements with spacing of 100 mm were put in the one fourth near to the support and the spacing of 150 mm were put in the middle span. Two points loading were used in the testing. The result shows that the load-carrying capacity of the self compacting reinforced concrete beam using polypropylene was a little bit higher than the self compacting reinforced concrete beam without polypropylene. The increment of load-carrying capacity of self compacting polypropylene fiber reinforced concrete was not so significant because the increment was only 2.80 % compare to self compacting non fiber reinforced concrete. And from the load-carrying capacity-deflection relationship curves show that both the self compacting polypropylene fiber reinforced concrete beam and the self compacting non fiber reinforced concrete beam were ductile beams.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rashid, A.; Nygaard, C.

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, theymore » 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.« less

3D modelling of the flow of self-compacting concrete with or without steel fibres. Part II: L-box test and the assessment of fibre reorientation during the flow

NASA Astrophysics Data System (ADS)

Deeb, R.; Kulasegaram, S.; Karihaloo, B. L.

2014-12-01

The three-dimensional Lagrangian particle-based smooth particle hydrodynamics method described in Part I of this two-part paper is used to simulate the flow of self-compacting concrete (SCC) with and without steel fibres in the L-box configuration. As in Part I, the simulation of the SCC mixes without fibres emphasises the distribution of large aggregate particles of different sizes throughout the flow, whereas the simulation of high strength SCC mixes which contain steel fibres is focused on the distribution of fibres and their orientation during the flow. The capabilities of this methodology are validated by comparing the simulation results with the L-box test carried out in the laboratory. A simple method is developed to assess the reorientation and distribution of short steel fibres in self-compacting concrete mixes during the flow. The reorientation of the fibres during the flow is used to estimate the fibre orientation factor (FOF) in a cross section perpendicular to the principal direction of flow. This estimation procedure involves the number of fibres cut by the section and their inclination to the cutting plane. This is useful to determine the FOF in practical image analysis on cut sections.

Evaluation of recycled concrete aggregates for their suitability in construction activities: An experimental study.

PubMed

Puthussery, Joseph V; Kumar, Rakesh; Garg, Anurag

2017-02-01

Construction and demolition waste disposal is a major challenge in developing nations due to its ever increasing quantities. In this study, the recycling potential of waste concrete as aggregates in construction activities was studied. The metal leaching from the recycled concrete aggregates (RCA) collected from the demolition site of a 50year old building, was evaluated by performing three different leaching tests (compliance, availability and Toxic Characteristic Leaching Procedure). The metal leaching was found mostly within the permissible limit except for Hg. Several tests were performed to determine the physical and mechanical properties of the fine and coarse aggregates produced from recycled concrete. The properties of recycled aggregates were found to be satisfactory for their utilization in road construction activities. The suitability of using recycled fine and coarse aggregates with Portland pozzolanic cement to make a sustainable and environmental friendly concrete mix design was also analyzed. No significant difference was observed in the compressive strength of various concrete mixes prepared by natural and recycled aggregates. However, only the tensile strength of the mix prepared with 25% recycled fine aggregates was comparable to that of the control concrete. For other mixes, the tensile strength of the concrete was found to drop significantly. In summary, RCA should be considered seriously as a building material for road construction, mass concrete works, lightly reinforced sections, etc. The present work will be useful for the waste managers and policy makers particularly in developing nations where proper guidelines are still lacking. Copyright © 2016 Elsevier Ltd. All rights reserved.

Performance evaluation of Arizona's LTPP SPS-1 project : strategic study of flexible pavement structural factors.

DOT National Transportation Integrated Search

2012-01-01

As part of the Long Term Pavement Performance (LTPP) Program, Arizona DOT constructed 16 SPS-1 test : sections on U.S. Route 93 near Kingman. The SPS-1 study was designed to study a variety of structural : sections in new asphalt concrete constructio...

The Fire Resistance Performance of Recycled Aggregate Concrete Columns with Different Concrete Compressive Strengths.

PubMed

Dong, Hongying; Cao, Wanlin; Bian, Jianhui; Zhang, Jianwei

2014-12-08

In order to ascertain the fire resistance performance of recycled aggregate concrete (RAC) components with different concrete compressive strengths, four full-scaled concrete columns were designed and tested under high temperature. Two of the four specimens were constructed by normal concrete with compressive strength ratings of C20 and C30, respectively, while the others were made from recycled coarse aggregate (RCA) concrete of C30 and C40, respectively. Identical constant axial forces were applied to specimens while being subjected to simulated building fire conditions in a laboratory furnace. Several parameters from the experimental results were comparatively analyzed, including the temperature change, vertical displacement, lateral deflection, fire endurance, and failure characteristics of specimens. The temperature field of specimens was simulated with ABAQUS Software (ABAQUS Inc., Provindence, RI, USA) and the results agreed quite well with those from the experiments. Results show that the rate of heat transfer from the surface to the interior of the column increases with the increase of the concrete's compressive strength for both RAC columns and normal concrete columns. Under the same initial axial force ratio, for columns with the same cross section, those with lower concrete compressive strengths demonstrate better fire resistance performance. The fire resistance performance of RAC columns is better than that of normal concrete columns, with the same concrete compressive strength.

Evaluation of various hot mix asphalt pavement thicknesses over rubblized concrete pavement.

DOT National Transportation Integrated Search

2011-07-01

In 1999, the Wisconsin DOT constructed two test sections as part of a rubblized PCC pavement project on I-39 to evaluate whether : increased HMA thickness could extend the pavement system's service life. Design thicknesses of the control and test sec...

Enamel coated steel reinforcement for improved durability and life-cycle performance of concrete structures: microstructure, corrosion, and deterioration

NASA Astrophysics Data System (ADS)

Tang, Fujian

This study is aimed (a) to statistically characterize the corrosion-induced deterioration process of reinforced concrete structures (concrete cracking, steel mass loss, and rebar-concrete bond degradation), and (b) to develop and apply three types of enamel-coated steel bars for improved corrosion resistance of the structures. Commercially available pure enamel, mixed enamel with 50% calcium silicate, and double enamel with an inner layer of pure enamel and an outer layer of mixed enamel were considered as various steel coatings. Electrochemical tests were respectively conducted on steel plates, smooth bars embedded in concrete, and deformed bars with/without concrete cover in 3.5 wt.% NaCl or saturated Ca(OH)2 solution. The effects of enamel microstructure, coating thickness variation, potential damage, mortar protection, and corrosion environment on corrosion resistance of the steel members were investigated. Extensive test results indicated that corrosion-induced concrete cracking can be divided into four stages that gradually become less correlated with corrosion process over time. The coefficient of variation of crack width increases with the increasing level of corrosion. Corrosion changed the cross section area instead of mechanical properties of steel bars. The bond-slip behavior between the corroded bars and concrete depends on the corrosion level and distribution of corrosion pits. Although it can improve the chemical bond with concrete and steel, the mixed enamel coating is the least corrosion resistant. The double enamel coating provides the most consistent corrosion performance and is thus recommended to coat reinforcing steel bars for concrete structures applied in corrosive environments. Corrosion pits in enamel-coated bars are limited around damage locations.

Recent Advances in Understanding Radiation Damage in Reactor Cavity Concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosseel, Thomas M; Field, Kevin G; Le Pape, Yann

License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has resulted in a renewed focus on long-term aging of materials at nuclear power plants (NPPs) including concrete. Large irreplaceable sections of most nuclear generating stations include concrete. The Expanded Materials Degradation Analysis, jointly performed by the Department of Energy, the Nuclear Regulatory Commission and Nuclear Industry, identified the urgent need to develop a consistent knowledge base on irradiation effects in concrete (Graves et al., (2014)). Much of the historical mechanical performance data of irradiated concrete (Hilsdorf et al., (1978)) does not accurately reflectmore » typical radiation conditions in NPPs or conditions out to 60 or 80 years of radiation exposure (Kontani et al., (2011)). To address these potential gaps in the knowledge base, the Electric Power Research Institute and Oak Ridge National Laboratory, are working to better understand radiation damage as a degradation mechanism. This paper outlines recent progress toward: 1) assessing the radiation environment in concrete biological shields and defining the upper bound of the neutron and gamma dose levels expected in the biological shield for extended operation, and estimating adsorbed dose, 2) evaluating opportunities to harvest and test irradiated concrete from international NPPs, 3) evaluating opportunities to irradiate prototypical concrete and its components under accelerated neutron and gamma dose levels to establish conservative bounds and inform damage models, 4) developing improved models to enhance the understanding of the effects of radiation on concrete and 5) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge including developing cooperative test programs to improve confidence in data obtained from various concretes and from accelerated irradiation experiments.« less

The Fire Resistance Performance of Recycled Aggregate Concrete Columns with Different Concrete Compressive Strengths

PubMed Central

Dong, Hongying; Cao, Wanlin; Bian, Jianhui; Zhang, Jianwei

2014-01-01

In order to ascertain the fire resistance performance of recycled aggregate concrete (RAC) components with different concrete compressive strengths, four full-scaled concrete columns were designed and tested under high temperature. Two of the four specimens were constructed by normal concrete with compressive strength ratings of C20 and C30, respectively, while the others were made from recycled coarse aggregate (RCA) concrete of C30 and C40, respectively. Identical constant axial forces were applied to specimens while being subjected to simulated building fire conditions in a laboratory furnace. Several parameters from the experimental results were comparatively analyzed, including the temperature change, vertical displacement, lateral deflection, fire endurance, and failure characteristics of specimens. The temperature field of specimens was simulated with ABAQUS Software (ABAQUS Inc., Provindence, RI, USA) and the results agreed quite well with those from the experiments. Results show that the rate of heat transfer from the surface to the interior of the column increases with the increase of the concrete’s compressive strength for both RAC columns and normal concrete columns. Under the same initial axial force ratio, for columns with the same cross section, those with lower concrete compressive strengths demonstrate better fire resistance performance. The fire resistance performance of RAC columns is better than that of normal concrete columns, with the same concrete compressive strength. PMID:28788279

Ultrasonic linear array validation via concrete test blocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoegh, Kyle, E-mail: hoeg0021@umn.edu; Khazanovich, Lev, E-mail: hoeg0021@umn.edu; Ferraro, Chris

2015-03-31

Oak Ridge National Laboratory (ORNL) comparatively evaluated the ability of a number of NDE techniques to generate an image of the volume of 6.5′ X 5.0′ X 10″ concrete specimens fabricated at the Florida Department of Transportation (FDOT) NDE Validation Facility in Gainesville, Florida. These test blocks were fabricated to test the ability of various NDE methods to characterize various placements and sizes of rebar as well as simulated cracking and non-consolidation flaws. The first version of the ultrasonic linear array device, MIRA [version 1], was one of 7 different NDE equipment used to characterize the specimens. This paper dealsmore » with the ability of this equipment to determine subsurface characterizations such as reinforcing steel relative size, concrete thickness, irregularities, and inclusions using Kirchhoff-based migration techniques. The ability of individual synthetic aperture focusing technique (SAFT) B-scan cross sections resulting from self-contained scans are compared with various processing, analysis, and interpretation methods using the various features fabricated in the specimens for validation. The performance is detailed, especially with respect to the limitations and implications for evaluation of a thicker, more heavily reinforced concrete structures.« less

Ten year performance of asphalt additive test sections : Lave Butte - Fremont Highway Junction Section, The Dalles - California Highway (US#97), Deschutes County, Oregon.

DOT National Transportation Integrated Search

1998-09-01

The durability of hot mix asphalt concrete (HMAC) overlays is important to the Oregon Department of Transportation (ODOT), as this is the most common form of surface rehabilitation on state roads. To see if several HMAC additives available in Oregon ...

IET. Movable test cell building (TAN624). Plans, sections, and elevations ...

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

IET. Movable test cell building (TAN-624). Plans, sections, and elevations show trapezoidal shape of front/rear elevations, vertical sliding door panels, wheels, periscope and camera locations, fixed concrete wall, and relationship to coupling station (TAN-620) and rail track. Ralph M. Parson 902-4-ANP-624-A 329. Date: February 1954. Approved by INEEL Classification Office for public release. INEEL Index code no. 035-0624-00-693-106911 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Guided-waves technique for inspecting the health of wall-covered building risers

NASA Astrophysics Data System (ADS)

Tse, Peter W.; Chen, J. M.; Wan, X.

2015-03-01

The inspection technique uses guided ultrasonic waves (GW) has been proven effective in detecting pipes' defects. However, as of today, the technique has not attracted much market attention because of insufficient field tests and lack of traceable records with proven results in commercial applications. In this paper, it presents the results obtained by using GW to inspect the defects occurred in real gas risers that are commonly installed in tall buildings. The purpose of having risers is to deliver gas from any building external piping system to each household unit of the building. The risers extend from the external wall of the building, penetrate thorough the concrete wall, into the kitchen or bathroom of each household unit. Similar to in-service pipes, risers are prone to corrosion due to water leaks into the concrete wall. However, the corrosion occurs in the section of riser, which is covered by the concrete wall, is difficult to be inspected by conventional techniques. Hence, GW technique was employed. The effectiveness of GW technique was tested by laboratory and on-site experiments using real risers gathered from tall buildings. The experimental results show that GW can partially penetrate thorough the riser's section that is covered by wall. The integrity of the wall-covered section of a riser can be determined by the reflected wave signals generated by the corroded area that may exit inside the wall-covered section. Based on the reflected wave signal, one can determine the health of the wall-covered riser.

Installation report : evaluation of asphalt additives.

DOT National Transportation Integrated Search

1987-01-01

Five asphalt additives that are supposed to improve the stability and flexibility characteristics of asphalt concrete were installed in pavement test sections on Route 58 in Halifax County. Polymers, latex rubbers, and a diatomaceous deposit were use...

Layer coefficients for NHDOT pavement materials

NASA Astrophysics Data System (ADS)

Janoo, Vincent C.

1994-09-01

In 1992, the New Hampshire Department of Transportation (NHDOT) experimented with the use of reclaimed asphalt concrete as a base course material, identified by NHDOT as reclaimed stabilized base (RSB). The RSB and a control test section were placed on Interstate 93 between exits 18 and 19. The RSB test section was designed to the same structural number (SN) as the control. To evaluate the structural capacity of these test sections, the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) conducted deflection tests using a Dynatest 8000 falling weight deflectometer (FWD). Preliminary analysis of the results by NHDOT personnel showed higher deflection in the reclaimed asphalt concrete test sections. The explanation was that the layer coefficient used for the RSB layer in the design was probably incorrect. A total of 10 test sections constituting the base course materials used by NHDOT were built near Bow, New Hampshire. CRREL evaluated and estimated the layer coefficients of the base course materials. The test program was developed to characterize the material in more than one way. Tests were conducted with the heavy weight deflectometer (HWD), dynamic cone penetrometer (DCP) and the Clegg hammer. In situ California bearing ratio (CBR) tests were also conducted. The deflection from the HWD were used with the WESDEF back calculation program to determine the layer moduli. The moduli were than used with the AASHTO Design Guide to calculate the layer coefficients. The layer coefficients were also determined with the method proposed by Rohde. The CBR values from the Clegg hammer, in situ CBR and DCP tests were also used in the relationships in the HDM model to determine the layer coefficients.

Reclaimed manufacturer asphalt roofing shingles in asphalt mixtures. Final research report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reed, A.B.

1999-04-23

The purpose of this project was to pave a test section using hot mix asphalt with roofing shingle pieces in the wearing and binder courses and to evaluate. The test project near Allentown, PA plus two other test projects in 1998 provide evidence of very good pavement performance. The bituminous concrete mix was modified with shredded shingles with a maximum size of 1/2 inch which added 1% of the asphalt content. The Department issued a statewide Provisional Specification titled Reclaimed Manufacturer Asphalt Roofing Shingles in Plant-Mixed Bituminous Concrete Courses'' on March 15, 1999. New manufacturer asphalt roofing shingle scrap includingmore » tab punch-outs can be successfully incorporated in bituminous concrete pavements if the shingles are shredded to 100% passing the 3/4 inch sieve. To take full advantage of the potential to replace a portion of the asphalt and therefore, reduce mix costs, shingles should be shredded to 100% passing minus 1/2 inch sieve.« less

Variation of Shrinkage Strain within the Depth of Concrete Beams.

PubMed

Jeong, Jong-Hyun; Park, Yeong-Seong; Lee, Yong-Hak

2015-11-16

The variation of shrinkage strain within beam depth was examined through four series of time-dependent laboratory experiments on unreinforced concrete beam specimens. Two types of beam specimens, horizontally cast and vertically cast, were tested; shrinkage variation was observed in the horizontally cast specimens. This indicated that the shrinkage variation within the beam depth was due to water bleeding and tamping during the placement of the fresh concrete. Shrinkage strains were measured within the beam depth by two types of strain gages, surface-attached and embedded. The shrinkage strain distribution within the beam depth showed a consistent tendency for the two types of gages. The test beams were cut into four sections after completion of the test, and the cutting planes were divided into four equal sub-areas to measure the aggregate concentration for each sub-area of the cutting plane. The aggregate concentration increased towards the bottom of the beam. The shrinkage strain distribution was estimated by Hobbs' equation, which accounts for the change of aggregate volume concentration.

Variation of Shrinkage Strain within the Depth of Concrete Beams

PubMed Central

Jeong, Jong-Hyun; Park, Yeong-Seong; Lee, Yong-Hak

2015-01-01

The variation of shrinkage strain within beam depth was examined through four series of time-dependent laboratory experiments on unreinforced concrete beam specimens. Two types of beam specimens, horizontally cast and vertically cast, were tested; shrinkage variation was observed in the horizontally cast specimens. This indicated that the shrinkage variation within the beam depth was due to water bleeding and tamping during the placement of the fresh concrete. Shrinkage strains were measured within the beam depth by two types of strain gages, surface-attached and embedded. The shrinkage strain distribution within the beam depth showed a consistent tendency for the two types of gages. The test beams were cut into four sections after completion of the test, and the cutting planes were divided into four equal sub-areas to measure the aggregate concentration for each sub-area of the cutting plane. The aggregate concentration increased towards the bottom of the beam. The shrinkage strain distribution was estimated by Hobbs’ equation, which accounts for the change of aggregate volume concentration. PMID:28793677

Application of Composite Mechanics to Composites Enhanced Concrete Structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Gotsis, Pascal K.

2006-01-01

A new and effective method is described to design composites to repair damage or enhance the overload strength of concrete infrastructures. The method is based on composite mechanics which is available in computer codes. It is used to simulate structural sections made from reinforced concrete which are typical in infrastructure as well as select reinforced concrete structures. The structural sections are represented by a number of layers through the thickness where different layers are used in concrete, and for the composite. The reinforced concrete structures are represented with finite elements where the element stiffness parameters are from the structural sections which are represented by composite mechanics. The load carrying capability of the structure is determined by progressive structural fracture. Results show up to 40 percent improvements for damage and for overload enhancement with relatively small laminate thickness for the structural sections and up to three times for the composite enhanced select structures (arches and domes).

Concrete with onyx waste aggregate as aesthetically valued structural concrete

NASA Astrophysics Data System (ADS)

Setyowati E., W.; Soehardjono, A.; Wisnumurti

2017-09-01

The utillization of Tulungagung onyx stone waste as an aggregate of concrete mixture will improve the economic value of the concrete due to the brighter color and high aesthetic level of the products. We conducted the research of 75 samples as a test objects to measure the compression stress, splits tensile stress, flexural tensile stress, elasticity modulus, porosity modulus and also studied 15 test objects to identify the concrete micro structures using XRD test, EDAX test and SEM test. The test objects were made from mix designed concrete, having ratio cement : fine aggregate : coarse aggregate ratio = 1 : 1.5 : 2.1, and W/C ratio = 0.4. The 28 days examination results showed that the micro structure of Tulungagung onyx waste concrete is similar with normal concrete. Moreover, the mechanical test results proved that Tulungagung onyx waste concretes also have a qualified level of strength to be used as a structural concrete with higher aesthetic level.

JENDL-4.0/HE Benchmark Test with Concrete and Iron Shielding Experiments at JAEA/TIARA

NASA Astrophysics Data System (ADS)

Konno, Chikara; Matsuda, Norihiro; Kwon, Saerom; Ohta, Masayuki; Sato, Satoshi

2017-09-01

As a benchmark test of JENDL-4.0/HE released in 2015, we have analyzed the concrete and iron shielding experiments with the quasi mono-energetic 40 and 65 MeV neutron sources at TIARA in JAEA by using MCNP5 and ACE files processed from JENDL-4.0/HE with NJOY2012. As a result, it was found out that the calculation results with JENDL-4.0/HE agreed with the measured ones in the concrete experiment well, while they underestimated the measured ones in the iron experiment with 65 MeV neutrons more for the thicker assemblies. We examined the 56Fe data of JENDL-4.0/HE in detail and it was considered that the larger non-elastic scattering cross sections of 56Fe caused the underestimation in the calculation with JENDL-4.0/HE for the iron experiment with 65 MeV neutrons.

Evaluation and adaptation of the Dobrolubov and Romer method of microscopic examination of hardened concrete : interim report : methods and equipment used in preparing and examining fluorescent ultrathin sections.

DOT National Transportation Integrated Search

1978-01-01

This report explains the methods and equipment used to produce fluorescent, impregnated, polished, ultrathin sections of portland cement concrete. These sections are used in the study of the microstructure of concrete and are examined with a microsco...

Properties of Sulfur Concrete.

DTIC Science & Technology

1979-07-06

36 Thermal Contraction . . . . . . . . . . . 37 Summary of Sulfur Concrete (unmodified) . . . 39 Modified Sulfur Concrete............ 40...Compressive strength of PCPD- modified sulfur concrete 47 20 Functional connection between reaction time and temperature in making DCPD- modified sulfur concrete...39 MODIFIED SULFUR CONCRETE In the previous section it was shown that sulfur concrete exhibits several undesirable properties, such as 1 poor

Ultimate strength capacity of a square hollow section filled with fibrous foamed concrete

NASA Astrophysics Data System (ADS)

Amirah Azra Khairuddin, Siti; Rahman, Norashidah Abd; Jamaluddin, Norwati; Jaini, Zainorizuan Mohd; Ali, Noorwirdawati

2017-11-01

Concrete-filled sections used as building columns have become popular due to their architectural and structural elements. In recent years, there has been a renewed call for the improvement of materials used as concrete to fill the composite columns. Among these materials, foamed concrete has received great attention due to its structural characteristics and its potential as a construction material used in hollow sections. However, its behaviors as infill material in a hollow section, such as its strength and failure mode, should be investigated. In this study, experimental research was conducted to compare the experimental and theoretical values of its ultimate strength capacity. Eight specimens of hollow steel sections with two different thicknesses were filled with fibrous foamed concrete and then subjected to compression load. The obtained results were compared with those obtained from a hollow section with the same thicknesses, but were filled with normal foamed concrete. Results show that the ultimate strength capacity of the experimental value is the same as that of the theoretical value based on Eurocode 4. The largest percentage values between theoretical and experimental results for thicknesses of 2 and 4 mm are 58% and 55%, respectively.

Final Report: Self-Consolidating Concrete Construction for Modular Units

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gentry, Russell; Kahn, Lawrence; Kurtis, Kimberly

This report focuses on work completed on DE-NE0000667, Self-Consolidating Concrete for Modular Units, in connection with the Department of Energy Nuclear Energy Enabling Technologies (DOE-NEET) program. This project was completed in the School of Civil and Environmental Engineering at the Georgia Institute of Technology, with Westinghouse Corporation as the industrial partner. The primary objective of this project was to develop self-consolidating concrete (also termed “self-compacting concrete” or SCC) mixtures so that concrete placement can be made into steel plate composite (SC) modular structures without the need for continuous concrete placement. As part of the research, SCC mixtures were developed andmore » validated to ensure sufficient shear capacity across cold-joints, while minimizing shrinkage and temperature increase during curing to enhance concrete bonding with the steel plate construction found in modular units. The SCC mixtures developed were able to carry shearing forces across the cold-joint boundaries. This “self-roughening” was achieved by adding a tailored fraction of lightweight aggregate (LWA) to the concrete mix, some of which raised to the surface during curing, forming a rough surface on which subsequent concrete placements were made. The self-roughening behavior was validated through three sets of structural tests. Shear friction on small-scale specimens with cold joints was assessed using varying fractions of LWA and with varying amounts of external steel plate reinforcement. The results show that the shear friction coefficient, to be used with the provisions of ACI 318-14, Section 22.9, can be taken as 1.35. Mid-scale beam tests were completed to assess the cold-joint capacity in both in-plane and out-of-plane bending. The results showed that the self-roughened joints performed as well as monolithic joints. The final assessment was a full-scale test using a steel composite module supplied by Westinghouse and similar in construction to the steel composite modules being assembled at the Vogtle and V.C. Summer plant expansions. The final test showed that the roughened cold-joint showed excellent shear and flexural capacity, and substantial ductility, when used in conjunction with steel composite construction.« less

Design and application of a small size SAFT imaging system for concrete structure

NASA Astrophysics Data System (ADS)

Shao, Zhixue; Shi, Lihua; Shao, Zhe; Cai, Jian

2011-07-01

A method of ultrasonic imaging detection is presented for quick non-destructive testing (NDT) of concrete structures using synthesized aperture focusing technology (SAFT). A low cost ultrasonic sensor array consisting of 12 market available low frequency ultrasonic transducers is designed and manufactured. A channel compensation method is proposed to improve the consistency of different transducers. The controlling devices for array scan as well as the virtual instrument for SAFT imaging are designed. In the coarse scan mode with the scan step of 50 mm, the system can quickly give an image display of a cross section of 600 mm (L) × 300 mm (D) by one measurement. In the refined scan model, the system can reduce the scan step and give an image display of the same cross section by moving the sensor array several times. Experiments on staircase specimen, concrete slab with embedded target, and building floor with underground pipe line all verify the efficiency of the proposed method.

Evaluation of portland cement concrete pavement with high slag content cement.

DOT National Transportation Integrated Search

2013-10-01

The performance of a section of concrete pavement built with 30 percent Ground Granulated Blast Furnace Slag (GGBFS) is compared to a control section of concrete pavement built with 25 percent GGBFS to determine if the higher slag content pavement is...

Dowel bar retrofit performance in Wisconsin.

DOT National Transportation Integrated Search

2010-05-01

In 1999, WisDOT constructed test sections on I-39 to evaluate the dowel bar retrofit (DBR) rehabilitation technique for faulted concrete pavement slabs. Two years later, mortar deterioration and debonding were noted in the dowel slots. In response to...

Slab Track at Facility for Accelerated Service Testing: Performance and Serviceability

DOT National Transportation Integrated Search

2018-02-01

The Transportation Technology Center, Inc., with funding by the Portland Cement Association and the Federal Railroad Administration, documented the available records associated with the performance of the concrete slab track section in the High Tonna...

Laboratory testing of a building envelope segment based on cellular concrete

NASA Astrophysics Data System (ADS)

Fořt, Jan; Pavlík, Zbyšek; Černý, Robert

2016-07-01

Hygrothermal performance of a building envelope based on cellular concrete blocks is studied in the paper. Simultaneously, the strain fields induced by the heat and moisture changes are monitored. The studied wall is exposed to the climatic load corresponding to the winter climatic conditions of the moderate year for Prague. The winter climatic exposure is chosen in order to simulate the critical conditions of the building structure from the point of view of material performance and temperature and humidity loading. The evaluation of hygrothermal performance of a researched wall is done on the basis of relative humidity and temperature profiles measured along the cross section of the cellular concrete blocks. Strain gauges are fixed on the wall surface in expected orientation of the blocks expansion. The obtained results show a good hygrothermal function of the analyzed cellular concrete wall and its insignificant strain.

Construction Condition and Damage Monitoring of Post-Tensioned PSC Girders Using Embedded Sensors.

PubMed

Shin, Kyung-Joon; Lee, Seong-Cheol; Kim, Yun Yong; Kim, Jae-Min; Park, Seunghee; Lee, Hwanwoo

2017-08-10

The potential for monitoring the construction of post-tensioned concrete beams and detecting damage to the beams under loading conditions was investigated through an experimental program. First, embedded sensors were investigated that could measure pre-stress from the fabrication process to a failure condition. Four types of sensors were installed on a steel frame, and the applicability and the accuracy of these sensors were tested while pre-stress was applied to a tendon in the steel frame. As a result, a tri-sensor loading plate and a Fiber Bragg Grating (FBG) sensor were selected as possible candidates. With those sensors, two pre-stressed concrete flexural beams were fabricated and tested. The pre-stress of the tendons was monitored during the construction and loading processes. Through the test, it was proven that the variation in thepre-stress had been successfully monitored throughout the construction process. The losses of pre-stress that occurred during a jacking and storage process, even those which occurred inside the concrete, were measured successfully. The results of the loading test showed that tendon stress and strain within the pure span significantly increased, while the stress in areas near the anchors was almost constant. These results prove that FBG sensors installed in a middle section can be used to monitor the strain within, and the damage to pre-stressed concrete beams.

Construction Condition and Damage Monitoring of Post-Tensioned PSC Girders Using Embedded Sensors

PubMed Central

Shin, Kyung-Joon; Lee, Seong-Cheol; Kim, Yun Yong; Kim, Jae-Min; Park, Seunghee; Lee, Hwanwoo

2017-01-01

The potential for monitoring the construction of post-tensioned concrete beams and detecting damage to the beams under loading conditions was investigated through an experimental program. First, embedded sensors were investigated that could measure pre-stress from the fabrication process to a failure condition. Four types of sensors were installed on a steel frame, and the applicability and the accuracy of these sensors were tested while pre-stress was applied to a tendon in the steel frame. As a result, a tri-sensor loading plate and a Fiber Bragg Grating (FBG) sensor were selected as possible candidates. With those sensors, two pre-stressed concrete flexural beams were fabricated and tested. The pre-stress of the tendons was monitored during the construction and loading processes. Through the test, it was proven that the variation in thepre-stress had been successfully monitored throughout the construction process. The losses of pre-stress that occurred during a jacking and storage process, even those which occurred inside the concrete, were measured successfully. The results of the loading test showed that tendon stress and strain within the pure span significantly increased, while the stress in areas near the anchors was almost constant. These results prove that FBG sensors installed in a middle section can be used to monitor the strain within, and the damage to pre-stressed concrete beams. PMID:28796156

Evaluation of workability and strength of green concrete using waste steel scrap

NASA Astrophysics Data System (ADS)

Neeraja, D.; Arshad, Shaik Mohammed; Nawaz Nadaf, Alisha K.; Reddy, Mani Kumar

2017-11-01

This project works on the study of workability and mechanical properties of concrete using waste steel scrap from the lathe industry. Lathe industries produce waste steel scrap from the lathe machines. In this study, an attempt is made to use this waste in concrete, as accumulation of waste steel scrap cause disposal problem. Tests like compressive test, split tensile test, NDT test (UPV test) were conducted to determine the impact of steel scrap in concrete. The percentages of steel scrap considered in the study were 0%, 0.5%, 1%, 1.5%, and 2% respectively by volume of concrete, 7 day, 28 days test were conducted to find out strength of steel scrap concrete. It is observed that split tensile strength of steel scrap concrete is increased slightly. Split tensile strength of Steel scrap concrete is found to be maximum with volume fraction of 2.0% steel scrap. The steel scrap gives good result in split tensile strength of concrete. From the study concluded that steel scrap can be used in concrete to reduce brittleness of concrete to some extent.

Analysis, testing and verification of the behavior of composite pavements under Florida conditions using a heavy vehicle simulator

NASA Astrophysics Data System (ADS)

Tapia Gutierrez, Patricio Enrique

Whitetopping (WT) is a rehabilitation method to resurface deteriorated asphalt pavements. While some of these composite pavements have performed very well carrying heavy load, other have shown poor performance with early cracking. With the objective of analyzing the applicability of WT pavements under Florida conditions, a total of nine full-scale WT test sections were constructed and tested using a Heavy Vehicle Simulator (HVS) in the APT facility at the FDOT Material Research Park. The test sections were instrumented to monitor both strain and temperature. A 3-D finite element model was developed to analyze the WT test sections. The model was calibrated and verified using measured FWD deflections and HVS load-induced strains from the test sections. The model was then used to evaluate the potential performance of these test sections under critical temperature-load condition in Florida. Six of the WT pavement test sections had a bonded concrete-asphalt interface by milling, cleaning and spraying with water the asphalt surface. This method produced excellent bonding at the interface, with shear strength of 195 to 220 psi. Three of the test sections were intended to have an unbonded concrete-asphalt interface by applying a debonding agent in the asphalt surface. However, shear strengths between 119 and 135 psi and a careful analysis of the strain and the temperature data indicated a partial bond condition. The computer model was able to satisfactorily model the behavior of the composite pavement by mainly considering material properties from standard laboratory tests and calibrating the spring elements used to model the interface. Reasonable matches between the measured and the calculated strains were achieved when a temperature-dependent AC elastic modulus was included in the analytical model. The expected numbers of repetitions of the 24-kip single axle loads at critical thermal condition were computed for the nine test sections based on maximum tensile stresses and fatigue theory. The results showed that 4" slabs can be used for heavy loads only for low-volume traffic. To withstand the critical load without fear of fatigue failure, 6" slabs and 8" slabs would be needed for joint spacings of 4' and 6', respectively.

Nuclear Rocket Test Facility Decommissioning Including Controlled Explosive Demolition of a Neutron-Activated Shield Wall

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael Kruzic

2007-09-01

Located in Area 25 of the Nevada Test Site, the Test Cell A Facility was used in the 1960s for the testing of nuclear rocket engines, as part of the Nuclear Rocket Development Program. The facility was decontaminated and decommissioned (D&D) in 2005 using the Streamlined Approach For Environmental Restoration (SAFER) process, under the Federal Facilities Agreement and Consent Order (FFACO). Utilities and process piping were verified void of contents, hazardous materials were removed, concrete with removable contamination decontaminated, large sections mechanically demolished, and the remaining five-foot, five-inch thick radiologically-activated reinforced concrete shield wall demolished using open-air controlled explosive demolitionmore » (CED). CED of the shield wall was closely monitored and resulted in no radiological exposure or atmospheric release.« less

Performance trends of rehabilitated AC pavements

DOT National Transportation Integrated Search

2000-10-01

The General Pavement Study (GPS) 6 experiment, "AC Overlay of AC Pavements," involves pavement test sections where an asphalt concrete (AC) overlay was placed on an existing AC pavement. This TechBrief summarizes the results of a study of the GPS-6 e...

IET exhaust gas duct, system layout, plan, and section. shows ...

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

IET exhaust gas duct, system layout, plan, and section. shows mounting brackets, concrete braces, divided portion of duct, other details. Ralph M. Parsons 902-5-ANP-712-S 429. Date: May 1954. Approved by INEEL Classification Office for public release. INEEL index code no. 035-0712-60-693-106980 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Uniaxial Compressive Constitutive Relationship of Concrete Confined by Special-Shaped Steel Tube Coupled with Multiple Cavities

PubMed Central

Wu, Haipeng; Cao, Wanlin; Qiao, Qiyun; Dong, Hongying

2016-01-01

A method is presented to predict the complete stress-strain curves of concrete subjected to triaxial stresses, which were caused by axial load and lateral force. The stress can be induced due to the confinement action inside a special-shaped steel tube having multiple cavities. The existing reinforced confined concrete formulas have been improved to determine the confinement action. The influence of cross-sectional shape, of cavity construction, of stiffening ribs and of reinforcement in cavities has been considered in the model. The parameters of the model are determined on the basis of experimental results of an axial compression test for two different kinds of special-shaped concrete filled steel tube (CFT) columns with multiple cavities. The complete load-strain curves of the special-shaped CFT columns are estimated. The predicted concrete strength and the post-peak behavior are found to show good agreement within the accepted limits, compared with the experimental results. In addition, the parameters of proposed model are taken from two kinds of totally different CFT columns, so that it can be concluded that this model is also applicable to concrete confined by other special-shaped steel tubes. PMID:28787886

Investigation on Wall Panel Sandwiched With Lightweight Concrete

NASA Astrophysics Data System (ADS)

Lakshmikandhan, K. N.; Harshavardhan, B. S.; Prabakar, J.; Saibabu, S.

2017-08-01

The rapid population growth and urbanization have made a massive demand for the shelter and construction materials. Masonry walls are the major component in the housing sector and it has brittle characteristics and exhibit poor performance against the uncertain loads. Further, the structure requires heavier sections for carrying the dead weight of masonry walls. The present investigations are carried out to develop a simple, lightweight and cost effective technology for replacing the existing wall systems. The lightweight concrete is developed for the construction of sandwich wall panel. The EPS (Expanded Polystyrene) beads of 3 mm diameter size are mixed with concrete and developed a lightweight concrete with a density 9 kN/m3. The lightweight sandwich panel is cast with a lightweight concrete inner core and ferrocement outer skins. This lightweight wall panel is tested for in-plane compression loading. A nonlinear finite element analysis with damaged plasticity model is carried out with both material and geometrical nonlinearities. The experimental and analytical results were compared. The finite element study predicted the ultimate load carrying capacity of the sandwich panel with reasonable accuracy. The present study showed that the lightweight concrete is well suitable for the lightweight sandwich wall panels.

Uniaxial Compressive Constitutive Relationship of Concrete Confined by Special-Shaped Steel Tube Coupled with Multiple Cavities.

PubMed

Wu, Haipeng; Cao, Wanlin; Qiao, Qiyun; Dong, Hongying

2016-01-29

A method is presented to predict the complete stress-strain curves of concrete subjected to triaxial stresses, which were caused by axial load and lateral force. The stress can be induced due to the confinement action inside a special-shaped steel tube having multiple cavities. The existing reinforced confined concrete formulas have been improved to determine the confinement action. The influence of cross-sectional shape, of cavity construction, of stiffening ribs and of reinforcement in cavities has been considered in the model. The parameters of the model are determined on the basis of experimental results of an axial compression test for two different kinds of special-shaped concrete filled steel tube (CFT) columns with multiple cavities. The complete load-strain curves of the special-shaped CFT columns are estimated. The predicted concrete strength and the post-peak behavior are found to show good agreement within the accepted limits, compared with the experimental results. In addition, the parameters of proposed model are taken from two kinds of totally different CFT columns, so that it can be concluded that this model is also applicable to concrete confined by other special-shaped steel tubes.

Highway concrete pavement technology development and testing. Volume 5, Field evaluation of Strategic Highway Research Program (SHRP) C-206 test sites (bridge deck overlays)

DOT National Transportation Integrated Search

2006-08-01

Two types of concrete overlays silica fume concrete (SFC) and latex-modified Type III portland cement concrete (LMC-III) were installed ant tested as part of the Strategic Highway Research Program (SHRP) Project C-206: Optimization of Highway Concret...

29 CFR 1926.704 - Requirements for precast concrete.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 8 2010-07-01 2010-07-01 false Requirements for precast concrete. 1926.704 Section 1926..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.704 Requirements for precast concrete. (a) Precast concrete wall units, structural framing...

Design equations for the assessment and FRP-strengthening of reinforced rectangular concrete columns under combined biaxial bending and axial loads

NASA Astrophysics Data System (ADS)

Alessandri, S.; Monti, G.

2008-05-01

A simple procedure is proposed for the assessment of reinforced rectangular concrete columns under combined biaxial bending and axial loads and for the design of a correct amount of FRP-strengthening for underdesigned concrete sections. Approximate closed-form equations are developed based on the load contour method originally proposed by Bresler for reinforced concrete sections. The 3D failure surface is approximated along its contours, at a constant axial load, by means of equations given as the sum of the acting/resisting moment ratio in the directions of principal axes of the sections, raised to a power depending on the axial load, the steel reinforcement ratio, and the section shape. The method is extended to FRP-strengthened sections. Moreover, to make it possible to apply the load contour method in a more practical way, simple closed-form equations are developed for rectangular reinforced concrete sections with a two-way steel reinforcement and FRP strengthenings on each side. A comparison between the approach proposed and the fiber method (which is considered exact) shows that the simplified equations correctly represent the section interaction diagram.

Laboratory and field performance of silane anti-strip agent

DOT National Transportation Integrated Search

1986-11-01

A previous ADOT research project resulted in strong evidence that the use of organo-silane as an asphalt additive was very effective in preventing stripping in asphalt concrete pavements. A test section approximately 2800 ft long and 12 ft wide incor...

Performance evaluation of Louisiana's AASHO satellite test sections : final report.

DOT National Transportation Integrated Search

1979-07-01

It is beyond the scope of this study to attempt to isolate the effect of individual design assumptions on pavement life. : A performance evaluation (to determine present serviceability, end of life, etc.) of selected Portland Cement Concrete (P.C.C.)...

Extruded Tunnel Lining System : Phase 1. Conceptual Design and Feasibility Testing.

DOT National Transportation Integrated Search

1979-09-01

The Extruded Tunnel Lining System (ETLS) has been conceived as a means of continuously placing the final concrete tunnel lining directly behind a tunnel boring machine. The system will shorten the time required to excavate and line a tunnel section, ...

Millabrading test evaluation : Norwood Road : M.P. 287.02 (Southbound Interstate 5) : construction report

DOT National Transportation Integrated Search

1999-09-01

The Oregon Department of Transportation (ODOT) continues to investigate alternatives for rehabilitating the rutting in concrete pavement sections. The millabrading system was proposed as an option to reduce the middle lane rut depths in a continuousl...

Texturing of concrete pavements : interim report No. 1.

DOT National Transportation Integrated Search

1975-11-01

The scope of this report is to describe the results obtained during the first twelve-month period of this field research project. It includes the construction of test sections and the evaluation period after the project was opened to traffic. Each te...

Application of empirical and mechanistic-empirical pavement design procedures to Mn/ROAD concrete pavement test sections

DOT National Transportation Integrated Search

1997-05-01

Current pavement design procedures are based principally on empirical approaches. The current trend toward developing more mechanistic-empirical type pavement design methods led Minnesota to develop the Minnesota Road Research Project (Mn/ROAD), a lo...

Performance of concrete joint sealants in hot climates

DOT National Transportation Integrated Search

1987-11-01

A research project was initiated in 1979 on project IR-17-1(126) to compare and evaluate several joint sealants. In 1982 another test section on project F 028-1-506 was established to evaluate several other sealants. This report documents the placeme...

Effect of section properties on load carrying capacity of 10m span precast concrete closed spandrel arch bridge with corrugated section

NASA Astrophysics Data System (ADS)

Ong, Chong Yong; Choong, Kok Keong; Miralimov, Mirzakhid

2017-10-01

Various precast concrete arch bridge systems have been developed since 1960's. The reinforced concrete section of these systems is solid rectangular which is not an efficient section. Inspired by the nature of banana tree trunk, a relatively new corrugated section of precast concrete arch bridge was introduced and patented in Malaysia in 2008. This folded plate section is an open section which tends to open under vehicular loading. Hence, effect of section properties on load carrying capacity of precast concrete closed spandrel arch bridge with corrugated section under vehicle loading is presented in this paper. The arch bridge model has a clear span of 10m with 2.5m, 3.0m and 3.5m clear rise. For the corrugated section dimension model, overall depth varies from 475mm to 575mm, top and bottom flange thickness varies from 135mm to 155mm and web thickness varies from 90mm to 120mm. Linear and non-linear computational analysis are carried out using 2D PLAXIS software (in longitudinal direction) and LUSAS software (in transverse direction). In longitudinal direction, the sagging moment in non-linear analysis increases approximately 18% compared to linear analysis for different rise span ratio. From the analysis results, as the rise of arch increases, the sagging moment and hogging moment increases, but the axial force decreases. Besides, as the overall depth of corrugated section increases, the internal forces of the arch also increase. In transverse direction, the maximum tensile stress of concrete at crown and haunch decreases as slenderness ratio increases.

Development of design parameters for virtual cement and concrete testing.

DOT National Transportation Integrated Search

2013-12-01

The development, testing, and certification of new concrete mix designs is an expensive and time-consuming aspect : of the concrete industry. A software package, named the Virtual Concrete and Cement Testing Laboratory (VCCTL), : has been developed b...

Report D : self-consolidating concrete (SCC) for infrastructure elements - creep, shrinkage and abrasion resistance.

DOT National Transportation Integrated Search

2012-08-01

Concrete specimens were fabricated for shrinkage, creep, and abrasion resistance : testing. Variations of self-consolidating concrete (SCC) and conventional concrete were : all tested. The results were compared to previous similar testing programs an...

A&M. TAN633. Hot cell floor plans, elevations, sections. Hole schedule ...

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

A&M. TAN-633. Hot cell floor plans, elevations, sections. Hole schedule (penetrations through concrete). Swing-door details. Ralph M. Parsons 1229-13-ANP/GE-3-633-A-3. Date: December 1956. Approved by INEEL Classification Office for public release. INNEL index code no. 034-0633-00-693-107317 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berke, N.S.; Dallaire, M.P.; Hicks, M.C.

Corrosion of steel in concrete is studied typically in uncracked concrete. In the field, however, concrete often has cracks that extend to the reinforcing steel. Electrochemical corrosion testing was performed in cracked concrete of two qualities. Results were compared to physical examination of the embedded reinforcement. Corrosion resistance improved significantly as the concrete properties and reinforcement cover approached that recommended in American Concrete Institute 318. Calcium nitrite additions to the concrete reduced corrosion significantly. Results indicated testing in cracked concrete should be performed in concrete representative of that specified in ACl 318.

Study on load test of 100m cross-reinforced deck type concrete box arch bridge

NASA Astrophysics Data System (ADS)

Shi, Jing Xian; Cheng, Ying Jie

2018-06-01

Found in the routine quality inspection of highway bridge that many vertical fractures on the main beam (10mT beam) of the steel reinforced concrete arch bridge near the hydropower station. In order to grasp the bearing capacity of this bridge under working conditions with cracks, the static load and dynamic load test of box arch bridge are carried out. The Midas civil theory is calculated by using the special plate trailer - 300 as the calculation load, and the deflection and stress of the critical section are tested by the equivalent cloth load in the test vehicle. The pulsation test, obstacles and no obstacle driving test were carried out. Experimental results show that the bridge under the condition of the test loads is in safe condition, main bearing component of the strength and stiffness meet the design requirements, the crack width does not increase, in the process of loading bridge overall work performance is good.

Texturing of concrete pavements : interim report No. 3.

DOT National Transportation Integrated Search

1977-08-01

The scope of this report is to describe the results obtained at the end of thirty-six months for the third twelve-month period of this field research project. It includes the construction of test sections and the evaluation period after the project w...

Field investigation of low-temperature cracking and stiffness moduli on selected roads with conventional and high modulus asphalt concrete

NASA Astrophysics Data System (ADS)

Judycki, Józef; Jaczewski, Mariusz; Ryś, Dawid; Pszczoła, Marek; Jaskuła, Piotr; Glinicki, Adam

2017-09-01

High Modulus Asphalt Concrete (HMAC) was introduced in Poland as a one of the solutions to the problem of rutting, type of deterioration common in the 1990s. After first encouraging trials in 2002 HMAC was widely used for heavily loaded national roads and motorways. However some concerns were raised about low-temperature cracking of HMAC. This was the main reason of the studies presented in this article were started. The article presents the comparison of performance of pavements constructed in typical contract conditions with the road bases made of HMAC and conventional asphalt concrete (AC). The field investigation was focused on the number of low-temperature cracks, bearing capacity (based on FWD test) of road sections localized in coldest region of Poland. Also load transfer efficiency of selected low-temperature cracks was assessed. FWD test confirmed lower deflections of pavements with HMAC and two times higher stiffness modulus of asphalt courses in comparison to pavements constructed with conventional AC mixtures. Relation of stiffness of asphalt layers and amount of low-temperature cracks showed that the higher stiffness modulus of asphalt layers could lead to increase of the number of low-temperature cracks. FWD test results showed that the load transfer efficiency of low-temperature cracks on pavements with HMAC presents very low values, very close to lack of load transfer. It was surprising as section with HMAC road base were aged from 2 to 5 years and presented very good bearing capacity.

Physical Characteristics of Laboratory Tested Concrete as a Substituion of Gravel on Normal Concrete

NASA Astrophysics Data System (ADS)

Butar-butar, Ronald; Suhairiani; Wijaya, Kinanti; Sebayang, Nono

2018-03-01

Concrete technology is highly potential in the field of construction for structural and non-structural construction. The amount uses of this concrete material raise the problem of solid waste in the form of concrete remaining test results in the laboratory. This waste is usually just discarded and not economically valuable. In solving the problem, this experiment was made new materials by using recycle material in the form of recycled aggregate which aims to find out the strength characteristics of the used concrete as a gravel substitution material on the normal concrete and obtain the value of the substitution composition of gravel and used concrete that can achieve the strength of concrete according to the standard. Testing of concrete characteristic is one of the requirements before starting the concrete mixture. This test using SNI method (Indonesian National Standard) with variation of comparison (used concrete : gravel) were 15: 85%, 25: 75%, 35:65%, 50:50 %, 75: 25%. The results of physical tests obtained the mud content value of the mixture gravel and used concrete is 0.03 larger than the standard of SNI 03-4142-1996 that is equal to 1.03%. so the need watering or soaking before use. The water content test results show an increase in the water content value if the composition of the used concrete increases. While the specific gravity value for variation 15: 85% until 35: 65% fulfilled the requirements of SNI 03-1969-1990. the other variasion show the specifics gravity value included on the type of light materials.

Behaviour of partially composite precast concrete sandwich panels under flexural and axial loads

NASA Astrophysics Data System (ADS)

Tomlinson, Douglas George

Precast concrete sandwich panels are commonly used on building exteriors. They are typically composed of two concrete wythes that surround rigid insulation. They are advantageous as they provide both structural and thermal resistance. The structural response of sandwich panels is heavily influenced by shear connectors that link the wythes together. This thesis presents a study on partially composite non-prestressed precast concrete wall panels. Nine flexure tests were conducted on a wall design incorporating 'floating' concrete studs and Glass Fibre Reinforced Polymer (GFRP) connectors. The studs encapsulate and stiffen the connectors, reducing shear deformations. Ultimate loads increased from 58 to 80% that of a composite section as the connectors' reinforcement ratio increased from 2.6 to 9.8%. This design was optimized by reinforcing the studs and integrating them with the structural wythe; new connectors composed of angled steel or Basalt-FRP (BFRP) were used. The load-slip response of the new connector design was studied through 38 double shear push-through tests using various connector diameters and insertion angles. Larger connectors were stronger but more likely to pull out. Seven flexure tests were conducted on the new wall design reinforced with different combinations of steel and BFRP connectors and reinforcement. Composite action varied from 50 to 90% depending on connector and reinforcement material. Following this study, the axial-bending interaction curves were established for the new wall design using both BFRP and steel connectors and reinforcement. Eight panels were axially loaded to predesignated loads then loaded in flexure to failure. A technique is presented to experimentally determine the effective centroid of partially composite sections. Beyond the tension and compression-controlled failure regions of the interaction curve, a third region was observed in between, governed by connector failure. Theoretical models were developed for the bond-slip behaviour of the shear connection and to analyze the full panel's flexural and axial response to determine the longitudinal shear force transferred between wythes and account for partial composite behavior. The models were validated against experiments and used to conduct a parametric study. Among several interesting findings, the study demonstrated how composite action increases with the slenderness of axially loaded panels.

Evaluation of flyash in lean concrete base and continuously reinforced concrete pavements : final report.

DOT National Transportation Integrated Search

1991-07-01

Proposed research on this project included five main objectives: 1) To test and evaluate the physical characteristics of flyash concrete in comparions to non-flyash concrete. Tests will be conducted to see if flyash concrete meets OSHD specifications...

Previous concrete as one of the technology to overcome the puddle

NASA Astrophysics Data System (ADS)

Agung Putra Handana, M.; Karolina, Rahmi; Syahputra, Eko; Zulfikar

2018-03-01

Some construction waste has been utilized as a material in certain concrete compositions for engineering building materials. One is a concrete that has been removed after testing at a laboratory called recycle concrete. Disposed concrete, crushed and filtered with filter number 50; 37.5; 19; 9.5; and 4.75 mm are subsequently converted into rough aggregate materials in the manufacture of pervious concrete to be tested for compressive strength and infiltration velocity to water. Pervious concrete test specimens in the form of cylinders with dimensions (15 x 30) cm and plate-shaped with dimension (100 x 100 x 10) cm with the quality plan Fc ' = 15 MPa at age 28 days. The research methodology consisted of testing of wear, test object preparation, periodic maintenance, visual inspection, compressive strength testing, and infiltration rate of specimens against water (based on ASTM C1701). Treatment of specimens by spraying periodically before the test time. From the results of the Los Angeles wear test, it appears that recycled aggregate has an average wear rate of 20.88% (based on SNI 03-2417-1991) on the Los Angeles test) and the visual test on the specimen is appropriate (based on SNI 03 -0691-1996 on paving block) as the basis for testing the specimens. The largest compressive strength was found in pervious concrete with 9.5 mm graded aggregates of 5.89 MPa, while the smallest compressive strength of 50 mm gradation was 2.15 MPa and had a compressive strength of 28% of pervious concrete compressive strength on generally (based on SNI 03-6805-2002). The fastest infiltration speed occurs in 50 mm pervious gradient concrete at 4.52 inc / hr and is late in 9.5 mm grading of 2.068 inc / hr or an inflation rate inflation rate of 54.25% for gradation of 9.5 mm to 50 mm gradation, So that in accordance with the purpose of pervious concrete use, concrete that can drain water to the bottom layer

The influence of using volcanic ash and lime ash as filler on compressive strength in self compacting concrete

NASA Astrophysics Data System (ADS)

Karolina, Rahmi; Panatap Simanjuntak, Murydrischy

2018-03-01

Self Compacting Concrete (SCC) is a technology which is developing today in which concrete solidifies by itself without using vibrator. Casting conventional concrete which has a lot of reinforcement bars sometimes finds difficulty in achieving optimal solidity. The method used to solve this problem is by using SCC technology. SCC was made by using filler, volcanic ash, and lime ash as the filling materials so that the concrete became more solid and hollow space could be filled up. The variation of using these two materials was 10%, 15%, 20%, and 25% of the cementitious mass and using 1% of superplasticizer from cementitious material. The supporting testing was done by using the test when the concrete was still fluid and when it was solid. Malleable concrete was tested by using EFNARC 2002 standard in slump flow test, v-funnel test, l-shaped box test, and j-ring test to obtain filling ability and passing ability. In this malleable lime concrete test, there was the decrease, compared with normal SCC concrete without adding volcanic ash and lime ash. Testing was also done in solid concrete in compressive strength, tensile strength, and concrete absorption. The result of the testing showed that the optimum tensile strength in Variation 1, without volcanic ash and lime ash – with 1% of superplasticizer was 39.556 MPa, the optimum tensile strength in Variation 1, without volcanic ash and lime ash- with 1% of super-plasticizer was 3.563 MPa, while the value of optimum absorption which occurred in Variation 5 (25% of volcanic ash + 25% of lime ash + 50% of cement + 1% of superplasticizer) was 1.313%. This was caused by the addition of volcanic ash and lime ash which had high water absorption.

Performance evaluation of Arizona's LTPP SPS-5 project : strategic study of rehabilitation of asphalt concrete pavements.

DOT National Transportation Integrated Search

2015-06-01

As part of the Long Term Pavement Performance (LTPP) Program, the Arizona Department of Transportation : (ADOT) constructed 11 Specific Pavement Study5 (SPS5) test sections on Interstate 8 near Casa Grande. The : SPS5 project studied a varie...

Monitoring and modeling of pavement response and performance task B : New York volume 3, I90.

DOT National Transportation Integrated Search

2012-05-01

This research presents the evaluation and comparison of two Portland-cement concrete (PCC) pavement test : sections with cement-treated permeable bases (CTPB) and dense-graded aggregate bases (DGAB) on the Interstate : 90 Thruway in New York. Two ins...

Coordination of load response instrumentation of SHRP pavements, Ohio University : final report, May 1999.

DOT National Transportation Integrated Search

1999-05-01

The Ohio Department of Transportation constructed an experimental pavement for the Strategic Highway Research (SHRP) on U.S. 23 north of Columbus, which included 40 asphalt and concrete test sections in the SPS-1, 2, 8 and 9 experiments. These sectio...

FAST CHOPPER DETECTOR HOUSE, TRA665. FIRST FLOOR, PLAN AND SECTION, ...

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

FAST CHOPPER DETECTOR HOUSE, TRA-665. FIRST FLOOR, PLAN AND SECTION, AS PROPOSED FOR MODIFICATION IN 1962. CONCRETE WALLS THREE FEET THICK. EXISTING WINDOWS IN MTR AND DETECTOR HOUSE WALLS WERE TO BE FILLED IN WITH HIGH-DENSITY BRICK. NOTE 20-METER MARK, WHERE THE FAST CHOPPER DETECTOR HAD BEEN LOCATED. F.C. TORKELSON 842-MTR-665-S-2, 4/1962. INL INDEX NO. 531-0665-60-851-150996, REV. 5. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

40 CFR 443.20 - Applicability; description of the asphalt concrete subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... asphalt concrete subcategory. 443.20 Section 443.20 Protection of Environment ENVIRONMENTAL PROTECTION... ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Concrete Subcategory § 443.20 Applicability; description of the asphalt concrete subcategory. The provisions of this subpart are applicable to...

40 CFR 443.20 - Applicability; description of the asphalt concrete subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... asphalt concrete subcategory. 443.20 Section 443.20 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Concrete Subcategory § 443.20 Applicability; description of the asphalt concrete subcategory. The provisions of this subpart are applicable to discharges...

40 CFR 443.20 - Applicability; description of the asphalt concrete subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... asphalt concrete subcategory. 443.20 Section 443.20 Protection of Environment ENVIRONMENTAL PROTECTION... ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Concrete Subcategory § 443.20 Applicability; description of the asphalt concrete subcategory. The provisions of this subpart are applicable to...

40 CFR 443.20 - Applicability; description of the asphalt concrete subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... asphalt concrete subcategory. 443.20 Section 443.20 Protection of Environment ENVIRONMENTAL PROTECTION... ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Concrete Subcategory § 443.20 Applicability; description of the asphalt concrete subcategory. The provisions of this subpart are applicable to...

40 CFR 443.20 - Applicability; description of the asphalt concrete subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... asphalt concrete subcategory. 443.20 Section 443.20 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Concrete Subcategory § 443.20 Applicability; description of the asphalt concrete subcategory. The provisions of this subpart are applicable to discharges...

Investigation of optimized graded concrete for Oklahoma.

DOT National Transportation Integrated Search

2013-07-01

This report presents the results of several novel test methods to investigate concrete for slip formed paving. These tests include the Box Test, a novel test to evaluate the response of concrete to vibration, the AIMS2, an automated test for aggregat...

Properties of concrete containing foamed concrete block waste as fine aggregate replacement

NASA Astrophysics Data System (ADS)

Muthusamy, K.; Budiea, A. M. A.; Zaidan, A. L. F.; Rasid, M. H.; Hazimmah, D. S.

2017-11-01

Environmental degradation due to excessive sand mining dumping at certain places and disposal of foamed concrete block waste from lightweight concrete producing industry are issues that should be resolved for a better and cleaner environment of the community. Thus, the main intention of this study is to investigate the potential of foamed concrete block waste as partial sand replacement in concrete production. The foamed concrete waste (FCW) used in this research that were supplied by a local lightweight concrete producing industry. The workability and compressive strength of concrete containing various percentage of foamed concrete waste as partial sand replacement has been investigated. Prior to the use, the foamed concrete waste were crushed to produce finer particles. Six concrete mixes containing various content of crushed foamed concrete waste that are 0%, 10%, 20%, 30%, 40% and 50% were used in this experimental work. Then the prepared specimens were placed in water curing until the testing age. Compressive strength test and flexural strength tests were conducted at 7, 14 and 28 days. The result shows that integration of crushed foamed concrete waste as partial sand replacement in concrete reduces the mix workability. It is interesting to note that both compressive strength and flexural strength of concrete improves when 30% crushed foamed concrete waste is added as partial sand replacement.

Latex modified fibrous concrete Sundial-Sandy River Section : interim report.

DOT National Transportation Integrated Search

1985-03-01

In November 1980, a contractor requested permission to use a 1.5 inch thick Latex Modified Fibrous Concrete (LMFC) overlay in lieu of a 2.5 inch low slump concrete (Iowa System) or a 2.5 inch unreinforced latex modified concrete. The overlays were to...

Testing of concrete by laser ablation

DOEpatents

Flesher, Dann J.; Becker, David L.; Beem, William L.; Berry, Tommy C.; Cannon, N. Scott

1997-01-01

A method of testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed.

Behavior of reinforcement SCC beams under elevated temperatures

NASA Astrophysics Data System (ADS)

Fathi, Hamoon; Farhang, Kianoosh

2015-09-01

This experimental study focuses on the behavior of heated reinforced concrete beams. Four types of concrete mixtures were used for the tested self-compacting concrete beams. A total of 72 reinforced concrete beams and 72 standard cylindrical specimens were tested. The compressive strength under uniaxial loading at 23 °C ranged from 30 to 45 MPa. The specimens were exposed to different temperatures. The test parameters of interest were the compressive strength and the temperature of the specimens. The effect of changes in the parameters was examined so as to control the behavior of the tested concrete and that of the reinforced concrete beam. The results indicated that flexibility and compressive strength of the reinforced concrete beams decreased at higher temperatures. Furthermore, heating beyond 400 °C produced greater variations in the structural behavior of the materials in both the cylindrical samples and the reinforced concrete beams.

Feasibility of Steel Fiber-Reinforced Rubberized Concrete in Cold Regions for High Volume Intersections

NASA Astrophysics Data System (ADS)

Abou Eid, Mahear A.

There are many challenges faced with the use of Portland Cement Concrete (PCC) in cold regions, but with the inclusion of new technologies such as steel fibers and recycled tire crumb rubber efficient construction may be possible. Research was conducted on a modified concrete material that included both steel fibers and crumb rubber. The composite material was called Steel Fiber-Reinforced Rubberized Concrete (SFRRC). The objective of this investigation was to provide evidence showing that SFRRC can reduce tire rutting compared to asphaltic pavement. In addition, the research showed that the SFRRC could withstand freeze-thaw cycles and increase service life of roadways. Several tests were performed to determine the characteristics of the material. Freeze-thaw testing was performed to determine compressive strength loss and visual deterioration of the material. Wheel tracker rut testing was performed both with the standard steel wheel and with a modified studded rubber tire to determine plastic deformation and rut resistance. An experimental test slab was cast in place on a public approach to observe the construction procedures, the effects of studded tire wear and the frost actions in cold region conditions. Based on freeze-thaw and wheel tracker test results and observations of the experimental test slab, the SFRRC material shows viability in cold regions for resisting freeze-thaw actions. The freeze-thaw testing resulted in increased compressive strength after 300 freeze-thaw cycles and very low deterioration of material compared to standard PCC. The wheel tracker testing resulted in very low plastic deformation and minor material rutting with use of the studded rubber tire. The test slab showed very minor surface wear, no freeze-thaw cracking and no rutting after one winter of use. It is recommended that further testing of the material be conducted by means of a large-scale trial section. This would provide information with respect to cost analysis and integration of the material into the Department of Transportation construction program.

Peculiarities of Thermal Treatment of Monolithic Reinforced Concrete Structures

NASA Astrophysics Data System (ADS)

Kuchin, V. N.; Shilonosova, N. V.

2017-11-01

A mathematical program has been developed that allows one to determine the parameters of heat treatment of monolithic structures. One of the quality indicators of monolithic reinforced concrete structures is the level of temperature stresses arising in the process of heat treatment and further operation of structures. In winter at heat treatment the distribution of temperatures along the cross-section of the structure is uneven. A favorable thermo-stressed state in a concrete massif occurs when using the preheating method, providing the concrete temperature in the center of the structure is greater than at the periphery. In this case, after the strength is set and the temperature is later equalized along the cross-section, the central part of the structure tends to decrease its dimensions more but the extreme zones prevent it. Therefore, the center is in a state of tension, and the extreme zones on the periphery are compressed. In compressed concrete there is a lesser chance of cracks or defects. The temperature gradient over the section of the structure, the stress in the concrete and its strength are determined. When calculating the temperature and strength fields, the stress level was determined - a value equal to the ratio of the tensile stresses in the section under consideration to the tensile strength of the concrete in this section at the same time. The nature of the change in stress level is determined by the massive structure and power of the formwork heaters. It is shown that under unfavorable conditions the stress level is close to the critical value. The greatest temperature gradient occurs in the outer layers adjacent to the heating formwork. A technology for concrete conditioning is proposed which makes it possible to reduce the temperature stresses along the cross-section of the structure. The time for concrete conditioning in the formwork is reduced. In its turn, it further reduces labor costs and the cost of concrete work along with the cost of heat treatment. The authors conduct the technical and economic comparison of heat treatment options for the structures. The duration of monolithic structures erection with the use of combined heat treatment decreases in comparison with the method of peripheral heating. The economic effect consists of the reduction of the cost to organize and perform temperature control, insulation, electricity.

Compressive Properties and Anti-Erosion Characteristics of Foam Concrete in Road Engineering

NASA Astrophysics Data System (ADS)

Li, Jinzhu; Huang, Hongxiang; Wang, Wenjun; Ding, Yifan

2018-01-01

To analyse the compression properties and anti-erosion characteristics of foam concrete, one dimensional compression tests were carried out using ring specimens of foam concrete, and unconfined compression tests were carried out using foam concrete specimens cured in different conditions. The results of one dimensional compression tests show that the compression curve of foam concrete has two critical points and three stages, which has significant difference with ordinary geotechnical materials such as soil. Based on the compression curve the compression modulus of each stage were determined. The results of erosion tests show that sea water has a slight influence on the long-term strength of foam concrete, while the sulphate solution has a significant influence on the long-term strength of foam concrete, which needs to pay more attention.

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 or...

7 CFR 3201.42 - Wood and concrete sealers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false Wood and concrete sealers. 3201.42 Section 3201.42... Designated Items § 3201.42 Wood and concrete sealers. (a) Definition. (1) Products that are penetrating liquids formulated to protect wood and/or concrete, including masonry and fiber cement siding, from damage...

7 CFR 3201.42 - Wood and concrete sealers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Wood and concrete sealers. 3201.42 Section 3201.42... Designated Items § 3201.42 Wood and concrete sealers. (a) Definition. (1) Products that are penetrating liquids formulated to protect wood and/or concrete, including masonry and fiber cement siding, from damage...

7 CFR 3201.42 - Wood and concrete sealers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 15 2012-01-01 2012-01-01 false Wood and concrete sealers. 3201.42 Section 3201.42... Designated Items § 3201.42 Wood and concrete sealers. (a) Definition. (1) Products that are penetrating liquids formulated to protect wood and/or concrete, including masonry and fiber cement siding, from damage...

9 CFR 91.26 - Concrete flooring.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Concrete flooring. 91.26 Section 91.26... LIVESTOCK FOR EXPORTATION Inspection of Vessels and Accommodations § 91.26 Concrete flooring. (a) Pens aboard an ocean vessel shall have a 3 inch concrete pavement, proportioned and mixed to give 2000 psi...

CORROSION PROCESS IN REINFORCED CONCRETE IDENTIFIED BY ACOUSTIC EMISSION

NASA Astrophysics Data System (ADS)

Kawasaki, Yuma; Kitaura, Misuzu; Tomoda, Yuichi; Ohtsu, Masayasu

Deterioration of Reinforced Concrete (RC) due to salt attack is known as one of serious problems. Thus, development of non-destructive evaluation (NDE) techniques is important to assess the corrosion process. Reinforcement in concrete normally does not corrode because of a passive film on the surface of reinforcement. When chloride concentration at reinfo rcement exceeds the threshold level, the passive film is destroyed. Thus maintenance is desirable at an early stage. In this study, to identify the onset of corrosion and the nucleation of corrosion-induced cracking in concrete due to expansion of corrosion products, continuous acoustic emission (AE) monitoring is applied. Accelerated corrosion and cyclic wet and dry tests are performed in a laboratory. The SiGMA (Simplified Green's functions for Moment tensor Analysis) proce dure is applied to AE waveforms to clarify source kinematics of micro-cracks locations, types and orientations. Results show that the onset of corrosion and the nu cleation of corrosion-induced cracking in concrete are successfully identified. Additionally, cross-sections inside the reinforcement are observed by a scanning electron microscope (SEM). From these results, a great promise for AE techniques to monitor salt damage at an early stage in RC structures is demonstrated.

Rigid and Flexible Pavement Aircraft Tie-Downs

DTIC Science & Technology

2010-05-01

Concrete Pier, Prior to PCC Placement Neenah anchors are equipped with two ½-in-diameter cored holes to allow insertion of a section of rebar through...facilitate this process, a Hilti drill was utilized to perform the concrete drilling process. The drill bit diameter exceeded the rebar diameter by...aggregate particles not become lodged against the rebar sections inside the dowel sleeves, impeding the flow of concrete and possibly creating air voids

International Intervention in Intra-State Conflicts: The Case in Sri Lanka

DTIC Science & Technology

2013-03-01

it comes to practice, this model is very simplistic. Most interveners do not follow this concrete sequence, and there is no definite criterion to...there was a significant and unavoidable concern. The second section addresses the first concrete foundation of India’s domestic setting for...was fueled primarily by domestic interests. The third section addresses the second concrete foundation laid by Sri Lankans for Indian intervention

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, T.L.; Foster, D. Jr.; Wilson, C.T.

The authors report on the results of the second phase of a four-phase program at Oak Ridge National Laboratory to develop a system to decontaminate concrete using microwave energy. The microwave energy is directed at the concrete surface through the use of an optimized wave guide antenna, or applicator, and this energy rapidly heats the free water present in the interstitial spaces of the concrete matrix. The resulting steam pressure causes the surface to burst in much the same way popcorn pops in a home microwave oven. Each steam explosion removes several square centimeters of concrete surface that are collectedmore » by a highly integrated wave guide and vacuum system. The authors call this process the microwave concrete decontamination, or MCD, process. In the first phase of the program the principle of microwaves concrete removal concrete surfaces was demonstrated. In these experiments, concrete slabs were placed on a translator and moved beneath a stationary microwave system. The second phase demonstrated the ability to mobilize the technology to remove the surfaces from concrete floors. Area and volume concrete removal rates of 10.4 cm{sup 2}/s and 4.9 cm{sup 3}/S, respectively, at 18 GHz were demonstrated. These rates are more than double those obtained in Phase 1 of the program. Deeper contamination can be removed by using a longer residence time under the applicator to create multiple explosions in the same area or by taking multiple passes over previously removed areas. Both techniques have been successfully demonstrated. Small test sections of painted and oil-soaked concrete have also been removed in a single pass. Concrete with embedded metal anchors on the surface has also been removed, although with some increased variability of removal depth. Microwave leakage should not pose any operational hazard to personnel, since the observed leakage was much less than the regulatory standard.« less

Asphalt additives in thick hot mixed asphalt-concrete pavements. Research report (Interim), Sep 86-Oct 90

DOE Office of Scientific and Technical Information (OSTI.GOV)

Button, J.W.; Prapnnachari, S.

Asphalt concrete field test pavements were placed in District 19 north of Texarkana on US-59/71 in 1987 and 1988 to evaluate the ability of certain asphalt additives to enhance resistance to cracking and rutting. Two 10-inch thick and 0.9 mile (approx.) long test pavements and a similar untreated control section were constructed in the northbound and southbound lanes for a total of 6 field trials. Asphalt additives were incorporated in both the 8-inch base and the overlying 2-inch surface layers. The additives evaluated included Goodyear LPF 5812, Chemkrete-CTI 102, Exxon Polybilt 102, and Styrelf 13. Samples of paving materials includingmore » aggregates, asphalts, compacted mixes, and pavement cores were collected, conveyed to the laboratory, and tested to provide detailed documentation of their properties. Tests included rheological properties of the binders before and after artificial aging, characterization of aggregate, Hveem and Marshall stability, stiffness as a function of temperature, tensile properties before and after moisture conditioning and artificial aging, air void content, creep, and permanent deformation. Field tests and visual evaluations have been conducted to objectively evaluate field performance. Results of these tests are reported herein. Within 6 months after construction of the base layers and prior to placement of the surface course, the Chemkrete modified base became severely cracked. As a result, the surface mix placed on this base section was treated with Goodyear latex rather than Chemkrete. All other modified pavements and the control section have performed well and exhibited essentially equivalent performance after 2 1/2 years in service.« less

Comparative field permeability measurement of permeable pavements using ASTM C1701 and NCAT permeameter methods.

PubMed

Li, Hui; Kayhanian, Masoud; Harvey, John T

2013-03-30

Fully permeable pavement is gradually gaining support as an alternative best management practice (BMP) for stormwater runoff management. As the use of these pavements increases, a definitive test method is needed to measure hydraulic performance and to evaluate clogging, both for performance studies and for assessment of permeability for construction quality assurance and maintenance needs assessment. Two of the most commonly used permeability measurement tests for porous asphalt and pervious concrete are the National Center for Asphalt Technology (NCAT) permeameter and ASTM C1701, respectively. This study was undertaken to compare measured values for both methods in the field on a variety of permeable pavements used in current practice. The field measurements were performed using six experimental section designs with different permeable pavement surface types including pervious concrete, porous asphalt and permeable interlocking concrete pavers. Multiple measurements were performed at five locations on each pavement test section. The results showed that: (i) silicone gel is a superior sealing material to prevent water leakage compared with conventional plumbing putty; (ii) both methods (NCAT and ASTM) can effectively be used to measure the permeability of all pavement types and the surface material type will not impact the measurement precision; (iii) the permeability values measured with the ASTM method were 50-90% (75% on average) lower than those measured with the NCAT method; (iv) the larger permeameter cylinder diameter used in the ASTM method improved the reliability and reduced the variability of the measured permeability. Copyright © 2013 Elsevier Ltd. All rights reserved.

Reuse of waste iron as a partial replacement of sand in concrete.

PubMed

Ismail, Zainab Z; Al-Hashmi, Enas A

2008-11-01

One of the major environmental issues in Iraq is the large quantity of waste iron resulting from the industrial sector which is deposited in domestic waste and in landfills. A series of 109 experiments and 586 tests were carried out in this study to examine the feasibility of reusing this waste iron in concrete. Overall, 130 kg of waste iron were reused to partially replace sand at 10%, 15%, and 20% in a total of 1703 kg concrete mixtures. The tests performed to evaluate waste-iron concrete quality included slump, fresh density, dry density, compressive strength, and flexural strength tests: 115 cubes of concrete were molded for the compressive strength and dry density tests, and 87 prisms were cast for the flexural strength tests. This work applied 3, 7, 14, and 28 days curing ages for the concrete mixes. The results confirm that reuse of solid waste material offers an approach to solving the pollution problems that arise from an accumulation of waste in a production site; in the meantime modified properties are added to the concrete. The results show that the concrete mixes made with waste iron had higher compressive strengths and flexural strengths than the plain concrete mixes.

Testing of concrete by laser ablation

DOEpatents

Flesher, D.J.; Becker, D.L.; Beem, W.L.; Berry, T.C.; Cannon, N.S.

1997-01-07

A method is disclosed for testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed. 1 fig.

Evaluation of repeatability of Kansas test method KT-73, "density, absorption and voids in hardened concrete," boil test.

DOT National Transportation Integrated Search

2015-06-01

For years, the Kansas Department of Transportation (KDOT) and concrete producers in the state have used a : Rapid Chloride Test for concrete cylinders, AASHTO T277. This test has been thought of as an appropriate quality : control test to evaluate pe...

Determination of Coefficient of Thermal Expansion (CTE) of 20MPa Mass Concrete Using Granite Aggregate

NASA Astrophysics Data System (ADS)

Chee Siang, GO

2017-07-01

Experimental test was carried out to determine the coefficient of thermal expansion (CTE) value of 20MPa mass concrete using granite aggregate. The CTE value was established using procedure proposed by Kada et al. 2002 in determining the magnitude of early-ages CTE through laboratory test which is a rather accurate way by eliminating any possible superimposed effect of others early-age thermal deformation shrinkages such as autogenous, carbonation, plastic and drying shrinkage. This was done by submitting granite concrete block samples instrumented with ST4 vibrating wire extensometers to thermal shocks. The response of the concrete samples to this shock results in a nearly instantaneous deformation, which are measured by the sensor. These deformations, as well as the temperature signal, are used to calculate the CTE. By repeating heat cycles, the variation in the early-ages of concrete CTE over time was monitored and assessed for a period of upto 7 days. The developed CTE value facilitating the verification and validation of actual maximum permissible critical temperature differential limit (rather than arbitrarily follow published value) of cracking potential. For thick sections, internal restraint is dominant and this is governed by differentials mainly. Of the required physical properties for thermal modelling, CTE is of paramount importance that with given appropriate internal restraint factor the condition of cracking due to internal restraint is governs by equation, ΔTmax= 3.663ɛctu / αc. Thus, it can be appreciated that an increase in CTE will lower the maximum allowable differential for cracking avoidance in mass concrete while an increase of tensile strain capacity will increase the maximum allowable temperature differential.

Assessment of optimum threshold and particle shape parameter for the image analysis of aggregate size distribution of concrete sections

NASA Astrophysics Data System (ADS)

Ozen, Murat; Guler, Murat

2014-02-01

Aggregate gradation is one of the key design parameters affecting the workability and strength properties of concrete mixtures. Estimating aggregate gradation from hardened concrete samples can offer valuable insights into the quality of mixtures in terms of the degree of segregation and the amount of deviation from the specified gradation limits. In this study, a methodology is introduced to determine the particle size distribution of aggregates from 2D cross sectional images of concrete samples. The samples used in the study were fabricated from six mix designs by varying the aggregate gradation, aggregate source and maximum aggregate size with five replicates of each design combination. Each sample was cut into three pieces using a diamond saw and then scanned to obtain the cross sectional images using a desktop flatbed scanner. An algorithm is proposed to determine the optimum threshold for the image analysis of the cross sections. A procedure was also suggested to determine a suitable particle shape parameter to be used in the analysis of aggregate size distribution within each cross section. Results of analyses indicated that the optimum threshold hence the pixel distribution functions may be different even for the cross sections of an identical concrete sample. Besides, the maximum ferret diameter is the most suitable shape parameter to estimate the size distribution of aggregates when computed based on the diagonal sieve opening. The outcome of this study can be of practical value for the practitioners to evaluate concrete in terms of the degree of segregation and the bounds of mixture's gradation achieved during manufacturing.

Factors affecting stall use for different freestall bases.

PubMed

Wagner-Storch, A M; Palmer, R W; Kammel, D W

2003-06-01

The objective of this study was to compare stall use (stall occupancy and cow position) by barn side for factors affecting stall use. A closed circuit television system recorded stall use four times per day for a 9-mo period starting May 9, 2001. Six factors were analyzed: stall base, distance to water, stall location within stall base section, stall location within barn, inside barn temperature, and length of time cows were exposed to stall bases. Two barn sides with different stocking densities were analyzed: low (66%), with cows milked by robotic milker; and high (100%), with cows milked 2X in parlor. Six stall base types were tested: two mattresses, a waterbed, a rubber mat, concrete, and sand (high side only). The base types were grouped 3 to 7 stalls/section and randomly placed in each row. Cows spent more time in mattress-based stalls, but the highest percentage lying was in sand-based stalls. The following significant stall occupancy percentages were found: sand had the highest percentage of cows lying on the high stocking density side (69%), followed by mattress type 1 (65%) > mattress type 2 (57%) > waterbed (45%) > rubber mat (33%) > concrete (23%). Mattress type 1 had the highest percentage stalls occupied (88%), followed by mattress type 2 (84%) > sand (79%) > soft rubber mat (65%) > waterbed (62%) > concrete (39%). On the low stocking rate side, mattress type 1 had the highest percentage cows lying (45%) and occupied (59.6%), followed by mattress type 2 > waterbed > soft rubber mat > concrete. Cow lying and stalls occupied percentages were highest for stalls 1) not at the end of a section, and 2) on the outside row, and varied by base type for time cows exposed to stalls and inside barn temperature. Lying and occupied percentages were different for different mattress types. The percentage of stalls with cows standing was higher for mat and mattress-based stalls. Results show mattress type 1 and sand to be superior and rubber mats and concrete inferior stall bases.

Optimizing the use of natural gravel Brantas river as normal concrete mixed with quality fc = 19.3 Mpa

NASA Astrophysics Data System (ADS)

Limantara, A. D.; Widodo, A.; Winarto, S.; Krisnawati, L. D.; Mudjanarko, S. W.

2018-04-01

The use of natural gravel (rivers) as concrete mixtures is rarely encountered after days of demands for a higher strength of concrete. Moreover, today people have found High-Performance Concrete which, when viewed from the rough aggregate consisted mostly of broken stone, although the fine grain material still used natural sand. Is it possible that a mixture of concrete using natural gravel as a coarse aggregate is capable of producing concrete with compressive strength equivalent to a concrete mixture using crushed stone? To obtain information on this, a series of tests on concrete mixes with crude aggregates of Kalitelu Crusher, Gondang, Tulungagung and natural stone (river gravel) from the Brantas River, Ngujang, Tulungagung in the Materials Testing Laboratory Tugu Dam Construction Project, Kab. Trenggalek. From concrete strength test results using coarse material obtained value 19.47 Mpa, while the compressive strength of concrete with a mixture of crushed stone obtained the value of 21.12 Mpa.

7 CFR 3201.87 - Wood and concrete stains.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false Wood and concrete stains. 3201.87 Section 3201.87... Designated Items § 3201.87 Wood and concrete stains. (a) Definition. Products that are designed to be applied as a finish for concrete and wood surfaces and that contain dyes or pigments to change the color...

7 CFR 3201.87 - Wood and concrete stains.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Wood and concrete stains. 3201.87 Section 3201.87... Designated Items § 3201.87 Wood and concrete stains. (a) Definition. Products that are designed to be applied as a finish for concrete and wood surfaces and that contain dyes or pigments to change the color...

7 CFR 2902.42 - Wood and concrete sealers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 15 2011-01-01 2011-01-01 false Wood and concrete sealers. 2902.42 Section 2902.42... Items § 2902.42 Wood and concrete sealers. (a) Definition. (1) Products that are penetrating liquids formulated to protect wood and/or concrete, including masonry and fiber cement siding, from damage caused by...

7 CFR 2902.42 - Wood and concrete sealers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 15 2010-01-01 2010-01-01 false Wood and concrete sealers. 2902.42 Section 2902.42... Items § 2902.42 Wood and concrete sealers. (a) Definition. (1) Products that are penetrating liquids formulated to protect wood and/or concrete, including masonry and fiber cement siding, from damage caused by...

Pozzolan cement study : final report.

DOT National Transportation Integrated Search

1979-12-01

An experimental section using Type 1P cement concrete was poured on an active construction project in south Louisiana, near Franklin. A comparison in quality was made between this section and the normal Type 1(B) cement concrete poured on the remaind...

Physical and mechanical properties of self-compacting concrete containing superplasticizer and metakaolin

NASA Astrophysics Data System (ADS)

Shahidan, Shahiron; Tayeh, Bassam A.; Jamaludin, A. A.; Bahari, N. A. A. S.; Mohd, S. S.; Zuki Ali, N.; Khalid, F. S.

2017-11-01

The development of concrete technology shows a variety of admixtures in concrete to produce special concrete. This includes the production of self-compacting concrete which is able to fill up all spaces, take formwork shapes and pass through congested reinforcement bars without vibrating or needing any external energy. In this study, the main objective is to compare the physical and mechanical properties of self-compacting concrete containing metakaolin with normal concrete. Four types of samples were produced to study the effect of metakaolin towards the physical and mechanical properties of self-compacting concrete where 0%, 5%, 10% and 15% of metakaolin were used as cement replacement. The physical properties were investigated using slump test for normal concrete and slump flow test for self-compacting concrete. The mechanical properties were tested for compressive strength and tensile strength. The findings of this study show that the inclusion of metakaolin as cement replacement can increase both compressive and tensile strength compared to normal concrete. The highest compressive strength was found in self-compacting concrete with 15% metakaolin replacement at 53.3 MPa while self-compacting concrete with 10% metakaolin replacement showed the highest tensile strength at 3.6 MPa. On top of that, the finishing or concrete surface of both cube and cylinder samples made of self-compacting concrete produced a smooth surface with the appearance of less honeycombs compared to normal concrete.

Investigation on Flexure Test of Composite Beam of Repair Materials and Substrate Concrete for Durable Repair

NASA Astrophysics Data System (ADS)

Pattnaik, Rashmi R.; Rangaraju, Prasada Rao

2014-12-01

An experimental study was conducted on composite beam of repair materials and substrate concrete to investigate the failures of concrete repair due to differences in strength of repair materials and substrate concrete. In this investigation the flexural strength, load-deflection curves and failure patterns of the composite beam specimens are studied for the durability of the concrete repair. Flexure test was conducted to simulate tensile stress in the concrete repair material. Compressive strength and split tensile strength of the repair materials and substrate concrete are investigated to aid in the analysis of the concrete repair. It was observed that the repair materials of higher compressive strength than the substrate concrete are causing an incompatible failure in the concrete repair.

Development of Mix Designs for RAP Concrete for Florida Concrete Test Road

DOT National Transportation Integrated Search

2017-12-01

The main objective of this study was to develop mix designs for concrete incorporating Reclaimed Asphalt Pavement (RAP) materials to be used in the Florida Concrete Test Road. Two different FDOT-approved RAP sources were selected and used in this stu...

Laboratory comparison of several tests for evaluating the transport properties of concrete.

DOT National Transportation Integrated Search

2006-01-01

The transport properties of concrete are a primary element in determining the durability of concrete. In this study, several new test methods that directly measure aspects of fluid and ionic transport in concrete were examined. ASTM C 1543 and ASTM C...

Implementation of ASTM C157: testing of length change of hardened concrete : technical summary.

DOT National Transportation Integrated Search

2016-09-01

The Kansas Department of Transportation (KDOT) has a history of using : tests such as concrete strength, permeability, and air void structure as design : and acceptance criteria on concrete paving and bridge deck projects. In 2012, : the KDOT Concret...

Numerical analysis on seismic behavior of reinforced concrete beam to concrete filled steel tubular column connections with ring-beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Yi., E-mail: zhaoyi091218@163.com; Xu, Li. Hua.

This paper presents numerical study of the seismic behavior of reinforced concrete beam to concrete filled steel tube column connections with ring-beam. The material stress-strain relations, element type and boundary condition are selected, which are consistent with actual situation. Then the seismic behavior of this type of joint are researched by ABAQUS, and finite element analyses are conducted under cyclic loading. Its parameters are discussed including thickness of steel tubular column wall, sectional dimension of the ring-beam and strength of the core concrete. The results show that the ultimate capacity of the connections is improved with sectional dimension of themore » ring-beam increased. In the meanwhile, the influence on skeleton curve of the joints is slight of which included thickness of steel tubular column wall and strength of the core concrete.« less

Rapid test methods for the evaluation of concrete properties.

DOT National Transportation Integrated Search

1982-01-01

The objective of the project was to place a CERL/Kelly-Vail testing unit and a microwave oven in the field to perform tests of plastic concrete on construction projects. : The CERL/K-V tests were to determine water and cement content of the concrete ...

Evaluation of repeatability of Kansas test method KT-73, "density, absorption and voids in hardened concrete," boil test : [technical summary].

DOT National Transportation Integrated Search

2015-06-01

For years, the Kansas Department of Transportation (KDOT) and concrete producers in : the state have used a Rapid Chloride Test for concrete cylinders, AASHTO T277. This : test has been thought of as an appropriate quality control test to evaluate pe...

Research notes : construction of rubber modified asphalt concrete (METRO RUMAC) test sections : N. Marine Drive in Portland, Oregon, S.E. Stark Street in Gresham, Oregon.

DOT National Transportation Integrated Search

1993-12-01

Government agencies are burdened with both pavement distress and solid waste disposal problems. In response to these problems, the METRO agency of the Portland urban area sponsored the development of specifications and mix design guidelines for a rub...

Properties of concrete containing coconut shell powder (CSP) as a filler

NASA Astrophysics Data System (ADS)

Leman, A. S.; Shahidan, S.; Nasir, A. J.; Senin, M. S.; Zuki, S. S. Mohd; Ibrahim, M. H. Wan; Deraman, R.; Khalid, F. S.; Azhar, A. T. S.

2017-11-01

Coconut shellsare a type of agricultural waste which can be converted into useful material. Therefore,this study was conducted to investigate the properties of concrete which uses coconut shell powder (CSP) filler material and to define the optimum percentage of CSP which can be used asfiller material in concrete. Comparisons have been made between normal concrete mixes andconcrete containing CSP. In this study, CSP was added into concrete mixes invaryingpercentages (0%, 2%, 4%, 6%, 8% and 10%). The coconut shell was grounded into afine powder before use. Experimental tests which have been conducted in this study include theslump test, compressive test and splitting tensile strength test. CSP have the potential to be used as a concrete filler and thus the findings of this study may be applied to the construction industry. The use of CSP as a filler in concrete can help make the earth a more sustainable and greener place to live in.

Polyester polymer concrete overlay.

DOT National Transportation Integrated Search

2013-01-01

Polyester polymer concrete (PPC) was used in a trial application on a section of pavement that suffers from extensive studded tire wear. The purpose of the trial section is to determine if PPC is a possible repair strategy for this type of pavement d...

Storage Area (1942 section), looking east, showing concrete structural elements ...

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

Storage Area (1942 section), looking east, showing concrete structural elements and wall opening to vaults - Fort McNair, Film Store House, Fort Lesley J. McNair, P Street between Third & Fourth Streets, Southwest, Washington, District of Columbia, DC

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

Analysis Method for Laterally Loaded Pile Groups Using an Advanced Modeling of Reinforced Concrete Sections.

PubMed

Stacul, Stefano; Squeglia, Nunziante

2018-02-15

A Boundary Element Method (BEM) approach was developed for the analysis of pile groups. The proposed method includes: the non-linear behavior of the soil by a hyperbolic modulus reduction curve; the non-linear response of reinforced concrete pile sections, also taking into account the influence of tension stiffening; the influence of suction by increasing the stiffness of shallow portions of soil and modeled using the Modified Kovacs model; pile group shadowing effect, modeled using an approach similar to that proposed in the Strain Wedge Model for pile groups analyses. The proposed BEM method saves computational effort compared to more sophisticated codes such as VERSAT-P3D, PLAXIS 3D and FLAC-3D, and provides reliable results using input data from a standard site investigation. The reliability of this method was verified by comparing results from data from full scale and centrifuge tests on single piles and pile groups. A comparison is presented between measured and computed data on a laterally loaded fixed-head pile group composed by reinforced concrete bored piles. The results of the proposed method are shown to be in good agreement with those obtained in situ.

Analysis Method for Laterally Loaded Pile Groups Using an Advanced Modeling of Reinforced Concrete Sections

PubMed Central

2018-01-01

A Boundary Element Method (BEM) approach was developed for the analysis of pile groups. The proposed method includes: the non-linear behavior of the soil by a hyperbolic modulus reduction curve; the non-linear response of reinforced concrete pile sections, also taking into account the influence of tension stiffening; the influence of suction by increasing the stiffness of shallow portions of soil and modeled using the Modified Kovacs model; pile group shadowing effect, modeled using an approach similar to that proposed in the Strain Wedge Model for pile groups analyses. The proposed BEM method saves computational effort compared to more sophisticated codes such as VERSAT-P3D, PLAXIS 3D and FLAC-3D, and provides reliable results using input data from a standard site investigation. The reliability of this method was verified by comparing results from data from full scale and centrifuge tests on single piles and pile groups. A comparison is presented between measured and computed data on a laterally loaded fixed-head pile group composed by reinforced concrete bored piles. The results of the proposed method are shown to be in good agreement with those obtained in situ. PMID:29462857

Evaluation of Durability Parameters of Concrete with Manufacture Sand and River Sand

NASA Astrophysics Data System (ADS)

Sangoju, Bhaskar; Ramesh, G.; Bharatkumar, B. H.; Ramanjaneyulu, K.

2017-09-01

Most of the states in our country have banned sand quarrying from the river beds, causing a scarcity of natural river sand for the construction sector. Manufacture sand (M-sand) is one of the alternate solutions to replace the river sand (R-sand) in concrete. The main aim of the present study is to evaluate the durability parameters of concrete with M-sand when compared to that of concrete with R-sand. Corrosion of reinforcement is one of the main deteriorating mechanisms of reinforced concrete due to the ingress of chloride ions or carbon-di-oxide. For comparative evaluation of durability parameters, accelerated tests such as Rapid Chloride Permeability Test, Rapid Chloride Migration Test and accelerated carbonation test were carried out on specimens of R-sand and M-sand. All tests were carried out after 90 days of casting. Test results reveal that the durability parameters of the concrete with M-sand in chloride induced environment is relatively better than that of concrete with R-sand and hence is recommended to use M-sand as a replacement to R-sand.

Mechanical properties of concrete containing recycled concrete aggregate (RCA) and ceramic waste as coarse aggregate replacement

NASA Astrophysics Data System (ADS)

Khalid, Faisal Sheikh; Azmi, Nurul Bazilah; Sumandi, Khairul Azwa Syafiq Mohd; Mazenan, Puteri Natasya

2017-10-01

Many construction and development activities today consume large amounts of concrete. The amount of construction waste is also increasing because of the demolition process. Much of this waste can be recycled to produce new products and increase the sustainability of construction projects. As recyclable construction wastes, concrete and ceramic can replace the natural aggregate in concrete because of their hard and strong physical properties. This research used 25%, 35%, and 45% recycled concrete aggregate (RCA) and ceramic waste as coarse aggregate in producing concrete. Several tests, such as concrete cube compression and splitting tensile tests, were also performed to determine and compare the mechanical properties of the recycled concrete with those of the normal concrete that contains 100% natural aggregate. The concrete containing 35% RCA and 35% ceramic waste showed the best properties compared with the normal concrete.

Assessing cryogenic testing of aggregates for concrete pavements

DOT National Transportation Integrated Search

1995-02-01

Damage to concrete pavements caused by freeze-thaw deterioration of concrete aggregate remains a serious problem. Current tests for determining an aggregate's freeze-thaw durability can take up to 70 days to perform and results from these tests don't...

Freeze-thaw performance testing of whole concrete railroad ties.

DOT National Transportation Integrated Search

2013-10-01

Freezing and thawing durability tests of prestressed concrete ties are normally performed according to ASTM C666 specifications. Small specimens are cut from the shoulders of concrete ties and tested through 300 cycles of freezing and thawing. Saw-cu...

Molded Concrete Center Mine Wall

NASA Technical Reports Server (NTRS)

Lewis, E. V.

1987-01-01

Proposed semiautomatic system forms concrete-foam wall along middle of coal-mine passage. Wall helps support roof and divides passage into two conduits needed for ventilation of coal face. Mobile mold and concrete-foam generator form sections of wall in place.

Application of Roller Compacted Concrete in Colorado's Roadways

DOT National Transportation Integrated Search

2012-10-01

Roller Compacted Concrete (RCC) is a no-slump concrete mixture that is transported, placed, and compacted with : the same construction equipment as asphalt pavement. RCCs were used to construct three sections of pavement in : Weld County Road 28 (WCR...

Experimental study of self-compacted concrete in hardened state

NASA Astrophysics Data System (ADS)

Parra Costa, Carlos Jose

The main aim of this work is to investigate the hardened behaviour of Self-Compacting Concrete (SCC). Self compacting Concrete is a special concrete that can flow in its gravity and fill in the formwork alone to its self-weight, passing through the bars and congested sections without the need of any internal or external vibration, while maintaining adequate homogeneity. SCC avoids most of the materials defects due to bleeding or segregation. With regard to its composition, SCC consists of the same components as traditional vibrated concrete (TC), but in different proportions. Thus, the high amount of superplasticizer and high powder content have to taken into account. The high workability of SCC does not allow to use traditional methods for measuring the fresh state properties, so new tests has developed (slump-flow, V-funnel, L-box, and others). The properties of the hardened SCC, which depend on the mix design, should be different from traditional concrete. In order to study the possible modifications of SCC hardened state properties, a review of the bibliography was done. The state of art was focused on the mechanical behaviour (compressive strength, tension strength and elastic modulus), on bond strength of reinforcement steel, and on material durability. The experimental program consisted in the production of two types of concretes: Self-Compacting Concrete and Traditional Concrete. Four different dosages was made with three different water/cement ratio and two strength types of Portland cement, in order to cover the ordinary strength used in construction. Based on this study it can be concluded that compressive strength of SCC and TC are similar (the differences are lesser than 10%), whereas the tensile strength of TC are up to 18% higher. The values of elastic modulus of both concrete are similar. On the other hand, in the ultimate state the bond strength of SCC and TC is similar, although SCC shows higher bond stiffness in the serviceability state (initial displacement). Thus SCC reaches higher average bond strength. Although the variation in bond strength at different elevations, due to top-bar effect, is also observed in SCC the extent is less significant than that of TC. Finally, tests show that water depth penetration under pressure is much lower for SCC than for TC.

Measurements and Monte-Carlo simulations of the particle self-shielding effect of B4C grains in neutron shielding concrete

NASA Astrophysics Data System (ADS)

DiJulio, D. D.; Cooper-Jensen, C. P.; Llamas-Jansa, I.; Kazi, S.; Bentley, P. M.

2018-06-01

A combined measurement and Monte-Carlo simulation study was carried out in order to characterize the particle self-shielding effect of B4C grains in neutron shielding concrete. Several batches of a specialized neutron shielding concrete, with varying B4C grain sizes, were exposed to a 2 Å neutron beam at the R2D2 test beamline at the Institute for Energy Technology located in Kjeller, Norway. The direct and scattered neutrons were detected with a neutron detector placed behind the concrete blocks and the results were compared to Geant4 simulations. The particle self-shielding effect was included in the Geant4 simulations by calculating effective neutron cross-sections during the Monte-Carlo simulation process. It is shown that this method well reproduces the measured results. Our results show that shielding calculations for low-energy neutrons using such materials would lead to an underestimate of the shielding required for a certain design scenario if the particle self-shielding effect is not included in the calculations.

Prediction model for carbonation depth of concrete subjected to freezing-thawing cycles

NASA Astrophysics Data System (ADS)

Xiao, Qian Hui; Li, Qiang; Guan, Xiao; Xian Zou, Ying

2018-03-01

Through the indoor simulation test of the concrete durability under the coupling effect of freezing-thawing and carbonation, the variation regularity of concrete neutralization depth under freezing-thawing and carbonation was obtained. Based on concrete carbonation mechanism, the relationship between the air diffusion coefficient and porosity in concrete was analyzed and the calculation method of porosity in Portland cement concrete and fly ash cement concrete was investigated, considering the influence of the freezing-thawing damage on the concrete diffusion coefficient. Finally, a prediction model of carbonation depth of concrete under freezing-thawing circumstance was established. The results obtained using this prediction model agreed well with the experimental test results, and provided a theoretical reference and basis for the concrete durability analysis under multi-factor environments.

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.

Acoustic emission monitoring of concrete columns and beams strengthened with fiber reinforced polymer sheets

NASA Astrophysics Data System (ADS)

Ma, Gao; Li, Hui; Zhou, Wensong; Xian, Guijun

2012-04-01

Acoustic emission (AE) technique is an effective method in the nondestructive testing (NDT) field of civil engineering. During the last two decades, Fiber reinforced polymer (FRP) has been widely used in repairing and strengthening concrete structures. The damage state of FRP strengthened concrete structures has become an important issue during the service period of the structure and it is a meaningful work to use AE technique as a nondestructive method to assess its damage state. The present study reports AE monitoring results of axial compression tests carried on basalt fiber reinforced polymer (BFRP) confined concrete columns and three-point-bending tests carried on BFRP reinforced concrete beams. AE parameters analysis was firstly utilized to give preliminary results of the concrete fracture process of these specimens. It was found that cumulative AE events can reflect the fracture development trend of both BFRP confined concrete columns and BFRP strengthened concrete beams and AE events had an abrupt increase at the point of BFRP breakage. Then the fracture process of BFRP confined concrete columns and BFRP strengthened concrete beams was studied through RA value-average frequency analysis. The RA value-average frequency tendencies of BFRP confined concrete were found different from that of BFRP strengthened concrete beams. The variation tendency of concrete crack patterns during the loading process was revealed.

Low Shrinkage Cement Concrete Intended for Airfield Pavements

NASA Astrophysics Data System (ADS)

Małgorzata, Linek

2017-10-01

The work concerns the issue of hardened concrete parameters improvement intended for airfield pavements. Factors which have direct or indirect influence on rheological deformation size were of particular interest. The aim of lab testing was to select concrete mixture ratio which would make hardened concrete less susceptible to influence of basic operating factors. Analyses included two research groups. External and internal factors were selected. They influence parameters of hardened cement concrete by increasing rheological deformations. Research referred to innovative cement concrete intended for airfield pavements. Due to construction operation, the research considered the influence of weather conditions and forced thermal loads intensifying concrete stress. Fresh concrete mixture parameters were tested and basic parameters of hardened concrete were defined (density, absorbability, compression strength, tensile strength). Influence of the following factors on rheological deformation value was also analysed. Based on obtained test results, it has been discovered that innovative concrete, made on the basis of modifier, which changes internal structure of concrete composite, has definitely lower values of rheological deformation. Observed changes of microstructure, in connection with reduced deformation values allowed to reach the conclusion regarding advantageous characteristic features of the newly designed cement concrete. Applying such concrete for airfield construction may contribute to extension of its operation without malfunction and the increase of its general service life.

Age differences in relationships between crystallized and fluid intelligences and problem solving.

PubMed

Hayslip, B; Sterns, H L

1979-05-01

One hundred and sixty-two subjects at three age levels were tested to examine the relationship between crystallized (Gc) and fluid (Gf) abilities and three problem solving tasks varying in the abstractness concreteness of their stimuli and emphasis on past experience. It was predicted that the difference in correlations between crystallized and fluid abilities and each of these tasks would increase with increased age. The hypotheses were partially supported in the young and elderly groups of subjects. On tasks using concrete stimuli, emphasizing past experience, where no cross-sectional decline was observed, Gc (relative to Gf) accounted for an increasing proportion of variance in performance with increased age. On tasks using abstract stimuli, de-emphasizing past experience, where significant cross-sectional declines were obtained, Gf (relative to Gc) correlated more highly with performance. Contrary to previous research, relationships between Gf and Bc supported a reintegration of abilities in old age.

Durable fiber reinforced self-compacting concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corinaldesi, V.; Moriconi, G

2004-02-01

In order to produce thin precast elements, a self-compacting concrete was prepared. When manufacturing these elements, homogenously dispersed steel fibers instead of ordinary steel-reinforcing mesh were added to the concrete mixture at a dosage of 10% by mass of cement. An adequate concrete strength class was achieved with a water to cement ratio of 0.40. Compression and flexure tests were carried out to assess the safety of these thin concrete elements. Moreover, serviceability aspects were taken into consideration. Firstly, drying shrinkage tests were carried out in order to evaluate the contribution of steel fibers in counteracting the high concrete strainsmore » due to a low aggregate-cement ratio. Secondly, the resistance to freezing and thawing cycles was investigated on concrete specimens in some cases superficially treated with a hydrophobic agent. Lastly, both carbonation and chloride penetration tests were carried out to assess durability behavior of this concrete mixture.« less

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

Monitoring the corrosion process of reinforced concrete using BOTDA and FBG sensors.

PubMed

Mao, Jianghong; Chen, Jiayun; Cui, Lei; Jin, Weiliang; Xu, Chen; He, Yong

2015-04-15

Expansion and cracking induced by the corrosion of reinforcement concrete is the major factor in the failure of concrete durability. Therefore, monitoring of concrete cracking is critical for evaluating the safety of concrete structures. In this paper, we introduce a novel monitoring method combining Brillouin optical time domain analysis (BOTDA) and fiber Bragg grating (FBG), based on mechanical principles of concrete expansion cracking. BOTDA monitors concrete expansion and crack width, while FBG identifies the time and position of cracking. A water-pressure loading simulation test was carried out to determine the relationship between fiber strain, concrete expansion and crack width. An electrical accelerated corrosion test was also conducted to evaluate the ability of this novel sensor to monitor concrete cracking under practical conditions.

A New Corrosion Sensor to Determine the Start and Development of Embedded Rebar Corrosion Process at Coastal Concrete

PubMed Central

Xu, Chen; Li, Zhiyuan; Jin, Weiliang

2013-01-01

The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate. PMID:24084117

A new corrosion sensor to determine the start and development of embedded rebar corrosion process at coastal concrete.

PubMed

Xu, Chen; Li, Zhiyuan; Jin, Weiliang

2013-09-30

The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate.

Modification of Existing Prestressed Girder Cross-Sections for the Optimal Structural Use of Ultra-High Performance Concrete

DOT National Transportation Integrated Search

2008-10-22

Ultra High Performance Concrete (UHPC) is a class of cementitious materials that share similar characteristics including very large compressive strengths, tensile strength greater than conventional concrete and high durability. The material consists ...

Compressive strength, flexural strength and water absorption of concrete containing palm oil kernel shell

NASA Astrophysics Data System (ADS)

Noor, Nurazuwa Md; Xiang-ONG, Jun; Noh, Hamidun Mohd; Hamid, Noor Azlina Abdul; Kuzaiman, Salsabila; Ali, Adiwijaya

2017-11-01

Effect of inclusion of palm oil kernel shell (PKS) and palm oil fibre (POF) in concrete was investigated on the compressive strength and flexural strength. In addition, investigation of palm oil kernel shell on concrete water absorption was also conducted. Total of 48 concrete cubes and 24 concrete prisms with the size of 100mm × 100mm × 100mm and 100mm × 100mm × 500mm were prepared, respectively. Four (4) series of concrete mix consists of coarse aggregate was replaced by 0%, 25%, 50% and 75% palm kernel shell and each series were divided into two (2) main group. The first group is without POF, while the second group was mixed with the 5cm length of 0.25% of the POF volume fraction. All specimen were tested after 7 and 28 days of water curing for a compression test, and flexural test at 28 days of curing period. Water absorption test was conducted on concrete cube age 28 days. The results showed that the replacement of PKS achieves lower compressive and flexural strength in comparison with conventional concrete. However, the 25% replacement of PKS concrete showed acceptable compressive strength which within the range of requirement for structural concrete. Meanwhile, the POF which should act as matrix reinforcement showed no enhancement in flexural strength due to the balling effect in concrete. As expected, water absorption was increasing with the increasing of PKS in the concrete cause by the porous characteristics of PKS

On the Processing of Spalling Experiments. Part I: Identification of the Dynamic Tensile Strength of Concrete

NASA Astrophysics Data System (ADS)

Forquin, P.; Lukić, B.

2017-11-01

The spalling technique based on the use of a single Hopkinson bar put in contact with the tested sample has been widely adopted as a reliable method for obtaining the tensile response of concrete and rock-like materials at strain rates up-to 200 s- 1. However, the traditional processing method, based on the use of Novikov acoustic approach and the rear face velocity measurement, remains quite questionable due to strong approximations of this data processing method. Recently a new technique for deriving cross-sectional stress fields of a spalling sample filmed with an ultra-high speed camera and based on using the full field measurements and the virtual fields method (VFM) was proposed. In the present work, this topic is perused by performing several spalling tests on ordinary concrete at high acquisition speed of 1Mfps to accurately measure the tensile strength, Young's modulus, strain-rate at failure and stress-strain response of concrete at high strain-rate. The stress-strain curves contain more measurement points for a more reliable identification. The observed tensile stiffness is up-to 50% lower than the initial compressive stiffness and the obtained peak stress was about 20% lower than the one obtained by applying the Novikov method. In order to support this claim, numerical simulations were performed to show that the change of stiffness between compression and tension highly affects the rear-face velocity profile. This further suggests that the processing based only on the velocity "pullback" is quite sensitive and can produce an overestimate of the tensile strength in concrete and rock-like materials.

Development and evaluation of vibrating Kelly Ball Test (VKelly test) for the workability of concrete.

DOT National Transportation Integrated Search

2015-03-01

Due to the low workability of slipform concrete mixtures, the science of rheology is not strictly applicable for such concrete. However, : the concept of rheological behavior may still be considered useful. A novel workability test method (Vibrating ...

Preliminary investigation on the suitablity of using fiber reinforced concrete in the construction of a hazardous waste disposal vessel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramey, M.R.; Daie-e, G.

1988-07-01

There are certain hazardous wastes that must be contained in an extremely secure vessel for transportation and disposal. The vessel, among other things, must be able to withstand relatively large impacts without rupturing. Such containment vessels therefore must be able to absorb substantial amounts of energy during an impact and still perform their function. One of the impacts that the vessel must withstand is a 30-foot fall onto an unyielding surface. For some disposal scenarios it is proposed to encase the waste in a steel enclosure which is to be surrounded by a thick layer of concrete which, in turn,more » is encased by a relatively thin steel shell. Tests on concrete in compression and flexure, including static, dynamic and impact tests, have shown that low modulus concretes tend to behave in a less brittle manner than higher modulus concretes. Tests also show that fiber reinforced concretes have significantly greater ductility, crack propagation resistance and toughness than conventional concretes. Since it is known that concrete is a reasonably brittle material, it is necessary to do impact tests on sample containment structures consisting of thin-walled metal containers having closed ends which are filled with concrete, grout, or fiber reinforced concrete. This report presents the results of simple tests aimed at observing the behavior of sample containment structures subjected to impacts due to a fall from 30 feet. 8 figs., 4 tabs.« less

Non-destructive testing techniques for the forensic engineering investigation of reinforced concrete buildings.

PubMed

Hobbs, Brian; Tchoketch Kebir, Mohamed

2007-04-11

This study describes in detail the results of a laboratory investigation where the compressive strength of 150mm side-length cubes was evaluated. Non-destructive testing (NDT) was carried out using ultrasonic pulse velocity (UPV) and impact rebound hammer (IRH) techniques to establish a correlation with the compressive strengths of compression tests. To adapt the Schmidt hammer apparatus and the ultrasonic pulse velocity tester to the type of concrete used in Algeria, concrete mix proportions that are recommended by the Algerian code were chosen. The resulting correlation curve for each test is obtained by changing the level of compaction, water/cement ratio and concrete age of specimens. Unlike other works, the research highlights the significant effect of formwork material on surface hardness of concrete where two different mould materials for specimens were used (plastic and wood). A combined method for the above two tests, reveals an improvement in the strength estimation of concrete. The latter shows more improvement by including the concrete density. The resulting calibration curves for strength estimation were compared with others from previous published literature.

Fire Resistance of Geopolymer Concretes

DTIC Science & Technology

2010-03-21

1 Project report – Grant FA23860814096, "Fire resistance of geopolymer concretes" – J. Provis, University of Melbourne 1. Background and...experimental program This project provided funding for us to carry out fire testing of geopolymer concrete specimens and associated laboratory...testing. The focus of this report will be the outcomes of the series of pilot-scale (4’×4’×6”) tests on geopolymer concrete panels, which were conducted

29 CFR 1926.704 - Requirements for precast concrete.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 8 2012-07-01 2012-07-01 false Requirements for precast concrete. 1926.704 Section 1926.704 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry...

29 CFR 1926.704 - Requirements for precast concrete.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 8 2013-07-01 2013-07-01 false Requirements for precast concrete. 1926.704 Section 1926.704 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry...

29 CFR 1926.704 - Requirements for precast concrete.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 8 2014-07-01 2014-07-01 false Requirements for precast concrete. 1926.704 Section 1926.704 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry...

29 CFR 1926.704 - Requirements for precast concrete.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 8 2011-07-01 2011-07-01 false Requirements for precast concrete. 1926.704 Section 1926.704 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry...

Friction evaluation of concrete paver blocks for airport pavement applications

NASA Technical Reports Server (NTRS)

Yager, Thomas J.

1992-01-01

The development and use of concrete paver blocks is reviewed and some general specifications for application of this type of pavement surface at airport facilities are given. Two different shapes of interlocking concrete paver blocks installed in the track surface at NASA Langley's Aircraft Landing Dynamics Facility (ALDF) are described. Preliminary cornering performance results from testing of 40 x 14 radial-belted and bias-ply aircraft tires are reviewed. These tire tests are part of a larger, ongoing joint NASA/FAA/Industry Surface Traction and Radial Tire (START) Program involving several different tire sizes. Both dry and wet surface conditions were evaluated on the two concrete paver block test surfaces and a conventional, nongrooved Portland cement concrete surface. Future test plans involving evaluation of other concrete paver block designs at the ALDF are indicated.

Concrete Durability in Harsh Environmental Conditions Exposed to Freeze Thaw Cycles

NASA Astrophysics Data System (ADS)

Hamze, Youssef

Under line Pathology of Materials; one of the environmental causes of damage effects on concrete is freeze thaw cycles, which deteriorate the concrete exposed to water in cold weather. An example of old concrete is a dam project that was built in Canada, in the early 1909-1913. This project was reconstructed in 1932, 1934 and 1972, and required renovation due to the ice abrasion with the freeze/thaw cycles. Before completing any renovation, it is required to analyze the structural stability and the concrete failures of this dam. An investigation was conducted to determine the quality of the concrete in the Piers and in the Bridge Deck Slab. It was also required to determine the basic materials' properties that constitute this project. This will improve the analysis of its stability [10]. Core samples were examined and used as test samples, for the Alkali-Silica reactivity test samples, as well as the compressive strength test, the Chloride Ion test, and the freeze thaw testing which was performed on two sets of 12 concrete core samples that were taken from different locations in the project. These locations are the representations of the age of the concrete. Thus, the age difference between the samples' two sets is four decades. Testing was performed on prisms cut from cores. ASTM C-666 procedure (A) was applied using an automatic test system [6]. It was suggested that a plan for renovation of this project should be performed after the analysis is undertaken to assess the conditions estimating the remaining life of the concrete in this project [15].

Monitoring the Corrosion Process of Reinforced Concrete Using BOTDA and FBG Sensors

PubMed Central

Mao, Jianghong; Chen, Jiayun; Cui, Lei; Jin, Weiliang; Xu, Chen; He, Yong

2015-01-01

Expansion and cracking induced by the corrosion of reinforcement concrete is the major factor in the failure of concrete durability. Therefore, monitoring of concrete cracking is critical for evaluating the safety of concrete structures. In this paper, we introduce a novel monitoring method combining Brillouin optical time domain analysis (BOTDA) and fiber Bragg grating (FBG), based on mechanical principles of concrete expansion cracking. BOTDA monitors concrete expansion and crack width, while FBG identifies the time and position of cracking. A water-pressure loading simulation test was carried out to determine the relationship between fiber strain, concrete expansion and crack width. An electrical accelerated corrosion test was also conducted to evaluate the ability of this novel sensor to monitor concrete cracking under practical conditions. PMID:25884790

Vehicle Test Facilities at Aberdeen Test Center and Yuma Test Center

DTIC Science & Technology

2012-02-27

boulders, concrete, steel 30.5 m 100 ft Corrosion Facility 27 Various corrosive environments NA NA Abrasive Mud Course 28 Sand loam 73 x 290 m 240 x...950 ft Fording Basin 30 Concrete 82 m 270 ft Underwater Fording Facility 31 Concrete 96 m 315 ft Amphibian Ramp 31 Bituminous concrete 6 x 15 m...Courses Fording Basin 97 Concrete (L x W) 67 x 25 m 220 x 82 ft Kofa Dust Course 98 Sand, Dust 3.2 km 2.0 mi Cibola Dust Course 99 Sand, Dust 6.3 km 3.9

Mechanical properties of polymer-modified porous concrete

NASA Astrophysics Data System (ADS)

Ariffin, N. F.; Jaafar, M. F. Md.; Shukor Lim, N. H. Abdul; Bhutta, M. A. R.; Hussin, M. W.

2018-04-01

In this research work, polymer-modified porous concretes (permeable concretes) using polymer latex and redispersible polymer powder with water-cement ratio of 30 %, polymer-cement ratios of 0 to 10 % and cement content of 300 kg/m3 are prepared. The porous concrete was tested for compressive strength, flexural strength, water permeability and void ratio. The cubes size of specimen is 100 mm ×100 mm × 100 mm and 150 mm × 150 mm × 150 mm while the beam size is 100 mm × 100 mm × 500 mm was prepared for particular tests. The tests results show that the addition of polymer as a binder to porous concrete gives an improvement on the strength properties and coefficient of water permeability of polymer-modified porous concrete. It is concluded from the test results that increase in compressive and flexural strengths and decrease in the coefficient of water permeability of the polymer-modified porous concrete are clearly observed with increasing of polymer-cement ratio.

Neoprene pads for capping concrete cylinders.

DOT National Transportation Integrated Search

1979-01-01

The possibility of using neoprene pads as an alternate to sulfur mortar for capping concrete specimens subjected to compression tests was investigated. In preliminary tests to determine the feasibility of the investigation, two batches of concrete we...

Performance of self-consolidating concrete in prestressed girders.

DOT National Transportation Integrated Search

2010-04-01

A structural investigation of self-consolidating concrete (SCC) in AASHTO Type I precast, : prestressed girders was performed. Six test girders were subjected to transfer length and : flexural testing. Three separate concrete mixtures, two girders pe...

Study of the lateral pressure of fresh concrete as related to the design of drilled shafts.

DOT National Transportation Integrated Search

1983-11-01

A series of tests were conducted to determine the effect of the consistency of : concrete, as measured by the slump test, on the lateral pressure of concrete. : Testing conditions simulated the construction of drilled shafts as practiced by the : Tex...

Role of reinforcement couplers in serviceability performance of concrete members

NASA Astrophysics Data System (ADS)

Ng, P. L.; Guan, G. X.; Kwan, A. K. H.

2017-10-01

Connection of reinforcing bars by couplers is a common form of reinforcement splicing. However, the variation of stiffness at the location of couplers and the potentially excessive residual slips are suspected to cause adverse impact on the serviceability, especially for structural members subjected to repeated loading. This paper studies the role of couplers in the serviceability performance of concrete members. Relevant provisions in design codes are reviewed and compared. Laboratory tests are conducted to investigate the slip behaviour of couplers. A section analysis approach based on equivalent stiffness model is proposed to account for the effects of couplers, and formulations of crack width calculation are explored for use in structural design.

Locating and characterizing a crack in concrete with diffuse ultrasound: A four-point bending test.

PubMed

Larose, Eric; Obermann, Anne; Digulescu, Angela; Planès, Thomas; Chaix, Jean-Francois; Mazerolle, Frédéric; Moreau, Gautier

2015-07-01

This paper describes an original imaging technique, named Locadiff, that benefits from the diffuse effect of ultrasound waves in concrete to detect and locate mechanical changes associated with the opening of pre-existing cracks, and/or to the development of diffuse damage at the tip of the crack. After giving a brief overview of the theoretical model to describe the decorrelation of diffuse waveforms induced by a local change, the article introduces the inversion procedure that produces the three dimensional maps of density of changes. These maps are interpreted in terms of mechanical changes, fracture opening, and damage development. In addition, each fracture is characterized by its effective scattering cross section.

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.

The nondestructive evaluation of high temperature conditioned concrete in conjunction with acoustic emission and x-ray computed tomography

NASA Astrophysics Data System (ADS)

Su, Yu-Min; Hou, Tsung-Chin; Lin, Li-Chiang; Chen, Gwan-Ying; Pan, Huang-Hsing

2016-04-01

Portland Cement Concrete plays a vital part of protecting structural rebars or steels when high-temperature fire incidents occur, that induces loss of evaporate water, dehydration of CH, and deconstruction of C-S-H. The objective of the study was to assess fire-damaged concrete in conjunction with nondestructive evaluation methods of acoustic emission, visual inspections, and X-ray computed tomography. The experimental program was to mix an Ordinary Portland Cement concrete firstly. Concrete cylinders with twenty-day moisture cure were treated in a furnace with 400 and 600°C for one hour. After temperature is cooled down, the concrete cylinders were brought to air or moisture re-curing for ten days. Due to the incident of the furnace, acoustic emission associated with splitting tensile strength test was not able to continue. Future efforts are planned to resume this unfinished task. However, two proposed tasks were executed and completed, namely visual inspections and voids analysis on segments obtained from X-ray CT facility. Results of visual inspections on cross-sectional and cylindrical length of specimens showed that both aggregates and cement pastes turned to pink or red at 600°C. More surface cracks were generated at 600°C than that at 400°C. On the other hand, voids analysis indicated that not many cracks were generated and voids were remedied at 400°C. However, a clear tendency was found that remedy by moisture curing may heal up to 2% voids of the concrete cylinder that was previously subject to 600°C of high temperature conditioning.

Strength and deformability of compressed concrete elements with various types of non-metallic fiber and rods reinforcement under static loading

NASA Astrophysics Data System (ADS)

Nevskii, A. V.; Baldin, I. V.; Kudyakov, K. L.

2015-01-01

Adoption of modern building materials based on non-metallic fibers and their application in concrete structures represent one of the important issues in construction industry. This paper presents results of investigation of several types of raw materials selected: basalt fiber, carbon fiber and composite fiber rods based on glass and carbon. Preliminary testing has shown the possibility of raw materials to be effectively used in compressed concrete elements. Experimental program to define strength and deformability of compressed concrete elements with non-metallic fiber reinforcement and rod composite reinforcement included design, manufacture and testing of several types of concrete samples with different types of fiber and longitudinal rod reinforcement. The samples were tested under compressive static load. The results demonstrated that fiber reinforcement of concrete allows increasing carrying capacity of compressed concrete elements and reducing their deformability. Using composite longitudinal reinforcement instead of steel longitudinal reinforcement in compressed concrete elements insignificantly influences bearing capacity. Combined use of composite rod reinforcement and fiber reinforcement in compressed concrete elements enables to achieve maximum strength and minimum deformability.

Durability of coconut shell powder (CSP) concrete

NASA Astrophysics Data System (ADS)

Leman, A. S.; Shahidan, S.; Senin, M. S.; Shamsuddin, S. M.; Anak Guntor, N. A.; Zuki, S. S. Mohd; Khalid, F. S.; Azhar, A. T. S.; Razak, N. H. S.

2017-11-01

The rising cost of construction in developing countries like Malaysia has led concrete experts to explore alternative materials such as coconut shells which are renewable and possess high potential to be used as construction material. Coconut shell powder in varying percentages of1%, 3% and 5% was used as filler material in concrete grade 30 and evaluated after a curing period of 7 days and 28days respectively. Compressive strength, water absorption and carbonation tests were conducted to evaluate the strength and durability of CSP concrete in comparison with normal concrete. The test results revealed that 1%, 3% and 5% of CSP concrete achieved a compressive strength of 47.65 MPa, 45.6 MPa and 40.55% respectively. The rate of water absorption of CSP concrete was recorded as 3.21%, 2.47%, and 2.73% for 1%, 3% and 5% of CSP concrete respectively. Although CSP contained a carbon composition of 47%, the carbonation test showed that CSP no signs of carbon were detected inside the concrete. To conclude, CSP offers great prospects as it demonstrated relatively high durability as a construction material.

The behavioural patterns and neural correlates of concrete and abstract verb processing in aphasia: A novel verb semantic battery.

PubMed

Alyahya, Reem S W; Halai, Ajay D; Conroy, Paul; Lambon Ralph, Matthew A

2018-01-01

Typically, processing is more accurate and efficient for concrete than abstract concepts in both healthy adults and individuals with aphasia. While, concreteness effects have been thoroughly documented with respect to noun processing, other words classes have received little attention despite tending to be less concrete than nouns. The aim of the current study was to explore concrete-abstract differences in verbs and identify their neural correlates in post-stroke aphasia. Given the dearth of comprehension tests for verbs, a battery of neuropsychological tests was developed in this study to assess the comprehension of concrete and abstract verbs. Specifically, a sensitive verb synonym judgment test was generated that varied both the items' imageability and frequency, and a picture-to-word matching test with numerous concrete verbs. Normative data were then collected and the tests were administered to a cohort of 48 individuals with chronic post-stroke aphasia to explore the behavioural patterns and neural correlates of verb processing. The results revealed significantly better comprehension of concrete than abstract verbs, aligning with the existing aphasiological literature on noun processing. In addition, the patients performed better during verb comprehension than verb production. Lesion-symptom correlational analyses revealed common areas that support processing of concrete and abstract verbs, including the left anterior temporal lobe, posterior supramarginal gyrus and superior lateral occipital cortex. A direct contrast between them revealed additional regions with graded differences. Specifically, the left frontal regions were associated with processing abstract verbs; whereas, the left posterior temporal and occipital regions were associated with processing concrete verbs. Moreover, overlapping and distinct neural correlates were identified in association with the comprehension and production of concrete verbs. These patient findings align with data from functional neuroimaging and neuro-stimulation, and existing models of language organisation.

Mechanical behaviour of fibre reinforced concrete using soft - drink can

NASA Astrophysics Data System (ADS)

Ilya, J.; Cheow Chea, C.

2017-11-01

This research was carried out to study the behaviour of concrete, specifically compressive and flexural strength, by incorporating recycled soft drink aluminium can as fibre reinforcement in the concrete. Another aim of the research is to determine the maximum proportion of fibres to be added in the concrete. By following standard mix design, Ordinary Portland Cement (OPC) concrete was made to have a target mean strength of 30 N/mm2 with not more than 30 mm of slump. Having the same workability, OPC concrete with 0%, 1% and 2% of soft drink can aluminium fibre was prepared based on weight of cement. The specimens were tested for compressive strength and flexural strength. Laboratory test results based on short term investigation reveals that the compressive strength and flexural strength of concrete containing fibre are higher than of normal OPC concrete. Among two volume fractions, concrete with 1% of soft drink can fibre have performed better result in compressive strength and flexural strength compared with 2% amount of soft drink can fibre. The optimum proportion of aluminium fibre to be added in the concrete as fibre reinforcement is 1% fibre content by weight of cement which gave all the positive response from all the tests conducted.

23. Cross section of newly completed concrete channel and trestle ...

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

23. Cross section of newly completed concrete channel and trestle supported steel flume, 1919. Courtesy of the Mandeville Department of Special Collections, Central Library, University of California, San Diego. - Lake Hodges Flume, Along San Dieguito River between Lake Hodges & San Dieguito Reservoir, Rancho Santa Fe, San Diego County, CA

In Situ Electrosynthesis of Polymethyl Methacrylate Within Ceramic Launch Pad Materials

NASA Technical Reports Server (NTRS)

Acevedo, Raul; Cardenas, Henry

2012-01-01

Electrokinetic deposition of methylmethacrylate is used to mitigate corrosion in reinforced concrete. The methylmethacrylate (MMA) monomer deposits in the pores in the concrete where it is converted into its polymer, polymethylmethacrylate, thus creating a barrier that also enhances the mechanical properties of the concrete. Previous to the MMA treatment an Electrokinetic deposition is used to transport calcium, sodium and potassium hydroxide particles through the capillary pores of concrete directly to the concrete reinforcement. The intent is to use these compounds as a sacrificial electrode layer during the electrokinetic deposition of methylmethacrylate monomer. Cylindrical reinforced concrete specimens were subjected to electrokinetic treatment and the specimens were tested to characterize porosity reduction and tensile splitting strength showing an increase in the tensile strength. In addition, nine specimens treated electro-kinetically and in long-term atmospheric exposure testing at NASA's Kennedy Space Center, seaside atmospheric exposure test site were tested to determine their corrosion rate.

Influence of bottom ash of palm oil on compressive strength of concrete

NASA Astrophysics Data System (ADS)

Saputra, Andika Ade Indra; Basyaruddin, Laksono, Muhamad Hasby; Muntaha, Mohamad

2017-11-01

The technological development of concrete demands innovation regarding the alternative material as a part of the effort in improving quality and minimizing reliance on currently used raw materials such as bottom ash of palm oil. Bottom ash known as domestic waste stemming from palm oil cultivation in East Kalimantan contains silica. Like cement in texture and size, bottom ash can be mixed with concrete in which the silica in concrete could help increase the compressive strength of concrete. This research was conducted by comparing between normal concrete and concrete containing bottom ash as which the materials were apart of cement replacement. The bottom ash used in this research had to pass sieve size (#200). The composition tested in this research involved ratio between cement and bottom ash with the following percentages: 100%: 0%, 90%: 10%, 85%: 15% and 80%: 20%. Planned to be within the same amount of compressive strength (fc 25 MPa), the compressive strength of concrete was tested at the age of 7, 14, and 28 days. Research result shows that the addition of bottom ash to concrete influenced workability in concrete, but it did not significantly influence the compressive strength of concrete. Based on the result of compressive strength test, the optimal compressive strength was obtained from the mixture of 100% cement and 0% bottom ash.

40 CFR 761.79 - Decontamination standards and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... disassembled electrical equipment), concrete, and non-porous surfaces covered with a porous surface, such as... person decontaminating porous surfaces other than concrete under paragraph (b)(4) of this section and non..., concrete, or non-porous surfaces. (1) The decontamination standard for water containing PCBs is: (i) Less...

40 CFR 761.79 - Decontamination standards and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... disassembled electrical equipment), concrete, and non-porous surfaces covered with a porous surface, such as... person decontaminating porous surfaces other than concrete under paragraph (b)(4) of this section and non..., concrete, or non-porous surfaces. (1) The decontamination standard for water containing PCBs is: (i) Less...

40 CFR 761.79 - Decontamination standards and procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... disassembled electrical equipment), concrete, and non-porous surfaces covered with a porous surface, such as... person decontaminating porous surfaces other than concrete under paragraph (b)(4) of this section and non..., concrete, or non-porous surfaces. (1) The decontamination standard for water containing PCBs is: (i) Less...

40 CFR 761.79 - Decontamination standards and procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... disassembled electrical equipment), concrete, and non-porous surfaces covered with a porous surface, such as... person decontaminating porous surfaces other than concrete under paragraph (b)(4) of this section and non..., concrete, or non-porous surfaces. (1) The decontamination standard for water containing PCBs is: (i) Less...

40 CFR 761.79 - Decontamination standards and procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... disassembled electrical equipment), concrete, and non-porous surfaces covered with a porous surface, such as... person decontaminating porous surfaces other than concrete under paragraph (b)(4) of this section and non..., concrete, or non-porous surfaces. (1) The decontamination standard for water containing PCBs is: (i) Less...

Study on Mechanical Properties of Concrete Using Plastic Waste as an Aggregate

NASA Astrophysics Data System (ADS)

Jaivignesh, B.; Sofi, A.

2017-07-01

Disposal of large quantity of plastic causes land, water and air pollution etc.., so a study is conducted to recycle the plastic in concrete. This work investigates about the replacement of natural aggregate with non-biodegradable plastic aggregate made up of mixed plastic waste in concrete. Several tests are conducted such as compressive strength of cube, split tensile strength of cylinder, flexural strength test of prism to identify the properties and behavior of concrete using plastic aggregate. Replacement of fine aggregate weight by 10%, 15%, 20% with Plastic fine (PF) aggregate and for each replacement of fine aggregate 15%, 20%, 25% of coarse aggregate replacement also conducted with Plastic Coarse(PC) aggregate. In literatures reported that the addition of plastic aggregate in concrete causes the reduction of strength in concrete due to poor bonding between concrete and plastic aggregate, so addition of 0.3% of steel fiber by weight of cement in concrete is done to improve the concrete strength. Totally 60 cubes, 60 cylinders and 40 prisms are casted to identify the compressive strength, split tensile strength and flexural strength respectively. Casted specimens are tested at 7 and 28 days. The identified results from concrete using plastic aggregate are compared with conventional concrete. Result shows that reduction in mechanical properties of plastic aggregate added concrete. This reduction in strength is mainly due to poor bond strength between cement and plastic aggregate.

Underwater Concrete Inspection Equipment

DTIC Science & Technology

1991-04-01

nondestructive testing of con- crete waterfront structures. One instrument is a magnetic rebar locator that locates rebar in concrete structures and measures the...amount of con- crete cover over the rebar . Another instrument is a rebound hammer that measures the surface hardness of the concrete . The third...development of three specialized instruments for the underwater nondestructive testing or concrete waterfront structures. One instrument is a magnetic rebar

Improving Non-Destructive Concrete Strength Tests Using Support Vector Machines

PubMed Central

Shih, Yi-Fan; Wang, Yu-Ren; Lin, Kuo-Liang; Chen, Chin-Wen

2015-01-01

Non-destructive testing (NDT) methods are important alternatives when destructive tests are not feasible to examine the in situ concrete properties without damaging the structure. The rebound hammer test and the ultrasonic pulse velocity test are two popular NDT methods to examine the properties of concrete. The rebound of the hammer depends on the hardness of the test specimen and ultrasonic pulse travelling speed is related to density, uniformity, and homogeneity of the specimen. Both of these two methods have been adopted to estimate the concrete compressive strength. Statistical analysis has been implemented to establish the relationship between hammer rebound values/ultrasonic pulse velocities and concrete compressive strength. However, the estimated results can be unreliable. As a result, this research proposes an Artificial Intelligence model using support vector machines (SVMs) for the estimation. Data from 95 cylinder concrete samples are collected to develop and validate the model. The results show that combined NDT methods (also known as SonReb method) yield better estimations than single NDT methods. The results also show that the SVMs model is more accurate than the statistical regression model. PMID:28793627

Coatings, sealants and filters to address bridge concrete deterioration and aesthetics : Phase I.

DOT National Transportation Integrated Search

2006-06-01

The study addresses experimental evaluation and testing of concrete coatings for maintenance purposes on structural (steel reinforced) concrete. The test methods employed are intended to identify coatings and sealers for eventual incorporation into a...

Report of concrete pavement evaluation : project 105 C-4181-01 Donahoo Road, Wyandotte County.

DOT National Transportation Integrated Search

2013-12-01

The physical properties of hardened concrete cores and fresh concrete test results were compared with aggregate : gradation workability differences. The concrete cores were taken from a rural two-lane concrete road in northeastern Kansas : constructe...

Lightweight Concrete : Mechanical Properties : TechBrief

DOT National Transportation Integrated Search

2013-06-01

There is a limited amount of test data on the mechanical properties of high-strength lightweight concrete (LWC) with a concrete unit weight (wc) between that of traditional LWC and normal weight concrete (NWC). Concrete with a wc in this range is als...

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.

[Effect of concreteness of target words on verbal working memory: an evaluation using Japanese version of reading span test].

PubMed

Kondo, H; Osaka, N

2000-04-01

Effects of concreteness and representation mode (kanji/hiragana) of target words on working memory during reading was tested using Japanese version of reading span test (RST), developed by Osaka and Osaka (1994). Concreteness and familiarity of target words and difficulty of sentences were carefully controlled. The words with high concreteness resulted in significantly higher RST scores, which suggests the high efficiency of working memory in processing these words. The results suggest that high concrete noun-words associated with visual clues consume less working memory capacity during reading. The effect of representation mode is different between subjects with high-RST and low-RST scores. Characteristic of the high concrete words that may be responsible for the effectiveness of processing are discussed.

Non-traditional shape GFRP rebars for concrete reinforcement

NASA Astrophysics Data System (ADS)

Claure, Guillermo G.

The use of glass-fiber-reinforced-polymer (GFRP) composites as internal reinforcement (rebars) for concrete structures has proven to be an alternative to traditional steel reinforcement due to significant advantages such as magnetic transparency and, most importantly, corrosion resistance equating to durability and structural life extension. In recent years, the number of projects specifying GFRP reinforcement has increased dramatically leading the construction industry towards more sustainable practices. Typically, GFRP rebars are similar to their steel counterparts having external deformations or surface enhancements designed to develop bond to concrete, as well as having solid circular cross-sections; but lately, the worldwide composites industry has taken advantage of the pultrusion process developing GFRP rebars with non-traditional cross-sectional shapes destined to optimize their mechanical, physical, and environmental attributes. Recently, circular GFRP rebars with a hollow-core have also become available. They offer advantages such as a larger surface area for improved bond, and the use of the effective cross-sectional area that is engaged to carry load since fibers at the center of a solid cross-section are generally not fully engaged. For a complete understanding of GFRP rebar physical properties, a study on material characterization regarding a quantitative cross-sectional area analysis of different GFRP rebars was undertaken with a sample population of 190 GFRP specimens with rebar denomination ranging from #2 to #6 and with different cross-sectional shapes and surface deformations manufactured by five pultruders from around the world. The water displacement method was applied as a feasible and reliable way to conduct the investigation. In addition to developing a repeatable protocol for measuring cross-sectional area, the objectives of establishing critical statistical information related to the test methodology and recommending improvements to existing provisions and standards allowing for a consistent universal norm for all GFRP rebars were reached. This dissertation also presents an evaluation of the structural behavior of reinforced concrete (RC) beams and slabs using the new type of GFRP rebar consisting of a non-traditional hollow-core shape compared to "traditional" solid round rebars with equivalent cross-sectional areas within the framework of two studies, respectively. To validate the design assumptions following ACI 440.1R design guidelines, two conditions were investigated: under-reinforced (failure controlled by rupture of GFRP rebar); and, over-reinforced (failure controlled by crushing of concrete). For comparison, a cyclic three-point bending load test matrix was developed: for beams, 3 under-reinforced and 3 over-reinforced with hollow-core and solid GFRP rebars, respectively, making a total of 12 RC specimens; for slabs, 3 under-reinforced and 3 over-reinforced with hollow-core and 2 types of solid GFRP rebars, respectively, making a total of 18 RC slabs. The studies on GFRP RC beams and slabs concluded that the hollow-core GFRP rebars were as effective as their solid counterpart and ACI 440.1R design guidelines were applicable to predict their performance. It was shown that final design may be controlled by the permissible deflections as governing parameter for elements under service conditions. Also, a final study with a test matrix containing six extra specimens was generated for post-fire residual strength evaluation of fire-exposed GFRP RC slabs along with temperature gradient in the slabs and dynamic mechanical analysis (DMA) investigation on GFRP samples extracted from the fire-exposed slabs. In this study, the ability of GFRP RC slabs to retain structural integrity during a standards fire exposure as well as determining the residual structural capacity were investigated. The residual strength evaluation of the fire-exposed slabs showed a range of results varying between +/- 10%, of the virgin slabs. And, 19 mm (0.75 in.) cover with normal weight concrete was shown to be adequate to provide the necessary fire protection to the GFRP rebars preventing irreversible damage for two-hour fire rated GFRP RC slabs subjected to service loads; also, from the DMA and glass transition temperature of samples extracted from the GFRP rebars, it is inferred that the resin had undergone a post curing phase.

Air void analyzer for plastic concrete : technical summary report.

DOT National Transportation Integrated Search

2008-11-01

The best protection against freeze-thaw cycles in concrete is to have a good air void : system. Although microscopic, concrete is a porous material. Conventional field tests, : the volumetric or pressure tests, only provide the volume of air voids in...

Concrete pavement quality control testing requirements needed for the super air meter : final report.

DOT National Transportation Integrated Search

2016-10-01

Concrete freeze-thaw durability is prominently linked to the air void system within the concrete. : Concrete pavements in Kansas undergo repetitive freeze-thaw cycles. Total air content measurements : currently used on fresh concrete do not provide a...

Concrete pavement quality control testing requirements needed for the super air meter : technical summary.

DOT National Transportation Integrated Search

2016-10-01

Concrete freeze-thaw durability is prominently linked to the air void system : within the concrete. Concrete pavements in Kansas undergo repetitive : freeze-thaw cycles. Total air content measurements currently used on fresh : concrete do not provide...

Strength of masonry blocks made with recycled concrete aggregates

NASA Astrophysics Data System (ADS)

Matar, Pierre; Dalati, Rouba El

The idea of recycling concrete of demolished buildings aims at preserving the environment. Indeed, the reuse of concrete as aggregate in new concrete mixes helped to reduce the expenses related to construction and demolition (C&D) waste management and, especially, to protect the environment by reducing the development rate of new quarries. This paper presents the results of an experimental study conducted on masonry blocks containing aggregates resulting from concrete recycling. The purpose of this study is to investigate the effect of recycled aggregates on compressive strength of concrete blocks. Tests were performed on series of concrete blocks: five series each made of different proportions of recycled aggregates, and one series of reference blocks exclusively composed of natural aggregates. Tests showed that using recycled aggregates with addition of cement allows the production of concrete blocks with compressive strengths comparable to those obtained on concrete blocks made exclusively of natural aggregates.

LOFT, TAN650. Camera facing southeast. From left to right: stack ...

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

LOFT, TAN-650. Camera facing southeast. From left to right: stack in distance, pre-amp wing, dome, north side of loft "service building." Note poured concrete wall of pre-amp wing on lower section; pumice block above. Date: May 2004. INEEL negative no. HD-39-19-3 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Test method research on weakening interface strength of steel - concrete under cyclic loading

NASA Astrophysics Data System (ADS)

Liu, Ming-wei; Zhang, Fang-hua; Su, Guang-quan

2018-02-01

The mechanical properties of steel - concrete interface under cyclic loading are the key factors affecting the rule of horizontal load transfer, the calculation of bearing capacity and cumulative horizontal deformation. Cyclic shear test is an effective method to study the strength reduction of steel - concrete interface. A test system composed of large repeated direct shear test instrument, hydraulic servo system, data acquisition system, test control software system and so on is independently designed, and a set of test method, including the specimen preparation, the instrument preparation, the loading method and so on, is put forward. By listing a set of test results, the validity of the test method is verified. The test system and the test method based on it provide a reference for the experimental study on mechanical properties of steel - concrete interface.

Stiffness analysis of glued connection of the timber-concrete structure

NASA Astrophysics Data System (ADS)

Daňková, Jana; Mec, Pavel; Majstríková, Tereza

2016-01-01

This paper presents results of experimental and mathematical analysis of stiffness characteristics of a composite timber-concrete structure. The composite timberconcrete structure presented herein is non-typical compared to similar types of building structures. The interaction between the timber and concrete part of the composite cross-section is not based on metal connecting elements, but it is ensured by a glued-in perforated mesh made of plywood. The paper presents results of experimental and mathematical analysis for material alternatives of the solution of the glued joint. The slip modulus values were determined experimentally. Data obtained from the experiment evaluated by means of regression analysis. Test results were also used as input data for the compilation of a 3D model of a composite structure by means of the 3D finite element model. On the basis of result evaluation, it can be stated that the stress-deformation behaviour at shear loading of this specific timber-concrete composite structure can be affected by the type of glue used. Parameters of the 3D model of both alternative of the structure represent well the behaviour of the composite structure and the model can be used for predicting design parameters of a building structure.

Report of concrete pavement evaluation : project 105 C-4181-01 Donahoo Road, Wyandotte County : [technical summary].

DOT National Transportation Integrated Search

2013-12-01

The physical properties of hardened concrete cores and fresh concrete test results were compared with aggregate gradation workability differences. The concrete cores were taken from a rural two-lane concrete road in northeastern Kansas constructed in...

Corrosion Behavior of Steel Reinforcement in Concrete with Recycled Aggregates, Fly Ash and Spent Cracking Catalyst.

PubMed

Gurdián, Hebé; García-Alcocel, Eva; Baeza-Brotons, Francisco; Garcés, Pedro; Zornoza, Emilio

2014-04-21

The main strategy to reduce the environmental impact of the concrete industry is to reuse the waste materials. This research has considered the combination of cement replacement by industrial by-products, and natural coarse aggregate substitution by recycled aggregate. The aim is to evaluate the behavior of concretes with a reduced impact on the environment by replacing a 50% of cement by industrial by-products (15% of spent fluid catalytic cracking catalyst and 35% of fly ash) and a 100% of natural coarse aggregate by recycled aggregate. The concretes prepared according to these considerations have been tested in terms of mechanical strengths and the protection offered against steel reinforcement corrosion under carbonation attack and chloride-contaminated environments. The proposed concrete combinations reduced the mechanical performance of concretes in terms of elastic modulus, compressive strength, and flexural strength. In addition, an increase in open porosity due to the presence of recycled aggregate was observed, which is coherent with the changes observed in mechanical tests. Regarding corrosion tests, no significant differences were observed in the case of the resistance of these types of concretes under a natural chloride attack. In the case of carbonation attack, although all concretes did not stand the highly aggressive conditions, those concretes with cement replacement behaved worse than Portland cement concretes.

Promoting the use of crumb rubber concrete in developing countries.

PubMed

Batayneh, Malek K; Marie, Iqbal; Asi, Ibrahim

2008-11-01

The use of accumulated waste materials in third world countries is still in its early phases. It will take courage for contractors and others in the construction industry to recycle selected types of waste materials in the concrete mixes. This paper addresses the recycling of rubber tires accumulated every year in Jordan to be used in concrete mixes. The main objectives of this research were to provide more scientific evidence to support the use of legislation or incentive-based schemes to promote the reuse of accumulated waste tires. This research focused on using crumb tires as a replacement for a percentage of the local fine aggregates used in the concrete mixes in Jordan. Different concrete specimens were prepared and tested in terms of uniaxial compression and splitting tension. The main variable in the mixture was the volumetric percentage of crumb tires used in the mix. The test results showed that even though the compressive strength is reduced when using the crumb tires, it can meet the strength requirements of light weight concrete. In addition, test results and observations indicated that the addition of crumb rubber to the mix has a limited effect toward reducing the workability of the mixtures. The mechanical test results demonstrated that the tested specimens of the crumb rubber concrete remained relatively intact after failure compared to the conventional concrete specimens. It is also concluded that modified concrete would contribute to the disposal of the non-decaying scrap tires, since the amount being accumulated in third world countries is creating a challenge for proper disposal. Thus, obliging authorities to invest in facilitating the use of waste tires in concrete, a fundamental material to the booming construction industry in theses countries, serves two purposes.

Assessment of technical condition of concrete pavement by the example of district road

NASA Astrophysics Data System (ADS)

Linek, M.; Nita, P.; Żebrowski, W.; Wolka, P.

2018-05-01

The article presents the comprehensive assessment of concrete pavement condition. Analyses included the district road located in the swietokrzyskie province, used for 11 years. Comparative analyses were conducted twice. The first analysis was carried out after 9 years of pavement operation, in 2015. In order to assess the extent of pavement degradation, the tests were repeated in 2017. Within the scope of field research, the traffic intensity within the analysed road section was determined. Visual assessment of pavement condition was conducted, according to the guidelines included in SOSN-B. Visual assessment can be extended by ground-penetrating radar measurements which allow to provide comprehensive assessment of the occurred structure changes within its entire thickness and length. The assessment included also performance parameters, i.e. pavement regularity, surface roughness and texture. Extension of test results by the assessment of changes in internal structure of concrete composite and structure observations by means of Scanning Electron Microscope allow for the assessment of parameters of internal structure of hardened concrete. Supplementing the observations of internal structure by means of computed tomography scan provides comprehensive information of possible discontinuities and composite structure. According to the analysis of the obtained results, conclusions concerning the analysed pavement condition were reached. It was determined that the pavement is distinguished by high performance parameters, its condition is good and it does not require any repairs. Maintenance treatment was suggested in order to extend the period of proper operation of the analysed pavement.

Performance Assessment of Refractory Concrete Used on the Space Shuttle's Launch Pad

NASA Technical Reports Server (NTRS)

Trejo, David; Calle, Luz Marina; Halman, Ceki

2005-01-01

The John F. Kennedy Space Center (KSC) maintains several facilities for launching space vehicles. During recent launches it has been observed that the refractory concrete materials that protect the steel-framed flame duct are breaking away from this base structure and are being projected at high velocities. There is significant concern that these projected pieces can strike the launch complex or space vehicle during the launch, jeopardizing the safety of the mission. A qualification program is in place to evaluate the performance of different refractory concretes and data from these tests have been used to assess the performance of the refractory concretes. However, there is significant variation in the test results, possibly making the existing qualification test program unreliable. This paper will evaluate data from past qualification tests, identify potential key performance indicators for the launch complex, and will recommend a new qualification test program that can be used to better qualify refractory concrete.

Plastometry for the Self-Compacting Concrete Mixes

NASA Astrophysics Data System (ADS)

Lapsa, V. Ā.; Krasnikovs, A.; Lusis, V.; Lukasenoks, A.

2015-11-01

Operative determination of consistence of self-compacting concrete mixes at plant or in construction conditions is an important problem in building practice. The Abram's cone, the Vebe's device, the U-box siphon, L-box or funnel tests are used in solving this problem. However, these field methods are targeted at determination of some indirect parameters of such very complicated paste-like material like concrete mix. They are not physical characteristics suitable for the rheological calculations of the coherence between the stress and strains, flow characteristics and the reaction of the concrete mix in different technological processes. A conical plastometer having higher precision and less sensitive to the inaccuracy of the tests in construction condition has been elaborated at the Concrete Mechanics Laboratory of RTU. In addition, a new method was elaborated for the calculation of plasticity limit τ0 taking into account the buoyancy force of the liquid or non-liquid concrete mix. In the present investigation rheological test of the concrete mix by use the plastometer and the method mentioned earlier was conducted for different self-compacting and not self-compacting concrete mixes.

Development of acoustic emission evaluation method for repaired prestressed concrete bridge girders.

DOT National Transportation Integrated Search

2011-06-01

Acoustic emission (AE) monitoring has proven to be a useful nondestructive testing tool in ordinary reinforced concrete beams. Over the past decade, however, the technique has also been used to test other concrete structures. It has been seen that ac...

CRASH TEST AND EVALUATION OF RESTRAINED SAFETY-SHAPE CONCRETE BARRIERS ON CONCRETE BRIDGE DECK

DOT National Transportation Integrated Search

2018-01-01

This research designed and tested a new portable concrete barrier that meets the performance of MASH TL-4 and can be used in temporary and permanent applications on bridge decks. Additionally, this new barrier system will minimize deflection, allowin...

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... asphalt) and the container (e.g., wood or metal forms, truck beds, roller surfaces). (b) Minimum biobased...

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... asphalt) and the container (e.g., wood or metal forms, truck beds, roller surfaces). (b) Minimum biobased...

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... asphalt) and the container (e.g., wood or metal forms, truck beds, roller surfaces). (b) Minimum biobased...

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... asphalt) and the container (e.g., wood or metal forms, truck beds, roller surfaces). (b) Minimum biobased...

The Effect of Adding PET (Polyethylen Terephthalate) Plastic Waste on SCC (Self-Compacting Concrete) to Fresh Concrete Behavior and Mechanical Characteristics

NASA Astrophysics Data System (ADS)

Aswatama W, K.; Suyoso, H.; Meyfa U, N.; Tedy, P.

2018-01-01

To study the effect PET waste plastics on SCC then PET plastic waste content for SCC is made into 2.5%; 5%; 7.5%; and 10%. As reference concrete is made SCC with 0% PET level. The results on all fresh concrete test items indicate that for all PET waste levels made are meeting the criteria as SCC. The effect of adding PET to fresh concrete behavior on all test items shows that the filling ability and passing ability of concrete work increases with increasing of PET. However, the increase in PET will decrease its mechanical properties. The result of heat test shows that the mechanical properties of concrete (compressive strength, splitting, and elastic modulus) after heating at 250°C temperature has not changed, while at 600°C has significant capacity decline. To clarify the differences between SCC before and after heating, microstructure analysis was done in the form of photo magnification of specimen using SEM (Scanning Electron Microscope).

Effects of Interlocking and Supporting Conditions on Concrete Block Pavements

NASA Astrophysics Data System (ADS)

Mahapatra, Geetimukta; Kalita, Kuldeep

2018-02-01

Concrete Block Paving (CBP) is widely used as wearing course in flexible pavements, preferably under light and medium vehicular loadings. Construction of CBP at site is quick and easy in quality control. Usually, flexible pavement design philosophy is followed in CBP construction, though it is structurally different in terms of small block elements with high strength concrete and their interlocking aspects, frequent joints and discontinuity, restrained edge etc. Analytical solution for such group action of concrete blocks under loading in a three dimensional multilayer structure is complex and thus, the need of conducting experimental studies is necessitated for extensive understanding of the load—deformation characteristics and behavior of concrete blocks in pavement. The present paper focuses on the experimental studies for load transfer characteristics of CBP under different interlocking and supporting conditions. It is observed that both interlocking and supporting conditions affect significantly on the load transfer behavior in CBP structures. Coro-lock block exhibits better performance in terms of load carrying capacity and distortion behavior under static loads. Plate load tests are performed over subgrade, granular sub-base (GSB), CBP with and without GSB using different block shapes. For an example case, the comparison of CBP with conventional flexible pavement section is also presented and it is found that CBP provides considerable benefit in terms of construction cost of the road structure.

Strength Calculation of Inclined Sections of Reinforced Concrete Elements under Transverse Bending

NASA Astrophysics Data System (ADS)

Filatov, V. B.

2017-11-01

The authors propose a design model to determine the strength of inclined sections of bent reinforced concrete elements without shear reinforcement for the action of transverse force taking into account the aggregate interlock forces in the inclined crack. The calculated dependences to find out the components of forces acting in an inclined section are presented. The calculated dependences are obtained from the consideration of equilibrium conditions of the block over the inclined crack. A comparative analysis of the experimental values of the failure loads of the inclined section and the theoretical values obtained for the proposed dependencies and normative calculation methods is performed. It is shown that the proposed design model makes it possible to take into account the effect the longitudinal reinforcement percentage has on the inclined section strength, the element cross section height without the introduction of empirical coefficients which contributes to an increase in the structural safety of design solutions including the safety of high-strength concrete elements.

Composite Grids for Reinforcement of Concrete Structures.

DTIC Science & Technology

1998-06-01

to greater compressive loads before induced shear failure occurs. Concrete columns were tested in compression to explore alter- native... columns were tested on the same day as the fiber-reinforced concrete columns . Load /deflection readings were taken with the load cell to determine the...ln) Figure 78. Ultimate load vs toughness for the different beam types tested . USACERLTR-98/81 141 £\\

Prefabricated Roof Beams for Hardened Shelters

DTIC Science & Technology

1993-08-01

beam with a composite concrete slab. Based on the results of the concept evaluation, a test program was designed and conducted to validate the steel...ultimaw, strength. The results of these tests showed that the design procedure accurately predicts the response of the ste,-confined concrete composite...BENDING OF EXTERNALLY REINFORCED CONCRETE BEAMS ........ 67 TABLE 9. SINGLE POINT LOAD BEAM TEST RESULTS

Mechanical Properties of Lightweight Concrete Using Recycled Cement-Sand Brick as Coarse Aggregates Replacement

NASA Astrophysics Data System (ADS)

Joohari, Ilya; Farhani Ishak, Nor; Amin, Norliyati Mohd

2018-03-01

This paper presents the result of replacing natural course aggregate with recycled cement-sand brick (CSB) towards the mechanical properties of concrete. Natural aggregates were used in this study as a control sample to compare with recycled coarse aggregates. This study was also carried to determine the optimum proportion of coarse aggregates replacement to produce lightweight concrete. Besides, this study was conducted to observe the crack and its behaviour development during the mechanical testing. Through this study, four types of concrete mixed were prepared, which were the control sample, 25%, 50% and 75% replacement of CSB. The test conducted to determine the effectiveness of recycled CSB as coarse aggregates replacement in this study were slump test, density measurement, compression test, and flexural test and. The strength of concrete was tested at 7 days and 28 days of curing. From the results obtained, the optimum proportion which produced the highest strength is 25% replacement of recycled CSB. The compressive and flexural strength has decreased by 10%-12% and 4%-34% respectively compared to the control sample. The presence of recycled coarse aggregates in sample has decreased the density of concrete by 0.8%-3% compared to the control sample.

Experimental and theoretical study of the operation of longitudinal sidewalls in reinforced concrete superstructures

NASA Astrophysics Data System (ADS)

Bokarev, Sergey; Efimov, Stefan

2017-11-01

In the present article, we report results of a laboratory experimental study of reinforced-concrete superstructure fragments with extended longitudinal boxing sidewalls. The study included laboratory tests and numerical experiments performed using a finite element model of fragments generated in specialized simulation software. The distribution of horizontal pressures over the height of longitudinal boxing sidewalls, the dependence of the bending moment in the root section of the sidewalls on the ballast-bed thickness under sleepers, and some other characteristics were examined. The results of the experimental and theoretical study have shown a good convergence of obtained data to each other and to the data obtained by an improved engineering calculation procedure proposed by the present authors.

Organic compounds in concrete from demolition works.

PubMed

Van Praagh, M; Modin, H; Trygg, J

2015-11-01

This study aims to verify the effect of physically removing the outer surface of contaminated concrete on total contents and on potential mobility of pollutants by means of leaching tests. Reclaimed concrete from 3 industrial sites in Sweden were included: A tar impregnated military storage, a military tar track-depot, as well as concrete constructions used for disposing of pesticide production surplus and residues. Solid materials and leachates from batch and column leaching tests were analysed for metals, Cl, F, SO4, DOC and contents of suspected organic compounds (polycyclic aromatic hydrocarbons, PAH, and pesticides/substances for pesticide production such as phenoxy acids, chlorophenols and chlorocresols, respectively). In case of PAH contaminated concrete, results indicate that removing 1 or 5 mm of the surface lead to total concentrations below the Swedish guidelines for recycling of aggregates and soil in groundwork constructions. 3 out of 4 concrete samples contaminated with pesticides fulfilled Swedish guidelines for contaminated soil. Results from batch and column leaching tests indicated, however, that concentrations above environmental quality standards for certain PAH and phenoxy acids, respectively, might occur at site when the crushed concrete is recycled in groundwork constructions. As leaching tests engaged in the study deviated from leaching test standards with a limited number of samples, the potential impact of the leaching tests' equipment on measured PAH and pesticide leachate concentrations has to be evaluated in future work. Copyright © 2015. Published by Elsevier Ltd.

SCHOOLS OF PRESTRESSED CONCRETE. PLANNING, DESIGN AND CONSTRUCTION OF EDUCATIONAL FACILITIES FOR SCHOOLS AND COLLEGES.

ERIC Educational Resources Information Center

LYMAN, ROBERT J.

THE USE OF PRESTRESSED CONCRETE IS EMPHASIZED IN THE AREAS OF SCHOOL PLANNING, DESIGN, AND CONSTRUCTION. THE PLANNING SECTION INCLUDES--(1) ROLES OF ACTIVE PARTIES AND RELATED ORGANIZATIONS, (2) PROCEDURES, AND (3) CONCEPTUAL DATA FOR SITE AND BUILDING. THE DESIGN SECTION CONTAINS--(1) DEVELOPMENT OF CONSTRUCTION SYSTEMS, (2) INTEGRATION OF…

Low - Cost Shore Protection. Final Report on the Shoreline Erosion Control Demonstration Program (Section 54) 1981

DTIC Science & Technology

1981-08-01

rubble- mound breakwater ......................... . ... 66 Ŗ-6 Statistics and costs for nylon-sandbag breakwater ...... ................... .... 68 2-7...64 2-16 Rubble- mound and concrete-box breakwater sections ........... .................... 65 2-17...a series of low, fixed offshore breakwaters utilizing three structural devices: rubble mound , nylon sandbags, and precast concrete boxes, as shown in

15. 'Concrete Bridge Over Salt River, Port Kenyon, Humboldt County, ...

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

15. 'Concrete Bridge Over Salt River, Port Kenyon, Humboldt County, California, A.J. Logan, County Surveyor, H.J. Brunnier, Consulting Engineer, March 7, 1919,' showing general plan, plan of top chord, elevation of main girder, transverse section, plan section at deck level. - Salt River Bridge, Spanning Salt River at Dillon Road, Ferndale, Humboldt County, CA

Influence of Tension Stiffening on the Flexural Stiffness of Reinforced Concrete Circular Sections

PubMed Central

Morelli, Francesco; Amico, Cosimo; Salvatore, Walter; Squeglia, Nunziante; Stacul, Stefano

2017-01-01

Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with circular section subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by comparing the experimental results carried out in past research and the numerical ones obtained by the model. Finally, a parametric study is executed in order to study the influence of axial compressive force on the flexural stiffness of reinforced concrete elements that are characterized by a circular section, comparing the secant stiffness evaluated at yielding and at maximum resistance, considering and not considering the effects of tension stiffness. PMID:28773028

Influence of Tension Stiffening on the Flexural Stiffness of Reinforced Concrete Circular Sections.

PubMed

Morelli, Francesco; Amico, Cosimo; Salvatore, Walter; Squeglia, Nunziante; Stacul, Stefano

2017-06-18

Within this paper, the assessment of tension stiffening effects on a reinforced concrete element with the circular sections subjected to axial and bending loads is presented. To this purpose, an enhancement of an analytical model already present within the actual technical literature is proposed. The accuracy of the enhanced method is assessed by comparing the experimental results carried out in past research and the numerical ones obtained by the model. Finally, a parametric study is executed in order to study the influence of axial compressive force on the flexural stiffness of reinforced concrete elements that are characterized by a circular section, comparing the secant stiffness evaluated at yielding and at maximum resistance, considering and not considering the effects of tension stiffness.

Acoustic Emission Monitoring of Multicell Reinforced Concrete Box Girders Subjected to Torsion

PubMed Central

Bagherifaez, Marya; Behnia, Arash; Majeed, Abeer Aqeel; Hwa Kian, Chai

2014-01-01

Reinforced concrete (RC) box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE) monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative for characterizing torsion fracture in the box girders. It was demonstrated through appropriate parametric analysis that the AE technique could be utilized to effectively classify fracture developed in the specimens for describing their mechanical behavior under torsion. AE events localization was presented to illustrate the trend of crack and damage propagation in different stages of fracture. It could be observed that spiral-like patterns of crack were captured through AE damage localization system and damage was quantified successfully in different stages of fracture by using smoothed b-value analysis. PMID:25180203

Experimental and finite element study of ultimate strength of continuous composite concrete slabs with steel decking

NASA Astrophysics Data System (ADS)

Gholamhoseini, Alireza

2018-03-01

Composite one-way concrete slabs with profiled steel decking as permanent formwork are commonly used in the construction industry. The steel decking supports the wet concrete of a cast in situ reinforced or post-tensioned concrete slab and, after the concrete sets, acts as external reinforcement. In this type of slab, longitudinal shear failure between the concrete and the steel decking is the most common type of failure at the ultimate load stage. Design codes require the experimental evaluation of the ultimate load capacity and longitudinal shear strength of each type of steel decking using full-scale tests on simple-span slabs. There is also no procedure in current design codes to evaluate the ultimate load capacity and longitudinal shear strength of continuous composite slabs and this is often assessed experimentally by full-scale tests. This paper presents the results of three full-scale tests up to failure on continuous composite concrete slabs cast with trapezoidal steel decking profile (KF70) that is widely used in Australia. Slab specimens were tested in four-point bending at each span with shear spans of span/4. The longitudinal shear failure of each slab is evaluated and the measured mid-span deflection, the end slip and the mid-span steel and concrete strains are also presented and discussed. Redistribution of bending moment in each slab is presented and discussed. A finite element model is proposed and verified by experimental data using interface element to model the bond properties between steel decking and concrete slab and investigate the ultimate strength of continuous composite concrete slabs.

Durability assessment of recycled concrete aggregates for use in new concrete.

DOT National Transportation Integrated Search

2012-06-01

The primary goal of this research project was to investigate the long-term durability of concrete incorporating : recycled concrete aggregate (RCA) through accelerated laboratory testing. Overall it was found that modifications to : standard aggregat...

An Investigation of Tendon Corrosion-Inhibitor Leakage into Concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Costello, J.F.; Naus, D.J.; Oland, C.B.

1999-07-05

During inspections performed at US nuclear power plants several years ago, some of the prestressed concrete containment had experienced leakage of the tendon sheathing filler. A study was conducted to indicate the extent of the leakage into the concrete and its potential effects on concrete properties. Concrete core samples were obtained from the Trojan Nuclear Plant. Examination and testing of the core samples indicated that the appearance of tendon sheathing filler on the surface was due to leakage of the filler from the conduits and its subsequent migration to the concrete surface through cracks that were present. Migration of themore » tendon sheathing filler was confined to the cracks with no perceptible movement into the concrete. Results of compressive strength tests indicated that the concrete quality was consistent in the containment and that the strength had increased relative to the strength at 28 days age.« less

Sound absorption coefficient of coal bottom ash concrete for railway application

NASA Astrophysics Data System (ADS)

Ramzi Hannan, N. I. R.; Shahidan, S.; Maarof, Z.; Ali, N.; Abdullah, S. R.; Ibrahim, M. H. Wan

2017-11-01

A porous concrete able to reduce the sound wave that pass through it. When a sound waves strike a material, a portion of the sound energy was reflected back and another portion of the sound energy was absorbed by the material while the rest was transmitted. The larger portion of the sound wave being absorbed, the lower the noise level able to be lowered. This study is to investigate the sound absorption coefficient of coal bottom ash (CBA) concrete compared to the sound absorption coefficient of normal concrete by carried out the impedance tube test. Hence, this paper presents the result of the impedance tube test of the CBA concrete and normal concrete.

Measurement of the Rheological Properties of High Performance Concrete: State of the Art Report

PubMed Central

Ferraris, Chiara F.

1999-01-01

The rheological or flow properties of concrete in general and of high performance concrete (HPC) in particular, are important because many factors such as ease of placement, consolidation, durability, and strength depend on the flow properties. Concrete that is not properly consolidated may have defects, such as honeycombs, air voids, and aggregate segregation. Such an important performance attribute has triggered the design of numerous test methods. Generally, the flow behavior of concrete approximates that of a Bingham fluid. Therefore, at least two parameters, yield stress and viscosity, are necessary to characterize the flow. Nevertheless, most methods measure only one parameter. Predictions of the flow properties of concrete from its composition or from the properties of its components are not easy. No general model exists, although some attempts have been made. This paper gives an overview of the flow properties of a fluid or a suspension, followed by a critical review of the most commonly used concrete rheology tests. Particular attention is given to tests that could be used for HPC. Tentative definitions of terms such as workability, consistency, and rheological parameters are provided. An overview of the most promising tests and models for cement paste is given.

Long-Term, Deep Ocean Test of Concrete Spherical Structures - Results after 13 Years.

DTIC Science & Technology

1985-07-01

corrosion of reinforcing steel are problems, even though the concrete becomes saturated with seawater. Uncoated concrete has a very low rate of permeation... concrete matrix nor corrosion of reinforcing steel are problems, even though the concrete becomes saturated with seawater. Uncoated concrete I has a...which concrete protects the steel against corrosion in the deep ocean environ- ment. The ocean depth range for the spheres corresponds to predicled

Concrete research

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The papers in this volume deal with various facets of concrete technology. The first four papers discuss concrete performance from the perspectives of design, specifications, and testing. The following three papers address the use and management of by-products in cementitious systems. Kakodkar et al. present the results of a study to determine the influence of five different Class C fly ashes on inhibiting the expansion of concrete due to alkali-silica reaction. Ramakrishnan et al. present the results of an extensive study to determine the influence of natural possolans in reducing the deleterious expansion of concrete due to alkai-silica reaction. Themore » test results showed that all the natural pozzolans used in the study, except one, were very effective in reducing the expansions due to alkali-silica reaction. Johnston discusses a modified interpretation of the ASTM P214 test results for determining potential reactivity of sands used for concrete in South Dakota.« less

Crack classification in concrete beams using AE parameters

NASA Astrophysics Data System (ADS)

Bahari, N. A. A. S.; Shahidan, S.; Abdullah, S. R.; Ali, N.; Zuki, S. S. Mohd; Ibrahim, M. H. W.; Rahim, M. A.

2017-11-01

The acoustic emission (AE) technique is an effective tool for the evaluation of crack growth. The aim of this study is to evaluate crack classification in reinforced concrete beams using statistical analysis. AE has been applied for the early monitoring of reinforced concrete structures using AE parameters such as average frequency, rise time, amplitude counts and duration. This experimental study focuses on the utilisation of this method in evaluating reinforced concrete beams. Beam specimens measuring 150 mm × 250 mm × 1200 mm were tested using a three-point load flexural test using Universal Testing Machines (UTM) together with an AE monitoring system. The results indicated that RA value can be used to determine the relationship between tensile crack and shear movement in reinforced concrete beams.

Effect of Fly-Ash on Corrosion Resistance Characteristics of Rebar Embedded in Recycled Aggregate Concrete

NASA Astrophysics Data System (ADS)

Revathi, Purushothaman; Nikesh, P.

2018-04-01

In the frame of an extended research programme dealing with the utilization of recycled aggregate in concrete, the corrosion resistance characteristics of rebars embedded in recycled aggregate concrete is studied. Totally five series of concrete mixtures were prepared with fly-ash as replacement for cement in the levels of 10-30% by weight of cement. Corrosion studies by 90 days ponding test, linear polarization test and impressed voltage tests were carried out, in order to investigate whether corrosion behaviour of the rebars has improved due to the replacement of cement with fly-ash. Results showed that the replacement of cement with fly-ash in the range of 20-30% improves the corrosion resistance characteristics of recycled aggregate concrete.

Effects of Aging and Environmental Conditions on Ammunition/Explosives Storage Magazines - Paper 1

DTIC Science & Technology

2010-07-01

dropped below 9.5.  Corrosion of the Reinforcing Steel: Steel reinforcement is normally placed within a 2 inches of a concrete surface. Under most...alkalinity of the concrete . The steel is also protected by the relatively high electrical resistance of the concrete . Still, corrosion of the...pressures to force the concrete /reinforcement steel bond to break. Corrosion of the steel will cause spalling, section loss of the steel, and eventually

Monitoring of Beachsaver Reef with Filter Blanket and Double-T Sill at Cape May Point, New Jersey, Section 227 Demonstration Site; First Year Monitoring - 2002-2003

DTIC Science & Technology

2005-07-01

evaluate the functional, structural, and economic performance of the patented Beachsaver Reef prefabricated concrete submerged breakwater and the less...expensive prefabricated concrete structure called a Double-T sill. This demonstration project was developed through a cooperative effort of the U.S...patented Beachsaver Reef prefabricated concrete submerged breakwater and a less expensive, prefabricated concrete structure called a Double-T sill. Data

Bond–Slip Relationship for CFRP Sheets Externally Bonded to Concrete under Cyclic Loading

PubMed Central

Li, Ke; Cao, Shuangyin; Yang, Yue; Zhu, Juntao

2018-01-01

The objective of this paper was to explore the bond–slip relationship between carbon fiber-reinforced polymer (CFRP) sheets and concrete under cyclic loading through experimental and analytical approaches. Modified beam tests were performed in order to gain insight into the bond–slip relationship under static and cyclic loading. The test variables are the CFRP-to-concrete width ratio, and the bond length of the CFRP sheets. An analysis of the test results in this paper and existing test results indicated that the slope of the ascending segment of the bond–slip curve decreased with an increase in the number of load cycles, but the slip corresponding to the maximum shear stress was almost invariable as the number of load cycles increased. In addition, the rate of reduction in the slope of the ascending range of the bond–slip curve during cyclic loading decreased as the concrete strength increased, and increased as the load level or CFRP-to-concrete width ratio enhanced. However, these were not affected by variations in bond length if the residual bond length was longer than the effective bond length. A bilinear bond–slip model for CFRP sheets that are externally bonded to concrete under cyclic loading, which considered the effects of the cyclic load level, concrete strength, and CFRP-to-concrete ratio, was developed based on the existing static bond–slip model. The accuracy of this proposed model was verified by a comparison between this proposed model and test results. PMID:29495383

Bond-Slip Relationship for CFRP Sheets Externally Bonded to Concrete under Cyclic Loading.

PubMed

Li, Ke; Cao, Shuangyin; Yang, Yue; Zhu, Juntao

2018-02-26

The objective of this paper was to explore the bond-slip relationship between carbon fiber-reinforced polymer (CFRP) sheets and concrete under cyclic loading through experimental and analytical approaches. Modified beam tests were performed in order to gain insight into the bond-slip relationship under static and cyclic loading. The test variables are the CFRP-to-concrete width ratio, and the bond length of the CFRP sheets. An analysis of the test results in this paper and existing test results indicated that the slope of the ascending segment of the bond-slip curve decreased with an increase in the number of load cycles, but the slip corresponding to the maximum shear stress was almost invariable as the number of load cycles increased. In addition, the rate of reduction in the slope of the ascending range of the bond-slip curve during cyclic loading decreased as the concrete strength increased, and increased as the load level or CFRP-to-concrete width ratio enhanced. However, these were not affected by variations in bond length if the residual bond length was longer than the effective bond length. A bilinear bond-slip model for CFRP sheets that are externally bonded to concrete under cyclic loading, which considered the effects of the cyclic load level, concrete strength, and CFRP-to-concrete ratio, was developed based on the existing static bond-slip model. The accuracy of this proposed model was verified by a comparison between this proposed model and test results.

Increased Durability of Concrete Made with Fine Recycled Concrete Aggregates Using Superplasticizers.

PubMed

Cartuxo, Francisco; de Brito, Jorge; Evangelista, Luis; Jiménez, José Ramón; Ledesma, Enrique F

2016-02-08

This paper evaluates the influence of two superplasticizers (SP) on the durability properties of concrete made with fine recycled concrete aggregate (FRCA). For this purpose, three families of concrete were tested: concrete without SP, concrete made with a regular superplasticizer and concrete made with a high-performance superplasticizer. Five volumetric replacement ratios of natural sand by FRCA were tested: 0%, 10%, 30%, 50% and 100%. Two natural gravels were used as coarse aggregates. All mixes had the same particle size distribution, cement content and amount of superplasticizer. The w/c ratio was calibrated to obtain similar slump. The results showed that the incorporation of FRCA increased the water absorption by immersion, the water absorption by capillary action, the carbonation depth and the chloride migration coefficient, while the use of superplasticizers highly improved these properties. The incorporation of FRCA jeopardized the SP's effectiveness. This research demonstrated that, from a durability point of view, the simultaneous incorporation of FRCA and high-performance SP is a viable sustainable solution for structural concrete production.

Experimental evaluation and design of unfilled and concrete-filled FRP composite piles, task 3 - FRP composite pile flexural testing.

DOT National Transportation Integrated Search

2014-06-01

The overall goal of this project is the experimental evaluation and design of unfilled and concrete-filled FRP : composite piles for load-bearing in bridges. This report covers Task 3, FRP Composite Pile Flexural Testing. : Hollow and concrete filled...

Highway concrete pavement technology development and testing : volume III, field evaluation of Strategic Highway Research Program (SHRP) C-205 test sites (high-performance concrete).

DOT National Transportation Integrated Search

2006-05-01

This research study, sponsored by the Federal Highway Administration, summarizes the field performance of eight high-early-strength (HES) : concrete patches between 1994 and 1998. The patches were constructed under the Strategic Highway Research Prog...

NORTH BASEMENT WALL. IBEAM COLUMNS HAVE BEEN ENCASED IN CONCRETE. ...

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

NORTH BASEMENT WALL. I-BEAM COLUMNS HAVE BEEN ENCASED IN CONCRETE. STEEL BEAMS LAY ACROSS FIRST FLOOR AWAITING CONCRETE POUR. CAMERA LOOKS SOUTHWEST. INL NEGATIVE NO. 735. Unknown Photographer, 10/6/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Mechanical Properties and Eco-Efficiency of Steel Fiber Reinforced Alkali-Activated Slag Concrete.

PubMed

Kim, Sun-Woo; Jang, Seok-Joon; Kang, Dae-Hyun; Ahn, Kyung-Lim; Yun, Hyun-Do

2015-10-30

Conventional concrete production that uses ordinary Portland cement (OPC) as a binder seems unsustainable due to its high energy consumption, natural resource exhaustion and huge carbon dioxide (CO₂) emissions. To transform the conventional process of concrete production to a more sustainable process, the replacement of high energy-consumptive PC with new binders such as fly ash and alkali-activated slag (AAS) from available industrial by-products has been recognized as an alternative. This paper investigates the effect of curing conditions and steel fiber inclusion on the compressive and flexural performance of AAS concrete with a specified compressive strength of 40 MPa to evaluate the feasibility of AAS concrete as an alternative to normal concrete for CO₂ emission reduction in the concrete industry. Their performances are compared with reference concrete produced using OPC. The eco-efficiency of AAS use for concrete production was also evaluated by binder intensity and CO₂ intensity based on the test results and literature data. Test results show that it is possible to produce AAS concrete with compressive and flexural performances comparable to conventional concrete. Wet-curing and steel fiber inclusion improve the mechanical performance of AAS concrete. Also, the utilization of AAS as a sustainable binder can lead to significant CO₂ emissions reduction and resources and energy conservation in the concrete industry.

Corrosion Behavior of Steel Reinforcement in Concrete with Recycled Aggregates, Fly Ash and Spent Cracking Catalyst

PubMed Central

Gurdián, Hebé; García-Alcocel, Eva; Baeza-Brotons, Francisco; Garcés, Pedro; Zornoza, Emilio

2014-01-01

The main strategy to reduce the environmental impact of the concrete industry is to reuse the waste materials. This research has considered the combination of cement replacement by industrial by-products, and natural coarse aggregate substitution by recycled aggregate. The aim is to evaluate the behavior of concretes with a reduced impact on the environment by replacing a 50% of cement by industrial by-products (15% of spent fluid catalytic cracking catalyst and 35% of fly ash) and a 100% of natural coarse aggregate by recycled aggregate. The concretes prepared according to these considerations have been tested in terms of mechanical strengths and the protection offered against steel reinforcement corrosion under carbonation attack and chloride-contaminated environments. The proposed concrete combinations reduced the mechanical performance of concretes in terms of elastic modulus, compressive strength, and flexural strength. In addition, an increase in open porosity due to the presence of recycled aggregate was observed, which is coherent with the changes observed in mechanical tests. Regarding corrosion tests, no significant differences were observed in the case of the resistance of these types of concretes under a natural chloride attack. In the case of carbonation attack, although all concretes did not stand the highly aggressive conditions, those concretes with cement replacement behaved worse than Portland cement concretes. PMID:28788613

Orientation of Steel Fibers in Magnetically Driven Concrete and Mortar.

PubMed

Xue, Wen; Chen, Ju; Xie, Fang; Feng, Bing

2018-01-22

The orientation of steel fibers in magnetically driven concrete and magnetically driven mortar was experimentally studied in this paper using a magnetic method. In the magnetically driven concrete, a steel slag was used to replace the coarse aggregate. In the magnetically driven mortar, steel slag and iron sand were used to replace the fine aggregate. A device was established to provide the magnetic force. The magnetic force was used to rotate the steel fibers. In addition, the magnetic force was also used to vibrate the concrete and mortar. The effect of magnetic force on the orientation of steel fibers was examined by comparing the direction of fibers before and after vibration. The effect of magnetically driven concrete and mortar on the orientation of steel fibers was also examined by comparing specimens to normal concrete and mortar. It is shown that the fibers could rotate about 90° in magnetically driven concrete. It is also shown that the number of fibers rotated in magnetically driven mortar was much more than in mortar vibrated using a shaking table. A splitting test was performed on concrete specimens to investigate the effect of fiber orientation. In addition, a flexural test was also performed on mortar test specimens. It is shown that the orientation of the steel fibers in magnetically driven concrete and mortar affects the strength of the concrete and mortar specimens.

Orientation of Steel Fibers in Magnetically Driven Concrete and Mortar

PubMed Central

Xue, Wen; Chen, Ju; Xie, Fang; Feng, Bing

2018-01-01

The orientation of steel fibers in magnetically driven concrete and magnetically driven mortar was experimentally studied in this paper using a magnetic method. In the magnetically driven concrete, a steel slag was used to replace the coarse aggregate. In the magnetically driven mortar, steel slag and iron sand were used to replace the fine aggregate. A device was established to provide the magnetic force. The magnetic force was used to rotate the steel fibers. In addition, the magnetic force was also used to vibrate the concrete and mortar. The effect of magnetic force on the orientation of steel fibers was examined by comparing the direction of fibers before and after vibration. The effect of magnetically driven concrete and mortar on the orientation of steel fibers was also examined by comparing specimens to normal concrete and mortar. It is shown that the fibers could rotate about 90° in magnetically driven concrete. It is also shown that the number of fibers rotated in magnetically driven mortar was much more than in mortar vibrated using a shaking table. A splitting test was performed on concrete specimens to investigate the effect of fiber orientation. In addition, a flexural test was also performed on mortar test specimens. It is shown that the orientation of the steel fibers in magnetically driven concrete and mortar affects the strength of the concrete and mortar specimens. PMID:29361798

Generalized Fracture Toughness and Compressive Strength of Sustainable Concrete Including Low Calcium Fly Ash.

PubMed

Golewski, Grzegorz Ludwik

2017-12-06

The paper presents the results of tests on the effect of the low calcium fly ash (LCFA) addition, in the amounts of: 0% (LCFA-00), 20% (LCFA-20) and 30% (LCFA-30) by weight of cement, on fracture processes in structural concretes. In the course of the experiments, compressive strength of concrete and fracture toughness for: I (tensile), II (in-plane shear) and III (anti-plane shear) models of cracking were measured. The tests determined the effect of age of concretes modified with LCFA on the analyzed parameters. The experiments were carried out after: 3, 7, 28, 90, 180 and 365 days of curing. Fracture toughness of concretes was determined in terms of the critical stress intensity factors: K I c S , K I I c , K I I I c and then a generalized fracture toughness K c was specified. The obtained results are significant for the analysis of concrete structures subjected to complex loading. The properties of composites with the additive of LCFA depend on the age of the concrete tested. Mature concretes exhibit high fracture toughness at 20% additive of LCFA, while the additive of LCFA in the amount of 30% weight of cement has a beneficial effect on the parameters of concrete only after half a year of curing.

Evaluation of Early-Age Concrete Compressive Strength with Ultrasonic Sensors.

PubMed

Yoon, Hyejin; Kim, Young Jin; Kim, Hee Seok; Kang, Jun Won; Koh, Hyun-Moo

2017-08-07

Surface wave velocity measurement of concrete using ultrasonic sensors requires testing on only one side of a member. Thus, it is applicable to concrete cast inside a form and is often used to detect flaws and evaluate the compressive strength of hardened concrete. Predicting the in situ concrete strength at a very early stage inside the form helps with determining the appropriate form removal time and reducing construction time and costs. In this paper, the feasibility of using surface wave velocities to predict the strength of in situ concrete inside the form at a very early stage was evaluated. Ultrasonic sensors were used to measure a series of surface waves for concrete inside a form in the first 24 h after placement. A continuous wavelet transform was used to compute the travel time of the propagating surface waves. The cylindrical compressive strength and penetration resistance tests were also performed during the test period. Four mixtures and five curing temperatures were used for the specimens. The surface wave velocity was confirmed to be applicable to estimating the concrete strength at a very early age in wall-like elements. An empirical formula is proposed for evaluating the early-age compressive strength of concrete considering the 95% prediction intervals.

Creep and cracking of concrete hinges: insight from centric and eccentric compression experiments.

PubMed

Schlappal, Thomas; Schweigler, Michael; Gmainer, Susanne; Peyerl, Martin; Pichler, Bernhard

2017-01-01

Existing design guidelines for concrete hinges consider bending-induced tensile cracking, but the structural behavior is oversimplified to be time-independent. This is the motivation to study creep and bending-induced tensile cracking of initially monolithic concrete hinges systematically. Material tests on plain concrete specimens and structural tests on marginally reinforced concrete hinges are performed. The experiments characterize material and structural creep under centric compression as well as bending-induced tensile cracking and the interaction between creep and cracking of concrete hinges. As for the latter two aims, three nominally identical concrete hinges are subjected to short-term and to longer-term eccentric compression tests. Obtained material and structural creep functions referring to centric compression are found to be very similar. The structural creep activity under eccentric compression is significantly larger because of the interaction between creep and cracking, i.e. bending-induced cracks progressively open and propagate under sustained eccentric loading. As for concrete hinges in frame-like integral bridge construction, it is concluded (i) that realistic simulation of variable loads requires consideration of the here-studied time-dependent behavior and (ii) that permanent compressive normal forces shall be limited by 45% of the ultimate load carrying capacity, in order to avoid damage of concrete hinges under sustained loading.

Evaluation of Early-Age Concrete Compressive Strength with Ultrasonic Sensors

PubMed Central

Yoon, Hyejin; Kim, Young Jin; Kim, Hee Seok; Kang, Jun Won; Koh, Hyun-Moo

2017-01-01

Surface wave velocity measurement of concrete using ultrasonic sensors requires testing on only one side of a member. Thus, it is applicable to concrete cast inside a form and is often used to detect flaws and evaluate the compressive strength of hardened concrete. Predicting the in situ concrete strength at a very early stage inside the form helps with determining the appropriate form removal time and reducing construction time and costs. In this paper, the feasibility of using surface wave velocities to predict the strength of in situ concrete inside the form at a very early stage was evaluated. Ultrasonic sensors were used to measure a series of surface waves for concrete inside a form in the first 24 h after placement. A continuous wavelet transform was used to compute the travel time of the propagating surface waves. The cylindrical compressive strength and penetration resistance tests were also performed during the test period. Four mixtures and five curing temperatures were used for the specimens. The surface wave velocity was confirmed to be applicable to estimating the concrete strength at a very early age in wall-like elements. An empirical formula is proposed for evaluating the early-age compressive strength of concrete considering the 95% prediction intervals. PMID:28783128

Generalized Fracture Toughness and Compressive Strength of Sustainable Concrete Including Low Calcium Fly Ash

PubMed Central

2017-01-01

The paper presents the results of tests on the effect of the low calcium fly ash (LCFA) addition, in the amounts of: 0% (LCFA-00), 20% (LCFA-20) and 30% (LCFA-30) by weight of cement, on fracture processes in structural concretes. In the course of the experiments, compressive strength of concrete and fracture toughness for: I (tensile), II (in-plane shear) and III (anti-plane shear) models of cracking were measured. The tests determined the effect of age of concretes modified with LCFA on the analyzed parameters. The experiments were carried out after: 3, 7, 28, 90, 180 and 365 days of curing. Fracture toughness of concretes was determined in terms of the critical stress intensity factors: KIcS, KIIc, KIIIc and then a generalized fracture toughness Kc was specified. The obtained results are significant for the analysis of concrete structures subjected to complex loading. The properties of composites with the additive of LCFA depend on the age of the concrete tested. Mature concretes exhibit high fracture toughness at 20% additive of LCFA, while the additive of LCFA in the amount of 30% weight of cement has a beneficial effect on the parameters of concrete only after half a year of curing. PMID:29211029

A unified bond theory, probabilistic meso-scale modeling, and experimental validation of deformed steel rebar in normal strength concrete

NASA Astrophysics Data System (ADS)

Wu, Chenglin

Bond between deformed rebar and concrete is affected by rebar deformation pattern, concrete properties, concrete confinement, and rebar-concrete interfacial properties. Two distinct groups of bond models were traditionally developed based on the dominant effects of concrete splitting and near-interface shear-off failures. Their accuracy highly depended upon the test data sets selected in analysis and calibration. In this study, a unified bond model is proposed and developed based on an analogy to the indentation problem around the rib front of deformed rebar. This mechanics-based model can take into account the combined effect of concrete splitting and interface shear-off failures, resulting in average bond strengths for all practical scenarios. To understand the fracture process associated with bond failure, a probabilistic meso-scale model of concrete is proposed and its sensitivity to interface and confinement strengths are investigated. Both the mechanical and finite element models are validated with the available test data sets and are superior to existing models in prediction of average bond strength (< 6% error) and crack spacing (< 6% error). The validated bond model is applied to derive various interrelations among concrete crushing, concrete splitting, interfacial behavior, and the rib spacing-to-height ratio of deformed rebar. It can accurately predict the transition of failure modes from concrete splitting to rebar pullout and predict the effect of rebar surface characteristics as the rib spacing-to-height ratio increases. Based on the unified theory, a global bond model is proposed and developed by introducing bond-slip laws, and validated with testing of concrete beams with spliced reinforcement, achieving a load capacity prediction error of less than 26%. The optimal rebar parameters and concrete cover in structural designs can be derived from this study.

Design and evaluation of high-volume fly ash (HVFA) concrete mixes, report B : bond behavior of mild reinforcing steel in HVFA concrete.

DOT National Transportation Integrated Search

2012-10-01

The main objective of this study was to determine the effect on bond performance : of high-volume fly ash (HVFA) concrete. The HVFA concrete test program consisted of : comparing the bond performance of two concrete mix designs with 70% cement : repl...

Experimental verification of concrete resistance against effect of low pH

NASA Astrophysics Data System (ADS)

Dobias, D.; Rehacek, S.; Pokorny, P.; Citek, D.; Kolisko, J.

2018-03-01

In the introductory part of this article, the principles of a concrete degradation by organic acids are mentioned, these acids occur, particularly in silage and haylage troughs, biogas stations, on concrete floors and grates in the vicinity of drinking basins with an addition of formic acid and also in fermenters and slurry reservoirs. In the experimental part, the first results of monitoring resistance of a concrete with a sealing admixture on the basis of styrene-acrylate against an effect of a low pH are presented. Additional accompanying tests are stated in the tested concretes.

Numerical analysis of composite STEEL-CONCRETE SECTIONS using integral equation of Volterra

NASA Astrophysics Data System (ADS)

Partov, Doncho; Kantchev, Vesselin

2011-09-01

The paper presents analysis of the stress and deflections changes due to creep in statically determinate composite steel-concrete beam. The mathematical model involves the equation of equilibrium, compatibility and constitutive relationship, i.e. an elastic law for the steel part and an integral-type creep law of Boltzmann — Volterra for the concrete part. On the basis of the theory of the viscoelastic body of Arutyunian-Trost-Bažant for determining the redistribution of stresses in beam section between concrete plate and steel beam with respect to time "t", two independent Volterra integral equations of the second kind have been derived. Numerical method based on linear approximation of the singular kernal function in the integral equation is presented. Example with the model proposed is investigated. The creep functions is suggested by the model CEB MC90-99 and the "ACI 209R-92 model. The elastic modulus of concrete E c (t) is assumed to be constant in time `t'. The obtained results from the both models are compared.

The effect of zeolite and diatomite on the corrosion of reinforcement steel in 1 M HCl solution

NASA Astrophysics Data System (ADS)

Gerengi, Husnu; Kurtay, Mine; Durgun, Hatice

The greatest disadvantage of reinforced concrete structures is the corrosion occurring in the reinforcement which, over time, causes a reduction in the reinforcement-concrete adherence and eventual sectional loss. The purpose of this study was to reveal the corrosion mechanism of ribbed reinforcement inside additive-free (reference), 20% zeolite-doped and 20% diatomite-doped concrete samples after exposure to 1 M HCl over 240 days. Electrochemical impedance spectroscopy (EIS) measurements were made every 10 days. Consequently, it was determined that the 20% zeolite-doped concrete samples had higher concrete and reinforcement resistance compared to the 20% diatomite-doped and the reference concrete, i.e. they exhibited less corrosion.

Mechanical properties and durability of crumb rubber concrete

NASA Astrophysics Data System (ADS)

Chylík, Roman; Trtík, Tomáš; Fládr, Josef; Bílý, Petr

2017-09-01

This paper is focused on concrete with admixture of rubber powder, generally called crumb rubber concrete (CRC). The inspiration was found in Arizona, where one of the first CRCs has been created. However, Arizona has completely different climates than Central Europe. Could we use the crumb rubber concrete on construction applications in the Central European climate too? The paper evaluates the influence of the rubber powder on material characteristics and durability of CRC. CRCs with various contents of fine and coarse crumb powder were compared. The tested parameters were slump, air content, permeability, resistance of concrete to water with deicing chemicals, compressive and splitting tensile strength. The tests showed that workability, compressive strength and permeability decreased as the amount of rubber increased, but the air content increased as the rubber content increased. Photos of air voids in cement matrix from electron microscope were captured. The results of laboratory tests showed that admixture of rubber powder in concrete could have a positive impact on durability of concrete and concurrently contribute to sustainable development. Considering the lower compressive strength, CRC is recommended for use in applications where the high strength of concrete is not required.

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.

The influence of main bar corrosion on bond strength in selfcompacting concrete

NASA Astrophysics Data System (ADS)

Ayop, S. S.; Emhemed, A. N. K.; Jamaluddin, N.; Sadikin, A.

2017-11-01

The experimental study was conducted to determine the influence of main bar corrosion on bond strength in self-compacting concrete (SCC). A total 16 tension pullout tests specimens reinforced with 10 mm and 14 mm diameter bar were used for the bond strength test. The properties of SCC were determined from the slump flow, T50cm, V-funnel and L box test. Reinforcing bars in the concrete were submitted to impressed current to accelerate the corrosion of the bar. It was found that the relationship between bond strength and concrete strength in un-corroded specimens differed from that of corroded specimens set in high-strength concrete because of brittleness in the corroded specimens, which caused a sudden loss of bond strength. The results revealed that specimens of un-corroded and corroded showed a higher percentage of bond strength degradation during the pullout tests.

Field Testing of Rapid Electrokinetic Nanoparticle Treatment for Corrosion Control of Steel in Concrete

NASA Technical Reports Server (NTRS)

Cardenas, Henry E.; Alexander, Joshua B.; Kupwade-Patil,Kunal; Calle, Luz Marina

2009-01-01

This work field tested the use of electrokinetics for delivery of concrete sealing nanoparticles concurrent with the extraction of chlorides. Several cylinders of concrete were batched and placed in immersion at the Kennedy Space Center Beach Corrosion Test Site. The specimens were batched with steel reinforcement and a 4.5 wt.% (weight percent) content of sodium chloride. Upon arrival at Kennedy Space Center, the specimens were placed in the saltwater immersion pool at the Beach Corrosion Test Site. Following 30 days of saltwater exposure, the specimens were subjected to rapid chloride extraction concurrent with electrokinetic nanoparticle treatment. The treatments were operated at up to eight times the typical current density in order to complete the treatment in 7 days. The findings indicated that the short-term corrosion resistance of the concrete specimens was significantly enhanced as was the strength of the concrete.

Experimental investigations on steel-concrete composite columns for varying parameters

NASA Astrophysics Data System (ADS)

Aparna, V.; Vivek, D.; Neelima, Kancharla; Karthikeyan, B.

2017-07-01

In this study, the experimental investigations on steel tubes filled with different types of concrete are presented. Steel tubes filled with fibre reinforced concrete using lathe waste and steel tube with concerned confined with steel mesh were investigated. The combinations were compared with steel tubes with conventional concrete. A total of 4 concrete filled steel tube (CFST) combinations were made with tubes of diameter 100 mm with wall thickness 1.6 mm and a height of 300 mm. Axial compression test to examine the resisting capacity of the columns and push-out test for noting the bond strength were performed. Coupon tests were also conducted to determine the mechanical properties of steel. The structural behaviour of the composite columns was evaluated from on the test results. It was observed that steel tube filled fibre reinforced possessed better bond strength and resistance to axial load.

Development of Vegetation-Pervious Concrete in Grid Beam System for Soil Slope Protection.

PubMed

Bao, Xiaohua; Liao, Wenyu; Dong, Zhijun; Wang, Shanyong; Tang, Waiching

2017-01-24

One of the most efficient and environmentally friendly methods for preventing a landslide on a slope is to vegetate it. Vegetation-pervious concretes have a promising potential for soil protection. In this study, the vegetation-pervious concrete with low alkalinity was developed and studied. Combined with a grid beam structure system, the stability and strength between the vegetation-pervious concrete and base soil are believed to be enhanced effectively. For improving plant adaptability, the alkalinity of concrete can be decreased innovatively by adding a self-designed admixture into the cement paste. The effects of the admixture content on alkalinity and compressive strength of the hardened pervious concrete were investigated using X-ray diffraction (XRD) and compression test, respectively. Meanwhile, the permeability of the vegetation-pervious concrete was studied as well. Through comparing with ordinary pervious concrete, the effect of low alkaline pervious concrete on vegetation growth was investigated in a small-scale field for ten weeks. The test results indicated that the alkalinity of the cement samples decreased with the increase of admixture content, and the vegetation grew successfully on previous concrete. By increasing the admixture content to approximately 3.6%, the compressive strength of pervious concrete was more than 25 MPa.

Experimental study on the strength parameter of Quarry Dust mixed Coconut Shell Concrete adding Coconut Fibre

NASA Astrophysics Data System (ADS)

Matangulu Shrestha, Victor; Anandh, S.; Sindhu Nachiar, S.

2017-07-01

Concrete is a heterogeneous mixture constitute of cement as the main ingredient with a different mix of fine and coarse aggregate. The massive use of conventional concrete has a shortfall in its key ingredients, natural sand and coarse aggregate, due to increased industrialisation and globalisation. To overcome the shortage of material, an alternate material with similar mechanical properties and composition has to be studied, as replacement of conventional concrete. Coconut shell concrete is a prime option as replacement of key ingredients of conventional concrete as coconut is produced in massive quantity in south East Asia. Coconut shell concrete is lightweight concrete and different research is still ongoing concerning about its mix design and composition in the construction industry. Concrete is weak in tension as compared to compression, hence the fibre is used to refrain the crack in the concrete. Coconut fibre is one of many fibres which can be used in concrete. The main aim of this project is to analyse the use of natural by-products in the construction industry, make light weight concrete and eco-friendly construction. This project concerns with the comparison of the mechanical properties of coconut shell concrete and conventional concrete, replacing fine aggregate with quarry dust using coconut fibre. M25 grade of concrete was adopted and testing of concrete was done at the age of 3, 7 and 28 days. In this concrete mix, sand was replaced completely in volumetric measurement by quarry dust. The result was analysed and compared with addition of coconut fibre at varying percentage of 1%, 2%, 3%, 4% and 5%. From the test conducted, coconut shell concrete with quarry dust has the maximum value at 4% of coconut fibre while conventional concrete showed the maximum value at 2% of coconut fibre.

Testing of selected metallic reinforcing bars for extending the service life of future concrete bridges : testing in outdoor concrete blocks.

DOT National Transportation Integrated Search

2002-01-01

To meet the challenge of a design life of 100 years for major concrete bridges, economical and corrosion-resistant reinforcing bars will be needed. The preliminary results for stainless steel-clad bars in a recent investigation funded by the Federal ...

Testing methods and techniques: Strength of materials and components. A compilation

NASA Technical Reports Server (NTRS)

1971-01-01

The methods, techniques, and devices used in testing the mechanical properties of various materials are presented. Although metals and metal alloys are featured prominently, some of the items describe tests on a variety of other materials, from concrete to plastics. Many of the tests described are modifications of standard testing procedures, intended either to adapt them to different materials and conditions, or to make them more rapid and accurate. In either case, the approaches presented can result in considerable cost savings and improved quality control. The compilation is presented in two sections. The first deals specifically with material strength testing; the second treats the special category of fracture and fatigue testing.

Effect of kenaf fiber in reinforced concrete slab

NASA Astrophysics Data System (ADS)

Syed Mohsin, S. M.; Baarimah, A. O.; Jokhio, G. A.

2018-04-01

The effect of kenaf fibers in reinforced concrete slab with different thickness is discusses and presented in this paper. Kenaf fiber is a type of natural fiber and is added in the reinforced concrete slab to improve the structure strength and ductility. For this study, three types of mixtures were prepared with fiber volume fraction of 0%, 1% and 2%, respectively. The design compressive strength considered was 20 MPa. Six cubes were prepared to be tested at 7th and 28th day. A total of six reinforced concrete slab with two variances of thickness were also prepared and tested under four-point bending test. The differences in the thickness is to study the potential of kenaf fiber to serve as part of shear reinforcement in reinforced concrete slab that was design to fail in shear. It was observed that, addition of kenaf fiber in reinforced concrete slab improves the flexural strength and ductility of the reinforced concrete slab. In the slab with reduction in thickness, the mode of failure change from brittle to ductile with the inclusion of kenaf fiber.

Determination of Temperature Rise and Temperature Differentials of CEMII/B-V Cement for 20MPa Mass Concrete using Adiabatic Temperature Rise Data

NASA Astrophysics Data System (ADS)

Chee Siang, GO

2017-07-01

Experimental test was carried out to determine the temperature rise characteristics of Portland-Fly-Ash Cement (CEM II/B-V, 42.5N) of Blaine fineness 418.6m2/kg and 444.6m2/kg respectively for 20MPa mass concrete under adiabatic condition. The estimation on adiabatic temperature rise by way of CIRIA C660 method (Construction Industry Research & Information Information) was adopted to verify and validate the hot-box test results by simulating the heat generation curve of the concrete under semi-adiabatic condition. Test result found that Portland fly-ash cement has exhibited decrease in the peak value of temperature rise and maximum temperature rise rate. The result showed that the temperature development and distribution profile, which is directly contributed from the heat of hydration of cement with time, is affected by the insulation, initial placing temperature, geometry and size of concrete mass. The mock up data showing the measured temperature differential is significantly lower than the technical specifications 20°C temperature differential requirement and the 27.7°C limiting temperature differential for granite aggregate concrete as stipulated in BS8110-2: 1985. The concrete strength test result revealed that the 28 days cubes compressive strength was above the stipulated 20MPa characteristic strength at 90 days. The test demonstrated that with proper concrete mix design, the use of Portland flyash cement, combination of chilled water and flake ice, and good insulation is effective in reducing peak temperature rise, temperature differential, and lower adiabatic temperature rise for mass concrete pours. As far as the determined adiabatic temperature rise result was concern, the established result could be inferred for in-situ thermal properties of 20MPa mass concrete application, as the result could be repeatable on account of similar type of constituent materials and concrete mix design adopted for permanent works at project site.

Impact of Air Entraining Method on the Resistance of Concrete to Internal Cracking

NASA Astrophysics Data System (ADS)

Wawrzeńczyk, Jerzy; Molendowska, Agnieszka

2017-10-01

This paper presents the test results of air entrained concrete mixtures made at a constant W/C ratio of 0.44. Three different air entraining agents were used: polymer microspheres, glass microspheres and a conventional air entraining admixture. The aim of this study was to compare the effectiveness of the air entraining methods. Concrete mixture tests were performed for consistency (slump test), density and, in the case of AEA series, air content by pressure method. Hardened concrete tests were performed for compressive strength, water absorption, resistance to chloride ingress, and freeze-thaw durability - resistance to internal cracking tests were conducted in accordance with PN-88/B-06250 on cube specimens and with the modified ASTM C666 A test method on beam specimens; porosity characteristics (A, A300, \\bar L) were determined to PN-EN 480-11:1998. No significant mass and length changes were recorded for the concrete air entrained with the conventional methods or with polymer microspheres. The results indicate that polymer microspheres are a very good alternative to traditional air entraining methods for concrete, providing effective air entrainment and protection from freezing and thawing. The glass microsphere-based concretes showed insufficient freeze-thaw resistance. The test results indicate that both the conventional methods (AEA) and the air entrainment by polymer microspheres are effective air entraining methods. It has to be noted that in the case of the use of polymer microspheres, a comparable value of \\bar L and a very good freeze-thaw resistance can be achieved at a noticeably lower air and micropore contents and at lower strength loss.

Concrete testing device provides substantial savings : fact sheet.

DOT National Transportation Integrated Search

2011-11-01

Current practices require a permeability test, ASTM C1202: "Standard Test Method for Electrical Indication of Concrete's Ability to resist Chloride Ion Penetration," for structures with potential salt water intrusion. The test is run at 56 days of ag...

Non-destructive testing of concrete.

DOT National Transportation Integrated Search

1979-11-01

This research project was initiated to evaluate the performance of an ultrasonic testing device device in predicting compressive strengths from tests performed on samples of fresh concrete. : The initial phase of this study involved laboratory perora...

Evaluation of acceptance strength tests for concrete pavements.

DOT National Transportation Integrated Search

2005-06-30

The North Carolina Department of Transportation has used traditionally flexural strength tests for acceptance : testing of Portland cement concrete pavements. This report summarizes a research project implemented to : investigate the feasibility of u...

Forensic testing of prestress concrete girders after forty years of service.

DOT National Transportation Integrated Search

2013-09-01

This report describes an investigation to quantify the behavior of precast, prestressed concrete : bridge girders made with high-strength concrete. As part of the investigation, four bridge : girders that were made with 77.2 MPs (11.2 ksi) concrete w...

Testing of Action of Direct Flame on Concrete

PubMed Central

Valek, Jaroslav; Novosad, Petr

2015-01-01

The paper states results of experimental exposition of concrete test specimens to direct flame. Concrete test specimens made from various mixtures differing in the type of aggregate, binder, dispersed reinforcement, and technological procedure were subjected to thermal load. Physicomechanical and other properties of all test specimens were tested before exposition to open flame: density, compressive strength, flexural strength, moisture content, and surface appearance. The specimens were visually observed during exposition to open flame and changes were recorded. Exposed surface was photographically documented before thermal load and at 10-minute intervals. Development of temperature of the specimens was documented with a thermocamera. After exposition to thermal load and cooling down, concrete specimens were visually observed, network of cracks was photographically documented, and maximal depth of spalled area was measured. PMID:25830162

The effect of water binder ratio and fly ash on the properties of foamed concrete

NASA Astrophysics Data System (ADS)

Saloma, Hanafiah, Urmila, Dea

2017-11-01

Foamed concrete is a lightweight concrete composed by cement, water, fine aggregate and evenly distributed foam. Foamed concrete is produced by adding foam to the mixture. The function of foam is to create air voids in the mixture, so the weight of the concrete becomes lighter. The foaming agent is diluted in water then given air pressure by foam generator to produce foam. This research utilizes coal combustion, which is fly ash as cementitious material with a percentage of 0%, 10%, 15%, and 20%. The purpose of the research is to examine the effect of water binder ratio 0.425, 0.450, 0.475, and 0.500 using fly ash on the properties of foamed concrete. Fresh concrete tests include slump flow and setting time test while hardened concrete tests include density and compressive strength. The maximum value of slump flow test result is 59.50 cm on FC-20-0.500 mixture with w/b = 0.500 and 20% of fly ash percentage. The results of the setting time tests indicate the fastest initial and final time are 335 and 720 minutes, respectively on FC-0-0.425 mixture with w/b = 0.425 without fly ash. The lowest density is 978.344 kg/m3 on FC-20-0.500 mixture with w/b = 0.500 and 20% of fly ash percentage. The maximum compressive strength value is 4.510 MPa at 28 days on FC-10-0.450 mixture with w/b = 0.450 and 10% of fly ash percentage.

Mechanical Properties and Eco-Efficiency of Steel Fiber Reinforced Alkali-Activated Slag Concrete

PubMed Central

Kim, Sun-Woo; Jang, Seok-Joon; Kang, Dae-Hyun; Ahn, Kyung-Lim; Yun, Hyun-Do

2015-01-01

Conventional concrete production that uses ordinary Portland cement (OPC) as a binder seems unsustainable due to its high energy consumption, natural resource exhaustion and huge carbon dioxide (CO2) emissions. To transform the conventional process of concrete production to a more sustainable process, the replacement of high energy-consumptive PC with new binders such as fly ash and alkali-activated slag (AAS) from available industrial by-products has been recognized as an alternative. This paper investigates the effect of curing conditions and steel fiber inclusion on the compressive and flexural performance of AAS concrete with a specified compressive strength of 40 MPa to evaluate the feasibility of AAS concrete as an alternative to normal concrete for CO2 emission reduction in the concrete industry. Their performances are compared with reference concrete produced using OPC. The eco-efficiency of AAS use for concrete production was also evaluated by binder intensity and CO2 intensity based on the test results and literature data. Test results show that it is possible to produce AAS concrete with compressive and flexural performances comparable to conventional concrete. Wet-curing and steel fiber inclusion improve the mechanical performance of AAS concrete. Also, the utilization of AAS as a sustainable binder can lead to significant CO2 emissions reduction and resources and energy conservation in the concrete industry. PMID:28793639

Us army corps of engineers - Engineering research and development center - Petrographic analysis of section 3 personnel tunnel concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, J. M.

The Concrete and Materials Branch (CMB) of the Geotechnical and Structures Laboratory was requested to perform an analysis on concrete cores collected from the north and south walls of the H-Canyon Section 3 Personnel Tunel, Savannah River Site, Aiken, South Carolina to determine the cause of the lower than expected compressive strength. This study examined five cores provided to the ERDC by the Department of Energy. The cores were logged in as CMB No. 170051-1 to 170051-5 and subjected to petrographic examination, air void analysis, chemical sprays, scanning electron microscopy, and x-ray diffraction.

Design and testing of tubular polymeric capsules for self-healing of concrete

NASA Astrophysics Data System (ADS)

Araújo, M.; Van Tittelboom, K.; Feiteira, J.; Gruyaert, E.; Chatrabhuti, S.; Raquez, J.-M.; Šavija, B.; Alderete, N.; Schlangen, E.; De Belie, N.

2017-10-01

Polymeric healing agents have proven their efficiency to heal cracks in concrete in an autonomous way. However, the bottleneck for valorisation of self-healing concrete with polymeric healing agents is their encapsulation. In the present work, the suitability of polymeric materials such as poly(methyl methacrylate) (PMMA), polystyrene (PS) and poly(lactic acid) (PLA) as carriers for healing agents in self-healing concrete has been evaluated. The durability of the polymeric capsules in different environments (demineralized water, salt water and simulated concrete pore solution) and their compatibility with various healing agents have been assessed. Next, a numerical model was used to simulate capsule rupture when intersected by a crack in concrete and validated experimentally. Finally, two real-scale self-healing concrete beams were made, containing the selected polymeric capsules (with the best properties regarding resistance to concrete mixing and breakage upon crack formation) or glass capsules and a reference beam without capsules. The self-healing efficiency was determined after crack creation by 3-point-bending tests.

Effect of notch position on fracture energy for foamed concrete

NASA Astrophysics Data System (ADS)

Naqiuddin Zamri, Mohd; Rahman, Norashidah Abd; Jaini, Zainorizuan Mohd; Shamila Bahador, Nurul

2017-11-01

Foamed concrete is one of the lightweight concrete used to replace normal concrete. Foamed concrete has potential as a building construction material in Malaysia due to low density range. However, the behavior of fracture energy on foamed concrete still under investigation. Therefore, a study to determine the fracture energy of foamed concrete was conducted. In this study, foamed concrete fracture energy was obtained using the three-point bending test methods develop by RILEM and Hillerborg. A total of 12 beams with different types of notch and positions of notch were tested on the load-deflection condition. In addition, a total of 9 cube samples were cast to support the result of fracture energy by using model from Bazant and Becq-Giraudon and Comite Euro-International du Beton (CEB). Results showed the far the position of the notch from midpoint, the higher the value of fracture energy. In this study, the value of fracture energy ranges between 15 N/m and 40 N/m.

Increased Durability of Concrete Made with Fine Recycled Concrete Aggregates Using Superplasticizers

PubMed Central

Cartuxo, Francisco; de Brito, Jorge; Evangelista, Luis; Jiménez, José Ramón; Ledesma, Enrique F.

2016-01-01

This paper evaluates the influence of two superplasticizers (SP) on the durability properties of concrete made with fine recycled concrete aggregate (FRCA). For this purpose, three families of concrete were tested: concrete without SP, concrete made with a regular superplasticizer and concrete made with a high-performance superplasticizer. Five volumetric replacement ratios of natural sand by FRCA were tested: 0%, 10%, 30%, 50% and 100%. Two natural gravels were used as coarse aggregates. All mixes had the same particle size distribution, cement content and amount of superplasticizer. The w/c ratio was calibrated to obtain similar slump. The results showed that the incorporation of FRCA increased the water absorption by immersion, the water absorption by capillary action, the carbonation depth and the chloride migration coefficient, while the use of superplasticizers highly improved these properties. The incorporation of FRCA jeopardized the SP’s effectiveness. This research demonstrated that, from a durability point of view, the simultaneous incorporation of FRCA and high-performance SP is a viable sustainable solution for structural concrete production. PMID:28787905

Evaluation of shrinkage and cracking in concrete of ring test by acoustic emission method

NASA Astrophysics Data System (ADS)

Watanabe, Takeshi; Hashimoto, Chikanori

2015-03-01

Drying shrinkage of concrete is one of the typical problems related to reduce durability and defilation of concrete structures. Lime stone, expansive additive and low-heat Portland cement are used to reduce drying shrinkage in Japan. Drying shrinkage is commonly evaluated by methods of measurement for length change of mortar and concrete. In these methods, there is detected strain due to drying shrinkage of free body, although visible cracking does not occur. In this study, the ring test was employed to detect strain and age cracking of concrete. The acoustic emission (AE) method was adopted to detect micro cracking due to shrinkage. It was recognized that in concrete using lime stone, expansive additive and low-heat Portland cement are effective to decrease drying shrinkage and visible cracking. Micro cracking due to shrinkage of this concrete was detected and evaluated by the AE method.

Portable apparatus with CRT display for nondestructive testing of concrete by the ultrasonic pulse method

NASA Technical Reports Server (NTRS)

Manta, G.; Gurau, Y.; Nica, P.; Facacaru, I.

1974-01-01

The development of methods for the nondestructive study of concrete structures is discussed. The nondestructive test procedure is based on the method of ultrasonic pulse transmission through the material. The measurements indicate that the elastic properties of concrete or other heterogeneous materials are a function of the rate of ultrasonic propagation. Diagrams of the test equipment are provided. Mathematical models are included to support the theoretical aspects.

Axial Compression Behavior of a New Type of Prefabricated Concrete Sandwich Wall Panel

NASA Astrophysics Data System (ADS)

Qun, Xie; Shuai, Wang; Chun, Liu

2018-03-01

A novel type of prefabricated concrete sandwich wall panel which could be used as a load-bearing structural element in buildings has been presented in this paper. Compared with the traditional sandwich panels, there are several typical characteristics for this wall system, including core columns confined by spiral stirrup along the cross-section of panel with 600mm spacing, precast foamed concrete block between two structural layers as internal insulation part, and a three-dimensional (3D) steel wire skeleton in each layer which is composed of two vertical steel wire meshes connected by horizontally short steel bar. All steel segments in the panel are automatically prefabricated in factory and then are assembled to form steel system in site. In order to investigate the structural behavior of this wall panel, two full-scale panels have been experimentally studied under axial compressive load. The test results show that the wall panel presents good load-bearing capacity and integral stiffness without out-of-plane flexural failure. Compared to the panel with planar steel wire mesh in concrete layer, the panel with 3D steel wire skeleton presents higher strength and better rigidity even in the condition of same steel ratio in panels which verifies that the 3D steel skeleton could greatly enhance the structural behavior of sandwich panel.

Crumb rubber modified asphalt concrete in Oregon : final report.

DOT National Transportation Integrated Search

2002-03-01

Since 1993, the Oregon Department of Transportation (ODOT) has been monitoring performance of seventeen rubber modified : asphalt and asphalt concrete sections constructed on Oregon highways. The study originated in response to the Intermodal Surface...

Premature deterioration of jointed plain concrete pavements.

DOT National Transportation Integrated Search

2011-04-29

Six sections of jointed plain concrete pavements (JPCP)s throughout the state were selected as candidates for the evaluation of premature deterioration. The data used in performing the evaluation included manual and historic automated distress survey...

Premature deterioration of jointed plain concrete pavements.

DOT National Transportation Integrated Search

2011-04-29

Six sections of jointed plain concrete pavements (JPCP)s throughout the state were selected as : candidates for the evaluation of premature deterioration. The data used in performing the evaluation included manual : and historic automated distress su...

Steel Fibers Reinforced Concrete Pipes - Experimental Tests and Numerical Simulation

NASA Astrophysics Data System (ADS)

Doru, Zdrenghea

2017-10-01

The paper presents in the first part a state of the art review of reinforced concrete pipes used in micro tunnelling realised through pipes jacking method and design methods for steel fibres reinforced concrete. In part two experimental tests are presented on inner pipes with diameters of 1410mm and 2200mm, and specimens (100x100x500mm) of reinforced concrete with metal fibres (35 kg / m3). In part two experimental tests are presented on pipes with inner diameters of 1410mm and 2200mm, and specimens (100x100x500mm) of reinforced concrete with steel fibres (35 kg / m3). The results obtained are analysed and are calculated residual flexural tensile strengths which characterise the post-cracking behaviour of steel fibres reinforced concrete. In the third part are presented numerical simulations of the tests of pipes and specimens. The model adopted for the pipes test was a three-dimensional model and loads considered were those obtained in experimental tests at reaching breaking forces. Tensile stresses determined were compared with mean flexural tensile strength. To validate tensile parameters of steel fibres reinforced concrete, experimental tests of the specimens were modelled with MIDAS program to reproduce the flexural breaking behaviour. To simulate post - cracking behaviour was used the method σ — ε based on the relationship stress - strain, according to RILEM TC 162-TDF. For the specimens tested were plotted F — δ diagrams, which have been superimposed for comparison with the similar diagrams of experimental tests. The comparison of experimental results with those obtained from numerical simulation leads to the following conclusions: - the maximum forces obtained by numerical calculation have higher values than the experimental values for the same tensile stresses; - forces corresponding of residual strengths have very similar values between the experimental and numerical calculations; - generally the numerical model estimates a breaking force greater than that obtained in the experimental tests. Experimental and numerical studies are used to establish the residual characteristic flexural tensile strength minimum guaranteed and limits of applicability of concrete pipes reinforced with steel fibres used in various field and loading situations.

Porosimetric, Thermal and Strength Tests of Aerated and Nonaerated Concretes

NASA Astrophysics Data System (ADS)

Strzałkowski, Jarosław; Garbalińska, Halina

2017-10-01

The paper presents the results of porosimetry tests of lightweight concretes, obtained with three research methods. Impact of different porosity structures on the basic thermal and strength properties was also evaluated. Tests were performed, using the pressure gauge method on fresh concrete mixes, as well as using the mercury porosimetry test and optic RapidAir method on specimens prepared from mature composites. The study was conducted on lightweight concretes, based on expanded clay aggregate and fly ash aggregate, in two variants: with non-aerated and aerated cement matrix. In addition, two reference concretes, based on normal aggregate, were prepared, also in two variants of matrix aeration. Changes in thermal conductivity λ and volumetric specific heat cv throughout the first three months of curing of the concretes were examined. Additionally, tests for compressive strength on cubic samples were performed during the first three months of curing. It was found that the pressure gauge method, performed on a fresh mix, gave lowered values of porosity, compared to the other methods. The mercury porosity tests showed high sensitivity in evaluation of pores smaller than 30μm. Unfortunately, this technique is not suitable for analysing pores greater than 300μm. On the other hand, the optical method proves good in evaluation of large pores, greater than 300μm. The paper also presents results of correlation of individual methods of porosity testing. A consolidated graph of the pore structure, derived from both mercury and optical methods, was presented, too. For the all of six tested concretes, differential graphs of porosity, prepared with both methods, show a very broad convergence. The thermal test results indicate usefulness of aeration of the cement matrix of the composites based on lightweight aggregates for the further reduction of the thermal conductivity coefficient λ of the materials. The lowest values of the λ coefficient were obtained for the aerated concretes based of fly ash aggregate. A diminishing influence of aeration on the volumetric heat capacity cv is clearly seen. Simultaneous aeration of the matrix and use of lightweight aggregates brought about also a significant decrease in the average compressive strength fcm of the tested composites.

Novel Concrete Temperature Monitoring Method Based on an Embedded Passive RFID Sensor Tag.

PubMed

Liu, Yongsheng; Deng, Fangming; He, Yigang; Li, Bing; Liang, Zhen; Zhou, Shuangxi

2017-06-22

This paper firstly introduces the importance of temperature control in concrete measurement, then a passive radio frequency identification (RFID) sensor tag embedded for concrete temperature monitoring is presented. In order to reduce the influences of concrete electromagnetic parameters during the drying process, a T-type antenna is proposed to measure the concrete temperature at the required depth. The proposed RFID sensor tag is based on the EPC generation-2 ultra-high frequency (UHF) communication protocol and operates in passive mode. The temperature sensor can convert the sensor signals to corresponding digital signals without an external reference clock due to the adoption of phase-locked loop (PLL)-based architecture. Laboratory experimentation and on-site testing demonstrate that our sensor tag embedded in concrete can provide reliable communication performance in passive mode. The maximum communicating distance between reader and tag is 7 m at the operating frequency of 915 MHz and the tested results show high consistency with the results tested by a thermocouple.

Compressive strength performance of OPS lightweight aggregate concrete containing coal bottom ash as partial fine aggregate replacement

NASA Astrophysics Data System (ADS)

Muthusamy, K.; Mohamad Hafizuddin, R.; Mat Yahaya, F.; Sulaiman, M. A.; Syed Mohsin, S. M.; Tukimat, N. N.; Omar, R.; Chin, S. C.

2018-04-01

Concerns regarding the negative impact towards environment due to the increasing use of natural sand in construction industry and dumping of industrial solid wastes namely coal bottom ash (CBA) and oil palm shell (OPS) has resulted in the development of environmental friendly lightweight concrete. The present study investigates the effect of coal bottom ash as partial fine aggregate replacement towards workability and compressive strength of oil palm shell lightweight aggregate concrete (OPS LWAC). The fresh and mechanical properties of this concrete containing various percentage of coal bottom ash as partial fine aggregate replacement were investigated. The result was compared to OPS LWAC with 100 % sand as a control specimen. The concrete workability investigated by conducting slump test. All specimens were cast in form of cubes and water cured until the testing age. The compressive strength test was carried out at 7 and 28 days. The finding shows that integration of coal bottom ash at suitable proportion enhances the strength of oil palm shell lightweight aggregate concrete.

Reuse of municipal solid wastes incineration fly ashes in concrete mixtures.

PubMed

Collivignarelli, Carlo; Sorlini, Sabrina

2002-01-01

This study is aimed at assessing the feasibility of concrete production using stabilized m.s.w. (municipal solid waste) incineration fly ashes in addition to natural aggregates. The tested fly ashes were washed and milled, then stabilized by a cement-lime process and finally were reused as a "recycled aggregate" for cement mixture production, in substitution of a natural aggregate (with dosage of 200-400 kg m(-3)). These mixtures, after curing, were characterized with conventional physical-mechanical tests (compression, traction, flexure, modulus of elasticity, shrinkage). In samples containing 200 kg(waste) m(-3)(concrete), a good compressive strength was achieved after 28 days of curing. Furthermore, concrete leaching behavior was evaluated by means of different leaching tests, both on milled and on monolithic samples. Experimental results showed a remarkable reduction of metal leaching in comparison with raw waste. In some cases, similar behavior was observed in "natural" concrete (produced with natural aggregates) and in "waste containing" concrete.

Novel Concrete Temperature Monitoring Method Based on an Embedded Passive RFID Sensor Tag

PubMed Central

Liu, Yongsheng; Deng, Fangming; He, Yigang; Li, Bing; Liang, Zhen; Zhou, Shuangxi

2017-01-01

This paper firstly introduces the importance of temperature control in concrete measurement, then a passive radio frequency identification (RFID) sensor tag embedded for concrete temperature monitoring is presented. In order to reduce the influences of concrete electromagnetic parameters during the drying process, a T-type antenna is proposed to measure the concrete temperature at the required depth. The proposed RFID sensor tag is based on the EPC generation-2 ultra-high frequency (UHF) communication protocol and operates in passive mode. The temperature sensor can convert the sensor signals to corresponding digital signals without an external reference clock due to the adoption of phase-locked loop (PLL)-based architecture. Laboratory experimentation and on-site testing demonstrate that our sensor tag embedded in concrete can provide reliable communication performance in passive mode. The maximum communicating distance between reader and tag is 7 m at the operating frequency of 915 MHz and the tested results show high consistency with the results tested by a thermocouple. PMID:28640188

An Experimental Study on Shrinkage Strains of Normal-and High-Strength Concrete-Filled Frp Tubes

NASA Astrophysics Data System (ADS)

Vincent, Thomas; Ozbakkaloglu, Togay

2017-09-01

It is now well established that concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs) are an attractive construction technique for new columns, however studies examining concrete shrinkage in CFFTs remain limited. Concrete shrinkage may pose a concern for CFFTs, as in these members the curing of concrete takes place inside the FRP tube. This paper reports the findings from an experimental study on concrete shrinkage strain measurements for CFFTs manufactured with normal- and high-strength concrete (NSC and HSC). A total of 6 aramid FRP (AFRP)-confined concrete specimens with circular cross-sections were manufactured, with 3 specimens each manufactured using NSC and HSC. The specimens were instrumented with surface and embedded strain gauges to monitor shrinkage development of exposed concrete and concrete sealed inside the CFFTs, respectively. All specimens were cylinders with a 152 mm diameter and 305 mm height, and their unconfined concrete strengths were 44.8 or 83.2 MPa. Analysis of the shrinkage measurements from concrete sealed inside the CFFTs revealed that embedment depth and concrete compressive strength only had minor influences on recorded shrinkage strains. However, an analysis of shrinkage measurements from the exposed concrete surface revealed that higher amounts of shrinkage can occur in HSC. Finally, it was observed that shrinkage strains are significantly higher for concrete exposed at the surface compared to concrete sealed inside the CFFTs.

Effects of Medium Temperature and Industrial By-Products on the Key Hardened Properties of High Performance Concrete.

PubMed

Safiuddin, Md; Raman, Sudharshan N; Zain, Muhammad Fauzi Mohd

2015-12-10

The aim of the work reported in this article was to investigate the effects of medium temperature and industrial by-products on the key hardened properties of high performance concrete. Four concrete mixes were prepared based on a water-to-binder ratio of 0.35. Two industrial by-products, silica fume and Class F fly ash, were used separately and together with normal portland cement to produce three concrete mixes in addition to the control mix. The properties of both fresh and hardened concretes were examined in the laboratory. The freshly mixed concrete mixes were tested for slump, slump flow, and V-funnel flow. The hardened concretes were tested for compressive strength and dynamic modulus of elasticity after exposing to 20, 35 and 50 °C. In addition, the initial surface absorption and the rate of moisture movement into the concretes were determined at 20 °C. The performance of the concretes in the fresh state was excellent due to their superior deformability and good segregation resistance. In their hardened state, the highest levels of compressive strength and dynamic modulus of elasticity were produced by silica fume concrete. In addition, silica fume concrete showed the lowest level of initial surface absorption and the lowest rate of moisture movement into the interior of concrete. In comparison, the compressive strength, dynamic modulus of elasticity, initial surface absorption, and moisture movement rate of silica fume-fly ash concrete were close to those of silica fume concrete. Moreover, all concretes provided relatively low compressive strength and dynamic modulus of elasticity when they were exposed to 50 °C. However, the effect of increased temperature was less detrimental for silica fume and silica fume-fly ash concretes in comparison with the control concrete.

Effects of Medium Temperature and Industrial By-Products on the Key Hardened Properties of High Performance Concrete

PubMed Central

Safiuddin, Md.; Raman, Sudharshan N.; Zain, Muhammad Fauzi Mohd.

2015-01-01

The aim of the work reported in this article was to investigate the effects of medium temperature and industrial by-products on the key hardened properties of high performance concrete. Four concrete mixes were prepared based on a water-to-binder ratio of 0.35. Two industrial by-products, silica fume and Class F fly ash, were used separately and together with normal portland cement to produce three concrete mixes in addition to the control mix. The properties of both fresh and hardened concretes were examined in the laboratory. The freshly mixed concrete mixes were tested for slump, slump flow, and V-funnel flow. The hardened concretes were tested for compressive strength and dynamic modulus of elasticity after exposing to 20, 35 and 50 °C. In addition, the initial surface absorption and the rate of moisture movement into the concretes were determined at 20 °C. The performance of the concretes in the fresh state was excellent due to their superior deformability and good segregation resistance. In their hardened state, the highest levels of compressive strength and dynamic modulus of elasticity were produced by silica fume concrete. In addition, silica fume concrete showed the lowest level of initial surface absorption and the lowest rate of moisture movement into the interior of concrete. In comparison, the compressive strength, dynamic modulus of elasticity, initial surface absorption, and moisture movement rate of silica fume-fly ash concrete were close to those of silica fume concrete. Moreover, all concretes provided relatively low compressive strength and dynamic modulus of elasticity when they were exposed to 50 °C. However, the effect of increased temperature was less detrimental for silica fume and silica fume-fly ash concretes in comparison with the control concrete. PMID:28793732

Probabilistic design of fibre concrete structures

NASA Astrophysics Data System (ADS)

Pukl, R.; Novák, D.; Sajdlová, T.; Lehký, D.; Červenka, J.; Červenka, V.

2017-09-01

Advanced computer simulation is recently well-established methodology for evaluation of resistance of concrete engineering structures. The nonlinear finite element analysis enables to realistically predict structural damage, peak load, failure, post-peak response, development of cracks in concrete, yielding of reinforcement, concrete crushing or shear failure. The nonlinear material models can cover various types of concrete and reinforced concrete: ordinary concrete, plain or reinforced, without or with prestressing, fibre concrete, (ultra) high performance concrete, lightweight concrete, etc. Advanced material models taking into account fibre concrete properties such as shape of tensile softening branch, high toughness and ductility are described in the paper. Since the variability of the fibre concrete material properties is rather high, the probabilistic analysis seems to be the most appropriate format for structural design and evaluation of structural performance, reliability and safety. The presented combination of the nonlinear analysis with advanced probabilistic methods allows evaluation of structural safety characterized by failure probability or by reliability index respectively. Authors offer a methodology and computer tools for realistic safety assessment of concrete structures; the utilized approach is based on randomization of the nonlinear finite element analysis of the structural model. Uncertainty of the material properties or their randomness obtained from material tests are accounted in the random distribution. Furthermore, degradation of the reinforced concrete materials such as carbonation of concrete, corrosion of reinforcement, etc. can be accounted in order to analyze life-cycle structural performance and to enable prediction of the structural reliability and safety in time development. The results can serve as a rational basis for design of fibre concrete engineering structures based on advanced nonlinear computer analysis. The presented methodology is illustrated on results from two probabilistic studies with different types of concrete structures related to practical applications and made from various materials (with the parameters obtained from real material tests).

Abstract and concrete repetitive thinking modes in alcohol-dependence.

PubMed

Grynberg, Delphine; de Timary, Philippe; Philippot, Pierre; D'Hondt, Fabien; Briane, Yasmine; Devynck, Faustine; Douilliez, Céline; Billieux, Joël; Heeren, Alexandre; Maurage, Pierre

2016-01-01

Emotional and interpersonal deficits play a crucial role in alcohol-related disorders as they predict alcohol consumption and relapse. Recent models of emotion regulation in psychopathology postulate that these deficits are centrally related to increased abstract/analytic repetitive thinking, combined with reduced concrete/experiential repetitive thinking. As this assumption has not been tested in addictions, this study aimed at investigating repetitive thinking modes in a large sample of alcohol-dependent individuals. One hundred recently detoxified alcohol-dependent individuals (29 females; mean age = 49.51-years-old) recruited during the 3rd week of their treatment in a detoxification center were compared to 100 healthy controls (29 females; mean age = 48.51-years-old) recruited in the experimenters' social network, matched at the group level for age, gender, and educational level. All participants completed the Mini Cambridge Exeter Repetitive Thought Scale measuring abstract/analytic and concrete/experiential repetitive thinking modes as well as complementary psychopathological measures (Beck Depression Inventory and State/Trait Anxiety Inventory). Alcohol-dependent individuals have similar levels of concrete repetitive thinking as controls but report significantly higher levels of abstract repetitive thinking (p < 0.001; d = 1.28). This effect remains significant after controlling for depression and anxiety. Relative to healthy controls, alcohol-dependent patients report more frequent use of abstract/analytic repetitive thinking, with preserved concrete/experiential thinking. Despite the cross-sectional nature of the study, the frequent use of abstract repetitive thinking thus appears to constitute a main feature of alcohol-dependence.

CONCRETE BLOCKS' ADVERSE EFFECTS ON INDOOR AIR AND RECOMMENDED SOLUTIONS

EPA Science Inventory

Air infiltration through highly permeable concrete blocks can allow entry of various serious indoor air pollutants. An easy approach to avoiding these pollutants is to select a less–air-permeable concrete block. Tests show that air permeability of concrete blocks can vary by a fa...

Lessons to be learned from rehabilitation of concrete structures in bleach plants in pulp and paper mills

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nixon, R.

The deterioration of concrete structures due to chloride induced reinforcing steel corrosion such as in elevated concrete floor slabs, columns, and beams in bleach plants is a constant and growing problem within the pulp and paper industry. In general, the condition analysis methods used for assessing the extent of bleach plant concrete degradation include physical testing of drilled concrete core samples, chloride ion concentration testing, half-cell potential measurements, and physical sounding of concrete surfaces, i.e. chain drag for topside surfaces and hammer sounding of soffit surfaces. While this paper does not promote any vastly different evaluative methods, it does sharemore » learnings relative to interpreting the data provided by these typical test methods. It further offers some recommendations on how to improve the use of these typical evaluation techniques and offers some other test methods which should be considered as valuable additions for such evaluations. One of the most common methods which has been used in the past for large scale bleach plant concrete restoration has been the application of site dry mixed shotcrete for rebuilding the soffits of floor slabs and the faces of columns and beams. More often than not, bulk mixed dry shotcrete repairs have not been cost-effective because they prematurely failed due to excessive hydration related shrinkage cracking, lack of sufficient adhesion to the parent concrete substrate or other problems related to poor durability or construction practice.« less

Development of Vegetation-Pervious Concrete in Grid Beam System for Soil Slope Protection

PubMed Central

Bao, Xiaohua; Liao, Wenyu; Dong, Zhijun; Wang, Shanyong; Tang, Waiching

2017-01-01

One of the most efficient and environmentally friendly methods for preventing a landslide on a slope is to vegetate it. Vegetation-pervious concretes have a promising potential for soil protection. In this study, the vegetation-pervious concrete with low alkalinity was developed and studied. Combined with a grid beam structure system, the stability and strength between the vegetation-pervious concrete and base soil are believed to be enhanced effectively. For improving plant adaptability, the alkalinity of concrete can be decreased innovatively by adding a self-designed admixture into the cement paste. The effects of the admixture content on alkalinity and compressive strength of the hardened pervious concrete were investigated using X-ray diffraction (XRD) and compression test, respectively. Meanwhile, the permeability of the vegetation-pervious concrete was studied as well. Through comparing with ordinary pervious concrete, the effect of low alkaline pervious concrete on vegetation growth was investigated in a small-scale field for ten weeks. The test results indicated that the alkalinity of the cement samples decreased with the increase of admixture content, and the vegetation grew successfully on previous concrete. By increasing the admixture content to approximately 3.6%, the compressive strength of pervious concrete was more than 25 MPa. PMID:28772454

Experimental Study on Welded Headed Studs Used In Steel Plate-Concrete Composite Structures Compared with Contactless Method of Measuring Displacement

NASA Astrophysics Data System (ADS)

Kisała, Dawid; Tekieli, Marcin

2017-10-01

Steel plate-concrete composite structures are a new innovative design concept in which a thin steel plate is attached to the reinforced concrete beam by means of welded headed studs. The comparison between experimental studies and theoretical analysis of this type of structures shows that their behaviour is dependent on the load-slip relationship of the shear connectors used to ensure sufficient bond between the concrete and steel parts of the structure. The aim of this paper is to describe an experimental study on headed studs used in steel plate-concrete composite structures. Push-out tests were carried out to investigate the behaviour of shear connectors. The test specimens were prepared according to standard push-out tests, however, instead of I-beam, a steel plate 16 mm thick was used to better reflect the conditions in the real structure. The test specimens were produced in two batches using concrete with significantly different compressive strength. The experimental study was carried out on twelve specimens. Besides the traditional measurements based on LVDT sensors, optical measurements based on the digital image correlation method (DIC) and pattern tracking methods were used. DIC is a full-field contactless optical method for measuring displacements in experimental testing, based on the correlation of the digital images taken during test execution. With respect to conventional methods, optical measurements offer a wider scope of results and can give more information about the material or construction behaviour during the test. The ultimate load capacity and load-slip curves obtained from the experiments were compared with the values calculated based on Eurocodes, American and Chinese design specifications. It was observed that the use of the relationships developed for the traditional steel-concrete composite structures is justified in the case of ultimate load capacity of shear connectors in steel plate-concrete composite structures.

Experimental investigation and damage assessment in a post tensioned concrete beam

NASA Astrophysics Data System (ADS)

Limongelli, Maria; Siegert, Dominique; Merliot, Erick; Waeytens, Julien; Bourquin, Frederic; Vidal, Roland; Le Corvec, Veronique; Guegen, Ivan; Cottineau, Louis-Marie

2017-04-01

This paper presents the results of an experimental campaign carried out on a prestressed concrete beam in the realm of the project SIPRIS (Systèmes Intelligents pour la Prévention des Risques Structurels), aimed to develop intelligent systems for the prevention of structural risk related to the aging of large infrastructures. The specimen was tested in several configurations aimed to re-produce several different phases of the 'life' of the beam: in the original undamaged state, under an increasing loss of tension in the cables, during and after cracking induced by a point load, after a strengthening intervention, after new cracking of the 'repaired' beam. Damage was introduced in a controlled way by means of three-point static bending tests. The transverse point loads were ap-plied at several different sections along the beam axis. Before and after each static test, the dy-namical response of the beam was measured under sine-sweep and impact tests by an extensive set of accelerometers deployed along the beam axis. The availability of both static and dynamic tests allows to investigate and compare their effectiveness to detect damages in the tensioned beam and to reliably identify the evolution of damage. The paper discusses the tests program and some results relevant to the dynamic characterization of the beam in the different phases.

Paleo-fluid flow in folded, poorly lithified Quaternary sediments revealed by diagenetic concretions developed during the growth of Quattro Castella Anticline (Northern Apennines, Italy)

NASA Astrophysics Data System (ADS)

Pizzati, Mattia; Balsamo, Fabrizio; Iacumin, Paola; Swennen, Rudy; Storti, Fabrizio

2017-04-01

Diagenetic concretions and mineral masses may provide a useful tool to better understand paleo-fluid flows in transforming porous media. Moreover, the selective cementation responsible of diagenetic alterations formation, plays a key role in diminishing sediments porosity and permeability and hence reservoir quality. In compressive settings of a fold-and-thrust-belt, the presence of deep or blind thrusts could lead to the generation of folds which may influence syn-kinematic sedimentation, deep fluids migration and shallow fluid flow pattern. In this contribution we present a multidisciplinary field and laboratory study on carbonate concretions developed in Quaternary poorly lithified, shallow marine syn-kinematic sediments of the Quattro Castella Anticline in Northern Apennines (Italy). The study site is located along the Enza River, where shallow marine to continental sediments are exposed along the forelimb of the fold nucleated during Late Miocene and still active today. Field mapping was aimed to link bedding attitude of syn-kinematic sediments with the geometry, arrangement, shape and size of concretionary bodies. The studied concretions are both tabular (i.e. parallel to sediment bedding) and elongate single or coalescent concretionary bodies (i.e. plunging at different angle to bedding dip throughout the stratigraphic section). Concretions dimensions range from a few centimeters in single elongate concretions, up to a few meters in tabular and coalescent ones. In situ permeability measurements and laboratory grain size analyses were performed along the studied section to constrain the petrophysical properties of sediments hosting carbonate concretions. Carbon and oxygen stable isotopes analyses on carbonate concretions (performed both on hand specimens and also on thin sections), together with petrographic and cathodoluminescence observations, were used to better constrain the diagenetic environment in which calcite precipitation occurred. Our results indicate that the growing anticline promoted the development of a local topographic and hydraulic gradient which induced cement precipitation in the form of carbonate concretions in syn-kinematic sediments. Such diagenetic alterations can be a good marker to reconstruct the paleo-fluid flow history in structurally complex siliciclastic reservoirs.

Effect of boron waste on the properties of mortar and concrete.

PubMed

Topçu, Iker Bekir; Boga, Ahmet Raif

2010-07-01

Utilization of by-products or waste materials in concrete production are important subjects for sustainable development and industrial ecology concepts. The usages as mineral admixtures or fine aggregates improve the durability properties of concrete and thus increase the economic and environmental advantages for the concrete industry. The effect of clay waste (CW) containing boron on the mechanical properties of concrete was investigated. CW was added in different proportions as cement additive in concrete. The effect of CW on workability and strength of concrete were analysed by fresh and hardened concrete tests. The results obtained were compared with control concrete properties and Turkish standard values. The results showed that the addition of CW had a small effect upon the workability of the concrete but an important effect on the reduction of its strength. It was observed that strength values were quite near to that of control concrete when not more than 10% CW was used in place of cement. In addition to concrete specimens, replacing cement with CW produced mortar specimens, which were investigated for their strength and durability properties. The tests of SO( 4) (2-) and Cl(-) effect as well as freeze-thaw behaviour related to the durability of mortar were performed. Consequently, it can be said that some improvements were obtained in durability properties even if mechanical properties had decreased with increasing CW content.

Experimental thermal characterization of concrete to be used in CP5.2 packaging system

NASA Astrophysics Data System (ADS)

Lo Frano, R.; Maggini, A.; Aquaro, D.

2017-01-01

This work deals with the experimental evaluation of the thermal conductivity of a concrete matrix to be used for embedding LILW bituminised Wastes into the packaging system. Such a type of packaging, identified with the acronym CP5.2, has been also qualified by executing at the Lab. Scalbatraio of Dep. of Civil and Industrial Engineering of the University of Pisa, an experimental test campaign accordingly to the IAEA regulations. In particular, the knowledge of the thermal conductivity is important because of the fire or furnace test to carry out in oven at 800 °C for 30 minutes. These data allowed to simulate pre-test conditions and to set up safety and operational fire test procedures. The concrete thermal conductivity was obtained by performing hot wire tests on cylindrical concrete samples for temperatures ranging from 100° to about 800°C. Thermal conductivity is determined at steady state condition. Results indicate a monotonically reduction of the thermal conductivity as the temperature increases. The comparison with concrete thermal conductivity data available in literature indicates a quite good agreement. Finally, visual and X-ray inspection of sample did not highlight the presence of micro/macro damages that would have affected the thermal performance of the concrete under study.

Asphalt concrete properties and performance in Alaska : final report

DOT National Transportation Integrated Search

1981-07-01

This report examines asphalt pavement properties of 117 older highway sections within the State of Alaska. Principal research objectives included: 1) documentation of commonly measured physical properties of the asphalt concrete cores and extracted a...

Performance evaluation of precast prestressed concrete pavement.

DOT National Transportation Integrated Search

2007-11-01

This report describes in detail an experimental investigation of an innovative precast prestressed concrete pavement (PPCP) system used to rehabilitate a 1,000 ft. section of interstate highway located on the northbound lanes of I-57 near Charleston,...

AC/CRC adjacent lane surfacing : construction report.

DOT National Transportation Integrated Search

1991-06-01

Asphaltic Concrete (AC) and Portland Cement Concrete (PCC) are common roadway materials used in Oregon. In a recent construction project -- Poverty Flats/Mecham Section -- the Oregon State Highway Division (OSHD) designed, as part of the project, a "...

Evaluation of self-consolidating concrete.

DOT National Transportation Integrated Search

2003-01-01

Conventional concrete tends to present a problem with regard to adequate consolidation in thin sections or areas of congested reinforcement, which leads to a large volume of entrapped air voids and compromises the strength and durability of the concr...

Design and evaluation of high-volume fly ash (HVFA) concrete mixes, report D : creep, shrinkage, and abrasion resistance of HVFA concrete.

DOT National Transportation Integrated Search

2012-10-01

The main objective of this study was to determine the effect on shrinkage, creep, : and abrasion resistance of high-volume fly ash (HVFA) concrete. The HVFA concrete : test program consisted of comparing the shrinkage, creep, and abrasion performance...

Experimental analysis of energy absorption behaviour of Al-tube filled with pumice lightweight concrete under axial loading condition

NASA Astrophysics Data System (ADS)

Rajak, D. K.; Deshpande, P. G.; Kumaraswamidhas, L. A.

2017-08-01

This Paper aimed at experimental investigation of compressive behaviour of square tube filled with pumice lightweight concrete (PLC). Square section of 20×20×30 mm is investigated, which is the backbone structure. The compression deformation result shows the better folding mechanism, displacement value, and energy absorption. PLC concrete filled with aluminium thin-wall tubes has been revealed superior energy absorption capacity (EAC) under low strain rate at room temperature. Superior EAC resulted as a result of mutual deformation benefit between aluminium section and PLC is also analysed. PLC was characterised by Fourier Transform Infrared (FTIR) and Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive X-ray Spectrometry (EDX) analysis for better understanding of material behaviour. Individual and comparative load bearing graphs is logged for better prospective of analysing. Novel approach aimed at validation of porous lightweight concrete for better lightweight EA filler material.

27. DIVERSION STRUCTURE WITH CONCRETE SIDEWALLS AND CONCRETE CHANNEL BEYOND, ...

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

27. DIVERSION STRUCTURE WITH CONCRETE SIDEWALLS AND CONCRETE CHANNEL BEYOND, A SHORT DISTANCE WEST OF D STREET ABOUT ONE-QUARTER MILE SOUTH OF 9TH AVENUE (SECTION 26). - Highline Canal, Sand Creek Lateral, Beginning at intersection of Peoria Street & Highline Canal in Arapahoe County (City of Aurora), Sand Creek lateral Extends 15 miles Northerly through Araphoe County, City & County of Denver, & Adams County to its end point, approximately 1/4 mile Southest of intersectioin of D Street & Ninth Avenue in Adams County (Rocky Mountain Arsenal, Commerce City Vicinity), Commerce City, Adams County, CO

Supplanting the rapid chloride permeability test with a quick measurement of concrete conductivity.

DOT National Transportation Integrated Search

2005-01-01

The rapid chloride permeability test (RCPT) (AASHTO T 277, ASTM C 1202) is increasingly being used as an acceptance test for concrete constructions in the transportation industry. As more and more projects are subject to such testing, the capabilitie...

Testing and analysis of LWT and SCB properties of asphaltic concrete mixtures.

DOT National Transportation Integrated Search

2011-06-01

The objective of this research is to implement the loaded wheel tracker and to evaluate a simplified semi-circular bend test as an end result parameter for testing asphaltic concrete mixtures. The research will focus on testing both plant produced lo...

Parameters of Concrete Modified with Glass Meal and Chalcedonite Dust

NASA Astrophysics Data System (ADS)

Kotwa, Anna

2017-10-01

Additives used for production of concrete mixtures affect the rheological properties and parameters of hardened concrete, including compressive strength, water resistance, durability and shrinkage of hardened concrete. By their application, the use of cement and production costs may be reduced. The scheduled program of laboratory tests included preparation of six batches of concrete mixtures with addition of glass meal and / or chalcedonite dust. Mineral dust is a waste product obtained from crushed aggregate mining, with grain size below 0,063μm. The main ingredient of chalcedonite dust is silica. Glass meal used in the study is a material with very fine grain size, less than 65μm. This particle size is present in 60% - 90% of the sample. Additives were used to replace cement in concrete mixes in an amount of 15% and 25%. The amount of aggregate was left unchanged. The study used Portland cement CEM I 42.5R. Concrete mixes were prepared with a constant rate w / s = 0.4. The aim of the study was to identify the effect of the addition of chalcedonite dust and / or glass meal on the parameters of hardened concrete, i.e. compressive strength, water absorption and capillarity. Additives used in the laboratory tests significantly affect the compressive strength. The largest decrease in compressive strength of concrete samples was recorded for samples with 50% substitutes of cement additives. This decrease is 34.35%. The smallest decrease in compressive strength was noted in concrete with the addition of 15% of chalcedonite dust or 15% glass meal, it amounts to an average of 15%. The study of absorption shows that all concrete with the addition of chalcedonite dust and glass meal gained a percentage weight increase between 2.7 ÷ 3.1% for the test batches. This is a very good result, which is probably due to grout sealing. In capillary action for the test batches, the percentage weight gains of samples ranges from 4.6% to 5.1%. However, the reference concrete obtained the lowest water absorption as compared to other batches.

The application research of microwave nondestructive testing and imaging based on ω-k algorithm

NASA Astrophysics Data System (ADS)

Qi, Shengxiang; Ren, Jian; Gu, Lihua; Xu, Hui; Wang, Yuanbo

2017-07-01

The Bridges had collapsed accidents in recent years due to bridges quality problems. Therefore, concretes nondestructive testing are particularly important. At present, most applications are Ground Penetrating Radar (GPR) technology in the detection of reinforced concretes structure. GPR are used the pulse method which alongside with definitive advantages, but the testing of the internal structure of the small thickness concretes has very low resolution by this method. In this paper, it's the first time to use the ultra-wideband (UWB) stepped frequency conversion radar above problems. We use vector network analyzer and double ridged horn antenna microwave imaging system to test the reinforced concretes block. The internal structure of the concretes is reconstructed with a method of synthetic aperture of ω-k algorithm. By this method, the depth of the steel bar with the diameter of 1cm is shown exactly in the depth of 450mm×400mm×500mm and the depth error do not exceed 1cm.

Optimization of superplasticizer in portland pozzolana cement mortar and concrete

NASA Astrophysics Data System (ADS)

Sathyan, Dhanya; Anand, K. B.; Mini, K. M.; Aparna, S.

2018-02-01

Chemical Admixtures are added to concrete at the time of mixing of its constituents to impart workability. The requirement of right workability is the essence of good concrete. It has been found that the use of optimum use of admixtures is very important since low dosage may result in loss of fluidity and over dosage could lead to segregation, bleeding, excessive air entrainment etc in concrete. Hence it is essential to find optimum dosage of superplasticizer for getting good strength and workability. But large number of trial tests are required in the field to find the saturation dosage of superplasticizer in concrete which requires more materials and consume more time. The paper deals with developing a co-relation between the quantity requirements of superplasticiser in mortar to that of cement concrete to get good workability. In this work for preparing mortar and concrete 4 brands of locally available Portland pozzolana cement (PPC) and superplasticizer (SP) belonging to 4 different families namely Polycarboxylate Ether (PCE), Lignosulphate (LS), Sulfonated Naphthalene Formaldehyde (SNF) and Sulfonated Melamine Formaldehyde (SMF) are used. Two different brands of SP’s are taken from each family. Workability study on the superplasticized mortar with cement to sand ratio 1:1.5 and water cement ratio of 0.4 was performed using marsh cone and flow table test and workability study on the concrete with same cement/sand ratio and water cement ratio was done using slump cone and flow table test. Saturation dosage of superplasticizer in mortar and concrete determined experimentally was compared to study the correlation between two. Compressive strength study on concrete cubes were done on concrete mixes with a superplasticizer dosage corresponding to the saturation dosage and a comparative study were done to analyse the improvement in the compressive strength with addition of superplasticizer from different family.

Leaching assessment of concrete made of recycled coarse aggregate: physical and environmental characterisation of aggregates and hardened concrete.

PubMed

Galvín, A P; Agrela, F; Ayuso, J; Beltrán, M G; Barbudo, A

2014-09-01

Each year, millions of tonnes of waste are generated worldwide, partially through the construction and demolition of buildings. Recycling the resulting waste could reduce the amount of materials that need to be manufactured. Accordingly, the present work has analysed the potential reuse of construction waste in concrete manufacturing by replacing the natural aggregate with recycled concrete coarse aggregate. However, incorporating alternative materials in concrete manufacturing may increase the pollutant potential of the product, presenting an environmental risk via ground water contamination. The present work has tested two types of concrete batches that were manufactured with different replacement percentages. The experimental procedure analyses not only the effect of the portion of recycled aggregate on the physical properties of concrete but also on the leaching behaviour as indicative of the contamination degree. Thus, parameters such as slump, density, porosity and absorption of hardened concrete, were studied. Leaching behaviour was evaluated based on the availability test performed to three aggregates (raw materials of the concrete batches) and on the diffusion test performed to all concrete. From an environmental point of view, the question of whether the cumulative amount of heavy metals that are released by diffusion reaches the availability threshold was answered. The analysis of concentration levels allowed the establishment of different groups of metals according to the observed behaviour, the analysis of the role of pH and the identification of the main release mechanisms. Finally, through a statistical analysis, physical parameters and diffusion data were interrelated. It allowed estimating the relevance of porosity, density and absorption of hardened concrete on diffusion release of the metals in study. Copyright © 2014 Elsevier Ltd. All rights reserved.

Study on Flexural Behaviour of Ternary Blended Reinforced Self Compacting Concrete Beam with Conventional RCC Beam

NASA Astrophysics Data System (ADS)

Marshaline Seles, M.; Suryanarayanan, R.; Vivek, S. S.; Dhinakaran, G.

2017-07-01

The conventional concrete when used for structures having dense congested reinforcement, the problems such as external compaction and vibration needs special attention. In such case, the self compacting concrete (SCC) which has the properties like flow ability, passing and filling ability would be an obvious answer. All those SCC flow behavior was governed by EFNARC specifications. In present study, the combination type of SCC was prepared by replacing cement with silica fume (SF) and metakaolin (MK) along with optimum dosages of chemical admixtures. From the fresh property test, cube compressive strength and cylinder split tensile strength, optimum ternary mix was obtained. In order to study the flexural behavior, the optimum ternary mix was taken in which beam specimens of size 1200 mm x 100 mm x 200 mm was designed as singly reinforced section according to IS: 456-2000, Limit state method. Finally the comparative experimental analysis was made between conventional RCC and SCC beams of same grade in terms of flexural strength namely yield load & ultimate load, load- deflection curve, crack size and pattern respectively.

MATERIALS TESTING REACTOR (MTR) BUILDING, TRA603. CONTEXTUAL VIEW OF MTR ...

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

MATERIALS TESTING REACTOR (MTR) BUILDING, TRA-603. CONTEXTUAL VIEW OF MTR BUILDING SHOWING NORTH SIDES OF THE HIGH-BAY REACTOR BUILDING, ITS SECOND/THIRD FLOOR BALCONY LEVEL, AND THE ATTACHED ONE-STORY OFFICE/LABORATORY BUILDING, TRA-604. CAMERA FACING SOUTHEAST. VERTICAL CONCRETE-SHROUDED BEAMS SUPPORT PRECAST CONCRETE PANELS. CONCRETE PROJECTION FORMED AS A BUNKER AT LEFT OF VIEW IS TRA-657, PLUG STORAGE BUILDING. INL NEGATIVE NO. HD46-42-1. Mike Crane, Photographer, 4/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Validation of mechanical models for reinforced concrete structures: Presentation of the French project ``Benchmark des Poutres de la Rance''

NASA Astrophysics Data System (ADS)

L'Hostis, V.; Brunet, C.; Poupard, O.; Petre-Lazar, I.

2006-11-01

Several ageing models are available for the prediction of the mechanical consequences of rebar corrosion. They are used for service life prediction of reinforced concrete structures. Concerning corrosion diagnosis of reinforced concrete, some Non Destructive Testing (NDT) tools have been developed, and have been in use for some years. However, these developments require validation on existing concrete structures. The French project “Benchmark des Poutres de la Rance” contributes to this aspect. It has two main objectives: (i) validation of mechanical models to estimate the influence of rebar corrosion on the load bearing capacity of a structure, (ii) qualification of the use of the NDT results to collect information on steel corrosion within reinforced-concrete structures. Ten French and European institutions from both academic research laboratories and industrial companies contributed during the years 2004 and 2005. This paper presents the project that was divided into several work packages: (i) the reinforced concrete beams were characterized from non-destructive testing tools, (ii) the mechanical behaviour of the beams was experimentally tested, (iii) complementary laboratory analysis were performed and (iv) finally numerical simulations results were compared to the experimental results obtained with the mechanical tests.

Hybrid Effect Evaluation of Steel Fiber and Carbon Fiber on the Performance of the Fiber Reinforced Concrete

PubMed Central

Song, Weimin; Yin, Jian

2016-01-01

Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF) and carbon fiber (CF) was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC), carbon fiber reinforced concrete (CFRC) and hybrid fiber reinforced concrete (HFRC) were explored at steel fiber volume fraction 0.5%, 1%, 1.5% and carbon fiber 0.1%, 0.2%, 0.3%. Results showed that the addition of steel fiber and carbon fiber can increase the compressive strength. SF, CF and the hybridization between them could increase the compressive toughness significantly. The impact test results showed that as the volume of fiber increased, the impact number of the first visible crack and the ultimate failure also increased. The improvement of toughness mainly lay in improving the crack resistance after the first crack. Based on the test results, the positive hybrid effect of steel fiber and carbon fiber existed in hybrid fiber reinforced concrete. The relationship between the compressive toughness and impact toughness was also explored. PMID:28773824

Hybrid Effect Evaluation of Steel Fiber and Carbon Fiber on the Performance of the Fiber Reinforced Concrete.

PubMed

Song, Weimin; Yin, Jian

2016-08-18

Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF) and carbon fiber (CF) was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC), carbon fiber reinforced concrete (CFRC) and hybrid fiber reinforced concrete (HFRC) were explored at steel fiber volume fraction 0.5%, 1%, 1.5% and carbon fiber 0.1%, 0.2%, 0.3%. Results showed that the addition of steel fiber and carbon fiber can increase the compressive strength. SF, CF and the hybridization between them could increase the compressive toughness significantly. The impact test results showed that as the volume of fiber increased, the impact number of the first visible crack and the ultimate failure also increased. The improvement of toughness mainly lay in improving the crack resistance after the first crack. Based on the test results, the positive hybrid effect of steel fiber and carbon fiber existed in hybrid fiber reinforced concrete. The relationship between the compressive toughness and impact toughness was also explored.

Corrosion performance tests for reinforcing steel in concrete : test procedures.

DOT National Transportation Integrated Search

2009-09-01

The existing test method to assess the corrosion performance of reinforcing steel embedded in concrete, mainly : ASTM G109, is labor intensive, time consuming, slow to provide comparative results, and often expensive. : However, corrosion of reinforc...

Monitoring of temperature fatigue failure mechanism for polyvinyl alcohol fiber concrete using acoustic emission sensors.

PubMed

Li, Dongsheng; Cao, Hai

2012-01-01

The applicability of acoustic emission (AE) techniques to monitor the mechanism of evolution of polyvinyl alcohol (PVA) fiber concrete damage under temperature fatigue loading is investigated. Using the temperature fatigue test, real-time AE monitoring data of PVA fiber concrete is achieved. Based on the AE signal characteristics of the whole test process and comparison of AE signals of PVA fiber concretes with different fiber contents, the damage evolution process of PVA fiber concrete is analyzed. Finally, a qualitative evaluation of the damage degree is obtained using the kurtosis index and b-value of AE characteristic parameters. The results obtained using both methods are discussed.

Monitoring of Temperature Fatigue Failure Mechanism for Polyvinyl Alcohol Fiber Concrete Using Acoustic Emission Sensors

PubMed Central

Li, Dongsheng; Cao, Hai

2012-01-01

The applicability of acoustic emission (AE) techniques to monitor the mechanism of evolution of polyvinyl alcohol (PVA) fiber concrete damage under temperature fatigue loading is investigated. Using the temperature fatigue test, real-time AE monitoring data of PVA fiber concrete is achieved. Based on the AE signal characteristics of the whole test process and comparison of AE signals of PVA fiber concretes with different fiber contents, the damage evolution process of PVA fiber concrete is analyzed. Finally, a qualitative evaluation of the damage degree is obtained using the kurtosis index and b-value of AE characteristic parameters. The results obtained using both methods are discussed. PMID:23012555

Research on Durability of Recycled Ceramic Powder Concrete

NASA Astrophysics Data System (ADS)

Chen, M. C.; Fang, W.; Xu, K. C.; Xie, L.

2017-06-01

Ceramic was ground into powder with 325 mesh and used to prepare for concrete. Basic mechanical properties, carbonation and chloride ion penetration of the concrete tests were conducted. In addition, 6-hour electric fluxes of recycled ceramic powder concrete were measured under loading. The results showed that the age strength of ceramics powder concrete is higher than that of the ordinary concrete and the fly ash concrete. The ceramic powder used as admixture would reduce the strength of concrete under no consideration of its impact factor; under consideration of the impact factor for ceramic powder as admixture, the carbonation resistance of ceramic powder concrete was significantly improved, and the 28 day carbonation depth of the ceramic powder concrete was only 31.5% of ordinary concrete. The anti-chloride-permeability of recycled ceramic powder concrete was excellent.

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

PubMed

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

2013-08-15

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.

Concrete probe-strength study : final report.

DOT National Transportation Integrated Search

1969-12-01

The Windsor probe - test system was evaluated for determining compressive strength of concrete by comparing probe strengths against cylinder and core strengths from both laboratory and field-poured concrete. Advantages and disadvantages of this syste...

Shear capacity of high-strength concrete pre-stressed girders.

DOT National Transportation Integrated Search

1998-05-01

As part of a project at the University of Minnesota to investigate the application of high-strength concrete in prestressed girders, four shear tests were performed on high-strength concrete prestressed girders.

X-ray-induced acoustic computed tomography of concrete infrastructure

NASA Astrophysics Data System (ADS)

Tang, Shanshan; Ramseyer, Chris; Samant, Pratik; Xiang, Liangzhong

2018-02-01

X-ray-induced Acoustic Computed Tomography (XACT) takes advantage of both X-ray absorption contrast and high ultrasonic resolution in a single imaging modality by making use of the thermoacoustic effect. In XACT, X-ray absorption by defects and other structures in concrete create thermally induced pressure jumps that launch ultrasonic waves, which are then received by acoustic detectors to form images. In this research, XACT imaging was used to non-destructively test and identify defects in concrete. For concrete structures, we conclude that XACT imaging allows multiscale imaging at depths ranging from centimeters to meters, with spatial resolutions from sub-millimeter to centimeters. XACT imaging also holds promise for single-side testing of concrete infrastructure and provides an optimal solution for nondestructive inspection of existing bridges, pavement, nuclear power plants, and other concrete infrastructure.

Permeation Properties and Pore Structure of Surface Layer of Fly Ash Concrete

PubMed Central

Liu, Jun; Qiu, Qiwen; Xing, Feng; Pan, Dong

2014-01-01

This paper presents an experimental study on the nature of permeation properties and pore structure of concrete surface layers containing fly ash. Concretes containing different dosages of fly ash as a replacement for cement (15% and 30% by weight of total cement materials, respectively) were investigated. Concrete without any fly ash added was also employed as the reference specimen. Laboratory tests were conducted to determine the surface layer properties of concrete including chloride transport, apparent water permeability and pore structure. The results demonstrate that incorporation of fly ash, for the early test period, promotes the chloride ingress at the surface layer of concrete but substituting proportions of fly ash may have little impact on it. With the process of chloride immersion, the chloride concentration at the surface layer of concrete with or without fly ash was found to be nearly the same. In addition, it is suggested that the water permeability at the concrete surface area is closely related to the fly ash contents as well as the chloride exposure time. Pore structure was characterized by means of mercury intrusion porosimetry (MIP) test and the scanning electron microscopy (SEM) images. The modification of pore structure of concrete submersed in distilled water is determined by the pozzolanic reaction of fly ash and the calcium leaching effect. The pozzolanic reaction was more dominant at the immersion time of 180 days while the calcium leaching effect became more evident after 270 days. PMID:28788677

Characterization of Radiation Fields for Assessing Concrete Degradation in Biological Shields of NPPs

NASA Astrophysics Data System (ADS)

Remec, Igor; Rosseel, Thomas M.; Field, Kevin G.; Pape, Yann Le

2017-09-01

Life extensions of nuclear power plants (NPPs) to 60 years of operation and the possibility of subsequent license renewal to 80 years have renewed interest in long-term material degradation in NPPs. Large irreplaceable sections of most nuclear generating stations are constructed from concrete, including safety-related structures such as biological shields and containment buildings; therefore, concrete degradation is being considered with particular focus on radiation-induced effects. Based on the projected neutron fluence values (E > 0.1 MeV) in the concrete biological shields of the US pressurized water reactor fleet and the currently available data on radiation effects on concrete, some decrease in mechanical properties of concrete cannot be ruled out during extended operation beyond 60 years. An expansion of the irradiated concrete database is desirable to ensure reliable risk assessment for extended operation of nuclear power plants.

Concrete density estimation by rebound hammer method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ismail, Mohamad Pauzi bin, E-mail: pauzi@nm.gov.my; Masenwat, Noor Azreen bin; Sani, Suhairy bin

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 containingmore » crushed granite.« less

The Effect of Temperature on Moisture Transport in Concrete.

PubMed

Wang, Yao; Xi, Yunping

2017-08-09

Most concrete structures and buildings are under temperature and moisture variations simultaneously. Thus, the moisture transport in concrete is driven by the moisture gradient as well as the temperature gradient. This paper presents an experimental approach for determining the effect of different temperature gradients on moisture distribution profiles in concrete. The effect of elevated temperatures under isothermal conditions on the moisture transport was also evaluated, and found not to be significant. The non-isothermal tests show that the temperature gradient accelerates the moisture transport in concrete. The part of increased moisture transfer due to the temperature gradient can be quantified by a coupling parameter D HT , which can be determined by the present test data. The test results indicated that D HT is not a constant but increases linearly with the temperature variation. A material model was developed for D HT based on the experimental results obtained in this study.

The Effect of Temperature on Moisture Transport in Concrete

PubMed Central

Wang, Yao; Xi, Yunping

2017-01-01

Most concrete structures and buildings are under temperature and moisture variations simultaneously. Thus, the moisture transport in concrete is driven by the moisture gradient as well as the temperature gradient. This paper presents an experimental approach for determining the effect of different temperature gradients on moisture distribution profiles in concrete. The effect of elevated temperatures under isothermal conditions on the moisture transport was also evaluated, and found not to be significant. The non-isothermal tests show that the temperature gradient accelerates the moisture transport in concrete. The part of increased moisture transfer due to the temperature gradient can be quantified by a coupling parameter DHT, which can be determined by the present test data. The test results indicated that DHT is not a constant but increases linearly with the temperature variation. A material model was developed for DHT based on the experimental results obtained in this study. PMID:28792460

Investigation of the use of tear-off shingles in asphalt concrete.

DOT National Transportation Integrated Search

2010-05-01

This investigation focused on the use of asphalt shingles that had been removed from roofs and recycled into asphalt concrete. Upon invitation by the Virginia Department of Transportation (VDOT), three asphalt contractors produced and placed sections...

Evaluation of a concrete pavement restoration project in Virginia.

DOT National Transportation Integrated Search

1994-01-01

The purpose of this Federal Highway Administration Demonstration Project was to evaluate the installation and performance of a section of I-81 in Botetourt County, Virginia, that was rehabilitated by concrete pavement restoration (CPR) methods. The s...

Asphalt concrete properties and performance in Alaska : executive summary

DOT National Transportation Integrated Search

1982-01-01

A major study of asphalt concrete properties and performance of Alaska's highways was completed in 1982. The project data base was obtained from 117 statewide pavement sections through numerous core samples and measurements of cracking, patching and ...

Texturing of concrete pavements : final report.

DOT National Transportation Integrated Search

1979-08-01

During the month of June, 1973, the plastic concrete surface of a section of Interstate 10 in the Baton Rouge area was textured using several different texturing techniques, such as burlap drag, brooms and metal tines. The purpose of this experimenta...

Live load testing and load rating of five reinforced concrete bridges.

DOT National Transportation Integrated Search

2014-10-01

Five cast-in-place concrete T-beam bridges Eustis #5341, Whitefield #3831, Cambridge #3291, Eddington #5107, : and Albion #2832 were live load tested. Revised load ratings were computed either using test data or detailed : analysis when possi...

Contribution a la caracterisation des betons endommages par des methodes de l'acoustique non lineaire. Application a la reaction alcalis-silice

NASA Astrophysics Data System (ADS)

Kodjo, Apedovi

The aim of this thesis is to contribute to the non-destructive characterization of concrete materials damaged by alkali-silica reaction (ASR). For this purpose, some nonlinear characterization techniques have been developed, as well as a nonlinear resonance test device. In order to optimize the sensitivity of the test device, the excitation module and signal processing have been improved. The nonlinear tests were conducted on seven samples of concrete damaged by ASR, three samples of concrete damaged by heat, three concrete samples damaged mechanically and three sound concrete samples. Since, nonlinear behaviour of the material is often attribute to its micro-defects hysteretic behaviour, it was shown at first that concrete damaged by ASR exhibits an hysteresis behaviour. To conduct this study, an acoustoelastic test was set, and then nonlinear resonance test device was used for characterizing sound concrete and concrete damaged by ASR. It was shown that the nonlinear technique can be used for characterizing the material without knowing its initial state, and also for detecting early damage in the reactive material. Studies were also carried out on the effect of moisture regarding the nonlinear parameters; they allowed understanding the low values of nonlinear parameters measured on concrete samples that were kept in high moisture conditions. In order to find a specific characteristic of damage caused by ASR, the viscosity of ASR gel was used. An approach, based on static creep analysis, performed on the material, while applying the nonlinear resonance technique. The spring-damping model of Maxwell was used for the interpretation of the results. Then, the creep time was analysed on samples damaged by ASR. It appears that the ASR gel increases the creep time. Finally, the limitations of the nonlinear resonance technique for in situ application have been explained and a new applicable nonlinear technique was initiated. This technique use an external source such as a mass for making non-linearity behaviour in the material, while an ultrasound wave is investigating the medium. Keywords. Concrete, Alkali-silica reaction, Nonlinear acoustics, Nonlinearity, Hysteresis, Damage diagnostics.

Laterally Loaded Partially Prestressed Concrete Piles

DTIC Science & Technology

1989-09-01

of an extensive test program onl laterali y ioadeu. partially pr- estressed concrete fender piles. The study Included service load range as well ats...12,000-psi design strength). Configura- tion G utilized 14 r:- estress strand, in an unsymmetric pattern. To provide a uniform concrete prestress of 540...sudden loss in load carrying capacity directly related to the loss of concrete area. The compression concrete fractured longitudinally and along the

Dynamic Impact Analyses and Tests of Concrete Overpacks - 13638

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sanghoon; Cho, Sang-Soon; Kim, Ki-Young

Concrete cask is an option for spent nuclear fuel interim storage which is prevailingly used in US. A concrete cask usually consists of metallic canister which confines the spent nuclear fuel and concrete overpack. When the overpack undergoes a severe missile impact which might be caused by a tornado or an aircraft crash, it should sustain acceptable level of structural integrity so that its radiation shielding capability and the retrievability of canister are maintained. Missile impact against a concrete overpack involves two damage modes, local damage and global damage. Local damage of concrete is usually evaluated by empirical formulas whilemore » the global damage is evaluated by finite element analysis. In many cases, those two damage modes are evaluated separately. In this research, a series of numerical simulations are performed using finite element analysis to evaluate the global damage of concrete overpack as well as its local damage under high speed missile impact. We consider two types of concrete overpack, one with steel in-cased concrete without reinforcement and the other with partially-confined reinforced concrete. The numerical simulation results are compared with test results and it is shown that appropriate modeling of material failure is crucial in this analysis and the results are highly dependent on the choice of failure parameters. (authors)« less

Materials Related Forensic Analysis and Special Testing : Drying Shrinkage Evaluation of Bridge Decks with Class AAA and Class W/WD Type K Cement

DOT National Transportation Integrated Search

2001-07-01

This work pertains to preparation of concrete drying shrinkage data for proposed concrete mixtures during normal concrete : trial batch verification. Selected concrete mixtures will include PennDOT Classes AAA and AA and will also include the use of ...

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.

Recyclability of Concrete Pavement Incorporating High Volume of Fly Ash.

PubMed

Yoshitake, Isamu; Ishida, Takeo; Fukumoto, Sunao

2015-08-21

Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass was experimentally investigated, focusing on the strength development at an early age. Limestone powder was added to improve the early strength; flexural strength at two days reached 3.5 MPa, the minimum strength for traffic service in Japan. The matured fly ash concrete made with a cement content of 200 kg/m3 achieved a flexural strength almost equal to that of the control concrete without fly ash. Additionally, Portland cement made from the tested fly ash concrete was tested to confirm recyclability, with the cement quality meeting the Japanese classification of ordinary Portland cement. Limestone-based recyclable fly ash concrete pavement is, thus, a preferred material in terms of sustainability.

Recyclability of Concrete Pavement Incorporating High Volume of Fly Ash

PubMed Central

Yoshitake, Isamu; Ishida, Takeo; Fukumoto, Sunao

2015-01-01

Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass was experimentally investigated, focusing on the strength development at an early age. Limestone powder was added to improve the early strength; flexural strength at two days reached 3.5 MPa, the minimum strength for traffic service in Japan. The matured fly ash concrete made with a cement content of 200 kg/m3 achieved a flexural strength almost equal to that of the control concrete without fly ash. Additionally, Portland cement made from the tested fly ash concrete was tested to confirm recyclability, with the cement quality meeting the Japanese classification of ordinary Portland cement. Limestone-based recyclable fly ash concrete pavement is, thus, a preferred material in terms of sustainability. PMID:28793518

Recycling of rubble from building demolition for low-shrinkage concretes.

PubMed

Corinaldesi, Valeria; Moriconi, Giacomo

2010-04-01

In this project concrete mixtures were prepared that were characterized by low ductility due to desiccation by using debris from building demolition, which after a suitable treatment was used as aggregate for partial replacement of natural aggregates. The recycled aggregate used came from a recycling plant, in which rubble from building demolition was selected, crushed, cleaned, sieved, and graded. Such aggregates are known to be more porous as indicated by the Saturated Surface Dry (SSD) moisture content. The recycled concrete used as aggregates were added to the concrete mixture in order to study their influence on the fresh and hardened concrete properties. They were added either after water pre-soaking or in dry condition, in order to evaluate the influence of moisture in aggregates on the performance of concrete containing recycled aggregate. In particular, the effect of internal curing, due to the use of such aggregates, was studied. Concrete behavior due to desiccation under dehydration was studied by means of both drying shrinkage test and German angle test, through which shrinkage under the restrained condition of early age concrete can be evaluated. Copyright 2009 Elsevier Ltd. All rights reserved.

Monitoring corrosion of rebar embedded in mortar using guided ultrasonic waves

NASA Astrophysics Data System (ADS)

Ervin, Benjamin Lee

This thesis investigates the use of guided mechanical waves for monitoring uniform and localized corrosion in steel reinforcing bars embedded in concrete. The main forms of structural deterioration from uniform corrosion in reinforced concrete are the destruction of the bond between steel and concrete, the loss of steel cross-sectional area, and the loss of concrete cross-sectional area from cracking and spalling. Localized corrosion, or pitting, leads to severe loss of steel cross-sectional area, creating a high risk of bar tensile failure and unintended transfer of loads to the surrounding concrete. Reinforcing bars were used to guide the waves, rather than bulk concrete, allowing for longer inspection distances due to lower material absorption, scattering, and divergence. Guided mechanical waves in low frequency ranges (50-200 kHz) and higher frequency ranges (2-8 MHz) were monitored in reinforced mortar specimens undergoing accelerated uniform corrosion. The frequency ranges chosen contain wave modes with varying amounts of interaction, i.e. displacement profile, at the material interface. Lower frequency modes were shown to be sensitive to the accumulation of corrosion product and the level of bond between the surrounding mortar and rebar. This allows for the onset of corrosion and bond deterioration to be monitored. Higher frequency modes were shown to be sensitive to changes in the bar profile surface, allowing for the loss of cross-sectional area to be monitored. Guided mechanical waves in the higher frequency range were also used to monitor reinforced mortar specimens undergoing accelerated localized corrosion. The high frequency modes were sensitive to the localized attack. Also promising was the unique frequency spectrum response for both uniform and localized corrosion, allowing the two corrosion types to be differentiated from through-transmission evaluation. The isolated effects of the reinforcing ribs, simulated debonding, simulated pitting, water surrounding, and mortar surrounding were also investigated using guided mechanical waves. Results are presented and discussed within the framework of a corrosion process degradation model and service life. A thorough review and discussion of the corrosion process, modeling the propagation of corrosion, nondestructive methods for monitoring corrosion in reinforced concrete, and guided mechanical waves have also been presented.

UHPC for Blast and Ballistic Protection, Explosion Testing and Composition Optimization

NASA Astrophysics Data System (ADS)

Bibora, P.; Drdlová, M.; Prachař, V.; Sviták, O.

2017-10-01

The realization of high performance concrete resistant to detonation is the aim and expected outcome of the presented project, which is oriented to development of construction materials for larger objects as protective walls and bunkers. Use of high-strength concrete (HSC / HPC - “high strength / performance concrete”) and high-fiber reinforced concrete (UHPC / UHPFC -“Ultra High Performance Fiber Reinforced Concrete”) seems to be optimal for this purpose of research. The paper describes the research phase of the project, in which we focused on the selection of specific raw materials and chemical additives, including determining the most suitable type and amount of distributed fiber reinforcement. Composition of UHPC was optimized during laboratory manufacture of test specimens to obtain the best desired physical- mechanical properties of developed high performance concretes. In connection with laboratory testing, explosion field tests of UHPC specimens were performed and explosion resistance of laboratory produced UHPC testing boards was investigated.

Strength and Microstructure of Concrete with Iron Ore Tailings as Replacement for River Sand

NASA Astrophysics Data System (ADS)

Umara Shettima, Ali; Ahmad, Yusof; Warid Hussin, Mohd; Zakari Muhammad, Nasiru; Eziekel Babatude, Ogunbode

2018-03-01

River Sand is one of the basic ingredients used in the production of concrete. Consequently, continuous consumption of sand in construction industry contributes significantly to depletion of natural resources. To achieve more sustainable construction materials, this paper reports the use of iron ore tailings (IOT) as replacement for river sand in concrete production. IOT is a waste product generated from the production of iron ore and disposed to land fill without any economic value. Concrete mixtures containing different amount of IOT were designed for grade C30 with water to cement ratio of 0.60. The percentage ratios of the river sand replacements by IOT were 25%, 50%, 75% and 100%. Concrete microstructure test namely, XRD and Field Emission Scanned Electron Microscopic/Energy dispersive X-ray Spectroscopy (FESEM/EDX) were conducted for control and IOT concretes in order to determine the interaction and performance of the concrete containing IOT. Test results indicated that the slump values of 130 mm and 80 to 110 mm were recorded for the control and IOT concretes respectively. The concrete sample of 50% IOT recorded the highest compressive strength of 37.7 MPa at 28 days, and the highest flexural strength of 5.5 MPa compared to 4.7 MPa for reference concrete. The texture of the IOT is rough and angular which was able to improve the strength of the concrete.

Mechanical and Durability Properties of Fly Ash Based Concrete Exposed to Marine Environment

NASA Astrophysics Data System (ADS)

Kagadgar, Sarfaraz Ahmed; Saha, Suman; Rajasekaran, C.

2017-06-01

Efforts over the past few years for improving the performance of concrete suggest that cement replacement with mineral admixtures can enhance the strength and durability of concrete. Feasibility of producing good quality concrete by using alccofine and fly ash replacements is investigated and also the potential benefits from their incorporation were looked into. In this study, an attempt has been made to assess the performance of concrete in severe marine conditions exposed upto a period of 150 days. This work investigates the influence of alccofine and fly ash as partial replacement of cement in various percentages (Alccofine - 5% replacement to cement content) and (fly ash - 0%, 15%, 30%, 50% & 60% to total cementitious content) on mechanical and durability properties (Permit ion permeability test and corrosion current density) of concrete. Usage of alccofine and high quantity of fly ash as additional cementitious materials in concrete has resulted in higher workability of concrete. Inclusion of alccofine shows an early strength gaining property whereas fly ash results in gaining strength at later stage. Concrete mixes containing 5% alccofine with 15% fly ash replacement reported greater compressive strength than the other concrete mixes cured in both curing conditions. Durability test conducted at 56 and 150 days indicated that concrete containing higher percentages of fly ash resulted in lower permeability as well lesser corrosion density.

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. Copyright © 2017 Elsevier B.V. All rights reserved.

Quality control of fireproof coatings for reinforced concrete structures

NASA Astrophysics Data System (ADS)

Gravit, Marina; Dmitriev, Ivan; Ishkov, Alexander

2017-10-01

The article analyzes methods of quality inspection of fireproof coatings (work flow, measuring, laboratory, etc.). In modern construction there is a problem of lack of distinct monitoring for the fire protection testing. There is a description of this testing for reinforced concrete structures. The article shows the results of calculation quality control of hatches as an example of fireproof coating for reinforced concrete structures.

Confinement Effect on Material Properties of RC Beams Under Flexure

NASA Astrophysics Data System (ADS)

Kulkarni, Sumant; Shiyekar, Mukund Ramchandra; Shiyekar, Sandip Mukund

2017-12-01

In structural analysis, especially in indeterminate structures, it becomes essential to know the material and geometrical properties of members. The codal provisions recommend elastic properties of concrete and steel and these are fairly accurate enough. The stress-strain curve for concrete cylinder or a cube specimen is plotted. The slope of this curve is modulus of elasticity of plain concrete. Another method of determining modulus of elasticity of concrete is by flexural test of a beam specimen. The modulus of elasticity most commonly used for concrete is secant modulus. The modulus of elasticity of steel is obtained by performing a tension test of steel bar. While performing analysis by any software for high rise building, cross area of plain concrete is taken into consideration whereas effects of reinforcement bars and concrete confined by stirrups are neglected. Present aim of study is to determine elastic properties of reinforced cement concrete beam. Two important stiffness properties such as AE and EI play important role in analysis of high rise RCC building idealized as plane frame. The experimental program consists of testing of beams (model size 150 × 150 × 700 mm) with percentage of reinforcement varying from 0.54 to 1.63% which commensurate with existing Codal provisions of IS:456-2000 for flexural member. The effect of confinement is considered in this study. The experimental results are verified by using 3D finite element techniques.

Tests for early acceptance of concrete.

DOT National Transportation Integrated Search

1985-01-01

A literature survey and limited study of laboratory concretes were conducted to evaluate various methods for predicting concrete strengths at 28 days based on procedures for accelerated strength development or measurement of strength of normally cure...

A test of the symbol interdependency hypothesis with both concrete and abstract stimuli.

PubMed

Malhi, Simritpal Kaur; Buchanan, Lori

2018-01-01

In Experiment 1, the symbol interdependency hypothesis was tested with both concrete and abstract stimuli. Symbolic (i.e., semantic neighbourhood distance) and embodied (i.e., iconicity) factors were manipulated in two tasks-one that tapped symbolic relations (i.e., semantic relatedness judgment) and another that tapped embodied relations (i.e., iconicity judgment). Results supported the symbol interdependency hypothesis in that the symbolic factor was recruited for the semantic relatedness task and the embodied factor was recruited for the iconicity task. Across tasks, and especially in the iconicity task, abstract stimuli resulted in shorter RTs. This finding was in contrast to the concreteness effect where concrete words result in shorter RTs. Experiment 2 followed up on this finding by replicating the iconicity task from Experiment 1 in an ERP paradigm. Behavioural results continued to show a reverse concreteness effect with shorter RTs for abstract stimuli. However, ERP results paralleled the N400 and anterior N700 concreteness effects found in the literature, with more negative amplitudes for concrete stimuli.

A test of the symbol interdependency hypothesis with both concrete and abstract stimuli

PubMed Central

Buchanan, Lori

2018-01-01

In Experiment 1, the symbol interdependency hypothesis was tested with both concrete and abstract stimuli. Symbolic (i.e., semantic neighbourhood distance) and embodied (i.e., iconicity) factors were manipulated in two tasks—one that tapped symbolic relations (i.e., semantic relatedness judgment) and another that tapped embodied relations (i.e., iconicity judgment). Results supported the symbol interdependency hypothesis in that the symbolic factor was recruited for the semantic relatedness task and the embodied factor was recruited for the iconicity task. Across tasks, and especially in the iconicity task, abstract stimuli resulted in shorter RTs. This finding was in contrast to the concreteness effect where concrete words result in shorter RTs. Experiment 2 followed up on this finding by replicating the iconicity task from Experiment 1 in an ERP paradigm. Behavioural results continued to show a reverse concreteness effect with shorter RTs for abstract stimuli. However, ERP results paralleled the N400 and anterior N700 concreteness effects found in the literature, with more negative amplitudes for concrete stimuli. PMID:29590121

Strength development of pervious concrete containing engineered biomass aggregate

NASA Astrophysics Data System (ADS)

Sharif, A. A. M.; Shahidan, S.; Koh, H. B.; Kandash, A.; Zuki, S. S. Mohd

2017-11-01

Pervious concrete with high porosity has good permeability and low mechanical strengths are commonly used in controlling storm water management. It is different from normal concrete. It is only containing single size of coarse aggregate and has lower density compared with normal concrete. This study was focused on the effect of Engineered Biomass Aggregate (EBA) on the compressive strength, void ratio and water permeability of pervious concrete. EBA was prepared by coating the biomass aggregate with epoxy resin. EBA was used to replace natural coarse aggregate ranging from 0% to 25%. 150 mm cube specimens were prepared and used to study the compressive strength, void ratio and water permeability. Compressive strength was tested at 7, 14 and 28 days. Meanwhile, void ratio and permeability tests were carried out on 28 days. The experimental results showed that pervious concrete containing EBA gained lower compressive strength. The compressive strength was reduced gradually by increasing the percentage of EBA. Overall, Pervious concrete containing EBA achieved higher void ratio and permeability.

Shear transfer capacity of reinforced concrete exposed to fire

NASA Astrophysics Data System (ADS)

Ahmad, Subhan; Bhargava, Pradeep; Chourasia, Ajay

2018-04-01

Shear transfer capacity of reinforced concrete elements is a function of concrete compressive strength and reinforcement yield strength. Exposure of concrete and steel to elevated temperature reduces their mechanical properties resulting in reduced shear transfer capacity of RC elements. The objective of present study is to find the effect of elevated temperature on shear transfer capacity of reinforced concrete. For this purpose pushoff specimens were casted using normal strength concrete. After curing, specimens were heated to 250°C and 500°C in an electric furnace. Cooled specimens were tested for shear transfer capacity in a universal testing machine. It was found that shear transfer capacity and stiffness (slope of load-slip curve) were reduced when the specimens were heated to 250°C and 500°C. Load level for the initiation of crack slip was found to be decreased as the temperature was increased. A simple analytical approach is also proposed to predict the shear transfer capacity of reinforced concrete after elevated temperature.

Manipulating Objects and Telling Words: A Study on Concrete and Abstract Words Acquisition

PubMed Central

Borghi, Anna M.; Flumini, Andrea; Cimatti, Felice; Marocco, Davide; Scorolli, Claudia

2011-01-01

Four experiments (E1–E2–E3–E4) investigated whether different acquisition modalities lead to the emergence of differences typically found between concrete and abstract words, as argued by the words as tools (WAT) proposal. To mimic the acquisition of concrete and abstract concepts, participants either manipulated novel objects or observed groups of objects interacting in novel ways (Training 1). In TEST 1 participants decided whether two elements belonged to the same category. Later they read the category labels (Training 2); labels could be accompanied by an explanation of their meaning. Then participants observed previously seen exemplars and other elements, and were asked which of them could be named with a given label (TEST 2). Across the experiments, it was more difficult to form abstract than concrete categories (TEST 1); even when adding labels, abstract words remained more difficult than concrete words (TEST 2). TEST 3 differed across the experiments. In E1 participants performed a feature production task. Crucially, the associations produced with the novel words reflected the pattern evoked by existing concrete and abstract words, as the first evoked more perceptual properties. In E2–E3–E4, TEST 3 consisted of a color verification task with manual/verbal (keyboard–microphone) responses. Results showed the microphone use to have an advantage over keyboard use for abstract words, especially in the explanation condition. This supports WAT: due to their acquisition modality, concrete words evoke more manual information; abstract words elicit more verbal information. This advantage was not present when linguistic information contrasted with perceptual one. Implications for theories and computational models of language grounding are discussed. PMID:21716582

Analysis of Within-Test Variability of Non-Destructive Test Methods to Evaluate Compressive Strength of Normal Vibrated and Self-Compacting Concretes

NASA Astrophysics Data System (ADS)

Nepomuceno, Miguel C. S.; Lopes, Sérgio M. R.

2017-10-01

Non-destructive tests (NDT) have been used in the last decades for the assessment of in-situ quality and integrity of concrete elements. An important step in the application of NDT methods concerns to the interpretation and validation of the test results. In general, interpretation of NDT results should involve three distinct phases leading to the development of conclusions: processing of collected data, analysis of within-test variability and quantitative evaluation of property under investigation. The analysis of within-test variability can provide valuable information, since this can be compared with that of within-test variability associated with the NDT method in use, either to provide a measure of the quality control or to detect the presence of abnormal circumstances during the in-situ application. This paper reports the analysis of the experimental results of within-test variability of NDT obtained for normal vibrated concrete and self-compacting concrete. The NDT reported includes the surface hardness test, ultrasonic pulse velocity test, penetration resistance test, pull-off test, pull-out test and maturity test. The obtained results are discussed and conclusions are presented.

Proportioning and performance evaluation of self-consolidating concrete

NASA Astrophysics Data System (ADS)

Wang, Xuhao

A well-proportioned self-consolidating concrete (SCC) mixture can be achieved by controlling the aggregate system, paste quality, and paste quantity. The work presented in this dissertation involves an effort to study and improve particle packing of the concrete system and reduce the paste quantity while maintaining concrete quality and performance. This dissertation is composed of four papers resulting from the study: (1) Assessing Particle Packing Based Self-Consolidating Concrete Mix Design; (2) Using Paste-To-Voids Volume Ratio to Evaluate the Performance of Self-Consolidating Concrete Mixtures; (3) Image Analysis Applications on Assessing Static Stability and Flowability of Self-Consolidating Concrete, and (4) Using Ultrasonic Wave Propagation to Monitor Stiffening Process of Self-Consolidating Concrete. Tests were conducted on a large matrix of SCC mixtures that were designed for cast-in-place bridge construction. The mixtures were made with different aggregate types, sizes, and different cementitious materials. In Paper 1, a modified particle-packing based mix design method, originally proposed by Brouwers (2005), was applied to the design of self-consolidating concrete (SCC) mixs. Using this method, a large matrix of SCC mixes was designed to have a particle distribution modulus (q) ranging from 0.23 to 0.29. Fresh properties (such as flowability, passing ability, segregation resistance, yield stress, viscosity, set time and formwork pressure) and hardened properties (such as compressive strength, surface resistance, shrinkage, and air structure) of these concrete mixes were experimentally evaluated. In Paper 2, a concept that is based on paste-to-voids volume ratio (Vpaste/Vvoids) was employed to assess the performance of SCC mixtures. The relationship between excess paste theory and Vpaste/Vvoids was investigated. The workability, flow properties, compressive strength, shrinkage, and surface resistivity of SCC mixtures were determined at various ages. Statistical analyses, response surface models and Tukey Honestly Significant Difference (HSD) tests, were conducted to relate the mix design parameters to the concrete performance. The work discussed in Paper 3 was to apply a digital image processing (DIP) method associated with a MATLAB algorithm to evaluate cross sectional images of self-consolidating concrete (SCC). Parameters, such as inter-particle spacing between coarse aggregate particles and average mortar to aggregate ratio defined as average mortar thickness index (MTI), were derived from DIP method and applied to evaluate the static stability and develop statistical models to predict flowability of SCC mixtures. The last paper investigated technologies available to monitor changing properties of a fresh mixture, particularly for use with self-consolidating concrete (SCC). A number of techniques were used to monitor setting time, stiffening and formwork pressure of SCC mixtures. These included longitudinal (P-wave) ultrasonic wave propagation, penetrometer based setting time, semi-adiabatic calorimetry, and formwork pressure. The first study demonstrated that the concrete mixes designed using the modified Brouwers mix design algorithm and particle packing concept had a potential to reduce up to 20% SCMs content compared to existing SCC mix proportioning methods and still maintain good performance. The second paper concluded that slump flow of the SCC mixtures increased with Vpaste/Vvoids at a given viscosity of mortar. Compressive trength increases with increasing Vpaste/Vvoids up to a point (~150%), after which the strength becomes independent of Vpaste/Vvoids, even slightly decreases. Vpaste/Vvoids has little effect on the shrinkage mixtures, while SCC mixtures tend to have a higher shrinkage than CC for a given Vpaste/Vvoids. Vpaste/Vvoids has little effects on surface resistivity of SCC mixtures. The paste quality tends to have a dominant effect. Statistical analysis is an efficient tool to identify the significance of influence factors on concrete performance. In third paper, proposed DIP method and MATLAB algorithm can be successfully used to derive inter-particle spacing and MTI, and quantitatively evaluate the static stability in hardened SCC samples. These parameters can be applied to overcome the limitations and challenges of existing theoretical frames and construct statistical models associated with rheological parameters to predict flowability of SCC mixtures. The outcome of this study can be of practical value for providing an efficient and useful tool in designing mixture proportions of SCC. Last paper compared several concrete performance measurement techniques, the P-wave test and calorimetric measurements can be efficiently used to monitor the stiffening and setting of SCC mixtures.

The evaluation of ordinary Portland cement concrete subject to elevated temperatures in conjunction with acoustic emission and splitting tensile test

NASA Astrophysics Data System (ADS)

Su, Yu-Min; Hou, Tsung-Chin; Chen, Guan-Ying; Hou, Ping-Ni

2017-04-01

The research objective was to evaluate Ordinary Portland Cement concrete subject to various elevated temperatures. Single OPC concrete mixture with water to cementitious (w/c) equal to 0.45 was proportioned. Concrete specimens were cast and placed in the curing tank in which water was saturated with calcium hydroxide. After ninety days of moist-cure, three elevated temperatures, namely 300, 600, and 900-°C, were carried out upon hardened concrete specimens. Furthermore, two post-damaged curing conditions were executed to recover damaged concrete specimens: one was to recure under 23°C with 50% humidity in a controlled environmental chamber and the other was to recure in the same curing tank. Acoustic emission apparatus coupled with the splitting tensile test was utilized and found able to assess damaged concrete. Before concrete subject to elevated temperatures, the development of indirect tensile strength versus displacement diagram fit well with the tendency of AE energy release. It was found there was a large amount of AE energy released when stress and displacement diagram developed about 40-50%. As such could be identified as the onset of first fracture and the plain concrete generally exhibited a quasi-brittle fracture with two major series of AE energy dissipations; however when concrete specimens were subject to elevated temperatures, the damaged concrete specimens displayed neither fracture pattern nor the "double-hump" AE energy dissipation in comparison with those of plain concrete.

Determination of concrete cover thickness in a reinforced concrete pillar by observation of the scattered electromagnetic field

NASA Astrophysics Data System (ADS)

Di Gregorio, Pietro Paolo; Frezza, Fabrizio; Mangini, Fabio; Pajewski, Lara

2017-04-01

The electromagnetic scattered field by a reinforced concrete structure is calculated by means of frequency-domain numerical simulations and by making use of the scattered-field formulation. The concrete pillar, used as supporting architectural element, is modelled as a parallelepiped shell made of concrete material inside which are present steel bars. In order to make the model simpler, the steel bars are supposed running parallel to the air-pillar interface. To excite the model, a linearly-polarized plane wave impinging normally with respect to the pillars surface, is adopted. We consider two different polarizations in order to determine the most useful in terms of scattered-field sensitivity. Moreover, a preliminary frequency sweep allows us to choose the most suitable operating frequency depending on the dimensions of the pillar cross-section, the steel bars cross-section and the concrete cover. All the three components of the scattered field are monitored along a line just above the interface air-pillar. The electromagnetic properties of the materials employed in this study are present in the literature and, since a frequency-domain technique is adopted, no further approximation is needed. The results obtained for different values of the concrete cover are compared, with the goal of determining the scattered field dependence on the concrete cover thickness. Considering different concrete cover thicknesses, we want to provide an electromagnetic method to obtain this useful parameter by observation of the scattered electromagnetic field. One of the practical applications of this study in the field of Civil Engineering may be the use of ground penetrating radar (GPR) techniques to monitor the thickness of the concrete that separates the metal bars embedded in the pillar from the outer surface. A correct distance is useful because the concrete cover serves as a protection against external agents avoiding corrosion of the bars that might prejudice the reinforced concrete; it ensures also an optimal transmission and distribution of the adhesion forces in the pillar. Acknowledgement This work is a contribution to COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.GPRadar.eu, www.cost.eu).

Development of testing machine for tunnel inspection using multi-rotor UAV

NASA Astrophysics Data System (ADS)

Iwamoto, Tatsuya; Enaka, Tomoya; Tada, Keijirou

2017-05-01

Many concrete structures are deteriorating to dangerous levels throughout Japan. These concrete structures need to be inspected regularly to be sure that they are safe enough to be used. The inspection method for these concrete structures is typically the impact acoustic method. In the impact acoustic method, the worker taps the surface of the concrete with a hammer. Thus, it is necessary to set up scaffolding to access tunnel walls for inspection. Alternatively, aerial work platforms can be used. However, setting up scaffolding and aerial work platforms is not economical with regard to time or money. Therefore, we developed a testing machine using a multirotor UAV for tunnel inspection. This test machine flies by a plurality of rotors, and it is pushed along a concrete wall and moved by using rubber crawlers. The impact acoustic method is used in this testing machine. This testing machine has a hammer to make an impact, and a microphone to acquire the impact sound. The impact sound is converted into an electrical signal and is wirelessly transmitted to the computer. At the same time, the position of the testing machine is measured by image processing using a camera. The weight and dimensions of the testing machine are approximately 1.25 kg and 500 mm by 500 mm by 250 mm, respectively.

Signs on concrete median barriers.

DOT National Transportation Integrated Search

2013-04-01

Concrete median barriers have been used throughout the state as permanent and temporary barriers for providing separation of traffic. Typically, these barriers are tested and considered crashworthy through crash testing according to National Cooperat...

1. EAST ENTRANCE FROM LOADING AREA. CONCRETE TUNNEL TO TEST ...

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

1. EAST ENTRANCE FROM LOADING AREA. CONCRETE TUNNEL TO TEST STAND 1-3 IS AT RIGHT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Instrumentation & Control Building, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

Surface resistivity test evaluation as an indicator of the chloride permeability of concrete.

DOT National Transportation Integrated Search

2012-12-01

Many agencies have adopted the standard tests for electrical : indication of concretes ability to resist chloride ion penetration : (AASHTO T 277 and ASTM C1202), commonly known as the rapid : chloride permeability test (RCPT), in their specificat...

Development of a Pavement Maintenance Management System. Volume 9. Development of Airfield Pavement Performance Prediction Models.

DTIC Science & Technology

1984-05-01

materials, traffic, and climate, were used to develop PCI and key distress prediction models for both asphalt-concrete- and jointed-concrete- surfaced...Predicted PCI for PCC and AC/PCC Pavements Using Model Presented in Section III ...... 35 31 Effect of PCC Thickness on the PCI as a Function of Age...of Corner Breaking Observed vs Predicted Percent of Corner Breaking Using Model Presented in Section III

Optimisation of industrial wastes reuse as construction materials.

PubMed

Collivignarelli, C; Sorlini, S

2001-12-01

This study concerns the reuse of two inorganic wastes, foundry residues and fly ashes from municipal solid waste incineration, as "recycled aggregate" in concrete production. This kind of reuse was optimised by waste treatment with the following steps: waste washing with water; waste stabilisation-solidification treatment with inorganic reagents; final grinding of the stabilised waste after curing for about 10-20 days. Both the treated wastes were reused in concrete production with different mix-designs. Concrete specimens were characterised by means of conventional physical-mechanical tests (compression, elasticity modulus, shrinkage) and different leaching tests. Experimental results showed that a good structural and environmental quality of "recycled concrete" is due both to a correct waste treatment and to a correct mix-design for concrete mixture.

The analysis of mechanical properties of non autoclaved aerated concrete with the substitution of fly ash and bottom ash

NASA Astrophysics Data System (ADS)

Karolina, R.; Muhammad, F.

2018-02-01

Based on PP. No.85 of 1999 on the management of hazardous and toxic (B3), fly ash and bottom ash wastes are categorized into B3 waste because there are heavy metal oxide contents that can pollute the environment. One form of environmental rescue that can be applied is to utilize waste fly ash and bottom ash in the manufacture of concrete. In this research, fly ash and bottom ash waste are used as substitution of cement and fine aggregate to make lightweight concrete. The purpose of this research is to know the mechanical properties of non-autoclaved aerated lightweight concrete (NAAC) with FA and BA substitution to cement and fine aggregate which is expected to improve the quality of concrete. The NAAC lightweight concrete in this study is divided into 4 categories: normal NAAC lightweight concrete, NAAC lightweight NAAC substituted concrete with FA, NAAC lightweight concrete substituted with BA, and NAAC combined light weight from FA and BA with variations of 10%, 20% And 30%. The test specimen used in cylindrical shape, which was tested at the age of 28 days, amounted to 90 pieces and consisted of 10 variations. Each variation amounted to 9 samples. Based on the test results with FA and BA substitutions of 10%, 20%, and 30%, the highest compressive strength was achieved in samples with FA 30% of 12.687 MPa, maximum tensile strength achieved in samples with FA 30% of 1,540 MPa, The highest absorption was achieved in normal NAAC of 5.66%. Based on the weight of the contents of all samples, samples can be categorized in lightweight concrete, since the weight of the contents is less than 1900 kg / m3.

Application of Micro-Electro-Mechanical Sensors Contactless NDT of Concrete Structures.

PubMed

Ham, Suyun; Popovics, John S

2015-04-17

The utility of micro-electro-mechanical sensors (MEMS) for application in air-coupled (contactless or noncontact) sensing to concrete nondestructive testing (NDT) is studied in this paper. The fundamental operation and characteristics of MEMS are first described. Then application of MEMS sensors toward established concrete test methods, including vibration resonance, impact-echo, ultrasonic surface wave, and multi-channel analysis of surface waves (MASW), is demonstrated. In each test application, the performance of MEMS is compared with conventional contactless and contact sensing technology. Favorable performance of the MEMS sensors demonstrates the potential of the technology for applied contactless NDT efforts. To illustrate the utility of air-coupled MEMS sensors for concrete NDT, as compared with conventional sensor technology.

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

Evaluating performance-based test and specifications for sulfate resistance in concrete

DOT National Transportation Integrated Search

2000-12-01

This research project involved an experimental evaluation of the sulfate resistance of various concretes and mortars for the purpose of establishing performance-based specifications for the durability of concrete against sulfate attack. The research ...

Internally cured concrete for pavement and bridge deck applications.

DOT National Transportation Integrated Search

2015-07-01

A laboratory and field testing program was conducted to evaluate the performance and usability of internally : cured concrete (ICC) using lightweight aggregates for bridge decks and concrete pavement slabs under Florida : conditions. The laboratory t...

Preliminary study to develop standard acceptance tests for pervious concrete.

DOT National Transportation Integrated Search

2017-05-01

Pervious concrete pavements are permeable pavement systems that are desired for their role in stormwater management and runoff control. Increased popularity in pervious concrete pavement applications has raised the need for the development of quality...

Fatigue testing of wood-concrete composite beams.

DOT National Transportation Integrated Search

2013-05-01

Currently, wood-concrete composite structural members are usually applied in building structures. There are a relatively small number (in the low 100s) of known bridge applications involving wood-concrete composites. A problem with using these novel ...

High Performance Concrete (HPC) bridge project for SR 43.

DOT National Transportation Integrated Search

2012-10-01

The objective of this research was to develop and test high performance concrete mixtures, made of locally available materials, having : durability characteristics that far exceed those of conventional concrete mixtures. Based on the results from the...

The Behavior and Durability of Self-Consolidating Concrete.

DOT National Transportation Integrated Search

2015-05-01

This report focuses on the production of self-consolidating concrete using local materials from Las Vegas, Nevada. Tests were conducted on eight self-consolidating concrete mixtures having two different percentages of fly-ash replacement (25% and 35%...

Structural-functional integrated concrete with macro-encapsulated inorganic PCM

NASA Astrophysics Data System (ADS)

Mohseni, Ehsan; Tang, Waiching; Wang, Zhiyu

2017-09-01

Over the last few years the application of thermal energy storage system incorporating phase change materials (PCMs) to foster productivity and efficiency of buildings energy has grown rapidly. In this study, a structural-functional integrated concrete was developed using macro-encapsulated PCM-lightweight aggregate (LWA) as partial replacement (25 and 50% by volume) of coarse aggregate in control concrete. The PCM-LWA was prepared by incorporation of an inorganic PCM into porous LWAs through vacuum impregnation. The mechanical and thermal performance of PCM-LWA concrete were studied. The test results revealed that though the compressive strength of concrete with PCM-LWA was lower than the control concrete, but ranged from 22.02 MPa to 42.88 MPa which above the minimum strength requirement for structural application. The thermal performance test indicated that macro-encapsulated PCM-LWA has underwent the phase change transition reducing the indoor temperature.

Retrieval of Concrete Words Involves More Contextual Information than Abstract Words: Multiple Components for the Concreteness Effect

ERIC Educational Resources Information Center

Xiao, Xin; Zhao, Di; Zhang, Qin; Guo, Chun-yan

2012-01-01

The current study used the directed forgetting paradigm in implicit and explicit memory to investigate the concreteness effect. Event-related potentials (ERPs) were recorded to explore the neural basis of this phenomenon. The behavioral results showed a clear concreteness effect in both implicit and explicit memory tests; participants responded…

Concrete Finisher: Apprenticeship Course Outline. Apprenticeship and Industry Training. 4805.2

ERIC Educational Resources Information Center

Alberta Advanced Education, 2005

2005-01-01

The graduate of the Concrete Finisher apprenticeship program is a certified journeyperson who will be able to: (1) perform tests to confirm concrete quality; (2) interpret building codes, plans and specifications as they apply to the trade; (3) place and finish concrete in a professional manner; (4) cut, patch, maintain and repair concrete…

Accelerated testing for studying pavement design and performance (FY 2000) : effectiveness of fiber reinforced and plain, ultra-thin concrete overlays on Portland Cement Concrete Pavement (PCCP).

DOT National Transportation Integrated Search

2003-11-01

The objective of the research was to compare the performance of fiber reinforced and plain PCC concrete overlay when used as a thin non-dowelled overlay on top of a rubblized, distressed concrete pavement. The experiment was conducted at the Accelera...

Transport processes in partially saturate concrete: Testing and liquid properties

NASA Astrophysics Data System (ADS)

Villani, Chiara

The measurement of transport properties of concrete is considered by many to have the potential to serve as a performance criterion that can be related to concrete durability. However, the sensitivity of transport tests to several parameters combined with the low permeability of concrete complicates the testing. Gas permeability and diffusivity test methods are attractive due to the ease of testing, their non-destructive nature and their potential to correlate to in-field carbonation of reinforced concrete structures. This work was aimed at investigating the potential of existing gas transport tests as a way to reliably quantify transport properties in concrete. In this study gas permeability and diffusivity test methods were analyzed comparing their performance in terms of repeatability and variability. The influence of several parameters was investigated such as moisture content, mixture proportions and gas flow. A closer look to the influence of pressure revealed an anomalous trend of permeability with respect to pressure. An alternative calculation is proposed in an effort to move towards the determination of intrinsic material properties that can serve as an input for service life prediction models. The impact of deicing salts exposure was also analyzed with respect to their alteration of the degree of saturation as this may affect gas transport in cementitious materials. Limited information were previously available on liquid properties over a wide range of concentrations. To overcome this limitation, this study quantified surface tension, viscosity in presence of deicing salts in a broad concentration range and at different temperatures. Existing models were applied to predict the change of fluid properties during drying. Vapor desorption isotherms were obtained to investigate the influence of deicing salts presence on the non-linear moisture diffusion coefficient. Semi-empirical models were used to quantify the initiation and the rate of drying using liquid properties and pore structure information as inputs. Concrete exposed to deicing salts resulted to have a reduced gas transport due to the higher degree of saturation (DOS). The higher DOS is believed to contribute to the premature deterioration observed in concrete pavements exposed to deicing salts. Moisture diffusion and moisture profiles in concrete are known to directly relate with the stresses generated during shrinkage and creep mechanisms. The alteration due to the presence of shrinkage reducing admixtures on drying was also investigated in this work. Liquid properties were used to predict the diffusion coefficient in presence of SRA. Moisture profiles obtained using Fick's second law for diffusion were compared to relative humidity profiles measured on concrete slabs. Results confirm that a qualitative prediction of drying in concrete elements is realistic when using this type of approach.

Contrastive Numerical Investigations on Thermo-Structural Behaviors in Mass Concrete with Various Cements

PubMed Central

Zhou, Wei; Feng, Chuqiao; Liu, Xinghong; Liu, Shuhua; Zhang, Chao; Yuan, Wei

2016-01-01

This work is a contrastive investigation of numerical simulations to improve the comprehension of thermo-structural coupled phenomena of mass concrete structures during construction. The finite element (FE) analysis of thermo-structural behaviors is used to investigate the applicability of supersulfated cement (SSC) in mass concrete structures. A multi-scale framework based on a homogenization scheme is adopted in the parameter studies to describe the nonlinear concrete behaviors. Based on the experimental data of hydration heat evolution rate and quantity of SSC and fly ash Portland cement, the hydration properties of various cements are studied. Simulations are run on a concrete dam section with a conventional method and a chemo-thermo-mechanical coupled method. The results show that SSC is more suitable for mass concrete structures from the standpoint of temperature control and crack prevention. PMID:28773517

Contrastive Numerical Investigations on Thermo-Structural Behaviors in Mass Concrete with Various Cements.

PubMed

Zhou, Wei; Feng, Chuqiao; Liu, Xinghong; Liu, Shuhua; Zhang, Chao; Yuan, Wei

2016-05-20

This work is a contrastive investigation of numerical simulations to improve the comprehension of thermo-structural coupled phenomena of mass concrete structures during construction. The finite element (FE) analysis of thermo-structural behaviors is used to investigate the applicability of supersulfated cement (SSC) in mass concrete structures. A multi-scale framework based on a homogenization scheme is adopted in the parameter studies to describe the nonlinear concrete behaviors. Based on the experimental data of hydration heat evolution rate and quantity of SSC and fly ash Portland cement, the hydration properties of various cements are studied. Simulations are run on a concrete dam section with a conventional method and a chemo-thermo-mechanical coupled method. The results show that SSC is more suitable for mass concrete structures from the standpoint of temperature control and crack prevention.

Laboratory Testing of Electro-Osmotic Pulse Technology to Reduce and Maintain Low Moisture Content in Concrete

DTIC Science & Technology

2009-02-01

technology minimizes harmful effects to concrete and rebar and prevents over drying, pore blocking and electrode polarization. Principles of EOP...LABORATORY TESTING OF ELECTRO-OSMOTIC PULSE TECHNOLOGY TO REDUCE AND MAINTAIN LOW MOISTURE CONTENT IN CONCRETE Orange S. Marshall, Vincent F...Laboratory 2009 Army Corrosion Summit Clearwater Beach, FL 6 January 2009 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting

Characterisation and management of concrete grinding residuals.

PubMed

Kluge, Matt; Gupta, Nautasha; Watts, Ben; Chadik, Paul A; Ferraro, Christopher; Townsend, Timothy G

2018-02-01

Concrete grinding residue is the waste product resulting from the grinding, cutting, and resurfacing of concrete pavement. Potential beneficial applications for concrete grinding residue include use as a soil amendment and as a construction material, including as an additive to Portland cement concrete. Concrete grinding residue exhibits a high pH, and though not hazardous, it is sufficiently elevated that precautions need to be taken around aquatic ecosystems. Best management practices and state regulations focus on reducing the impact on such aquatic environment. Heavy metals are present in concrete grinding residue, but concentrations are of the same magnitude as typically recycled concrete residuals. The chemical composition of concrete grinding residue makes it a useful product for some soil amendment purposes at appropriate land application rates. The presence of unreacted concrete in concrete grinding residue was examined for potential use as partial replacement of cement in new concrete. Testing of Florida concrete grinding residue revealed no dramatic reactivity or improvement in mortar strength.

40 CFR 278.2 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Applicability. 278.2 Section 278.2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) CRITERIA FOR THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN...

40 CFR 278.2 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Applicability. 278.2 Section 278.2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) CRITERIA FOR THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN...

40 CFR 278.2 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Applicability. 278.2 Section 278.2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) CRITERIA FOR THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN...

40 CFR 278.2 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Applicability. 278.2 Section 278.2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) CRITERIA FOR THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN...

40 CFR 278.2 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Applicability. 278.2 Section 278.2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) CRITERIA FOR THE MANAGEMENT OF GRANULAR MINE TAILINGS (CHAT) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN...

Full-scale bonded concrete overlay on IH-30 in Ft. Worth, Texas

DOT National Transportation Integrated Search

2000-10-01

This report presents the research and recommendations regarding the rehabilitation of an urban section of IH-30 in west Fort Worth, Texas. Bonded concrete overlays have proven to be a viable solution for rehabilitation of heavily traveled pavement se...

I-10 pavement distress : Ramah-Westover, east & west sections : technical assistance report.

DOT National Transportation Integrated Search

1995-03-01

A fourteen mile, 6.5-8.0 inch asphalt concrete overlay of continuously reinforced concrete pavement demonstrated delamination, leaching, and rutting distress prior to acceptance in June 1989. Twentysix areas ranging from 20-1000 feet were either part...

Evaluation of a movable concrete barrier system.

DOT National Transportation Integrated Search

1994-01-01

The movable concrete barrier (MCB) system consists of 1-m-long sections of barrier connected by steel pins in hinges to form a barrier wall that is moved laterally with a transport/transfer vehicle. The MCB system allows for the quick closing and ope...

Isolation and identification of bacteria to improve the strength of concrete.

PubMed

Krishnapriya, S; Venkatesh Babu, D L; G, Prince Arulraj

2015-05-01

The objective of this research work is to isolate and identify calcite precipitating bacteria and to check the suitability of these bacteria for use in concrete to improve its strength. Bacteria to be incorporated in concrete should be alkali resistant to endure the high pH of concrete and endospore forming to withstand the mechanical stresses induced in concrete during mixing. They must exhibit high urease activity to precipitate calcium carbonate in the form of calcite. Bacterial strains were isolated from alkaline soil samples of a cement factory and were tested for urease activity, potential to form endospores and precipitation of calcium carbonate. Based on these results, three isolates were selected and identified by 16S rRNA gene sequencing. They were identified as Bacillus megaterium BSKAU, Bacillus licheniformis BSKNAU and Bacillus flexus BSKNAU. The results were compared with B. megaterium MTCC 1684 obtained from Microbial Type Culture Collection and Gene Bank, Chandigarh, India. Experimental work was carried out to assess the influence of bacteria on the compressive strength and tests revealed that bacterial concrete specimens showed enhancement in compressive strength. The efficiency of bacteria toward crack healing was also tested. Substantial increase in strength and complete healing of cracks was observed in concrete specimens cast with B. megaterium BSKAU, B. licheniformis BSKNAU and B. megaterium MTCC 1684. This indicates the suitability of these bacterial strains for use in concrete. The enhancement of strength and healing of cracks can be attributed to the filling of cracks in concrete by calcite which was visualized by scanning electron microscope. Copyright © 2015 Elsevier GmbH. All rights reserved.

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.

Polymer concrete overlay test program : final report.

DOT National Transportation Integrated Search

1981-12-01

The results in this report were obtained during the test program which began in 1973. Physical properties of various polymer concretes are listed. They include compressive strength, splitting tensile strength, bond strength, the modulus of elasticity...

Development of a Failure Theory for Concrete

DOT National Transportation Integrated Search

2012-07-31

The failure behavior of concrete materials is not completely understood because conventional test methods fail to assess the : material response independent of the sample size and shape. : To study the influence of strength affecting test conditions,...

The quest for performance-related specifications for hydraulic cement concrete.

DOT National Transportation Integrated Search

1982-01-01

This paper reviews some of the problems associated with quality assurance for hydraulic cement concrete and the difficulties of relating the results of quality control and acceptance testing to the performance of the concrete facility. The importance...

Development of design parameters for virtual cement and concrete testing : [summary].

DOT National Transportation Integrated Search

2013-12-01

At its most basic, concrete is made from cement : and aggregate, often Portland cement and gravel : (or in Florida, limestone). Varying ingredients and : their proportions directly influences the behavior : of the final cement and concrete products. ...

Accelerated determination of ASR susceptibility during concrete prism testing through nonlinear impact resonance ultrasonic spectroscopy.

DOT National Transportation Integrated Search

2013-10-01

"Accurate, reliable, and timely laboratory assessment of concrete mixturesaggregates combined with : cementitious materialsis a critical component in ensuring the durability of concrete infrastructure from the : adverse effects of the alkali-si...

Testing guide for implementing concrete paving quality control procedures.

DOT National Transportation Integrated Search

2008-03-01

Construction of portland cement concrete pavements is a complex process. A small fraction of the concrete pavements constructed in the : United States over the last few decades have either failed prematurely or exhibited moderate to severe distress. ...

Performance of concrete incorporating colloidal nano-silica

NASA Astrophysics Data System (ADS)

Zeidan, Mohamed Sabry

Nanotechnology, as one of the most modern fields of science, has great market potential and economic impact. The need for research in the field of nanotechnology is continuously on the rise. During the last few decades, nanotechnology was developing rapidly into many fields of applied sciences, engineering and industrial applications, especially through studies of physics, chemistry, medicine and fundamental material science. These new developments may be attributed to the fact that material properties and performance can be significantly improved and controlled through nano-scale processes and nano-structures. This research program aims at 1) further understanding the behavior of cementitious materials when amended on the nano-scale level and 2) exploring the effect of this enhancement on the microstructure of cement matrix. This study may be considered as an important step towards better understanding the use of nano-silica in concrete. The main goal of the study is to investigate the effect of using colloidal nano-silica on properties of concrete, including mechanical properties, durability, transport properties, and microstructure. The experimental program that was conducted included a laboratory investigation of concrete mixtures in which nano-silica was added to cement or to a combination of cement and Class F fly ash. Various ratios of nano-silica were used in concrete mixtures to examine the extent and types of improvements that could be imparted to concrete. The conducted experimental program assessed these improvements in terms of reactivity, mechanical properties, and durability of the mixtures under investigation. Advanced testing techniques---including mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM)---were used to investigate the effect of nano-silica on the microstructure of the tested mixtures. In addition, the effect of nano-silica on the alkali-silica reaction (ASR) was examined using various techniques, including testing of accelerated mortar-bar and strength. Furthermore, this study investigated the deterioration of concrete caused by salt crystallization in concrete pores. This physical effect of salt on concrete may cause significant damage under certain environmental conditions in regions where soil is laden with large amounts of certain salts. The effect of nano-silica on this special type of environmental attack was explored by means of a new non-standard testing procedure, including the simulation of changing seasons, on concrete specimens partially immersed in salt solution. These concrete specimens represented concrete structures with foundations in salt-rich soils.

Data on optimum recycle aggregate content in production of new structural concrete.

PubMed

Paul, Suvash Chandra

2017-12-01

This data presented herein are the research summary of "mechanical behavior and durability performance of concrete containing recycled concrete aggregate" (Paul, 2011) [1]. The results reported in this article relate to an important parameter of optimum content of recycle concrete aggregate (RCA) in production of new concrete for both structural and non-structural applications. For the purpose of the research various types of physical, mechanical and durability tests are performed for concrete made with different percentages of RCA. Therefore, this data set can be a great help of the readers to understand the mechanism of RCA in relates to the concrete properties.

Dataset of producing and curing concrete using domestic treated wastewater

PubMed Central

Asadollahfardi, Gholamreza; Delnavaz, Mohammad; Rashnoiee, Vahid; Fazeli, Alireza; Gonabadi, Navid

2015-01-01

We tested the setting time of cement, slump and compressive and tensile strength of 54 triplicate cubic samples and 9 cylindrical samples of concrete with and without a Super plasticizer admixture. We produced concrete samples made with drinking water and treated domestic wastewater containing 300, 400 kg/m3 of cement before chlorination and then cured concrete samples made with drinking water and treated wastewater. Second, concrete samples made with 350 kg/m3 of cement with a Superplasticizer admixture made with drinking water and treated wastewater and then cured with treated wastewater. The compressive strength of all the concrete samples made with treated wastewater had a high coefficient of determination with the control concrete samples. A 28-day tensile strength of all the samples was 96–100% of the tensile strength of the control samples and the setting time was reduced by 30 min which was consistent with a ASTMC191 standard. All samples produced and cured with treated waste water did not have a significant effect on water absorption, slump and surface electrical resistivity tests. However, compressive strength at 21 days of concrete samples using 300 kg/m3 of cement in rapid freezing and thawing conditions was about 11% lower than concrete samples made with drinking water. PMID:26862577

Dataset of producing and curing concrete using domestic treated wastewater.

PubMed

Asadollahfardi, Gholamreza; Delnavaz, Mohammad; Rashnoiee, Vahid; Fazeli, Alireza; Gonabadi, Navid

2016-03-01

We tested the setting time of cement, slump and compressive and tensile strength of 54 triplicate cubic samples and 9 cylindrical samples of concrete with and without a Super plasticizer admixture. We produced concrete samples made with drinking water and treated domestic wastewater containing 300, 400 kg/m(3) of cement before chlorination and then cured concrete samples made with drinking water and treated wastewater. Second, concrete samples made with 350 kg/m(3) of cement with a Superplasticizer admixture made with drinking water and treated wastewater and then cured with treated wastewater. The compressive strength of all the concrete samples made with treated wastewater had a high coefficient of determination with the control concrete samples. A 28-day tensile strength of all the samples was 96-100% of the tensile strength of the control samples and the setting time was reduced by 30 min which was consistent with a ASTMC191 standard. All samples produced and cured with treated waste water did not have a significant effect on water absorption, slump and surface electrical resistivity tests. However, compressive strength at 21 days of concrete samples using 300 kg/m(3) of cement in rapid freezing and thawing conditions was about 11% lower than concrete samples made with drinking water.

PFC2D simulation of thermally induced cracks in concrete specimens

NASA Astrophysics Data System (ADS)

Liu, Xinghong; Chang, Xiaolin; Zhou, Wei; Li, Shuirong

2013-06-01

The appearance of cracks exposed to severe environmental conditions can be critical for concrete structures. The research is to validate Particle Flow Code(PFC2D) method in the context of concrete thermally-induced cracking simulations. First, concrete was discreted as meso-level units of aggregate, cement mortar and the interfaces between them. Parallel bonded-particle model in PFC2D was adapted to describe the constitutive relation of the cementing material. Then, the concrete mechanics meso-parameters were obtained through several groups of biaxial tests, in order to make the numerical results comply with the law of the indoor test. The concrete thermal meso-parameters were determined by compared with the parameters in the empirical formula through the simulations imposing a constant heat flow to the left margin of concrete specimens. At last, a case of 1000mm×500mm concrete specimen model was analyzed. It simulated the formation and development process of the thermally-induced cracks under the cold waves of different durations and temperature decline. Good agreements in fracture morphology and process were observed between the simulations, previous studies and laboratory data. The temperature decline limits during cold waves were obtained when its tensile strength was given as 3MPa. And it showed the feasibility of using PFC2D to simulate concrete thermally-induced cracking.

Void detection beneath reinforced concrete sections: The practical application of ground-penetrating radar and ultrasonic techniques

NASA Astrophysics Data System (ADS)

Cassidy, Nigel J.; Eddies, Rod; Dods, Sam

2011-08-01

Ground-penetrating radar (GPR) and ultrasonic 'pulse echo' techniques are well-established methods for the imaging, investigation and analysis of steel reinforced concrete structures and are important civil engineering survey tools. GPR is, arguably, the more widely-used technique as it is suitable for a greater range of problem scenarios (i.e., from rebar mapping to moisture content determination). Ultrasonic techniques are traditionally associated with the engineering-based, non-destructive testing of concrete structures and their integrity analyses (e.g., flaw detection, shear/longitudinal velocity determination, etc). However, when used in an appropriate manner, both techniques can be considered complementary and provide a unique way of imaging the sub-surface that is suited to a range of geotechnical problems. In this paper, we present a comparative study between mid-to-high frequency GPR (450 MHz and 900 MHz) and array-based, shear wave, pulse-echo ultrasonic surveys using proprietary instruments and conventional GPR data processing and visualisation techniques. Our focus is the practical detection of sub-metre scale voids located under steel reinforced concrete sections in realistic survey conditions (e.g., a capped, relict mine shaft or vent). Representative two-dimensional (2D) sections are presented for both methods illustrating the similarities/differences in signal response and the temporal-spatial target resolutions achieved with each technique. The use of three-dimensional data volumes and time slices (or 'C-scans') for advanced interpretation is also demonstrated, which although common in GPR applications is under-utilised as a technique in general ultrasonic surveys. The results show that ultrasonic methods can perform as well as GPR for this specific investigation scenario and that they have the potential of overcoming some of the inherent limitations of GPR investigations (i.e., the need for careful antenna frequency selection and survey design in order to image through the rebar meshes). More importantly, we show that standard GPR data collection, processing and visualisation techniques can be used with both types of data without users needing to change existing operational protocols or survey criteria.

Non-destructive inspection protocol for reinforced concrete barriers and bridge railings

NASA Astrophysics Data System (ADS)

Chintakunta, Satish R.; Boone, Shane D.

2014-02-01

Reinforced concrete highway barriers and bridge railings serve to prevent errant vehicles from departing the travel way at grade separations. Despite the important role that they play in maintaining safety and their ubiquitous nature, barrier inspection rarely moves beyond visual inspection. In August 2008, a tractor-trailer fatally departed William Preston Lane, Jr. Memorial Bridge after it dislodged a section of the bridge barrier. Investigations following the accident identified significant corrosion of the anchor bolts attaching the bridge railing to the bridge deck. As a result of the information gathered during its investigation of the accident, the National Transportation Safety Board (NTSB) made recommendations to the Federal Highway Administration concerning Non-Destructive Evaluation (NDE) of concrete bridge railings. The Center for nondestructive evaluation (NDE) at Turner Fairbank Highway Research Center in McLean, VA is currently evaluating feasibility of using four technologies - ground penetrating radar (GPR), ultrasonic pulse-echo, digital radiography and infrared thermal imaging methods to develop bridge inspection methods that augment visual inspections, offer reliable measurement techniques, and are practical, both in terms of time and cost, for field inspection work. Controlled samples containing predefined corrosion levels in reinforcing steel were embedded at barrier connection points for laboratory testing. All four NDE techniques were used in the initial phase I testing. An inspection protocol for detecting and measuring the corrosion of reinforced steel embedded in the anchorage system will be developed as part of phase II research. The identified technologies shall be further developed for field testing utilizing a structure with a barrier in good condition and a structure with a barrier in poor condition.

On impedance measurement of reinforced concrete on the surface for estimate of corroded rebar

NASA Astrophysics Data System (ADS)

Sasamoto, Akira; Yu, Jun; Harada, Yoshihisa; Iwata, Masahiro; Noguchi, Kazuhiro

2017-04-01

In an estimate of health monitoring for reinforced concrete, corrosion degree of rebar is important parameter but is not easy to be estimated by non destructive testing. A few test method such as half cell method or polarization resistance method could be a 'perfect' nondestructive method if luckily having had wired connection to rebar without destructing target concrete. In this presentation it is reported the experimental result that an impedance measurement on surface of reinforced concretes is able to distinguish corroded rebar from healthy rebar. The contact electrode on concrete surface are simple structure made of urethane sponge and needle. Impedance measurement are carried out with frequency response analyzer with frequency range from 0.01Hz to 1MHz, typical amplitude of imposed voltage are 10 volt. We made concrete specimens under two different corrosion process. One process(pre corrosion) has rebars corroded by electrolysis in salty water before concrete casting and another process (post corrosion) has concrete specimens being corroded during the curing. The results of application of developed method to these corroded specimens show the method is useful to estimate corrosion level of rebars.

Investigation of Tensile Creep of a Normal Strength Overlay Concrete.

PubMed

Drexel, Martin; Theiner, Yvonne; Hofstetter, Günter

2018-06-12

The present contribution deals with the experimental investigation of the time-dependent behavior of a typical overlay concrete subjected to tensile stresses. The latter develop in concrete overlays, which are placed on existing concrete structures as a strengthening measure, due to the shrinkage of the young overlay concrete, which is restrained by the substrate concrete. Since the tensile stresses are reduced by creep, creep in tension is investigated on sealed and unsealed specimens, loaded at different concrete ages. The creep tests as well as the companion shrinkage tests are performed in a climatic chamber at constant temperature and constant relative humidity. Since shrinkage depends on the change of moisture content, the evolution of the mass water content is determined at the center of each specimen by means of an electrolytic resistivity-based system. Together with the experimental results for compressive creep from a previous study, a consistent set of time-dependent material data, determined for the same composition of the concrete mixture and on identical specimens, is now available. It consists of the hygral and mechanical properties, creep and shrinkage strains for both sealed and drying conditions, the respective compliance functions, and the mass water contents in sealed and unsealed, loaded and load-free specimens.

Posttest analysis of a laboratory-cast monolith of salt-saturated concrete. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wakeley, L.D.; Poole, T.S.

A salt-saturated concrete was formulated for laboratory testing of cementitious mixtures with potential for use in disposal of radioactive wastes in a geologic repository in halite rock. Cores were taken from a laboratory-cast concrete monolith on completion of tests of permeability, strain, and stress. The cores were analyzed for physical and chemical evidence of brine migration through the concrete, and other features with potential impact on installation of crete plugs at the Waste Isolation Pilot Plant (WIPP) in New Mexico. The posttest analyses of the cores provided evidence of brine movement along the interface between concrete and pipe, and littlemore » indication of permeability through the monolith itself. There may also have been diffusion of chloride into the monolith without actual brine flow.« less

Smart photonic coating for civil engineering field: for a future inspection technology on concrete bridge

NASA Astrophysics Data System (ADS)

Fudouzi, Hiroshi; Tsuchiya, Koichi; Todoroki, Shin-ichi; Hyakutake, Tsuyoshi; Nitta, Hiroyuki; Nishizaki, Itaru; Tanaka, Yoshikazu; Ohya, Takao

2017-04-01

Here we will propose the conceptual new idea of the inspection of concrete bridge using smart materials and mobile IoT system. We apply opal photonic crystal film to detect cracks on concrete infrastructures. High quality opal photonic crystal films were coated on black color PET sheet over 1000 cm2 area. The opal film sheet was cut and adhered to concrete or mortar test pieces by epoxy resin. In the tensile test, the structural color of the opal sheet was changed when the crack was formed. As a demonstration, we have installated the opal film sheet on the wall of the concrete bridge. Our final purpose is the color change will be recorded by portable CCD devices, and send to expert via IoT network.

High velocity penetration into fibre-reinforced concrete materials - protection of buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, W.F.; Watson, A.J.; Armstrong, P.J.

1983-05-01

Fibre reinforced concrete suitable for spraying onto existing structures is being examined to assess its resistance to penetration by 7.62mm diameter armour piercing projectiles. A major test programme is being carried out to examine the influence of aggregate type and fibre type. For each aggregate/fibre combination a statistical method is being used to plan test series which will lead to optimization of the concrete in terms of water/cement ratio, fibre content and aggregate/cement ratio. The minimum thickness of optimized concretes to resist penetration by the projectile and minimise spall and scabbing, will be determined. The mechanics of the impact andmore » penetration event are being studied and a possible method of deflecting the projectile within the concrete is suggested.« less

Polymer concrete overlay test program : interim report.

DOT National Transportation Integrated Search

1974-11-01

This report describes work done on various combinations of monomers and polymer concrete mixes and identifies the mixes showing the greatest potential for use in bridge deck overlays . Presented are test results showing physical properties of various...

11. REINFORCED CONCRETE SLAB ROOF FROM THE SOUTHERN EDGE, VIEW ...

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

11. REINFORCED CONCRETE SLAB ROOF FROM THE SOUTHERN EDGE, VIEW TOWARDS NORTH. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-2, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

13. REINFORCED CONCRETE SLAB ROOF FROM SOUTHWESTERN EDGE, VIEW TOWARDS ...

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

13. REINFORCED CONCRETE SLAB ROOF FROM SOUTHWESTERN EDGE, VIEW TOWARDS NORTHEAST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-1, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

12. REINFORCED CONCRETE SLAB ROOF FROM NORTHEASTERN EDGE, VIEW TOWARDS ...

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

12. REINFORCED CONCRETE SLAB ROOF FROM NORTHEASTERN EDGE, VIEW TOWARDS SOUTHWEST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-1, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

11. REINFORCED CONCRETE SLAB ROOF, GUARD RAIL AT CENTER, VIEW ...

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

11. REINFORCED CONCRETE SLAB ROOF, GUARD RAIL AT CENTER, VIEW TOWARDS NORTHWEST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-1, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

2. FLAME DEFLECTOR FROM THE REINFORCED CONCRETE SLAB ROOF, VIEW ...

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

2. FLAME DEFLECTOR FROM THE REINFORCED CONCRETE SLAB ROOF, VIEW TOWARDS SOUTHWEST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-2, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

12. REINFORCED CONCRETE SLAB ROOF FROM THE NORTHERN EDGE, VIEW ...

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

12. REINFORCED CONCRETE SLAB ROOF FROM THE NORTHERN EDGE, VIEW TOWARDS SOUTH. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-2, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

9. FLAME DEFLECTOR FROM REINFORCED CONCRETE SLAB ROOF, VIEW TOWARDS ...

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

9. FLAME DEFLECTOR FROM REINFORCED CONCRETE SLAB ROOF, VIEW TOWARDS NORTHWEST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-1, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

9. REINFORCED CONCRETE SLAB ROOF FROM NORTHEAST EDGE, VIEW TOWARDS ...

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

9. REINFORCED CONCRETE SLAB ROOF FROM NORTHEAST EDGE, VIEW TOWARDS SOUTHWEST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-4, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

13. REINFORCED CONCRETE SLAB ROOF FROM THE NORTHERN EDGE, VIEW ...

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

13. REINFORCED CONCRETE SLAB ROOF FROM THE NORTHERN EDGE, VIEW TOWARDS SOUTHWEST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-2, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

10. REINFORCED CONCRETE SLAB ROOF FROM SOUTHEAST EDGE, VIEW TOWARDS ...

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

10. REINFORCED CONCRETE SLAB ROOF FROM SOUTHEAST EDGE, VIEW TOWARDS NORTHWEST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-4, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO