Science.gov

Sample records for salado mass concrete

  1. Variability in properties of Salado Mass Concrete

    SciTech Connect

    Wakeley, L.D.; Harrington, P.T.; Hansen, F.D.

    1995-08-01

    Salado Mass Concrete (SMC) has been developed for use as a seal component in the Waste Isolation Pilot Plant. This concrete is intended to be mixed from pre-bagged materials, have an initial slump of 10 in., and remain pumpable and placeable for two hours after mixing. It is a mass concrete because it will be placed in monoliths large enough that the heat generated during cement hydration has the potential to cause thermal expansion and subsequent cracking, a phenomenon to avoid in the seal system. This report describes effects on concrete properties of changes in ratio of water to cement, batch size, and variations in characteristics of different lots of individual components of the concrete. The research demonstrates that the concrete can be prepared from laboratory-batched or pre-bagged dry materials in batches from 1.5 ft{sup 3} to 5.0 yd{sup 3}, with no chemical admixtures other than the sodium chloride added to improve bonding with the host rock, at a water-to-cement ratio ranging from 0.36 to 0.42. All batches prepared according to established procedures had adequate workability for at least 1.5 hours, and achieved or exceeded the target compressive strength of 4500 psi at 180 days after casting. Portland cement and fly ash from different lots or sources did not have a measurable effect on concrete properties, but variations in a shrinkage-compensating cement used as a component of the concrete did appear to affect workability. A low initial temperature and the water-reducing and set-retarding functions of the salt are critical to meeting target properties.

  2. Assessing Workability Complaints in Mass Concrete Construction

    DTIC Science & Technology

    1993-04-01

    up primarily of rigid pipes. It appears that poorly maintained vibrators are frequently proposed for use in consolidating mass concrete . Use of such... vibrators can give the false im- pression of unworkable concrete and result in poorly consolidated concrete . Only vibrators in good operating...units is presented on page vi. 5 Chapt~er 2 Survey Results The survey also indicated that mass concrete is frequently vibrated improp- erly. Improper

  3. Workability of Mass Concrete. Report 2. Supplemental Proportioning Parameters.

    DTIC Science & Technology

    1996-09-01

    proportions for mass concrete with assurance that the concrete will have adequate workability. The initial phase of this study was to obtain information...Corps of Engineers (HQUSACE), as a part of Civil Works Investigation Studies Work Unit 32768, "Workability of Mass Concrete ." The study was conducted...Paul F. Mlakar, Chief, Concrete and Materials Division (CMD), and Mr. Edward F. O’Neil, Acting Chief, Engineering Mechanics Branch (EMB), CMD. Dr

  4. 13. MASS OF POURED CONCRETE IN IRREGULAR STEPPED LAYERS AT ...

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

    13. MASS OF POURED CONCRETE IN IRREGULAR STEPPED LAYERS AT THE BASE OF THE LEFT (EAST) BUTTRESS. CAMERA FACING SOUTHWEST. - Salinas Dam, Salinas River near Pozo Road, Santa Margarita, San Luis Obispo County, CA

  5. Evaluation of Parameters Affecting Thermal Stresses in Mass Concrete

    DTIC Science & Technology

    1991-01-01

    ABAQUS , a finite-element program capable of performing complete incremental construction analyses of complex mass concrete structures during and...following construction. ’The report describes a user-defined aging creep material model, UMAT, used with ABAQUS to account for the changes in concrete...model to evolve the onset and effects of cracking. In addition to material aging, ABAQUS includes the (Continued) 14. SUBJECT TERMS 15. NUMBER OF PAGES

  6. No-slump Roller-Compacted Concrete (RCC) for use in mass concrete construction

    NASA Astrophysics Data System (ADS)

    Saucier, K. L.

    1984-10-01

    The use of no-slump, roller-compacted concrete (RCC) in mass concrete construction was investigated. RCC is concrete having no slump but containing the minimum amount of water necessary to achieve consolidation with a vibrating roller. Tests were conducted to: (1) optimize mixtures for application of no-slump techniques, (2) develop a consistency and quality control technique, (3) determine methods of improving hardened lifts joints, (4) determine the relative frost resistance of RCC, (5) evaluate the erosion susceptibility, and (6) discover economical methods of obtaining void-free vertical surfaces. Indications are that: (1) the curb concrete is viable method of forming and containing RCC; (2) the degree of compaction achieved is dependent on the stiffness and the paste content of the mixture, the lift thickness, and the individual roller; (3) the tensile strength of the untreated joints increased with paste content and quality from approximately 25 percent for relatively lean RCC to approximately 50 percent for richer RCC; (4) erosion resistance at 35-ft/sec fluid velocity of RCC is good; (5) resistance to freezing and thawing of the RCC is poor, apparently due to a poor air void system; and (6) surface treatment with a mortar gun (shotcrete) appears to be a practical method to achieve smooth vertical surfaces.

  7. Mechanical Properties of Mass Concrete at Early Ages

    DTIC Science & Technology

    1991-08-01

    material properties during the time that concrete is undergoing the greatest amount of thermal activity and physical change (i.e. early ages, less than 3...Type II, low alkali (LA) portland cement meeting ASTM C 150 and a Class C fly ash meeting ASTM C 618 [11 i]. The fine aggregate was a natural sand...usually require that specially developed or modified models be used. It should also be noted that the use- of high percentages of pozzolans in mass

  8. The development of a lower heat concrete mixture for mass concrete placement conditions

    NASA Astrophysics Data System (ADS)

    Crowley, Aaron Martin

    The hydration process of portland cement (PC) is exothermic; therefore, the thermal behavior of concrete has to be taken into consideration when placed in a large mass. The research presented involves a Tennessee Department of Transportation (TDOT) Class S (seal) portland cement concrete (PCC) which is used as a foundation seal during construction of bridge abutments and piers. A Class S PCC mixture meeting the 2006 TDOT specifications has the potential to generate excessive amounts of heat and induce thermal cracking in structural elements. The purpose of the study is to reduce the heat generation of a Class S PCC while maintaining adequate values of other engineering properties. Due to the possibility of underwater placement of a Class S PCC, reduction in the total cementing materials content were not considered in this study. Five candidate mixtures were used to compare against a typical TDOT Class S mixture. The five candidate Class S-LH (lower heat) mixtures were 45, 60, 70% Grade 120 slag substitutions for PC as well as two ternary mixtures containing Grade 120 slag and Class F fly ash. Ten batches of each mixture were produced. All plastic and hardened properties met TDOT 604.03 Class S requirements for analytical comparison. The 70% Grade 120 slag Class S-LH mixture was analytically superior for all hardened properties and at reducing heat generation. Since the 70% Grade 120 slag Class S-LH mixture proved to be superior in laboratory conditions; it was selected for further evaluation in the field testing portion of the research. The 70% Grade 120 slag mixture produced a significantly lower maximum temperature as well as a significantly lower maximum differential temperature than a TDOT Class S mixture with 20% Class C fly ash in side-by-side 18 cubic yard cube field placements. Research results and literature recommend that engineers should decide when mass concrete conditions are appropriate during construction practices. When mass concrete conditions are

  9. Performance of intact and partially degraded concrete barriers in limiting mass transport

    SciTech Connect

    Walton, J.C. )

    1992-06-01

    Mass transport through concrete barriers and release rate from concrete vaults are quantitatively evaluated. The thorny issue of appropriate diffusion coefficients for use in performance assessment calculations is covered, with no ultimate solution found. Release from monolithic concrete vaults composed of concrete waste forms is estimated with a semi-analytical solution. A parametric study illustrates the importance of different parameters on release. A second situation of importance is the role of a concrete shell or vault placed around typical waste forms in limiting mass transport. In both situations, the primary factor controlling concrete performance is cracks. The implications of leaching behavior on likely groundwater concentrations is examined. Frequently, lower groundwater concentrations can be expected in the absence of engineered covers that reduce infiltration.

  10. Characterization of VX on concrete using ion trap secondary ionization mass spectrometry.

    PubMed

    Groenewold, G S; Appelhans, A D; Gresham, G L; Olson, J E; Jeffery, M; Weibel, M

    2000-01-01

    The nerve agent VX (O-ethyl S-2-diisopropylaminoethyl methyl phosphonothiolate) was analyzed on the surface of concrete samples using an ion trap secondary ion mass spectrometer (IT-SIMS). It was found that VX could be detected down to an absolute quantity of 5 ng on a concrete chip, or to a surface coverage of 0.0004 monolayers on crushed concrete. To achieve these levels of detection, the m/z 268-->128 ion fragmentation was measured using MS2, where m/z 268 corresponds to [VX + H]+, and 128 corresponds to a diisopropylvinylammonium isomer, that is formed by the elimination of the phosphonothiolate moiety. Detection at these levels was accomplished by analyzing samples that had been recently exposed to VX, i.e., within an hour. When the VX-exposed concrete samples were aged, the SIMS signature for intact VX had disappeared, which signaled the degradation of the compound on the concrete surface. The VX signature was replaced by ions which are interpreted in terms of VX degradation products, which appear to be somewhat long lived on the concrete surface. These compounds include ethylmethylphosphonic acid (EMPA), diisopropyl taurine (DIPT), diisopropylaminoethanethiol (DESH), bis(diisopropylaminoethane) disulfide [(DES)2], and a particularly tenacious compound that may correspond to diisopropylvinylamine (DIVA), or an isomer thereof. It was found that the thiolamine-derived degradation products DIPT, DESH, and (DES)2 were removed with isopropyl alcohol extraction. However, the DIVA-related degradation product was observed to strongly adhere to the concrete surface for longer than one week. Although quantitation was not possible in this set of experiments, the results clearly show the rapid degradation of VX on concrete, as well as the surface sensitivity of the IT-SIMS for intact VX and its adsorptive degradation products.

  11. Hydraulic testing of Salado Formation evaporites at the Waste Isolation Pilot Plant site: Second interpretive report

    SciTech Connect

    Beauheim, R.L.; Roberts, R.M.; Dale, T.F.; Fort, M.D.; Stensrud, W.A.

    1993-12-01

    Pressure-pulse, constant-pressure flow, and pressure-buildup tests have been performed in bedded evaporites of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site to evaluate the hydraulic properties controlling brine flow through the Salado. Transmissivities have been interpreted from six sequences of tests conducted on five stratigraphic intervals within 15 m of the WIPP underground excavations.

  12. Durability of concrete materials in high-magnesium brine

    SciTech Connect

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

    1994-03-01

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

  13. Direct analysis of ethylenediaminetetraacetic acid (EDTA) on concrete by reactive-desorption electrospray ionization mass spectrometry.

    PubMed

    Lebeau, D; Reiller, P E; Lamouroux, C

    2015-01-01

    Analysis of organic ligands such as ethylenediaminetetraacetic acid (EDTA) is today an important challenge due to their ability to increase the mobility of radionuclides and metals. Reactive desorption electrospray ionization mass spectrometry (reactive-DESI-MS) was used for direct analysis of EDTA on concrete samples. EDTA forms complexes and those with Fe(III) ions are among the most thermodynamically favored. This complexing capacity was used to improve the specific detection of EDTA directly on a concrete matrix by doping the solvent spray of DESI with a solution of FeCl3 to selectively create the complex between EDTA and Fe(III). Thus, EDTA sensitivity was largely improved by two orders of magnitude with reactive-DESI-MS experiments thanks to the specific detection of EDTA as a [EDTA-4H+Fe(III)](-) complex. The proof of principle that reactive DESI can be applied to concrete samples to detect EDTA has been demonstrated. Its capacity for semi-quantitative determination and localization of EDTA under ambient conditions and with very little sample preparation, minimizing sample manipulations and solvent volumes, two important conditions for the development of new methodologies in the field of analytical chemistry, has been shown.

  14. Study of mass attenuation coefficients and effective atomic numbers of bismuth-ground granulated blast furnace slag concretes

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Singh, Sukhpal

    2016-05-01

    Five samples of Bismuth-Ground granulated blast furnace slag (Bi-GGBFS) concretes were prepared using composition (0.6 cement + x Bi2O3 + (0.4-x) GGBFS, x = 0.05, 0.10, 0.15, 0.20 and 0.25) by keeping constant water (W) cement (C) ratio. Mass attenuation coefficients (μm) of these prepared samples were calculated using a computer program winXCOM at different gamma ray energies, whereas effective atomic numbers (Zeff) is calculated using mathematical formulas. The radiation shielding properties of Bi-GGBFS concrete has been compared with standard radiation shielding concretes.

  15. Non-Salado flow and transport position paper. Revision 1

    SciTech Connect

    Axness, C.; Beauheim, R.; Behl, Y.

    1994-12-15

    The US Department of Energy (DOE) is preparing to request the US Environmental Protection Agency (EPA) to certify compliance of the Waste Isolation Pilot Plant (WIPP) with long-term requirements of the environmental Radiation Protection Standards for Management and Standards for Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Waste (40 CFR Part 191). The DOE must also demonstrate compliance with the long-term requirements of the Land Disposal Restrictions of the Resource Conservation and Recovery Act (RCRA) (40 CFR Part 268.6). Sandia National Laboratories (SNL) has ben conducting iterative performance assessments (PAs) for the the WIPP to provide guidance to the project on the technical activities required to determine long-term performance of the WIPP disposal system. The most recent PA was conducted in 1992. The objectives of this paper are to: (1) Identify and describe the relationship between non-Salado hydrology and the array of scenarios that might be relevant to the long-term performance of the repository. (2) Identify and describe the array of conceptual and mechanistic models that are required to evaluate the scenarios for the purpose of compliance. (3) Identify and describe the data/information that are required to support the conceptual and mechanistic models.

  16. Estimation of explosive charge mass used for explosions on concrete surface for the forensic purpose.

    PubMed

    Bjelovuk, Ivana D; Jaramaz, Slobodan; Mickovic, Dejan

    2012-03-01

    The method of choice used by most terrorists for achieving political goals remains the utilization of explosive devices and there is always visible evidence at a crime scene after the deployment of such devices. Given favorable circumstances, forensic analysis can determine the cause of the explosion - the type of the explosive device, the means of detonation, the type and mass of the explosive charge that has been used and perhaps provide information to lead to the identity of the individual who may have constructed or deployed the explosive device, etc. Evidence of an explosion may take the form of a crater or other damage which may provide some information facilitating and estimating the mass of explosive material used. This paper reports the findings obtained by performing experimental explosions of known charges on a concrete surface, in order to establish the correlation between the charge weight and the effects of the explosion. Known masses of explosives were fired and the dimensions of craters made by explosions were measured. Five empirical equations for estimation of the explosive charge mass from crater dimensions were used.

  17. Effect of coal combustion fly ash use in concrete on the mass transport release of constituents of potential concern.

    PubMed

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

    2014-05-01

    Concerns about the environmental safety of coal combustion fly ash use as a supplemental cementitious material have necessitated comprehensive evaluation of the potential for leaching concrete materials containing fly ash used as a cement replacement. Using concrete formulations representative of US residential and commercial applications, test monoliths were made without fly ash replacement (i.e., controls) and with 20% or 45% of the portland cement fraction replaced by fly ash from four coal combustion sources. In addition, microconcrete materials were created with 45% fly ash replacement based on the commercial concrete formulation but with no coarse aggregate and an increased fine aggregate fraction to maintain aggregate-paste interfacial area. All materials were cured for 3 months prior to mass transport-based leach testing of constituents of potential concern (i.e., Sb, As, B, Ba, Cd, Cr, Mo, Pb, Se, Tl and V) according to EPA Method 1315. The cumulative release results were consistent with previously tested samples of concretes and mortars from international sources. Of the 11 constituents tested, only Sb, Ba, B, Cr and V were measured in quantifiable amounts. Microconcretes without coarse aggregate were determined to be conservative surrogates for concrete in leaching assessment since cumulative release from microconcretes were only slightly greater than the associated concrete materials. Relative to control materials without fly ash, concretes and microconcretes with fly ash replacement of cement had increased 28-d and 63-d cumulative release for a limited number 10 comparison cases: 2 cases for Sb, 7 cases for Ba and 1 case for Cr. The overall results suggest minimal leaching impact from fly ash use as a replacement for up to 45% of the cement fraction in typical US concrete formulations; however, scenario-specific assessment based on this leaching evaluation should be used to determine if potential environmental impacts exist.

  18. Rio Salado Community College Adjunct Faculty Staffing and Development Program, July 1989-August 1990.

    ERIC Educational Resources Information Center

    Rio Salado Community Coll., AZ.

    In July 1989, Rio Salado Community College established an Adjunct Faculty Staffing and Development Program (AFSDP) with the following goals: to insure excellence in instruction through content consistency and the use of effective teaching and learning strategies; to increase adjunct faculty identification with the college and appreciation of the…

  19. Student Hotline Procedural Manual. Instructional Technology and Design. Rio Salado Community College. Revised.

    ERIC Educational Resources Information Center

    Rio Salado Community Coll., AZ.

    Rio Salado Community College offers a variety of alternative delivery courses utilizing different forms of instructional technology (e.g., broadcast and cable television, radio, audio and video cassettes, and computer-managed instruction) for both credit and non-credit instruction. This manual provides information for student operators of a…

  20. Heat and Mass Transfer in the Concrete of Special Industrial Installations (Teplo- i Massoperenos v Betone Spetsial’nykh Promyshlennykh Sooruzheniy)

    DTIC Science & Technology

    1976-07-01

    calculating the effective coefficient of heat tranfer based on the necessity for reducing the intensity of thermal exchange by approximately 100 times...TL 538 ADA03O93 Draft Transl’ation 5384 July 197 HEAT AND MASS TRANSFER IN THE CONCRETE OF SPECIAL INDUSTRIAL INSTALLATIONS I.V. Zasedatelev and V.G...gations of special features of the heat and mass transfer processes in concrete Exunination and analysis of mathematical models of the processes, experi

  1. Effects of micro-sized and nano-sized WO3 on mass attenauation coefficients of concrete by using MCNPX code.

    PubMed

    Tekin, H O; Singh, V P; Manici, T

    2017-03-01

    In the present work the effect of tungsten oxide (WO3) nanoparticles on mass attenauation coefficients of concrete has been investigated by using MCNPX (version 2.4.0). The validation of generated MCNPX simulation geometry has been provided by comparing the results with standard XCOM data for mass attenuation coefficients of concrete. A very good agreement between XCOM and MCNPX have been obtained. The validated geometry has been used for definition of nano-WO3 and micro-WO3 into concrete sample. The mass attenuation coefficients of pure concrete and WO3 added concrete with micro-sized and nano-sized have been compared. It was observed that shielding properties of concrete doped with WO3 increased. The results of mass attenauation coefficients also showed that the concrete doped with nano-WO3 significanlty improve shielding properties than micro-WO3. It can be concluded that addition of nano-sized particles can be considered as another mechanism to reduce radiation dose.

  2. Hydraulic Testing of Salado Formation Evaporites at the Waste Isolation Pilot Plant Site: Final Report

    SciTech Connect

    Beauheim, Richard L.; Domski, Paul S.; Roberts, Randall M.

    1999-07-01

    This report presents interpretations of hydraulic tests conducted in bedded evaporates of the Salado Formation from May 1992 through May 1995 at the Waste Isolation Pilot Plant (WIPP) site in southeastern New Mexico. The WIPP is a US Department of Energy research and development facility designed to demonstrate safe disposal of transuranic wastes from the nation's defense programs. The WIPP disposal horizon is located in the lower portion of the Permian Salado Formation. The hydraulic tests discussed in this report were performed in the WIPP underground facility by INTERA inc. (now Duke Engineering and Services, Inc.), Austin, Texas, following the Field Operations Plan and Addendum prepared by Saulnier (1988, 1991 ) under the technical direction of Sandia National Laboratories, Albuquerque, New Mexico.

  3. Assessment of actinide mass embedded in large concrete waste packages by photon interrogation and photofission.

    PubMed

    Gmar, M; Jeanneau, F; Lainé, F; Makil, H; Poumarède, B; Tola, F

    2005-01-01

    This paper describes a method based on photofission developed in our laboratory to characterize in depth large waste packages. The method consists in using photons of high-energy (Bremsstrahlung radiation) in order to induce reactions of photofission on the heavy nuclei present in the wastes. The measurement of the delayed neutrons allows quantifying the actinides in the wastes. We present the first results of measurement performed with a concrete mock-up of 870l and two real waste packages.

  4. How Concrete Is Concrete?

    ERIC Educational Resources Information Center

    Gravemeijer, Koeno

    2011-01-01

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

  5. Gas chromatographic-mass spectrometric characterisation of amiton and the recovery of amiton from concrete, paint, rubber and soil matrices.

    PubMed

    Borrett, Veronica T; Gan, Tiang-Hong; Lakeland, Barry R; Leslie, D Ralph; Mathews, Robert J; Mattsson, Eric R; Riddell, Stuart; Tantaro, Vince

    2003-06-27

    Amiton [O,O-diethyl S-[2-(diethylamino)ethyl] phosphorothiolate], is an organophosphorus chemical included in Schedule 2 of the Chemical Weapons Convention (CWC). Verification provisions under the CWC rely on the existence of a database of analytical information for scheduled chemicals and related compounds. Little analytical information is available for amiton. In this study, gas chromatography-mass spectrometry (GC-MS) characterisation of amiton and its typical impurities (including by-products and degradation products), supported by selective GC detection and 31P NMR data, was undertaken. Twenty-one compounds, including a by-product unique to amiton from an industrial source, were identified. Involatile degradation products of amiton were derivatised to enable their identification by GC-MS. The recovery of amiton from matrices that may be expected in an inspection scenario (i.e. concrete, paint, rubber and soil) was also examined. Paint and concrete matrices were the most useful matrices for the detection of amiton, and its by-products and degradation products. Amiton was readily detected in these matrices after 28 days.

  6. Histopathological changes in the gills and liver of Prochilodus lineatus from the Salado River basin (Santa Fe, Argentina).

    PubMed

    Troncoso, Ileana C; Cazenave, Jimena; Bacchetta, Carla; Bistoni, María de Los Angeles

    2012-06-01

    This study evaluated the histopathological changes in gills and liver of Prochilodus lineatus inhabiting the Salado River basin. Fish were collected in four different sampling stations. The histological lesions in the tissues were examined under light microscopy and evaluated with quantitative analyses. The morphometric analysis of the gills showed a significant shortening of secondary lamellae and a lower percentage of area for gas exchange in fish from station 1 (an urban area, located near the mouth of the Salado River) in comparison with fish gills from the reference site (station 4, a relatively pristine area). Moreover, a significantly higher area occupied with necrotic foci and the occurrence of an important inflammatory response were observed in fish liver of station 1 than the samples caught from other stations. Thus, histopathological evidences showed differences among sites, which could be related to different environmental conditions.

  7. Reconnaissance Study of the Archaeological and Related Resources of the Lower Puerco and Salado Drainages, Central New Mexico.

    DTIC Science & Technology

    1980-01-01

    representative of the typical of the foothills discussed above. At valley and adjacent mesas. Lower tempera- Magdalena, twelve miles southwest of the tures...the drainage valley has been cut. the Puerco and Salado were the scene of such Represented in the gravels are examples of movements, every major rock ...the Puerco was 100 feet totally unaware of the erosional event at Los (30.5 in) wide with vertical banks 20 to 30 Quelites. Making extensive use of

  8. The Interplay of In Situ Stress Ratio and Transverse Isotropy in the Rock Mass on Prestressed Concrete-Lined Pressure Tunnels

    NASA Astrophysics Data System (ADS)

    Simanjuntak, T. D. Y. F.; Marence, M.; Schleiss, A. J.; Mynett, A. E.

    2016-11-01

    This paper presents the mechanical and hydraulic behaviour of passively prestressed concrete-lined pressure tunnels embedded in elastic transversely isotropic rocks subjected to non-uniform in situ stresses. Two cases are distinguished based on whether the in situ vertical stress in the rock mass is higher, or lower than the in situ horizontal stress. A two-dimensional finite element model was used to study the influence of dip angle, α, and horizontal-to-vertical stress ratio, k, on the bearing capacity of prestressed concrete-lined pressure tunnels. The study reveals that the in situ stress ratio and the orientation of stratifications in the rock mass significantly affect the load sharing between the rock mass and the lining. The distribution of stresses and deformations as a result of tunnel construction processes exhibits a symmetrical pattern for tunnels embedded in a rock mass with either horizontal or vertical stratification planes, whereas it demonstrates an unsymmetrical pattern for tunnels embedded in a rock mass with inclined stratification planes. The results obtained for a specific value α with coefficient k are identical to that for α + 90° with coefficient 1/ k by rotating the tunnel axis by 90°. The maximum internal water pressure was determined by offsetting the prestress-induced hoop strains at the final lining intrados against the seepage-induced hoop strains. As well as assessing the internal water pressure, this approach is capable of identifying potential locations where longitudinal cracks may occur in the final lining.

  9. Seismic activity response as observed in mantled howlers (Alouatta palliata), Cuero y Salado Wildlife Refuge, Honduras.

    PubMed

    Snarr, Kymberley Anne

    2005-10-01

    This report documents the response of wild mantled howlers (Alouatta palliata) to coseismic activity (seismic activity at the time of an earthquake). During field work on the north coast of Honduras, data were collected on a habituated troop of mantled howlers as they responded to coseismic activity. The seismic event occurred on 13 February 2001 at 0822 hours local time with a magnitude of Richter scale 6.6, focus depth of approximately 15 km at a distance of 341 km from the epicentre to the field site, Cuero y Salado. At the field site, based upon Jeffreys and Bullen (1988), body waves, noted as P and S waves, arrived at 60 and 87 s, respectively, with surface waves arriving approximately 103 s post-origin time of the seismic event. While there are three reports on non-human primate response to coseismic activity in the literature, they report on captive non-human primates. This is the first documented response on a non-captive troop. In addition, this report compares the intensity measure encountered by a wild troop of howlers and one captive group of orangutans as set out by the Modified Mercalli Intensity scale. The Modified Mercalli measure of intensity is one of two standard measures of seismic activity and rates what a person sees and feels at their location (Wood and Neumann 1931; Richter 1958). Thus, arboreal nonhuman primates are found to respond to coseismic activity ranging from Level IV to Level VI as based upon the modified Mercalli intensity scale.

  10. Literature review and recommendation of methods for measuring relative permeability of anhydrite from the Salado Formation at the Waste Isolation Pilot Plant

    SciTech Connect

    Christiansen, R.L.; Howarth, S.M.

    1995-08-01

    This report documents a literature review of methods for measuring relative permeability as applied to low permeability anhydrite rock samples from the Salado Formation. About one hundred papers were reviewed, and four methods were identified as promising techniques for measuring the relative permeability of the Salado anhydrite: (1) the unsteady-state high-rate method, (2) the unsteady-state stationary-liquid method, (3) the unsteady-state centrifuge method, and (4) the unsteady-state low-rate method. Except for the centrifuge method, all have been used for low permeability rocks. The unsteady-state high-rate method is preferred for measuring relative permeability of Salado anhydrite, and the unsteady-state stationary-liquid method could be well suited for measuring gas relative permeability of Salado anhydrite. The unsteady-state low-rate method, which combines capillary pressure effects with relative permeability concepts may also prove effective. Likewise, the unsteady-state centrifuge method may be an efficient means for measuring brine relative permeability for Salado anhydrite, especially at high gas saturations.

  11. 40 CFR Appendix A to Part 194 - Certification of the Waste Isolation Pilot Plant's Compliance With the 40 CFR Part 191 Disposal...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Department shall use Salado mass concrete (consistent with that proposed for the shaft seal system, and as described in Appendix SEAL of Docket A-93-02, Item II-G-1) instead of fresh water concrete. Condition...

  12. 40 CFR Appendix A to Part 194 - Certification of the Waste Isolation Pilot Plant's Compliance With the 40 CFR Part 191 Disposal...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Department shall use Salado mass concrete (consistent with that proposed for the shaft seal system, and as described in Appendix SEAL of Docket A-93-02, Item II-G-1) instead of fresh water concrete. Condition...

  13. Interpretation of in-situ pressure and flow measurements of the Salado Formation at the Waste Isolation Pilot Plant

    SciTech Connect

    Howarth, S.M.; Peterson, E.W.; Lagus, P.L.; Lie, K.; Finley, S.J.; Nowak, E.J.

    1991-01-01

    This paper describes preliminary interpretation of in-situ pressure and flow measurements of the Salado Formation at the Waste Isolation Pilot Plant (WIPP). The WIPP facility is located 660 m underground in the Salado, a bedded salt deposit. Shut-in pressure tests were conducted prior to, and subsequent to, the mining of a circular drift in order to evaluate excavation effects on pore pressure, permeability, and host rock heterogeneity. Borehole deformation was measured during these tests and used to correct for changes in the test region volume due to salt creep effects. Preliminary pre-excavation results indicate that the flow properties of this layered host rock are heterogeneous. Resulting pore pressures range from 1 to 14 MPa and permeabilities range from below measurable to about 1 nanodarcy. Normalized borehole diameter change rates were between {minus}4 and 63 microstrains/day. Shut-in pressures and borehole diameters in all test boreholes were affected by the excavation of Room Q coincident with the advances of the boring machine. Preliminary results from post-excavation test results show decreased pore pressures compared to pre-excavation values.

  14. Multiple biomarkers responses in Prochilodus lineatus allowed assessing changes in the water quality of Salado River basin (Santa Fe, Argentina).

    PubMed

    Cazenave, Jimena; Bacchetta, Carla; Parma, María J; Scarabotti, Pablo A; Wunderlin, Daniel A

    2009-11-01

    This field study assessed water quality of Salado River basin by using a set of biomarkers in the fish Prochilodus lineatus. Multiple biomarkers were measured, including morphological indexes (condition factor, liver somatic index), hematological (red and white blood cells) and biochemical (glucose, total protein and cholinesterase activity) parameters. Besides, detoxication and oxidative stress markers (antioxidant enzymes, lipid peroxidation) were measured in liver, gills and kidney. Despite water quality assessment did not show marked differences among sites, biomarkers responses indicate that fish are living under stressful environmental conditions. According to multivariate analysis glucose, glutathione S-transferase activity, lipid peroxidation levels and the count of white blood cells are key biomarkers to contribute to discrimination of sites. So, we suggest use those biomarkers in future monitoring of freshwater aquatic systems.

  15. Rotifer dynamics in three shallow lakes from the Salado river watershed (Argentina): the potential modulating role of incident solar radiation.

    PubMed

    Diovisalvi, Nadia; Rennella, Armando M; Zagarese, Horacio E

    2015-11-01

    In turbid Pampean lakes, incident solar radiation is a major driver of plankton seasonal dynamics. Higher light availability in summer translates into higher primary production, and therefore more food for zooplankton grazers. However, experimental evidence suggests that food produced under the high irradiance conditions prevailing in summer are less suitable to sustain rotifer population growth than that produced under the lower irradiance conditions typical of winter. Here, we analysed time series datasets corresponding to three shallow lakes from the Salado river watershed. This analysis provided evidence for similar seasonal patterns of rotifer relative abundance over a large geographic area. In addition, we performed life table experiments to test the hypothesis that natural seston produced in winter could sustain higher population growth rates than seston produced in summer. We suggest that the natural seasonal changes in temperature and food generate successive time windows, which may be capitalized by the different grazer species, resulting in predictable phenology of grazer populations.

  16. Phytoplankton chlorophyte structure as related to ENSO events in a saline lowland river (Salado River, Buenos Aires, Argentina).

    PubMed

    Solari, Lía C; Gabellone, Néstor A; Claps, María C; Casco, María A; Quaíni, Karina P; Neschuk, Nancy C

    2014-04-01

    We analyzed the phytoplankton present in the lower sector of the Salado River (Buenos Aires, Argentina) for 10 years (1995-2005) and detected significant changes occurring in chlorophyte abundance and species richness during La Niña event (1998-1999), which period was analyzed throughout the entire basin (main stream and tributaries). We compared the physicochemical and biologic variables between two El Niño-La Niña-Southern Oscillation (ENSO) periods - El Niño (March 1997-January 1998) and La Niña (May 1998-May 1999) - to identify possible indicators of a relationship between climatic anomalies and chlorophyte performance. Chlorophyte density increased during the La Niña. Under normal or extreme hydrologic conditions, mobile (Chlamydomonas spp.) and nonmobile (Monoraphidium spp.) chlorophytes codominated. These species belonged to Reynolds's functional groups X1 and X2, those typical of nutrient-enriched environments. Comparative analyses between El Niño and La Niña periods indicated significant differences in physicochemical (K(+), dissolved polyphenols, particulate reactive phosphorus, alkalinity, pH) and biologic (species diversity and richness, phytoplankton and chlorophyte total densities) variables between the two periods at all basin sites. During the La Niña condition, species richness was greater owing to interconnected shallow lakes and drainage-channel inputs, while the Shannon diversity index was lower because of the high abundance values of Monoraphidium minutum. A detailed analysis of the chlorophytes in the entire basin, indicated that changes in density and species dominance occurred on a regional scale although diverse chlorophyte assemblages were identified in the different sectors of the Salado River basin. After La Niña event, the entire basin had the potential to revert to the previous density values, showing the resilience to global environmental changes and the ability to reestablish the general conditions of stability.

  17. Evaluation of methods for measuring relative permeability of anhydride from the Salado Formation: Sensitivity analysis and data reduction

    SciTech Connect

    Christiansen, R.L.; Kalbus, J.S.; Howarth, S.M.

    1997-05-01

    This report documents, demonstrates, evaluates, and provides theoretical justification for methods used to convert experimental data into relative permeability relationships. The report facilities accurate determination of relative permeabilities of anhydride rock samples from the Salado Formation at the Waste Isolation Pilot Plant (WIPP). Relative permeability characteristic curves are necessary for WIPP Performance Assessment (PA) predictions of the potential for flow of waste-generated gas from the repository and brine flow into repository. This report follows Christiansen and Howarth (1995), a comprehensive literature review of methods for measuring relative permeability. It focuses on unsteady-state experiments and describes five methods for obtaining relative permeability relationships from unsteady-state experiments. Unsteady-state experimental methods were recommended for relative permeability measurements of low-permeability anhydrite rock samples form the Salado Formation because these tests produce accurate relative permeability information and take significantly less time to complete than steady-state tests. Five methods for obtaining relative permeability relationships from unsteady-state experiments are described: the Welge method, the Johnson-Bossler-Naumann method, the Jones-Roszelle method, the Ramakrishnan-Cappiello method, and the Hagoort method. A summary, an example of the calculations, and a theoretical justification are provided for each of the five methods. Displacements in porous media are numerically simulated for the calculation examples. The simulated product data were processed using the methods, and the relative permeabilities obtained were compared with those input to the numerical model. A variety of operating conditions were simulated to show sensitivity of production behavior to rock-fluid properties.

  18. Phytoplankton chlorophyte structure as related to ENSO events in a saline lowland river (Salado River, Buenos Aires, Argentina)

    PubMed Central

    Solari, Lía C; Gabellone, Néstor A; Claps, María C; Casco, María A; Quaíni, Karina P; Neschuk, Nancy C

    2014-01-01

    We analyzed the phytoplankton present in the lower sector of the Salado River (Buenos Aires, Argentina) for 10 years (1995–2005) and detected significant changes occurring in chlorophyte abundance and species richness during La Niña event (1998–1999), which period was analyzed throughout the entire basin (main stream and tributaries). We compared the physicochemical and biologic variables between two El Niño–La Niña–Southern Oscillation (ENSO) periods – El Niño (March 1997–January 1998) and La Niña (May 1998–May 1999) – to identify possible indicators of a relationship between climatic anomalies and chlorophyte performance. Chlorophyte density increased during the La Niña. Under normal or extreme hydrologic conditions, mobile (Chlamydomonas spp.) and nonmobile (Monoraphidium spp.) chlorophytes codominated. These species belonged to Reynolds's functional groups X1 and X2, those typical of nutrient-enriched environments. Comparative analyses between El Niño and La Niña periods indicated significant differences in physicochemical (K+, dissolved polyphenols, particulate reactive phosphorus, alkalinity, pH) and biologic (species diversity and richness, phytoplankton and chlorophyte total densities) variables between the two periods at all basin sites. During the La Niña condition, species richness was greater owing to interconnected shallow lakes and drainage-channel inputs, while the Shannon diversity index was lower because of the high abundance values of Monoraphidium minutum. A detailed analysis of the chlorophytes in the entire basin, indicated that changes in density and species dominance occurred on a regional scale although diverse chlorophyte assemblages were identified in the different sectors of the Salado River basin. After La Niña event, the entire basin had the potential to revert to the previous density values, showing the resilience to global environmental changes and the ability to reestablish the general conditions of

  19. Interpretation of brine-permeability tests of the Salado Formation at the Waste Isolation Pilot Plant site: First interim report

    SciTech Connect

    Beauheim, R.L. ); Saulnier, G.J. Jr.; Avis, J.D. )

    1991-08-01

    Pressure-pulse tests have been performed in bedded evaporites of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site to evaluate the hydraulic properties controlling brine flow through the Salado. Hydraulic conductivities ranging from about 10{sup {minus}14} to 10{sup {minus}11} m/s (permeabilities of about 10{sup {minus}21} to 10{sup {minus}18} m{sup 2}) have been interpreted from nine tests conducted on five stratigraphic intervals within eleven meters of the WIPP underground excavations. Tests of a pure halite layer showed no measurable permeability. Pore pressures in the stratigraphic intervals range from about 0.5 to 9.3 MPa. An anhydrite interbed (Marker Bed 139) appears to be one or more orders of magnitude more permeable than the surrounding halite. Hydraulic conductivities appear to increase, and pore pressures decrease, with increasing proximity to the excavations. These effects are particularly evident within two to three meters of the excavations. Two tests indicated the presence of apparent zero-flow boundaries about two to three meters from the boreholes. The other tests revealed no apparent boundaries within the radii of influence of the tests, which were calculated to range from about four to thirty-five meters from the test holes. The data are insufficient to determine if brine flow through evaporites results from Darcy-like flow driven by pressure gradients within naturally interconnected porosity or from shear deformation around excavations connecting previously isolated pores, thereby providing pathways for fluids at or near lithostatic pressure to be driven towards the low-pressure excavations. Future testing will be performed at greater distances from the excavations to evaluate hydraulic properties and processes beyond the range of excavation effects.

  20. Comparison of Seismic Responses for Reinforced Concrete Buildings with Mass and Stiffness Irregularities Using Pushover and Nonlinear Time History Analysis

    NASA Astrophysics Data System (ADS)

    Teruna, D. R.

    2017-03-01

    Pushover analysis or also known as nonlinear static procedures (NSP) have been recognized in recent years for practical evaluation of seismic demands and for structural design by estimating a structural building capacities and deformation demands. By comparing these demands and capacities at the performance level interest, the seismic performance of a building can be evaluated. However, the accuracy of NSP for assessment irregular building is not yet a fully satisfactory solution, since irregularities of a building influence the dynamic responses of the building. The objective of the study presented herein is to understand the nonlinear behaviour of six story RC building with mass irregularities at different floors and stiffness irregularity at first story (soft story) using NSP. For the purpose of comparison on the performance level obtained with NSP, nonlinear time history analysis (THA) were also performed under ground motion excitation with compatible to response spectra design. Finally, formation plastic hinges and their progressive development from elastic level to collapse prevention are presented and discussed.

  1. Diffusion of Radionuclides in Concrete and Soil

    SciTech Connect

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

    2012-04-25

    One of the methods being considered for safely disposing of Category 3 low-level radioactive wastes is to encase the waste in concrete. Such concrete encasement would contain and isolate the waste packages from the hydrologic environment and would act as an intrusion barrier. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages. The mobilized radionuclides may escape from the encased concrete by mass flow and/or diffusion and move into the surrounding subsurface environment. Therefore, it is necessary to assess the performance of the concrete encasement structure and the ability of the surrounding soil to retard radionuclide migration. The objective of our study was to measure the diffusivity of Re, Tc and I in concrete containment and the surrounding vadose zone soil. Effects of carbonation, presence of metallic iron, and fracturing of concrete and the varying moisture contents in soil on the diffusivities of Tc and I were evaluated.

  2. Durable fiber reinforced self-compacting concrete

    SciTech Connect

    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 strains 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.

  3. Configuration and Correlation of Fluvial Terrace Deposits In the Lower Rio Salado Valley: A Record of Magmatic Uplift and Active Normal Faulting in the Rio Grande Rift

    NASA Astrophysics Data System (ADS)

    Sion, B. D.; Axen, G. J.; Phillips, F. M.; Harrison, B.

    2015-12-01

    The Rio Salado is a western tributary of the Rio Grande whose valley is flanked by six major terrace levels. The Rio crosses several active rift-related normal faults and the active, mid-crustal Socorro Magma Body (SMB; a sill at 19 km depth that is actively doming the land surface), providing an unusual opportunity to explore the effects of deep magma emplacement and active faulting on the terraces. Rio Salado terraces were mapped using a high-resolution DEM and digital color stereophotographs and were projected onto a valley-parallel vertical plane to construct longitudinal profiles. Three new soil pits were described to aid terrace correlation. A net incision rate of 0.41 ± 0.06 m/ka was inferred from the correlation of a major fill-cut terrace to the 122 ± 18 ka Airport surface ~25 km south of the Rio Salado. This incision rate is >1.5 times more rapid than estimated rates nearby or in other parts of New Mexico, but yields age estimates for other terraces that are consistent with soil development. Terrace gradients in the Rio Salado have increased through time, indicating either stream response to Rio Grande incision or footwall tilting from the Quaternary Loma Blanca fault (LBF). Two terraces in the LBF hanging wall are back-tilted relative to their footwall counterparts, suggesting a listric geometry for the LBF. However, two others (Qtf and Qtc) are east-tilted relative to their footwall counterparts. Both Qtf and Qtc merge eastward with the next youngest terrace in the flight, and Qtc is arched, consistent with an earlier episode of surface uplift above the SMB. Future work will involve (a) additional terrace mapping over the SMB, (b) cosmogenic 36Cl depth profile dating of the Rio Salado terraces to determine incision rates, allow regional terrace correlations, and constrain fault-slip slip rates and the record of SMB-related surface uplift, and (c) numerical modeling of SMB inflation constrained by uplift signals.

  4. Stratigraphy of the fluvial deposits of the Salado river basin, Buenos Aires Province: Lithology, chronology and paleoclimate

    NASA Astrophysics Data System (ADS)

    Fucks, E.; Pisano, M. F.; Huarte, R. A.; Di Lello, C. V.; Mari, F.; Carbonari, J. E.

    2015-07-01

    The regional landscape of the Salado depression is related to weathering, eolian and fluvial processes generated under different climatic conditions. Although during most of the Holocene the climatic conditions were warm and humid, previously, a vast plain dominated by deflation processes and enhanced by weathering processes was developed in an arid environment. Fluvial deposits produced afterwards are continuous and lithologically homogeneous, which allows differentiation and characterization of the entire stratigraphic sequence. The stratigraphic units of this area, closely related to the paleoclimatic conditions, are recognized and characterized. Three lithostratigraphic units of fluvial origin (Members) and two paleosols have been differentiated. The first ones were grouped in the Luján Formation. Some of the units are related to other ones previously recognized in this area (La Chumbiada Member and La Pelada Geosol), but others have no similarity or relationship with previously known units (Gorch and Puente Las Gaviotas Members, and Frigorífico Belgrano Geosol). Radiocarbon ages suggest that the fluvial sequences were deposited after the glacial maximum, corresponding to MIS 1, except for the basal levels of the lower member which is late Late Pleistocene. Although the general paleoclimatic conditions were related to warm and humid climate, events related to water deficits were also recognized, which could be related to the Younger Dryas, the middle Holocene and the late Holocene.

  5. Refractory concretes

    DOEpatents

    Holcombe, Jr., Cressie E.

    1979-01-01

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

  6. Diversity of extremophilic bacteria in the sediment of high-altitude lakes located in the mountain desert of Ojos del Salado volcano, Dry-Andes.

    PubMed

    Aszalós, Júlia Margit; Krett, Gergely; Anda, Dóra; Márialigeti, Károly; Nagy, Balázs; Borsodi, Andrea K

    2016-09-01

    Ojos del Salado, the highest volcano on Earth is surrounded by a special mountain desert with extreme aridity, great daily temperature range, intense solar radiation, and permafrost from 5000 meters above sea level. Several saline lakes and permafrost derived high-altitude lakes can be found in this area, often surrounded by fumaroles and hot springs. The aim of this study was to gain information about the bacterial communities inhabiting the sediment of high-altitude lakes of the Ojos del Salado region located between 3770 and 6500 m. Altogether 11 sediment samples from 4 different altitudes were examined with 16S rRNA gene based denaturing gradient gel electrophoresis and clone libraries. Members of 17 phyla or candidate divisions were detected with the dominance of Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes. The bacterial community composition was determined mainly by the altitude of the sampling sites; nevertheless, the extreme aridity and the active volcanism had a strong influence on it. Most of the sequences showed the highest relation to bacterial species or uncultured clones from similar extreme environments.

  7. Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico. [Freezing-point depression

    SciTech Connect

    Stein, C.L.

    1985-09-01

    A suite of samples composed primarily of halite from the upper Castile and lower Salado Formations of the Permian Basin was selected from Waste Isolation Pilot Plant (WIPP) core for a reconnaissance study of fluid inclusions. Volume percent of these trapped fluids averaged 0.7% to 1%. Freezing-point depressions varied widely and appeared to be unrelated to fluid-inclusion type, to sedimentary facies, or to stratigraphic depth. However, because very low freezing points were usually associated with anhydrite, a relation may exist between freezing-point data and lithology. Dissolved sulfate values were constant through the Castile, then decreased markedly with lesser depth in the lower Salado. This trend correlates very well with observed mineralogy and is consistent with an interpretation of the occurrence of secondary polyhalite as a result of gypsum or anhydrite alteration with simultaneous consumption of dissolved sulfate from the coexisting fluids. Together with the abundance and distribution of fluid inclusions in primary or ''hopper'' crystal structures, this evidence suggests that inclusions seen in these halites did not migrate any significant geographical distance since their formation. 28 refs., 17 figs., 2 tabs.

  8. Geodatabase Development in Support of Integrated Hydrologic Forecasting for an Ungaged Ephemeral Channel: Rio Salado, New Mexico

    NASA Astrophysics Data System (ADS)

    Beeson, P.; Duffy, C.

    2004-05-01

    This research is constructing an integrated, multi-process model for estimating long-term streamflow in an ephemeral, ungaged basin, the Rio Salado in central New Mexico. The semi-arid basin drains 3575km2 and with seasonal channel flow from summer thunderstorms and winter precipitation. The basin is presently ungaged although streamflow records near the outlet with the Rio Grande are available for 1948-1984. The research will test the hypothesis that integrated models incorporating land surface, soil moisture, groundwater and streamflow processes can be used to forecast ungaged basin response. The focus of this paper is to develop a strategy for supporting the physical model with an appropriate space-time data for geometry, physical parameters and forcing for the model. The creation of an integrated database, instead of a collection of data layers, provides a stronger foundation for building water resources applications in Geographic Information Systems. We use the ArcHydro Data Model with the geodatabase environment for geospatial and time series data for water resources. The results of this research demonstrate the process of collecting geospatial data in its many forms and populating a geodatabase for support of the integrated hydrologic model. Here we use MODHMS (developed by HydroGeologic Inc.), which is a fully integrated and comprehensive hydrologic model that is physically-based, spatially-distributed framework that includes 3-D variably saturated subsurface flow, 2-D areal overland flow, and flow through a network of 1-D channels. Layers required include vector data like polygons (geology and soils), lines (stream networks with cross-sections), points (monitoring points including bore holes), and raster data which includes gridded digital elevation model and satellites (ie ASTER for determining reaches that are perennial or ephemeral). A variety of interfaces exist for accessing the geodatabase, including ESRI ArcMap, Microsoft Access, Microsoft Excel

  9. Hydraulic testing around Room Q: Evaluation of the effects of mining on the hydraulic properties of Salado Evaporites

    SciTech Connect

    Domski, P.S.; Upton, D.T.; Beauheim, R.L.

    1996-03-01

    Room Q is a 109-m-long cylindrical excavation in the Salado Formation at the Waste Isolation Pilot Plant (WIPP) site. Fifteen boreholes were drilled and instrumented around Room Q so that tests could be conducted to determine the effects of room excavation on the hydraulic properties of the surrounding evaporate rocks. Pressure-buildup and pressure-pulse tests were conducted in all of the boreholes before Room Q was mined. The data sets from only eight of the boreholes are adequate for parameter estimation, and five of those are of poor quality. Constant-pressure flow tests and pressure-buildup tests were conducted after Room Q was mined, producing eleven interpretable data sets, including two of poor quality. Pre-mining transmissivities interpreted from the three good-quality data sets ranged from 1 x 10{sup -15} to 5 x 10{sup -14} m{sup 2}/s (permeability-thickness products of 2 x 10{sup -22} to 9 x 10{sup -21} m{sup 3}) for test intervals ranging in length from 0.85 to 1.37 m. Pre-mining average permeabilities, which can be considered representative of undisturbed, far-field conditions, were 6 x 10{sup -20} and 8 x 10{sup -20} m{sup 2} for anhydrite, and 3 x 10{sup -22} m{sup 2} for halite. Post-mining transmissivities interpreted from the good-quality data sets ranged from 1 x 10{sup -16} to 3 x 10{sup -13} m{sup 2}/s (permeability-thickness products of 2 x 10{sup -23} to 5 x 10{sup -20} m{sup 3}). Post-mining average permeabilities for anhydrite ranged from 8 x 10{sup -20} to 1 x 10{sup -19} m{sup 2}. The changes in hydraulic properties and pore pressures that were observed can be attributed to one or a combination of three processes: stress reduction, changes in pore connectivity, and flow towards Room Q. The effects of the three processes cannot be individually quantified with the available data.

  10. Mass

    SciTech Connect

    Quigg, Chris

    2007-12-05

    In the classical physics we inherited from Isaac Newton, mass does not arise, it simply is. The mass of a classical object is the sum of the masses of its parts. Albert Einstein showed that the mass of a body is a measure of its energy content, inviting us to consider the origins of mass. The protons we accelerate at Fermilab are prime examples of Einsteinian matter: nearly all of their mass arises from stored energy. Missing mass led to the discovery of the noble gases, and a new form of missing mass leads us to the notion of dark matter. Starting with a brief guided tour of the meanings of mass, the colloquium will explore the multiple origins of mass. We will see how far we have come toward understanding mass, and survey the issues that guide our research today.

  11. Lunar concrete for construction

    NASA Technical Reports Server (NTRS)

    Cullingford, Hatice S.; Keller, M. Dean

    1988-01-01

    Feasibility of using concrete for lunar-base construction has been discussed recently without relevant data for the effects of vacuum on concrete. Experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the moon are provided in this paper along with specific conclusions from the existing data base.

  12. Lunar concrete for construction

    NASA Technical Reports Server (NTRS)

    Cullingford, Hatice S.; Keller, M. Dean

    1992-01-01

    Feasibility of using concrete for lunar base construction was discussed recently without relevant data for the effects of vacuum on concrete. Our experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the Moon are provided in this paper, along with specific conclusions from the existing database.

  13. Lunar concrete for construction

    SciTech Connect

    Cullingford, H.S.; Keller, M.D.

    1988-01-01

    Feasibility of using concrete for lunar-base construction has been discussed recently without relevant data for the effects of vacuum on concrete. Our experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the moon are provided in this paper along with specific conclusions from the existing data base. 10 refs., 3 figs., 2 tabs.

  14. Properties of Sulfur Concrete.

    DTIC Science & Technology

    1979-07-06

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

  15. Controlling chloride ions diffusion in concrete.

    PubMed

    Zeng, Lunwu; Song, Runxia

    2013-11-28

    The corrosion of steel in concrete is mainly due to the chemical reaction between the chloride ions and iron ions. Indeed, this is a serious threaten for reinforced concrete structure, especially for the reinforced concrete structure in the sea. So it is urgent and important to protect concrete against chloride ions corrosion. In this work, we report multilayer concrete can cloak chloride ions. We formulated five kinds of concrete A, B, C, D and E, which are made of different proportion of cement, sand and glue, and fabricated six-layer (ABACAD) cylinder diffusion cloak and background media E. The simulation results show that the six-layer mass diffusion cloak can protect concrete against chloride ions penetration, while the experiment results show that the concentration gradients are parallel and equal outside the outer circle in the diffusion flux lines, the iso-concentration lines are parallel outside the outer circle, and the concentration gradients in the inner circle are smaller than those outside the outer circle.

  16. Microstructure of high-strength foam concrete

    SciTech Connect

    Just, A.; Middendorf, B.

    2009-07-15

    Foam concretes are divided into two groups: on the one hand the physically foamed concrete is mixed in fast rotating pug mill mixers by using foaming agents. This concrete cures under atmospheric conditions. On the other hand the autoclaved aerated concrete is chemically foamed by adding aluminium powder. Afterwards it is cured in a saturated steam atmosphere. New alternatives for the application of foam concretes arise from the combination of chemical foaming and air curing in manufacturing processes. These foam concretes are new and innovative building materials with interesting properties: low mass density and high strength. Responsible for these properties are the macro-, meso- and microporosity. Macropores are created by adding aluminium powder in different volumes and with different particle size distributions. However, the microstructure of the cement matrix is affected by meso- and micropores. In addition, the matrix of the hardened cement paste can be optimized by the specific use of chemical additives for concrete. The influence of aluminium powder and chemical additives on the properties of the microstructure of the hardened cement matrices were investigated by using petrographic microscopy as well as scanning electron microscopy.

  17. Reinforced Concrete Modeling

    DTIC Science & Technology

    1982-07-01

    AFWL-TR-82-9 AFWL-TR-82-9 REINFORCED CONCRETE MODELING H. L. Schreyer J. W. Jeter, Jr. New Mexico Engineering Reseprch Institute University of New...Subtitle) S. TYPE OF REPORT & PERIOD COVERED REINFORCED CONCRETE MODELING Final Report 6. PERFORMING OtG. REPORT NUMBER NMERI TA8-9 7. AUTHORg) S...loading were identified and used to evaluate current concrete models . Since the endochronic and viscoplastic models provide satisfactory descriptions

  18. 51. DETAIL VIEW OF VIVIANNA ERA CONCRETE HOUSE WITH CONCRETE ...

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

    51. DETAIL VIEW OF VIVIANNA ERA CONCRETE HOUSE WITH CONCRETE PATIO SLAB LOOKING SOUTHWEST. NOTICE MINE WORKINGS BACKGROUND LEFT. - Mariscal Quicksilver Mine & Reduction Works, Terlingua, Brewster County, TX

  19. HIGH-COMPRESSIVE-STRENGTH CONCRETE.

    DTIC Science & Technology

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

  20. Pedogenic Carbonate Concretions in the Russian Chernozem

    SciTech Connect

    Mikhailova, E. A.; Post, C. J.; Magrini-Bair, K.; Castle, J. W.

    2006-12-01

    Pedogenic carbonate concretions are commonly found in grassland soils, but their origin is not fully understood. This study was conducted to determine the radiocarbon age, the stable isotope geochemistry, and chemical composition of carbonate concretions in the Russian Chernozem, one of the typical soils in grasslands. Three sites were sampled: a native grassland field (not cultivated for at least 300 years), an adjacent 50-year continuous fallow field in the V. V. Alekhin Central-Chernozem Biosphere State Reserve in the Kursk region of Russia, and a continuously cropped field in the Experimental Station of the Kursk Institute of Agronomy and Soil Erosion Control. All sampled soils were classified as fine-silty, mixed, frigid Pachic Hapludolls. The mineralogical composition of concretions varies from low-magnesium calcite to pure calcite. The concretion contains 0.05% N, 6.4% C, and has [delta]13C and [delta]18O values of -10.9[per mille sign] (the per mill symbol, parts per thousand) and -7.8[per mille sign], respectively. The outside part of the carbonate concretion is 1909 +/- 40 14C age Before Present (B.P.) compared with 1693 +/- 40 14C age B.P. for the inside part of the same concretion, even though the concretion is found in the C horizon of much older age (10,902 +/- 63 14C age B.P.). Remnants of soil organic matter in concretions are closely associated with the cropped and fallow/plowed soils by pyrolysis molecular beam mass spectrometry.

  1. Late Quaternary vegetation and climate history of a perennial river canyon in the Rīo Salado basin (22°S) of Northern Chile

    USGS Publications Warehouse

    Latorre, Claudio; Betancourt, Julio L.; Arroyo, Mary T.K.

    2006-01-01

    Plant macrofossils from 33 rodent middens sampled at three sites between 2910 and 3150 m elevation in the main canyon of the Rīo Salado, northern Chile, yield a unique record of vegetation and climate over the past 22,000 cal yr BP. Presence of low-elevation Prepuna taxa throughout the record suggests that mean annual temperature never cooled by more than 5°C and may have been near-modern at 16,270 cal yr BP. Displacements in the lower limits of Andean steppe and Puna taxa indicate that mean annual rainfall was twice modern at 17,520-16,270 cal yr BP. This pluvial event coincides with infilling of paleolake Tauca on the Bolivian Altiplano, increased ENSO activity inferred from a marine core near Lima, abrupt deglaciation in southern Chile, and Heinrich Event 1. Moderate to large increases in precipitation also occurred at 11,770-9550 (Central Atacama Pluvial Event), 7330-6720, 3490-2320 and at 800 cal yr BP. Desiccation occurred at 14,180, 8910-8640, and 4865 cal yr BP. Compared to other midden sites in the region, early Holocene desiccation seems to have happened progressively earlier farther south. Emerging trends from the cumulative midden record in the central Atacama agree at millennial timescales with improved paleolake chronologies for the Bolivian Altiplano, implying common forcing through changes in equatorial Pacific sea-surface temperature gradients.

  2. The Structure of Concrete Operational Thought.

    ERIC Educational Resources Information Center

    Tomlinson-Keasey, C.: And Others

    1979-01-01

    In a four-year longitudinal study of the development of concrete operational thought, children were administered tests assessing seriation; numeration; class inclusion; hierarchical classification; and conservation of mass, weight, and volume. Levels of seriation and numeration skills in kindergarten were powerful predictors of the acquisition of…

  3. Effective determination of the long-lived nuclide 41Ca in nuclear reactor bioshield concretes: comparison of liquid scintillation counting and accelerator mass spectrometry.

    PubMed

    Warwick, P E; Croudace, I W; Hillegonds, D J

    2009-03-01

    The routine application of liquid scintillation counting to (41)Ca determination has been hindered by the absence of traceable calibration standards of known (41)Ca activity concentrations. The introduction of the new IRMM (41)Ca mass-spectrometric standards with sufficiently high (41)Ca activities for radiometric detection has partly overcome this although accurate measurement of stable Ca concentrations coupled with precise half-life data are still required to correct the certified (41)Ca:(40)Ca ratios to (41)Ca activity concentrations. In this study, (41)Ca efficiency versus quench curves have been produced using the IRMM standard, and their accuracy validated by comparison with theoretical calculations of (41)Ca efficiencies. Further verification of the technique was achieved through the analysis of (41)Ca in a reactor bioshield core that had been previously investigated for other radionuclide variations. Calcium-41 activity concentrations of up to 25 Bq/g were detected. Accelerator mass spectrometry (AMS) measurements of the same suite of samples showed a very good agreement, providing validation of the procedure. Calcium-41 activity concentrations declined exponentially with distance from the core of the nuclear reactor and correlated well with the predicted neutron flux.

  4. Antifouling marine concrete

    SciTech Connect

    Vind, H P; Mathews, C W

    1980-07-01

    Various toxic agents were evaluated as the their capability to prevent or inhibit the attachment of marine fouling organisms to concrete. Creosote and bis-(tri-n-butyltin) oxide (TBTO) were impregnated into porous aggregate which was used in making concrete. Cuprous oxide, triphenyltin hydroxide (TPTH), and 2-2-bis-(p-methoxyphenyl)-1,1,1-trichloroethane (methoxychlor) were used as dry additives. Two proprietary formulations were applied as coatings on untreated concrete. Test specimens were exposed at Port Hueneme, CA, and Key Biscayne, FL. The efficacy of toxicants was determined by periodically weighing the adhering fouling organisms. Concrete prepared with an aggregate impregnated with a TBTO/creosote mixture has demonstrated the best antifouling performance of those specimens exposed for more than one year. The two proprietary coatings and the concrete containing methoxychlor, TPTH, and cuprous oxide as dry additives have exhibited good antifouling properties, but they have been exposed for a shorter time. The strength of concrete containing the toxicants was acceptable, and the toxicants did not increase the corrosion rate of reinforcing rods. Organotin compounds were essentially unchanged in concrete specimens exposed 6 1/2 years in seawater.

  5. 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.

  6. Antifouling marine concrete

    SciTech Connect

    Vind, H P; Mathews, C W

    1980-07-01

    Various toxic agents were evaluated as to their capability to prevent or inhibit the attachment of marine fouling organisms to concrete for OTEC plants. Creosote and bis-(tri-n-butyltin) oxide (TBTO) were impregnated into porous aggregate which was used in making concrete. Cuprous oxide, triphenyltin hydroxide (TPTH), and 2-2-bis-(p-methoxyphenyl)-1,1,1-trichloroethane (methoxychlor) were used as dry additives. Two proprietary formulations were applied as coatings on untreated concrete. Test specimens were exposed at Port Hueneme, CA, and Key Biscayne, FL. The efficacy of toxicants was determined by periodically weighing the adhering fouling organisms. Concrete prepared with an aggregate impregnated with a TBTO/creosote mixture has demonstrated the best antifouling performance of those specimens exposed for more than one year. The two proprietary coatings and the concrete containing methoxychlor, TPTH, and cuprous oxide as dry additives have exhibited good antifouling properties, but they have been exposed for a shorter time. The strength of concrete containing the toxicants was acceptable, and the toxicants did not increase the corrosion rate of reinforcing rods. Organotin compounds were essentially unchanged in concrete specimens exposed 6-1/2 years in seawater.

  7. Concrete: Potential material for Space Station

    NASA Technical Reports Server (NTRS)

    Lin, T. D.

    1992-01-01

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

  8. 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.

  9. 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.

  10. Corrosion-resistant sulfur concretes

    NASA Astrophysics Data System (ADS)

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

    1983-04-01

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

  11. Permeability of Clay Concretes

    NASA Astrophysics Data System (ADS)

    Solomon, F.; Ekolu, S. O.

    2015-11-01

    This paper presents an investigation on the effect of clay addition on water permeability and air permeability of concretes. Clay concrete mixes consisted of 0 to 40% clay content incorporated as cement replacement. Flow methods using triaxial cells and air permeameters were used for measuring the injected water and air flows under pressure. It was found that the higher the clay content in the mixture, the greater the permeability. At higher water-cement ratios (w/c), the paste matrix is less dense and easily allows water to ingress into concrete. But at high clay contents of 30 to 40% clay, the variation in permeability was significantly diminished among different concrete mixtures. It was confirmed that air permeability results were higher than the corresponding water permeability values when all permeability coefficients were converted to intrinsic permeability values.

  12. Strengthening lightweight concrete

    NASA Technical Reports Server (NTRS)

    Auskern, A.

    1972-01-01

    Polymer absorption by lightweight concretes to improve bonding between cement and aggregate and to increase strength of cement is discussed. Compressive strength of treated cement is compared with strength of untreated product. Process for producing polymers is described.

  13. Lightweight polymer concrete composites

    SciTech Connect

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

    1985-08-01

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

  14. Shear Resistance between Concrete-Concrete Surfaces

    NASA Astrophysics Data System (ADS)

    Kovačovic, Marek

    2013-12-01

    The application of precast beams and cast-in-situ structural members cast at different times has been typical of bridges and buildings for many years. A load-bearing frame consists of a set of prestressed precast beams supported by columns and diaphragms joined with an additionally cast slab deck. This article is focused on the theoretical and experimental analyses of the shear resistance at an interface. The first part of the paper deals with the state-of-art knowledge of the composite behaviour of concrete-concrete structures and a comparison of the numerical methods introduced in the relevant standards. In the experimental part, a set of specimens with different interface treatments was tested until failure in order to predict the composite behaviour of coupled beams. The experimental part was compared to the numerical analysis performed by means of FEM basis nonlinear software.

  15. Performance of "Waterless Concrete"

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  16. Binary Effect of Fly Ash and Palm Oil Fuel Ash on Heat of Hydration Aerated Concrete

    PubMed Central

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern. PMID:24696646

  17. Binary effect of fly ash and palm oil fuel ash on heat of hydration aerated concrete.

    PubMed

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa; Sajjadi, Seyed Mahdi

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern.

  18. SLAM: a sodium-limestone concrete ablation model

    SciTech Connect

    Suo-Anttila, A.J.

    1983-12-01

    SLAM is a three-region model, containing a pool (sodium and reaction debris) region, a dry (boundary layer and dehydrated concrete) region, and a wet (hydrated concrete) region. The model includes a solution to the mass, momentum, and energy equations in each region. A chemical kinetics model is included to provide heat sources due to chemical reactions between the sodium and the concrete. Both isolated model as well as integrated whole code evaluations have been made with good results. The chemical kinetics and water migration models were evaluated separately, with good results. Several small and large-scale sodium limestone concrete experiments were simulated with reasonable agreement between SLAM and the experimental results. The SLAM code was applied to investigate the effects of mixing, pool temperature, pool depth and fluidization. All these phenomena were found to be of significance in the predicted response of the sodium concrete interaction. Pool fluidization is predicted to be the most important variable in large scale interactions.

  19. Reclamation chain of waste concrete: A case study of Shanghai.

    PubMed

    Xiao, Jianzhuang; Ma, Zhiming; Ding, Tao

    2016-02-01

    A mass of construction and demolition (C&D) waste are generated in Shanghai every year, and it has become a serious environment problem. Reclaiming the waste concrete to produce recycled aggregate (RA) and recycled aggregate concrete (RAC) is an effective method to reduce the C&D waste. This paper develops a reclamation chain of waste concrete based on the researches and practices in Shanghai. C&D waste management, waste concrete disposition, RA production and RAC preparation are discussed respectively. In addition, technical suggestions are also given according to the findings in practical engineering, which aims to optimize the reclamation chain. The results show that the properties of RA and RAC can well meet the requirement of design and practical application through a series of technical measures. The reclamation chain of waste concrete is necessary and appropriate for Shanghai, which provides more opportunities for the wider application of RA and RAC, and it shows a favorable environmental benefit.

  20. 26. Evening view of concrete mixing plant, concrete placement tower, ...

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

    26. Evening view of concrete mixing plant, concrete placement tower, cableway tower, power line and derrick. Photographer unknown, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  1. Electrokinetic decontamination of concrete

    SciTech Connect

    Lomasney, H.

    1995-10-01

    The U.S. Department of Energy has assigned a priority to the advancement of technology for decontaminating concrete surfaces which have become contaminated with radionuclides, heavy metals, and toxic organics. This agency is responsible for decontamination and decommissioning of thousands of buildings. Electrokinetic extraction is one of the several innovative technologies which emerged in response to this initiative. This technique utilizes an electropotential gradient and the subsequent electrical transport mechanism to cause the controlled movement of ionics species, whereby the contaminants exit the recesses deep within the concrete. This report discusses the technology and use at the Oak Ridge k-25 plant.

  2. Structural Materials: 95. Concrete

    SciTech Connect

    Naus, Dan J

    2012-01-01

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

  3. Precast Concrete Pavements

    DTIC Science & Technology

    1981-11-01

    Gorsuch 1962, Kruse 1966, Jacoby 1967, and Hargett 1970). The final slab design used in construction is shown in Figure 2. These slabs were 6 ft wide, 24...Experiment Station, CE, Vicksburg, Miss. Gorsuch , R. F. 1962. "Preliminary Investigation of Precast Prestressed Concrete Pavements," MS Thesis, South Dakota

  4. High temperature polymer concrete

    DOEpatents

    Fontana, J.J.; Reams, W.

    1984-05-29

    This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system.

  5. Concrete Block Pavements

    DTIC Science & Technology

    1983-03-01

    1967, Cedergren 1974, Federal Highway .’,U .. V,47 -’":: 37 Administration 1980). Block pavements have essentially the same prob- lems with moisture...Vicksburg, Miss. Cedergren , H. R. 1974. Drainage of Highway and Airfield Pavements, John Wiley and Sons, New VOk. I Cement and Concrete Association

  6. Heidrun concrete TLP: Update

    SciTech Connect

    Munkejord, T.

    1995-10-01

    This paper gives a summary of the Heidrun substructure including tethers and foundations. The focus will although be on the concrete substructure. The Heidrun Field is located in 345 m water depth in the northern part of the Haltenbanken area, approximately 100N miles from the west coast of mid-Norway. The field is developed by means of a concrete Tension Leg Platform (TLP) by Conoco Norway Inc. The TLP will be moored by 16 steel tethers, arranged in groups of four per corner, which secure the substructure (hull) to the concrete foundations. A general view of the TLP is shown. The Heidrun TLP will be the northern most located platform in the North Sea when installed at Haltenbanken in 1995. Norwegian Contractors a.s (NC) is undertaking the Engineering, Procurement, Construction and Installation (EPCI) contract for the Heidrun TLP substructure. This comprises the complete delivery of the hull with two module support beams (MSB), including all mechanical outfitting. Furthermore, NC will perform all marine operations related to the substructure. For the concrete foundations NC has performed the detailed engineering work and has been responsible for the two to field and installation of the foundations.

  7. Micromechanics of Concrete.

    DTIC Science & Technology

    1988-01-25

    reflects the dispersion of the coarse aggregates on the mesoscale. Specifically, the experimental measure- ments indicate ( Mindess and Young 1981, Zaitsev...Mecanique des Materiaux Solides, Dunod, Paris. Mindess , S. and J. Young (1981), Concrete, Prentice-Hall Inc., Englewood Cliffs, NJ. Mura, T. (1982

  8. Frost resistance of concrete surfaces coated with waterproofing materials

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  9. Concrete lunar base investigation

    NASA Technical Reports Server (NTRS)

    Lin, T. D.; Senseney, Jonathan A.; Arp, Larry Dean; Lindbergh, Charles

    1989-01-01

    This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar based subjected to one atmosphere internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design: (1) during construction; (2) under pressurization; and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the air-tightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the moon.

  10. Concrete lunar base investigation

    NASA Technical Reports Server (NTRS)

    Lin, T. D.; Senseny, Jonathan A.; Arp, Larry D.; Lindbergh, Charles

    1992-01-01

    This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar base subjected to 1-atm internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design (1) during construction, (2) under pressurization, and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the airtightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the Moon.

  11. Penetration of concrete targets

    SciTech Connect

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

    1993-08-01

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

  12. Concrete containment aging study

    SciTech Connect

    Pachner, J.; Tai, T.M.; Naus, D.

    1994-04-01

    In 1989, IAEA initiated a pilot study on the management of aging of nuclear power plant components. The Phase I and II studies of concrete containment are discussed. With the data base, plant owners will be able to review and enhance their existing programs. IAEA will analyze data provided by participating plants and the report is scheduled to be released by late 1994 (final report release mid-1995).

  13. Mechanics of Concrete II

    DTIC Science & Technology

    1990-10-18

    diffusivity of undamaged concrete is a problem in itself since the diffusivity of the thin transition zones (at the aggregate- cement matrix interface...C3A anhydride remains in the cement after the hydration. Assuming that the amount of gypsum added to portland cement3 clinker is 4% of Mcm (Biczok 1972...enables establishment of rational relationships between the chemical composition of the hardened cement paste, morphology of the pore system, and defect

  14. Tonsil concretions and tonsilloliths.

    PubMed

    Pruet, C W; Duplan, D A

    1987-05-01

    Although infrequently seen in many clinical practices, tonsillar concretions can be the source of both fetor oris and physical and social concern for the patient. Though stones rarely form in the tonsil or peritonsillar area, the findings of calcified objects or stones anywhere within the body has long been a subject of interest. The salient features of these entities and their relevance to clinical practice are discussed in this article.

  15. Nondestructive Concrete Characterization System

    DTIC Science & Technology

    2013-05-20

    Park, NC 27709-2211 15. SUBJECT TERMS Ultrasonic Pulse Velocity (UPV), Impact-Echo, Ultrasonic Pulse-Echo, Ultrasonic Attenuation, STTR Report Aldo... ultrasonic testing in conjunction with the resonance frequency. All results were within the specified tolerance of ±1 ft. The compressive strength of the...concrete blocks was measured by measuring the P-wave and S-wave time of travel with the pitch-catch method of ultrasonic testing. All results were

  16. Fiber reinforced concrete solar collector

    SciTech Connect

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

    1985-05-07

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

  17. Chlorine signal attenuation in concrete.

    PubMed

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  18. Optimization of reinforced concrete slabs

    NASA Technical Reports Server (NTRS)

    Ferritto, J. M.

    1979-01-01

    Reinforced concrete cells composed of concrete slabs and used to limit the effects of accidental explosions during hazardous explosives operations are analyzed. An automated design procedure which considers the dynamic nonlinear behavior of the reinforced concrete of arbitrary geometrical and structural configuration subjected to dynamic pressure loading is discussed. The optimum design of the slab is examined using an interior penalty function. The optimization procedure is presented and the results are discussed and compared with finite element analysis.

  19. 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

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

    PubMed Central

    Ferraris, Chiara F.

    2001-01-01

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

  1. Corrosion control of steel-reinforced concrete

    NASA Astrophysics Data System (ADS)

    Chung, D. D. L.

    2000-10-01

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

  2. Temperature and pore pressure distribution in a concrete slab during the microwave decontamination process

    SciTech Connect

    Li, W.; Ebadian, M.A.; White, T.L.; Grubb, R.G.; Foster, D. Jr.

    1994-10-01

    As an application of microwave engineering, the new technology of concrete decontamination and decommissioning using microwave energy has been recently developed. The temperature and pore pressure within the concrete are studied theoretically in this paper. The heat and mass transfer within the porous concrete, coupled with temperature dependent dielectric property are investigated. The effects of microwave frequency (f), microwave power intensity (Q{sub 0,ave}), concrete porosity ({phi}) on the temperature and pore pressure distributions and their variations are fully discussed. The effects of the variation of complex dielectric permittivity ({epsilon}) and presentation of different steel reinforcements are also illustrated.

  3. Concrete Operations and Attentional Capacity.

    ERIC Educational Resources Information Center

    Chapman, Michael; Lindenberger, Ulman

    1989-01-01

    To test predictions regarding the attentional capacity requirements of Piaget's stage of concrete operations, a battery of concrete operational tasks and two measures of attentional capacity were administered to 120 first-, second-, and third-graders. Findings concern class inclusion, transitivity of length and weight, and multiplication of…

  4. The Concrete and Pavement Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

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

  5. 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.

  6. Multiscale Constitutive Modeling of Asphalt Concrete

    NASA Astrophysics Data System (ADS)

    Underwood, Benjamin Shane

    Multiscale modeling of asphalt concrete has become a popular technique for gaining improved insight into the physical mechanisms that affect the material's behavior and ultimately its performance. This type of modeling considers asphalt concrete, not as a homogeneous mass, but rather as an assemblage of materials at different characteristic length scales. For proper modeling these characteristic scales should be functionally definable and should have known properties. Thus far, research in this area has not focused significant attention on functionally defining what the characteristic scales within asphalt concrete should be. Instead, many have made assumptions on the characteristic scales and even the characteristic behaviors of these scales with little to no support. This research addresses these shortcomings by directly evaluating the microstructure of the material and uses these results to create materials of different characteristic length scales as they exist within the asphalt concrete mixture. The objectives of this work are to; 1) develop mechanistic models for the linear viscoelastic (LVE) and damage behaviors in asphalt concrete at different length scales and 2) develop a mechanistic, mechanistic/empirical, or phenomenological formulation to link the different length scales into a model capable of predicting the effects of microstructural changes on the linear viscoelastic behaviors of asphalt concrete mixture, e.g., a microstructure association model for asphalt concrete mixture. Through the microstructural study it is found that asphalt concrete mixture can be considered as a build-up of three different phases; asphalt mastic, fine aggregate matrix (FAM), and finally the coarse aggregate particles. The asphalt mastic is found to exist as a homogenous material throughout the mixture and FAM, and the filler content within this material is consistent with the volumetric averaged concentration, which can be calculated from the job mix formula. It is also

  7. Technology Solutions Case Study: Insulating Concrete Forms

    SciTech Connect

    none,

    2012-10-01

    This Pacific Northwest National Laboratory project investigated insulating concrete forms—rigid foam, hollow walls that are filled with concrete for highly insulated, hurricane-resistant construction.

  8. Nuclear Power Plant Concrete Structures

    SciTech Connect

    Basu, Prabir; Labbe, Pierre; Naus, Dan

    2013-01-01

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

  9. Solar-Array Substrate From Glass-Reinforced Concrete

    NASA Technical Reports Server (NTRS)

    Eirls, J. L.

    1985-01-01

    Design elminiates glass superstrate and associated metal framing. Panel has two trapezoidal stiffening ribs for structural support. Strategic placement of ribs with embedded support tubes (standard PVC tubing) minimizes bending moments and resulting stresses produced by installation and windloads. Glass-reinforced concrete panel has smooth flat surface suitable for solar substrate and includes structural bracing for rigidity and design adaptable to mass production.

  10. Environmental durability of polymer concrete

    SciTech Connect

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

    1996-12-31

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

  11. Rapid Testing of Fresh Concrete

    DTIC Science & Technology

    1975-05-01

    Cementforenlng, Oslo, 1952). 1.1 Orchard, 0. F., "The Effect of the Vacum Process on Concrete Mix Design ," Symposiwn on Mix Design and Qualify Control...ASTM, Vol 33, Part I (1933), pp 297-307. Orchard, D. F., "The Effect of the Vacuum Process on Concrete Mix Design ," Symposium on Mix Design and... Designed for Use in Determining Constituents of Fresh Concrete," Public floads, Vol 13, No. 9 (1932), p 151. 9 Cook, G. C, "Effect of Time of Haul

  12. Concrete Construction Using Slipform Techniques.

    DTIC Science & Technology

    1982-11-01

    Operations 75 4.1.3 Ramp, Curb, Gutter, Sidewalk and Median Paving "/ 4.1.4 Canal Lining 80 4.2 Cast-in-Place Pipe 82 4.3 Tunnel Inverts 83 4.4...101 APPENDIX B - Bibliography 102 b. -E CHAPTER 1 INTRODUCTION 1.1 BACKGROUND The formwork for concrete structures represents a critical part of...concrete construction, in terms of cost and importance toward getting the job done properly and on time. In fact, concrete formwork frequently costs more

  13. 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.

  14. Concrete density estimation by rebound hammer method

    SciTech Connect

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

    2016-01-22

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

  15. 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.

  16. Migrating corrosion inhibitor protection of concrete

    SciTech Connect

    Bjegovic, D.; Miksic, B.

    1999-11-01

    Migrating corrosion inhibitors (MCI) were developed to protect steel rebar from corrosion in concrete. They were designed to be incorporated as an admixture during concrete batching or used for surface impregnation of existing concrete structures. Two investigations are summarized. One studied the effectiveness of MCIs as a corrosion inhibitor for steel rebar when used as an admixture in fresh concrete mix. The other is a long-term study of MCI concrete impregnation that chronicles corrosion rates of rebar in concrete specimens. Based on data from each study, it was concluded that migrating corrosion inhibitors are compatible with concrete and effectively delay the onset of corrosion.

  17. Concrete density estimation by rebound hammer method

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

  18. Microstructural investigations on aerated concrete

    SciTech Connect

    Narayanan, N.; Ramamurthy, K.

    2000-03-01

    Aerated concrete is characterized by the presence of large voids deliberately included in its matrix to reduce the density. This study reports the investigations conducted on the structure of cement-based autoclaved aerated concrete (AAC) and non-AAC with sand or fly ash as the filler. The reasons for changes in compressive strength and drying shrinkage are explained with reference to the changes in the microstructure. Compositional analysis was carried out using XRD. It was observed that fly ash responds poorly to autoclaving. The process of pore refinement in fly ash mixes is discussed with reference to the formation of Hadley grains as well as fly ash hydration. The paste-void interface in aerated concrete investigated in relation to the paste-aggregate interface in normal concrete revealed the existence of an interfacial transition zone.

  19. PORTLAND CEMENT CONCRETE FOR ANTARCTICA.

    DTIC Science & Technology

    formulation of recommended procedures for batching, mixing, placing, and curing of portland cement concrete in Antarctica. The pertinent features of the mix and design and related procedures are given. (Author)

  20. Electrically conductive polymer concrete coatings

    DOEpatents

    Fontana, J.J.; Elling, D.; Reams, W.

    1990-03-13

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  1. Electrically conductive polymer concrete coatings

    DOEpatents

    Fontana, J.J.; Elling, D.; Reams, W.

    1988-05-26

    A sprayable electrically conductive polymer concrete coating for vertical and overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt% calcined coke breeze, 40 wt% vinyl ester resin with 3.5 wt% modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag. 4 tabs.

  2. Electrically conductive polymer concrete coatings

    DOEpatents

    Fontana, Jack J.; Elling, David; Reams, Walter

    1990-01-01

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  3. 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.

  4. Protective coatings for concrete

    SciTech Connect

    NAGY, KATHRYN L.; CYGAN, RANDALL T.; BRINKER, C. JEFFREY; SELLINGER, ALAN

    2000-05-01

    The new two-layer protective coating developed for monuments constructed of limestone or marble was applied to highway cement and to tobermorite, a component of cement, and tested in batch dissolution tests. The goal was to determine the suitability of the protective coating in retarding the weathering rate of concrete construction. The two-layer coating consists of an inner layer of aminoethylaminopropylsilane (AEAPS) applied as a 25% solution in methanol and an outer layer of A2** sol-gel. In previous work, this product when applied to calcite powders, had resulted in a lowering of the rate of dissolution by a factor of ten and was shown through molecular modeling to bind strongly to the calcite surface, but not too strongly so as to accelerate dissolution. Batch dissolution tests at 22 C of coated and uncoated tobermorite (1.1 nm phase) and powdered cement from Gibson Blvd. in Albuquerque indicated that the coating exhibits some protective behavior, at least on short time scales. However, the data suggest that the outer layer of sol-gel dissolves in the high-pH environment of the closed system of cement plus water. Calculated binding configuration and energy of AEAPS to the tobermorite surface suggests that AEAPS is well-suited as the inner layer binder for protecting tobermorite.

  5. Nanogranular origin of concrete creep.

    PubMed

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-06-30

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium-silicate-hydrates (C-S-H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C-S-H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C-S-H forms: low density, high density, ultra-high density. We demonstrate that the creep rate ( approximately 1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years.

  6. Nanogranular origin of concrete creep

    PubMed Central

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-01-01

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium–silicate–hydrates (C–S–H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C–S–H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C–S–H forms: low density, high density, ultra-high density. We demonstrate that the creep rate (≈1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years. PMID:19541652

  7. 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

  8. 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.

  9. Detection of sub-horizontal flaws in concrete using the synthetic aperture focusing technique

    NASA Astrophysics Data System (ADS)

    Hosseini, Zahra

    Concrete deteriorates over time due to environmental changes and/or poor construction processes which can eventually lead to partial or total failure of a structure. Deterioration in concrete manifests itself in different forms such as: freeze and thaw, chemical attack, surface and internal flaws. Concrete and shotcrete linings are widely used as support systems in underground excavations. Surprisingly, a fragmented, damaged shotcrete support system can actually create a less stable environment than the unsupported rock mass. Detection of internal flaws remains a difficult task as they are not always observable on the surface. Yet, the potential to expand and cause damage to the structure is omnipresent. The focus of this work is to locate and characterize two main and common features in concrete structures, (1) sub-horizontal cracks; (2) rock-concrete interfaces. Traditionally, this has been difficult to detect by currently available NDT methods. To obtain high resolution images of cracks in concrete, an extension of the ultrasonic nondestructive technique known as Synthetic Aperture Focusing Technique (SAFT) has been used. However, in order to achieve our research objective, we developed a modified SAFT code in this work. The results of this study demonstrate that the resolving power of our modified 3D SAFT algorithm can provide an accurate profile of both a rock-concrete interface and/or cracks with angles varying from 5 to 15 degrees within concrete slabs having thicknesses of up to twenty centimetres.

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

    PubMed

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

    2017-03-01

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

  11. Fracture Mechanics Modelling of an In Situ Concrete Spalling Experiment

    NASA Astrophysics Data System (ADS)

    Siren, Topias; Uotinen, Lauri; Rinne, Mikael; Shen, Baotang

    2015-07-01

    During the operation of nuclear waste disposal facilities, some sprayed concrete reinforced underground spaces will be in use for approximately 100 years. During this time of use, the local stress regime will be altered by the radioactive decay heat. The change in the stress state will impose high demands on sprayed concrete, as it may suffer stress damage or lose its adhesion to the rock surface. It is also unclear what kind of support pressure the sprayed concrete layer will apply to the rock. To investigate this, an in situ experiment is planned in the ONKALO underground rock characterization facility at Olkiluoto, Finland. A vertical experimental hole will be concreted, and the surrounding rock mass will be instrumented with heat sources, in order to simulate an increase in the surrounding stress field. The experiment is instrumented with an acoustic emission system for the observation of rock failure and temperature, as well as strain gauges to observe the thermo-mechanical interactive behaviour of the concrete and rock at several levels, in both rock and concrete. A thermo-mechanical fracture mechanics study is necessary for the prediction of the damage before the experiment, in order to plan the experiment and instrumentation, and for generating a proper prediction/outcome study due to the special nature of the in situ experiment. The prediction of acoustic emission patterns is made by Fracod 2D and the model later compared to the actual observed acoustic emissions. The fracture mechanics model will be compared to a COMSOL Multiphysics 3D model to study the geometrical effects along the hole axis.

  12. Dynamic Increase Factors for Concrete

    DTIC Science & Technology

    1998-08-01

    Strain Rate Effects on Fracture, S. Mindess and S.P. Shah, editors, December 1985, pp. 1-13. 35. Weerheijm, J., Reinhardt, H.W., “Modelling of...Out of Anchored Reinforcing Bars,” Transactions of the Japan Concrete Institute, Vol. 15, 1994, pp. 459-466. 50. Bentur, A. S., S. Mindess and N. P...Society Symposia Proceedings Vol. 64 (S. Mindess and S. P. Shah, eds.), Pittsburgh, 1986, pp. 225-234. 51. Banthia, N. P., “Impact Resistance of Concrete

  13. Assessing the concreteness of relational representation.

    PubMed

    Rein, Jonathan R; Markman, Arthur B

    2010-11-01

    Research has shown that people's ability to transfer abstract relational knowledge across situations can be heavily influenced by the concrete objects that fill relational roles. This article provides evidence that the concreteness of the relations themselves also affects performance. In 3 experiments, participants viewed simple relational patterns of visual objects and then identified these same patterns under a variety of physical transformations. Results show that people have difficulty generalizing to novel concrete forms of abstract relations, even when objects are unchanged. This suggests that stimuli are initially represented as concrete relations by default. In the 2nd and 3rd experiments, the number of distinct concrete relations in the training set was increased to promote more abstract representation. Transfer improved for novel concrete relations but not for other transformations such as object substitution. Results indicate that instead of automatically learning abstract relations, people's relational representations preserve all properties that appear consistently in the learning environment, including concrete objects and concrete relations.

  14. Models for estimation of service life of concrete barriers in low-level radioactive waste disposal

    SciTech Connect

    Walton, J.C.; Plansky, L.E.; Smith, R.W. )

    1990-09-01

    Concrete barriers will be used as intimate parts of systems for isolation of low level radioactive wastes subsequent to disposal. This work reviews mathematical models for estimating the degradation rate of concrete in typical service environments. The models considered cover sulfate attack, reinforcement corrosion, calcium hydroxide leaching, carbonation, freeze/thaw, and cracking. Additionally, fluid flow, mass transport, and geochemical properties of concrete are briefly reviewed. Example calculations included illustrate the types of predictions expected of the models. 79 refs., 24 figs., 6 tabs.

  15. Bonded Concrete Overlays: Construction and Performance.

    DTIC Science & Technology

    1980-09-01

    report provides a review and summary of surface preparation of the existing slab, joint and crack treatment, bonding methods, concrete overlay mixtures...34Bonded, Thin-Lift Portland Cement Concrete Re- surfacing," Report on Project HRlgl, Clayton County and Iowa Highway Research Board, September 1977...34Resurfacing and Patching Concrete Pavement with Bonded Concrete ," Proceedings, Highway Research Board, Vol. 35, 1956. 8. Gillette, R. W.,"A 10-Year Report

  16. Corrosion Behavior of Steel Fibrous Concrete

    DTIC Science & Technology

    1977-05-01

    Crvtaiue wi ,rerse sido it necessaty m’d Identify by block number) steel fibrous concrete corrosion cracked fibrous concrete 20 ABST RACT (Continue...dissolved gas in liq- Although chloride ions affect the rate of steel corro- uids. sion in concrete , corrosion can occur without them. Verbeck has...repcrted that steel subjected to a concrete Corrosion of steel will not occur without water. Not environment normally develops a protective oxide film

  17. Molecular Survey of Concrete Biofilm Microbial Communities

    EPA Science Inventory

    Although several studies have shown that bacteria can deteriorate concrete structures, there is very little information on the composition of concrete microbial communities. To this end, we studied different microbial communities associated with concrete biofilms using 16S rRNA g...

  18. RADON GENERATION AND TRANSPORT IN AGED CONCRETE

    EPA Science Inventory

    The report gives results of a characterization of radon generation and transport in Florida concretes sampled from 12- to 45-year-old residential slabs. It also compares measurements from old concrete samples to previous measurements on newly poured Florida residential concretes....

  19. Lightweight concrete with enhanced neutron shielding

    SciTech Connect

    Brindza, Paul Daniel; Metzger, Bert Clayton

    2016-09-13

    A lightweight concrete containing polyethylene terephthalate in an amount of 20% by total volume. The concrete is enriched with hydrogen and is therefore highly effective at thermalizing neutrons. The concrete can be used independently or as a component of an advanced neutron radiation shielding system.

  20. 9 CFR 91.26 - Concrete flooring.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 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...

  1. 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...

  2. 9 CFR 91.26 - Concrete flooring.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 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...

  3. 9 CFR 91.26 - Concrete flooring.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 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...

  4. 9 CFR 91.26 - Concrete flooring.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 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...

  5. The Use of Electrodiffusion for Removing Chlorides from Concrete

    NASA Astrophysics Data System (ADS)

    Alsabry, A.

    2016-12-01

    The article presents a description of ion migration in a concrete pore liquid caused by an external electric field. The equation of the flow of aggressive chloride ions is formulated on the basis of partial equations of mass balance. It is assumed that electrochemical potential is in classical form, then an attempt is made to determine the average diffusion coefficient using the inverse diffusion Eq.(3.9).

  6. Concrete Finisher Program. Apprenticeship Training.

    ERIC Educational Resources Information Center

    Alberta Learning, Edmonton. Apprenticeship and Industry Training.

    This document presents information about the apprenticeship training program of Alberta, Canada, in general and the concrete finishing program in particular. The first part of the document discusses the following items: Alberta's apprenticeship and industry training system; the apprenticeship and industry training committee structure; local…

  7. High temperature polymer concrete compositions

    SciTech Connect

    Fontana, J.J.; Reams, W.

    1985-02-19

    This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers is a liquid system.

  8. Quick-setting concrete and a method for making quick-setting concrete

    DOEpatents

    Wagh, Arun S.; Singh, Dileep; Pullockaran, Jose D.; Knox, Lerry

    1997-01-01

    A method for producing quick setting concrete is provided comprising hydrng a concrete dry mixture with carbonate solution to create a slurry, and allowing the slurry to cure. The invention also provides for a quick setting concrete having a predetermined proportion of CaCO.sub.3 of between 5 and 23 weight percent of the entire concrete mixture, and whereby the concrete has a compression strength of approximately 4,000 pounds per square inch (psi) within 24 hours after pouring.

  9. Microbiologically induced deterioration of concrete - A Review

    PubMed Central

    Wei, Shiping; Jiang, Zhenglong; Liu, Hao; Zhou, Dongsheng; Sanchez-Silva, Mauricio

    2013-01-01

    Microbiologically induced deterioration (MID) causes corrosion of concrete by producing acids (including organic and inorganic acids) that degrade concrete components and thus compromise the integrity of sewer pipelines and other structures, creating significant problems worldwide. Understanding of the fundamental corrosion process and the causal agents will help us develop an appropriate strategy to minimize the costs in repairs. This review presents how microorganisms induce the deterioration of concrete, including the organisms involved and their colonization and succession on concrete, the microbial deterioration mechanism, the approaches of studying MID and safeguards against concrete biodeterioration. In addition, the uninvestigated research area of MID is also proposed. PMID:24688488

  10. Hematite ``Blueberry`` Concretion Doublet and Triplets on Mars: Iron Oxide Twin Analogs From Utah

    NASA Astrophysics Data System (ADS)

    Chan, M. A.; Parry, W. T.; Park, A. S.

    2005-12-01

    Spherical concretions on Earth and Mars comprise a record of diagenetic history that may not otherwise be preserved in the more common host rock. Hematite spherules of Meridiani Planum show some joined forms of twos and threes. Joined iron oxide concretions making doublets and triplets also occur in the Jurassic Navajo Sandstone of southern Utah, and can serve as an analog to understanding why joined forms occur on Mars. The geometries of in situ Utah examples suggest two processes for creating connected forms. In one concretion growth mechanism, occasional coalescing of single forms may result from the growth of doublets or triplets in overly close proximity (typically less than 15% of a population). Joined concretions of roughly equal sizes can be aligned in a row; unequal size concretions take on the shapes of ``snowmen``, or attached ``satellites``. Where cementation is pervasive, individual concretions may grow and coalesce into a lumpy layer or cemented mass along preferential flow paths or preferential nucleation sites. In the second mechanism, nearly all (more than 75%) of the concretions form doublets that are conjoined. The occurrence of dominant twins indicates that these concretions are not coincidental as in the first mechanism. Dominant twin concretions occur regularly and evenly throughout fairly homogeneous host rock. More unusual twins show additional small twin warts suggesting duplicated nucleation and precipitation. Normally, iron oxide concretion precipitation begins when the oxide saturation reaches a precipitation threshold. Precipitation produces chemical gradients, and competition between reaction and diffusion rates determines the spacing between concretions. These factors in combination with reactant supply, competitive growth phenomena and a complex self-organizing processes may contribute to development of internal structure with varying layers of iron-depleted zones to resistant iron-cemented shells. The pervasive nature of sandstone

  11. Estimation of Concrete's Porosity by Ultrasounds

    NASA Astrophysics Data System (ADS)

    Benouis, A.; Grini, A.

    Durability of concrete depends strongly on porosity; this conditions the intensity of the interactions of the concrete with the aggressive agents. The pores inside the concrete facilitate the process of damage, which is generally initiated on the surface. The most used measurement is undoubtedly the measurement of porosity accessible to water. The porosimetry by intrusion with mercury constitutes a tool for investigation of the mesoporosity. The relationship between concrete mixtures, porosity and ultrasonic velocity of concrete samples measured by ultrasonic NDT is investigated. This experimental study is interested in the relations between the ultrasonic velocity measured by transducers of 7.5 mm and 49.5 mm diameter and with 54 kHz frequency. Concrete specimens (160 mm diameter and 320 mm height) are fabricated with concrete of seven different mixtures (various W/C and S/S + G ratios), which gave porosities varying between 7% and 16%. Ultrasonic velocities in concrete were measured in longitudinal direction. Finally the results showed the influence of ratio W/C, where the porosity of the concretes of a ratio W/C _0,5 have correctly estimated by ultrasonic velocity. The integration of the concretes of a lower ratio, in this relation, caused a great dispersion. Porosity estimation of concretes with a ratio W/C lower than 0,5 became specific to each ratio.

  12. Properties of low-strength concrete for Meeks Cabin Dam modification project, Wyoming

    SciTech Connect

    Dolen, T.P.; Benavidez, A.A.

    1998-10-01

    Low-strength, plastic concrete mixtures were proportioned to construct a cut-off wall through permeable features in the foundation of Meeks Cabin Dam, Wyoming. Low strength concrete was required to match the deformation properties of the concrete with the embankment materials in the dam. The mixtures were proportioned with zero (control mixture), 10, 15, and 20% bentonite by mass of cement plus bentonite. The bentonite reduces compressive strength and elastic properties when compared to conventional concrete. Mixtures were proportioned to meet the desired fresh and hardened concrete properties. All mixtures met the 8 in. (200 mm) slump required for tremie placing. The design compressive strength is 200 lb/in.{sup 2} (1,380 kPa) at 7 days and 400 lb/in.{sup 2} (2,760 kPa) at 28 days. The 15% bentonite mixture met the strength requirements and was chosen for more detailed testing. Additional tests evaluated the triaxial shear strength, flow-pump permeability, and erodibility of the low-strength, hardened concrete, and determined the effect of adding a retarding mixture on setting time and slump loss of fresh concrete.

  13. Application of orthogonal test method in mix proportion design of recycled lightweight aggregate concrete

    NASA Astrophysics Data System (ADS)

    Zhao, Zhanshan; An, Le; Zhang, Yijing; Yuan, Jie

    2017-03-01

    Recycled lightweight aggregate concrete was made with construction waste and ceramsite brick mainly including brick. Using the orthogonal test method, the mix proportion of recycled lightweight aggregate concrete was studied, and the Influence regularity and significance of water binder ratio, fly ash, sand ratio, the amount of recycled aggregate proportion on the compressive strength of concrete, the strong influence of mass ratio, slump expansion degree was studied. Through the mean and range analysis of the test results, the results show that the water binder ratio has the greatest influence on the 28d intensity of recycled lightweight aggregate concrete. Secondly, the fly ash content, the recycled aggregate replacement rate and the sand ratio have little influence. For the factors of expansion: the proportion of fly ash = water binder ratio sand >sand rate> recycled aggregate replacement rate. When the content of fly ash is about 30%, the expanded degree of recycled lightweight aggregate concrete is the highest, and the workability of that is better and the strength of concrete with 28d and 56d are the highest. When the content of brickbat is about 40% brick particles, the strength of concrete reaches the highest.

  14. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect

    Bovaird, Chase C.; Jansik, Danielle P.; Wellman, Dawn M.; Wood, Marcus I.

    2011-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. The information present in the report provides data that (1) measures the effect of concrete wasteform properties likely to influence radionuclide migration; and (2) quantifies the rate of carbonation of concrete materials in a simulated vadose zone repository.

  15. Laser ablation studies of concrete

    SciTech Connect

    Savina, M.; Xu, Z.; Wang, Y.; Reed, C.; Pellin, M.

    1999-10-20

    Laser ablation was studied as a means of removing radioactive contaminants from the surface and near-surface regions of concrete. The authors present the results of ablation tests on cement and concrete samples using a 1.6 kW pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied using cement and high density concrete as targets. Ablation efficiency and material removal rates were determined as functions of irradiance and pulse overlap. Doped samples were also ablated to determine the efficiency with which surface contaminants were removed and captured in the effluent. The results show that the cement phase of the material melts and vaporizes, but the aggregate portion (sand and rock) fragments. The effluent consists of both micron-size aerosol particles and chunks of fragmented aggregate material. Laser-induced optical emission spectroscopy was used to analyze the surface during ablation. Analysis of the effluent showed that contaminants such as cesium and strontium were strongly segregated into different regions of the particle size distribution of the aerosol.

  16. Sodium Exposure Tests on Limestone Concrete Used as Sacrificial Protection Layer in FBR

    SciTech Connect

    Parida, F.C.; Das, S.K.; Sharma, A.K.; Rao, P.M.; Ramesh, S.S.; Somayajulu, P.A.; Malarvizhi, B.; Kasinathan, N.

    2006-07-01

    Hot sodium coming in contact with structural concrete in case of sodium leak in FBR system cause damage as a result of thermo-chemical attack by burning sodium. In addition, release of free and bound water from concrete leads to generation of hydrogen gas, which is explosive in nature. Hence limestone concrete, as sacrificial layer on the structural concrete in FBR, needs to be qualified. Four concrete blocks of dimension 600 mm x 600 mm x 300 mm with 300 mm x 300 mm x 150 mm cavity were cast and subjected to controlled sodium exposure tests. They have composition of ordinary portland cement, water, fine and coarse aggregate of limestone in the ratio of 1: 0.58: 2.547: 3.817. These blocks were subjected to preliminary inspection by ultrasonic pulse velocity technique and rebound hammer tests. Each block was exposed for 30 minutes to about 12 kg of liquid sodium ({approx} 120 mm liquid column) at 550 deg. C in open air, after which sodium was sucked back from the cavity of the concrete block into a sodium tank. On-line temperature monitoring was carried out at strategic locations of sodium pool and concrete block. After removing sodium from the cavity and cleaning the surfaces, rebound hammer testing was carried out on each concrete block at the same locations where data were taken earlier at pre-exposed stage. The statistical analysis of rebound hammer data revealed that one of the concrete block alone has undergone damage to the extent of 16%. The loss of mass occurred for all the four blocks varied from 0.6 to 2.4% due to release of water during the test duration. Chemical analysis of sodium in concrete samples collected from cavity floor of each block helped in generation of depth profiles of sodium monoxide concentration for each block. From this it is concluded that a bulk penetration of sodium up to 30 mm depth has taken place. However it was also observed that at few local spots, sodium penetrated into concrete up to 50 mm. Cylindrical core samples of 50 mm

  17. Radionuclide Migration through Sediment and Concrete: 16 Years of Investigations

    SciTech Connect

    Golovich, Elizabeth C.; Mattigod, Shas V.; Snyder, Michelle MV; Powers, Laura; Whyatt, Greg A.; Wellman, Dawn M.

    2014-11-01

    The Waste Management Project provides safe, compliant, and cost-effective waste management services for the Hanford Site and the U.S. Department of Energy (DOE) complex. Part of these services includes safe disposal of low-level waste and mixed low-level waste at the Hanford Low-Level Waste Burial Grounds in accordance with the requirements of DOE Order 435.1, Radioactive Waste Management. To partially satisfy these requirements, performance assessment analyses were completed and approved. DOE Order 435.1 also requires continuing data collection to increase confidence in the critical assumptions used in these analyses to characterize the operational features of the disposal facility that are relied on to satisfy the performance objectives identified in the order. Cement-based solidification and stabilization is considered for hazardous waste disposal because it is easily done and cost-efficient. One critical assumption is that concrete will be used as a waste form or container material at the Hanford Site to control and minimize the release of radionuclide constituents in waste into the surrounding environment. Concrete encasement would contain and isolate the waste packages from the hydrologic environment and act as an intrusion barrier. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages. The radionuclides iodine-129, selenium-75, technetium-99, and uranium-238 have been identified as long-term dose contributors (Mann et al. 2001; Wood et al. 1995). Because of their anionic nature in aqueous solutions, these constituents of potential concern may be released from the encased concrete by mass flow and/or diffusion and migrate into the surrounding subsurface environment (Serne et al. 1989; 1992; 1993a, b; 1995). Therefore, it is necessary to assess the performance of the concrete encasement structure and the ability of the surrounding soil to retard radionuclide migration. Each of the

  18. Glass fiber reinforced concrete for terrestrial photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Maxwell, H.

    1979-01-01

    The use of glass-fiber-reinforced concrete (GRC) as a low-cost structural substrate for terrestrial solar cell arrays is discussed. The properties and fabrication of glass-reinforced concrete structures are considered, and a preliminary design for a laminated solar cell assembly built on a GRC substrate is presented. A total cost for such a photovoltaic module, composed of a Korad acrylic plastic film front cover, an aluminum foil back cover, an ethylene/vinyl acetate pottant/adhesive and a cotton fabric electrical isolator in addition to the GRC substrate, of $9.42/sq m is projected, which is less than the $11.00/sq m cost goal set by the Department of Energy. Preliminary evaluations are concluded to have shown the design capabilities and cost effectiveness of GRC; however, its potential for automated mass production has yet to be evaluated.

  19. The jet impingement phase of molten core-concrete interactions

    SciTech Connect

    Sienicki, J.J.; Spencer, B.W.

    1986-01-01

    Scoping calculations have been carried out demonstrating that a significant and abrupt reduction in the corium temperature may be realized when molten corium drains as a jet from a localized breach in the RPV lower head to impinge upon the concrete basemat. The temperature decrease may range from a value of approx.170 K (approx.140 K) for limestone (basaltic) aggregate concrete to a value approaching the initial corium superheat depending upon whether the forced convection impingement heat flux is assumed to be controlled by either thermal conduction across a slag film layer or the temperature boundary condition represented by a corium crust. The magnitude of the temperature reduction remains significant as the initial corium temperature, impinging corium mass, and initial localized breach size are varied over their range of potential values.

  20. Computational homogenization of diffusion in three-phase mesoscale concrete

    NASA Astrophysics Data System (ADS)

    Nilenius, Filip; Larsson, Fredrik; Lundgren, Karin; Runesson, Kenneth

    2014-08-01

    A three dimensional (3D) mesoscale model of concrete is presented and employed for computational homogenization in the context of mass diffusion. The mesoscale constituents of cement paste, aggregates and interfacial transition zone (ITZ) are contained within a statistical volume element (SVE) on which homogenization is carried out. The model implementation accounts for ITZ anisotropy thereby the diffusivity tensor depends on the normal of the aggregate surface. The homogenized response is compared between 3D and 2D SVEs to study the influence of the third spatial dimension, and for varying mesoscale compositions to study the influence of aggregate content on concrete diffusivity. The computational results show that the effective diffusivity of 3D SVEs is about 40 % greater than 2D SVEs when ITZ is excluded for the SVE, and 17 % when ITZ is included. The results are in agreement with the upper Hashin-Shtrikman bound when ITZ is excluded, and close to the Taylor assumption when ITZ is included.

  1. Clogging in permeable concrete: A review.

    PubMed

    Kia, Alalea; Wong, Hong S; Cheeseman, Christopher R

    2017-05-15

    Permeable concrete (or "pervious concrete" in North America) is used to reduce local flooding in urban areas and is an important sustainable urban drainage system. However, permeable concrete exhibits reduction in permeability due to clogging by particulates, which severely limits service life. This paper reviews the clogging mechanism and current mitigating strategies in order to inform future research needs. The pore structure of permeable concrete and characteristics of flowing particulates influence clogging, which occurs when particles build-up and block connected porosity. Permeable concrete requires regular maintenance by vacuum sweeping and pressure washing, but the effectiveness and viability of these methods is questionable. The potential for clogging is related to the tortuosity of the connected porosity, with greater tortuosity resulting in increased potential for clogging. Research is required to develop permeable concrete that can be poured on-site, which produces a pore structure with significantly reduced tortuosity.

  2. Beneficial Use of Carbon Dioxide in Precast Concrete Production

    SciTech Connect

    Shao, Yixin

    2014-06-26

    The feasibility of using carbon dioxide as feedstock in precast concrete production is studied. Carbon dioxide reacts with calcium compounds in concrete, producing solid calcium carbonates in binding matrix. Two typical precast products are examined for their capacity to store carbon dioxide during the production. They are concrete blocks and fiber-cement panels. The two products are currently mass produced and cured by steam. Carbon dioxide can be used to replace steam in curing process to accelerate early strength, improve the long-term durability and reduce energy and emission. For a reaction within a 24-hour process window, the theoretical maximum possible carbon uptake in concrete is found to be 29% based on cement mass in the product. To reach the maximum uptake, a special process is developed to promote the reaction efficiency to 60-80% in 4-hour carbon dioxide curing and improve the resistance to freeze-thaw cycling and sulfate ion attack. The process is also optimized to meet the project target of $10/tCO2 in carbon utilization. By the use of self-concentrating absorption technology, high purity CO2 can be produced at a price below $40/t. With low cost CO2 capture and utilization technologies, it is feasible to establish a network for carbon capture and utilization at the vicinity of carbon sources. If all block produces and panel producers in United States could adopt carbon dioxide process in their production in place of steam, carbon utilization in these two markets alone could consume more than 2 Mt CO2/year. This capture and utilization process can be extended to more precast products and will continue for years to come.

  3. Does Concrete Self-Decontaminate VX

    DTIC Science & Technology

    2003-07-01

    DOES CONCRETE SELF-DECONTAMINATE VX? George W. Wagner, Richard J. O’Connor, and Lawrence R. Procell U.S. Army Edgewood Chemical ...this method avoids the problem of tenuous extraction procedures. In a recently published paper, Groenewold et al.2 examined the fate of dilute VX...concrete employed by Groenewold et al.,2 the current study examines VX droplets on the order of several µL to determine the behavior of VX on concrete in

  4. Phase 2 microwave concrete decontamination results

    SciTech Connect

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

    1995-04-01

    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 collected 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.

  5. Radiation shielding concrete made of Basalt aggregates.

    PubMed

    Alhajali, S; Yousef, S; Kanbour, M; Naoum, B

    2013-04-01

    In spite of the fact that Basalt is a widespread type of rock, there is very little available information on using it as aggregates for concrete radiation shielding. This paper investigates the possibility of using Basalt for the aforementioned purpose. The results have shown that Basalt could be used successfully for preparing radiation shielding concrete, but some attention should be paid to the choice of the suitable types of Basalt and for the neutron activation problem that could arise in the concrete shield.

  6. Laboratory Characterization of Gray Masonry Concrete

    DTIC Science & Technology

    2007-08-01

    ER D C/ G SL T R- 07 -2 3 Laboratory Characterization of Gray Masonry Concrete Erin M. Williams, Stephen A. Akers, and Paul A. Reed...07-23 August 2007 Laboratory Characterization of Gray Masonry Concrete Erin M. Williams, Stephen A. Akers, and Paul A. Reed Geotechnical and...constitutive property behavior of a gray masonry concrete . A total of 38 mechanical property tests were successfully completed: two hydrostatic

  7. Polypropylene Fibers in Portland Cement Concrete Pavements.

    DTIC Science & Technology

    1992-08-01

    Bibliography on Fiber- Reinforced Cement and Concrete," Miscellaneous Paper C-76-6, with supplements 1, 2, 3, and 4 ( 1977 , 1979, 1980, and 1982), US Army... Mindess , S., Bentur, A., Yan, C., and Vondran, G., "Impact Resistance of Concrete Containing Both Conventional Steel Reinforcement and Fibrillated...Roads, Streets, Walks, and Open Storage Areas," TM 5-822-6/AFM 88-7, Chap. 7, Washington, DC, 1977 . 18. __ , "Concrete Floor Slabs on Grade Subjected

  8. Economic analysis of recycling contaminated concrete

    SciTech Connect

    Stephen, A.; Ayers, K.W.; Boren, J.K.; Parker, F.L.

    1997-02-01

    Decontamination and Decommissioning activities in the DOE complex generate large volumes of radioactively contaminated and uncontaminated concrete. Currently, this concrete is usually decontaminated, the contaminated waste is disposed of in a LLW facility and the decontaminated concrete is placed in C&D landfills. A number of alternatives to this practice are available including recycling of the concrete. Cost estimates for six alternatives were developed using a spreadsheet model. The results of this analysis show that recycling alternatives are at least as economical as current practice.

  9. Experimental needs of high temperature concrete

    SciTech Connect

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

    1985-01-01

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

  10. Seismic behavior of lightweight concrete columns

    NASA Astrophysics Data System (ADS)

    Rabbat, B. G.; Daniel, J. I.; Weinmann, T. L.; Hanson, N. W.

    1982-09-01

    Sixteen full-scale, column-beam assemblies, which represented a portion of a frame subjected to simulated seismic loading, were tested. Controlled test parameters included concrete type, column size, amount of main column steel, size and spacing of column confining hoops, and magnitude of column axial load. The columns were subjected to constant axial load and slow moment reversals at increasing inelastic deformations. Test data showed that properly designed lightweight concrete columns maintained ductility and strength when subjected to large inelastic deformations from load reversals. Confinement requirements for normal weight concrete columns were shown to be applicable to lightweight concrete columns up to thirty percent of the design strength.

  11. Pentek concrete scabbling system: Baseline report; Summary

    SciTech Connect

    1997-07-31

    The Pentek concrete scabbling system consists of the MOOSE{reg_sign} scabbler, the SQUIRREL{reg_sign}-I and SQUIRREL{reg_sign}-III scabblers, and VAC-PAC. The scabblers are designed to scarify concrete floors and slabs using cross section, tungsten carbide tipped bits. The bits are designed to remove concrete in 3/8 inch increments. The bits are either 9-tooth or demolition type. The scabblers are used with a vacuum system designed to collect and filter the concrete dust and contamination that is removed from the surface. The safety and health evaluation during the human factors assessment focused on two main areas: noise and dust.

  12. Proceedings of the concrete decontamination workshop

    SciTech Connect

    Halter, J.M.; Sullivan, R.G.; Currier, A.J.

    1980-05-28

    Fourteen papers were presented. These papers describe concrete surface removal methods and equipment, as well as experiences in decontaminating and removing both power and experimental nuclear reactors.

  13. Assessment of deterioration in RHA-concrete due to magnesium sulphate attack

    NASA Astrophysics Data System (ADS)

    Habeeb, G. A.; Mahmud, H. B.; Hamid, N. B. A. A.

    2010-12-01

    The assessment of magnesium sulphate attack on concretes containing rice husk ash (RHA, 20wt% of the cementitious materials) with various average particle sizes was investigated. The total cementitious materials were 390 kg and the water-to-binder ratio (W/B) was 0.53 for all mixtures. Specimens were initially cured in water for 7 d and then immersed in the 3wt% magnesium sulphate solution for up to 111 d of exposure. The specimens were subjected to drying-wetting cycles to accelerate sulphate attack. In addition to the visual monitoring of the specimens, the concrete specimens were subsequently tested for compressive strength, dynamic modulus of elasticity, and length and mass changes. The results show that the specimens exposed to sulphate attack exhibit higher strength and dynamic modulus than those kept in water. The length change is negligible and can be attributed to the normal swelling of concrete. On the other hand, concretes suffers mass loss and surface spalling and softening; the fine RHA-concrete results in a better resistance. For the accelerated sulphate attack method used in this study, mass change and visual monitoring are recommended for assessing the deterioration degree and the effectiveness of supplementary cementitious materials to resist sulphate attack.

  14. High temperature polymer concrete compositions

    DOEpatents

    Fontana, Jack J.; Reams, Walter

    1985-01-01

    This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system. A preferred formulation emphasizing the major necessary components is as follows: ______________________________________ Component A: Silica sand 60-77 wt. % Silica flour 5-10 wt. % Portland cement 15-25 wt. % Acrylamide 1-5 wt. % Component B: Styrene 50-60 wt. % Trimethylolpropane 35-40 wt. % trimethacrylate ______________________________________ and necessary initiators, accelerators, and surfactants.

  15. Annotated Bibliography: Polymers in Concrete.

    DTIC Science & Technology

    1982-10-01

    example, the untreated cements let water through the 2 -ton pressure after 7 days aging, while cement containing 33 wt. percent resin No. 89 ( prepared ...100 parts were mixed with 300 parts local zone 2 concreting (14 0 mesh and 45 parts 40 percent II latex ( prepared by aq. emulsion poly - merization...condition for polymer-modified mortars using special super high early strength cement is the combined air and water cure such as 2 -day-20*C-moist, 5-day-20°C

  16. Spall Damage of Concrete Structures

    DTIC Science & Technology

    1988-06-01

    likely also strain-rate sensitive . Fiber-reinforced concrete has been extensively studied. Various types of fiber material, including nylon, glass, and...60/40) 0.95 AMATOL (50/50) 0.97 ANFO (9416 Am Nil Fuel oil) 0.82 1-100 Composition A-3 1.09 1.07 5-50 Composition B 1.11 0.98 5-50 Composition C-4 1.37...defines the boundary between threshold spall and medium spall and deflections less than 4.17 percent of the free span. The heavy damage curve defines

  17. Application of concrete in marine structures

    SciTech Connect

    Rashid, A.; Nygaard, C.

    1997-07-01

    The use of concrete in marine environment has gained tremendous popularity in the past decade and is continued to be a very popular material for marine industry in the world today. It has a very diversified use from large offshore platforms and floating structures in the North Sea, Canada and South America to offshore loading terminals and junction platforms in shallow waters in the marshes of southern Louisiana in the Gulf of Mexico. Also, precast concrete sections are extensively used all over the world in the construction of marine structures. Because of their large variety of shapes and sizes, they can be tailored to fit multiple applications in marine environment. The added quality control in the fabrication yard and the ease of installation by lifting makes them a very attractive option. The use of precast concrete sections is gaining a lot of popularity in South America. A lot of fabrication yards are manufacturing these sections locally. There are hundreds of offshore concrete platforms utilizing these sections in Lake Maracaibo, Venezuela. The paper discusses the use of concrete for offshore structures including floaters. It describes some general concepts and advantages to be gained by the use of concrete (precast and cast-in-place) in marine environment. It also discusses some general design considerations required for the use of different types of precast concrete sections that can be utilized for oil and gas platforms and loading terminals. Lastly the paper describes some typical examples of concrete platforms built out of concrete piles, precast concrete girders and beam sections and concrete decking.

  18. 36. VAL, DETAIL OF TYPICAL INTERIOR OF CONCRETE 'A' FRAME ...

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

    36. VAL, DETAIL OF TYPICAL INTERIOR OF CONCRETE 'A' FRAME STRUCTURE SHOWING PAINTED CONCRETE WALLS, CONCRETE STAIRS AND INTERIOR WOOD DOOR. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  19. Quick-setting concrete and a method for making quick-setting concrete

    DOEpatents

    Wagh, A.S.; Singh, D.; Pullockaran, J.D.; Knox, L.

    1997-04-29

    A method for producing quick setting concrete is provided comprising mixing a concrete dry mixture with carbonate solution to create a slurry, and allowing the slurry to cure. The invention also provides for a quick setting concrete having a predetermined proportion of CaCO{sub 3} of between 5 and 23 weight percent of the entire concrete mixture, and whereby the concrete has a compression strength of approximately 4,000 pounds per square inch (psi) within 24 hours after pouring. 2 figs.

  20. Testing of plain and fibrous concrete single cavity prestressed concrete reactor vessel models

    SciTech Connect

    Oland, C.B.

    1985-01-01

    Two single-cavity prestressed concrete reactor vessel (PCRV) models were fabricated and tested to failure to demonstrate the structural response and ultimate pressure capacity of models cast from high-strength concretes. Concretes with design compressive strengths in excess of 70 MPa (10,000 psi) were developed for this investigation. One model was cast from plain concrete and failed in shear at the head region. The second model was cast from fiber reinforced concrete and failed by rupturing the circumferential prestressing at the sidewall of the structure. The tests also demonstrated the capabilities of the liner system to maintain a leak-tight pressure boundary. 3 refs., 4 figs.

  1. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect

    Wellman, Dawn M.; Jansik, Danielle P.; Golovich, Elizabeth C.; Cordova, Elsa A.

    2012-09-24

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of LLW and MLLW, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  2. Investigation of modified asphalt concrete

    NASA Astrophysics Data System (ADS)

    Zimich, Vita

    2016-01-01

    Currently the problem of improving the asphalt quality is very urgent. It is used primarily as topcoats exposed to the greatest relative to the other layers of the road, dynamic load - impact and shear. The number of cars on the road, the speed of their movement, as well as the traffic intensity increase day by day. We have to upgrade motor roads, which entails a huge cost. World experience shows that the issue is urgent not only in Russia, but also in many countries in Europe, USA and Asia. Thus, the subject of research is the resistance of asphalt concrete to water and its influence on the strength of the material at different temperatures, and resistance of pavement to deformation. It is appropriate to search for new modifiers for asphaltic binder and mineral additives for asphalt mix to form in complex the skeleton of the future asphalt concrete, resistant to atmospheric condensation, soil characteristics of the road construction area, as well as the growing road transport load. The important task of the work is searching special modifying additives for bitumen binder and asphalt mixture as a whole, which will improve the quality of highways, increasing the period between repairs. The methods described in the normative-technical documentation were used for the research. The conducted research allowed reducing the frequency of road maintenance for 7 years, increasing it from 17 to 25 years.

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

    ERIC Educational Resources Information Center

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

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

  4. RADON GENERATION AND TRANSPORT THROUGH CONCRETE FOUNDATIONS

    EPA Science Inventory

    The report gives results of an examination of radon generation and transport through Florida residential concretes for their contribution to indoor radon concentrations. Radium concentrations in the 11 concretes tested were all <2.5 pCi/g and radon emanation coefficients were all...

  5. Assessing the Concreteness of Relational Representation

    ERIC Educational Resources Information Center

    Rein, Jonathan R.; Markman, Arthur B.

    2010-01-01

    Research has shown that people's ability to transfer abstract relational knowledge across situations can be heavily influenced by the concrete objects that fill relational roles. This article provides evidence that the concreteness of the relations themselves also affects performance. In 3 experiments, participants viewed simple relational…

  6. "Concreteness Fading" Promotes Transfer of Mathematical Knowledge

    ERIC Educational Resources Information Center

    McNeil, Nicole M.; Fyfe, Emily R.

    2012-01-01

    Recent studies have suggested that educators should avoid concrete instantiations when the goal is to promote transfer. However, concrete instantiations may benefit transfer in the long run, particularly if they are "faded" into more abstract instantiations. Undergraduates were randomly assigned to learn a mathematical concept in one of three…

  7. An Endochronic Plasticity Theory for Concrete.

    DTIC Science & Technology

    1985-02-20

    Strain Curves for Concrete Under Multiaxial Load His- tories," CEAE Department, Univ. of Colo., Boulder. 18. Stankowski, T., and K. H. Gerstle (1983...T. (1983), "Concrete Under Multiaxial Load Histories," M. S. Thesis, CEAE Department, University of Colorado, Boulder. 31. Valanis, K. C., and C. F

  8. Properties and uses of concrete, appendix B

    NASA Technical Reports Server (NTRS)

    Corley, Gene

    1992-01-01

    Concretes that can now be formed have properties which may make them valuable for lunar or space construction. These properties include high compressive strength, good flexural strength (when reinforced), and favorable responses to temperature extremes (even increased strength at low temperatures). These and other properties of concrete are discussed.

  9. A Study on the Cover Failure in Concrete Structure Following Concrete Deterioration

    SciTech Connect

    Choo, Y.H.; Lee, Y.H.; Lee, C.M.; Lee, K.J.

    2008-07-01

    The RC (Reinforced Concrete) structures in the spent fuel dry storage is required structural integrity for a long period of the service life time. A study on the concrete cracking behavior by stress on concrete is necessary for life time estimation of structures because concrete cracking can reduce the radiation shielding performance and deteriorate the durability of spent fuel dry storage. The purpose of this study is to analyze the relationship between the range of the steel expansion and the crack creation and propagation using the ABAQUS tool. Parameters used in this study were concrete strength, concrete cover depth and the steel diameter. The value of steel radius to volume expansion was applied to suppose the expansion of reinforcing bar under the load condition. As a result of this case study, it is confirmed that the critical steel expansion which can initiate cracking is proportional to tensile strength. And primary factors which effect crack creation of concrete cover are in order of concrete strength, cover thickness and steel diameter. If concrete strength is lowered about its 30%, the rate of surface crack occurrence accelerates 15 times maximally. The critical expansion value of steel increased as the increment of concrete cover depth. The surface cracking of concrete cover was created at the value of steel expansion, ranging from 0.019 to 0.051 mm under the cover depth 50 mm. (authors)

  10. RCC for seismic design. [Roller-Compacted Concrete

    SciTech Connect

    Wong, N.C.; Forrest, M.P.; Lo, S.H. )

    1994-09-01

    This article describes how the use of roller-compacted concrete is saving $10 million on the seismic retrofit of Southern California's historic multiple-arch Littlerock Dam. Throughout its 70-year existence, the Littlerock Dam in Southern California's Angeles National Forest has been a subject of the San Andreas Fault, could this 28-arch dam withstand any major movement from that fault line, much less the big one'' Working with the state's Division of Safety of Dams, Woodward-Clyde Consultants, Oakland, Calif., performed stability and stress analyses to find the answer. The evaluation showed that, as feared, the dam failed to meet required seismic safety criteria, principally due to its lack of lateral stability, a deficiency inherent in multiple-arch dams. To provide adequate seismic stability the authors developed a rehabilitation design centered around the use of roller-compacted concrete (RCC) to construct a gravity section between and around the downstream portions of the existing buttresses. The authors also proposed that the arches be resurfaced and stiffened with steel-fiber-reinforced silica fume. The alternative design would have required filling the arch bays between the buttresses with mass concrete at a cost of $22.5 million. The RCC buttress repair construction, scheduled for completion this fall, will cost about $13 million.

  11. Supporting Concrete Visual Thinking in Multiplicative Reasoning: Difficulties and Opportunities.

    ERIC Educational Resources Information Center

    Kaput, James J.

    1989-01-01

    Describes environments for concretely enacting multiplication and division. Discusses difficulties occurring when students use one of the concrete environments to model situations involving modified environments. (YP)

  12. Aerated concrete with mineral dispersed reinforcing additives

    NASA Astrophysics Data System (ADS)

    Berdov, G. I.; Ilina, L. V.; Mukhina, I. N.; Rakov, M. A.

    2015-01-01

    To guarantee the production of aerated concrete with the lowest average density while ensuring the required strength it is necessary to use a silica component with a surface area of 250-300 m2 / kg. The article presents experimental data on grinding the silica component together with clinker to the optimum dispersion. This allows increasing the strength of non-autoclaved aerated concrete up to 33%. Furthermore, the addition to aerated concrete the mixture of dispersed reinforcing agents (wollastonite, diopside) and electrolytes with multiply charged cations and anions (1% Fe2 (SO4)3; Al2 (SO4)3) provides the growth of aerated concrete strength at 30 - 75%. As a cohesive the clinker, crushed together with silica and mineral supplements should be used. This increases the strength of aerated concrete at 65% in comparing with Portland cement.

  13. Recent biogenic phosphorite: Concretions in mollusk kidneys

    USGS Publications Warehouse

    Doyle, L.J.; Blake, N.J.; Woo, C.C.; Yevich, P.

    1978-01-01

    Phosphorite concretions have been detected in the kidneys of two widespread species ofmollusks, Mercenaria mercenaria and Argopecten irradians, which have relatively high population densities. These concretions are thefirst documentation of the direct biogenic formation of phosphorite grains. The concretions are principally amorphous calcium phosphate, which upon being heated yields an x-ray diffraction pattern which is essentially that of chlorapatite. These concretions appear to be a normal formation of the excretory process of mollusks under reproductive, environmental, or pollutant-induced stress. Biogenic production of phosphorite concretions over long periods of time and diagenetic change from amorphous to crystalline structure, coupled with secondary enrichment, may account for the formation of some marine phosphorite desposits which are not easily explained by the chemical precipitation- replacement hypothesis. Copyright ?? 1978 AAAS.

  14. Studies on recycled aggregates-based concrete.

    PubMed

    Rakshvir, Major; Barai, Sudhirkumar V

    2006-06-01

    Reduced extraction of raw materials, reduced transportation cost, improved profits, reduced environmental impact and fast-depleting reserves of conventional natural aggregates has necessitated the use of recycling, in order to be able to conserve conventional natural aggregate. In this study various physical and mechanical properties of recycled concrete aggregates were examined. Recycled concrete aggregates are different from natural aggregates and concrete made from them has specific properties. The percentages of recycled concrete aggregates were varied and it was observed that properties such as compressive strength showed a decrease of up to 10% as the percentage of recycled concrete aggregates increased. Water absorption of recycled aggregates was found to be greater than natural aggregates, and this needs to be compensated during mix design.

  15. Electrical Resistance Tomography imaging of concrete

    SciTech Connect

    Karhunen, Kimmo; Seppaenen, Aku; Lehikoinen, Anssi; Monteiro, Paulo J.M.; Kaipio, Jari P.

    2010-01-15

    We apply Electrical Resistance Tomography (ERT) for three dimensional imaging of concrete. In ERT, alternating currents are injected into the target using an array of electrodes attached to the target surface, and the resulting voltages are measured using the same electrodes. These boundary measurements are used for reconstructing the internal (3D) conductivity distribution of the target. In reinforced concrete, the metallic phases (reinforcing bars and fibers), cracks and air voids, moisture gradients, and the chloride distribution in the matrix carry contrast with respect to conductivity. While electrical measurements have been widely used to characterize the properties of concrete, only preliminary results of applying ERT to concrete imaging have been published so far. The aim of this paper is to carry out a feasibility evaluation with specifically cast samples. The results indicate that ERT may be a feasible modality for non-destructive evaluation of concrete.

  16. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS.

    SciTech Connect

    Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P.; Chang, T.Y.

    2001-03-22

    This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits.

  17. Application of clearance automatic laser inspection system to clearance measurement of concrete waste

    SciTech Connect

    Sasaki, Michiya; Ogino, Haruyuki; Hattori, Takatoshi

    2007-07-01

    Recently, the Clearance Automatic Laser Inspection System (CLALIS) has been developed for the clearance measurement of metal scraps. It utilizes three-dimensional (3D) laser scanning, y-ray measurement and Monte Carlo calculation, and has outstanding detection ability. For the clearance measurement of concrete segments, the effect of background (BG) gamma rays from natural radionuclides in the measurement target, such as K-40 and the radioactive decay products of Th-232 and U-238, should be compensated for to ensure adequate waste management. Since NE102A plastic scintillation detectors are used for y-ray measurement in CLALIS, it is impossible to distinguish between count rates of natural radionuclides and contaminants on the basis of gamma-ray energy information. To apply CLALIS to the clearance measurement of concrete segments, the original activity evaluation method was improved by adding a new compensation procedure. In this procedure, BG count rate due to natural radionuclides is estimated by a Monte Carlo calculation with pre-analyzed data of a representative sample of the measurement target. The activity concentration of natural radionuclides in concrete differs markedly depending on the production location of its components, such as cement and aggregates. In this study, using six mock concrete waste samples, which were composed of cement and fine aggregate from various production locations, the accuracy of BG compensation was experimentally estimated. In addition, the accuracy of calibration for concrete waste was also estimated using a number of mock concrete segments of small and large triangular prisms. By considering the uncertainties of BG compensation and calibration, the detection limit of CLALIS for concrete waste was estimated. As a result, it was revealed that CLALIS could be applied to the clearance measurement of concrete segments when the mass of the measurement target is greater than approximately 1.1 kg and the key radionuclide is Co-60

  18. Radiation Damage In Reactor Cavity Concrete

    SciTech Connect

    Field, Kevin G; Le Pape, Yann; Naus, Dan J; Remec, Igor; Busby, Jeremy T; Rosseel, Thomas M; Wall, Dr. James Joseph

    2015-01-01

    License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has established a renewed focus on long-term aging of nuclear generating stations materials, and recently, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete. The Expanded Materials Degradation Analysis (EMDA), jointly performed by the Department of Energy, the Nuclear Regulatory Commission and Industry, identified the urgent need to develop a consistent knowledge base on irradiation effects in concrete. Much of the historical mechanical performance data of irradiated concrete does not accurately reflect typical radiation conditions in NPPs or conditions out to 60 or 80 years of radiation exposure. To address these potential gaps in the knowledge base, The Electric Power Research Institute and Oak Ridge National Laboratory are working to disposition radiation damage as a degradation mechanism. This paper outlines the research program within this pathway including: (i) defining the upper bound of the neutron and gamma dose levels expected in the biological shield concrete for extended operation (80 years of operation and beyond), (ii) determining the effects of neutron and gamma irradiation as well as extended time at temperature on concrete, (iii) evaluating opportunities to irradiate prototypical concrete under accelerated neutron and gamma dose levels to establish a conservative bound and share data obtained from different flux, temperature, and fluence levels, (iv) evaluating opportunities to harvest and test irradiated concrete from international NPPs, (v) developing cooperative test programs to improve confidence in the results from the various concretes and research reactors, (vi) furthering the understanding of the effects of radiation on concrete (see companion paper) and (vii) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge.

  19. 27 CFR 9.163 - Salado Creek.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the levee on the east bank of the Delta-Mendota Canal in section 35, T5S, R7E; then (3) Proceed southeast approximately 0.3 miles along the Delta-Mendota Canal levee road to its intersection with...

  20. 27 CFR 9.163 - Salado Creek.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the levee on the east bank of the Delta-Mendota Canal in section 35, T5S, R7E; then (3) Proceed southeast approximately 0.3 miles along the Delta-Mendota Canal levee road to its intersection with...

  1. 27 CFR 9.163 - Salado Creek.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the levee on the east bank of the Delta-Mendota Canal in section 35, T5S, R7E; then (3) Proceed southeast approximately 0.3 miles along the Delta-Mendota Canal levee road to its intersection with...

  2. 27 CFR 9.163 - Salado Creek.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the levee on the east bank of the Delta-Mendota Canal in section 35, T5S, R7E; then (3) Proceed southeast approximately 0.3 miles along the Delta-Mendota Canal levee road to its intersection with...

  3. 27 CFR 9.163 - Salado Creek.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... across the California Aqueduct and then north, to the road's intersection with the light duty road atop... Avenue to its intersection with the California Aqueduct, then continue generally south approximately 1.4 miles along the aqueduct to its intersection with Fink Road in section 19, T6S, R8E; then (11)...

  4. Examination of Behavior of Fresh Concrete Under Pressure

    NASA Astrophysics Data System (ADS)

    Yücel, K. T.

    2012-05-01

    Transporting fresh concrete constitutes a significant part of the production process. Transferring ready-mixed concrete on-site is done using concrete pumps. Recent developments in concrete technology, and in mineral and chemical additives, have resulted in new developments in pumping techniques and the use of different concrete mixtures and equipment. These developments required further knowledge of the behavior of fresh concrete under pressure. Two criteria were determined for the pumpability of concrete: the power required to move the concrete or of the repulsive force; and the cohesion of the fresh concrete. It would be insufficient to relate pumpability to these two criteria; the values of segregation pressure, diffusion ability, water retention capacity, and side friction of the mixture are significant parameters in ensuring that concrete is pumped freely along the pipe. To solve the pumpability problem, friction stresses should be determined as a function of the linear pressure gradient, the pressure leading to segregation of the fresh concrete should be determined, and tests for the bleeding of concrete under pressure should be examined. The scope of the research is the examination of the behavior of fresh concrete under pressure. To determine the segregation pressures, a test apparatus was designed for the bleeding of concrete under pressure. The main purpose of the study is to determine whether the concrete can be pumped easily and whether it will lose its cohesion during the pumping, based on tests of concrete workability and bleeding of concrete under pressure.

  5. Concrete Paving Blocks: An Overview

    DTIC Science & Technology

    1993-08-11

    REPORT TYPE AND DATES COVERED 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS C)gErE PAVING’ S0C4(S: At4N OVERVIEW 6. AUTHOR(S) tlCHfL K. AM U EUT5Av-T) C1 VI L...C13p c~cTE ePvI4G 3LCas PA\\I~f1EpJT W~f 40MIANCE (0~ PA ;Fs eAVrEENT DES 1I6M PVEA Y~~f~F C _S a~ 9L CONCRETE PAVING BLODCKS AN OVERVIEW by LT MCHAEL K...papers are published elsewhere. This report examines CBP’s from several perspectives in order to provide an overview of this alternative pavement

  6. Immobilization of iodine in concrete

    DOEpatents

    Clark, Walter E.; Thompson, Clarence T.

    1977-04-12

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3-20 wt. % iodine as Ba(IO.sub.3).sub.2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO.sub.3).sub.2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. BACKGROUND OF THE INVENTION This invention was made in the course of, or under a contract with the Energy Research and Development Administration. It relates in general to reactor waste solidification and more specifically to the immobilization of fission product radioactive iodine recovered from irradiated nuclear fuel for underground storage.

  7. Lunar cement and lunar concrete

    NASA Technical Reports Server (NTRS)

    Lin, T. D.

    1991-01-01

    Results of a study to investigate methods of producing cements from lunar materials are presented. A chemical process and a differential volatilization process to enrich lime content in selected lunar materials were identified. One new cement made from lime and anorthite developed compressive strengths of 39 Mpa (5500 psi) for 1 inch paste cubes. The second, a hypothetical composition based on differential volatilization of basalt, formed a mineral glass which was activated with an alkaline additive. The 1 inch paste cubes, cured at 100C and 100 percent humidity, developed compressive strengths in excess of 49 Mpa (7100 psi). Also discussed are tests made with Apollo 16 lunar soil and an ongoing investigation of a proposed dry mix/steam injection procedure for casting concrete on the Moon.

  8. Furfuryl alcohol polymer concretes for use in all-weather repairs of concrete and asphalt surfaces

    SciTech Connect

    Kukacka, L.E.; Sugama, T.

    1985-04-01

    The following criteria were established: high strength at an age of 1 h, placement of the materials must be possible during heavy precipitation over temperatures ranging from -32/sup 0/ to 52/sup 0/C, and the chemical constituents should be low cost and have long-term stability when contained in a maximum of three packages during storage. A formulation consisting of furfuryl alcohol monomer (FA), ..cap alpha..,..cap alpha..,..cap alpha..- trichlorotoluene, pyridine, silane, zinc chloride, silica filler, and coarse aggregate meets these requirements. Optimized formulations were established for use with premixed and percolation placement methods. The premixed formulation is compatible with moisture contents up to 4% by weight of the total mass, which simulates placement in a 2.54 cm/h rainfall. The working time for the FA-PC slurry can be controlled at greater than or equal to 15 min over the entire operating temperature range by simply varying the ..cap alpha..,..cap alpha..,..cap alpha..-trichlorotoluene catalyst concentration while holding all of the other constituents constant. Prototype equipment for the mixing and placement of FA-PC was demonstrated: a concrete transit mix supply of mixed aggregate, a hopper-fed volumetric feed screw which supplied aggregate at a known rate to a mixing screw, and a monomer pump and spray nozzle. The unit mixed and delivered FA-PC at approx.182 kg/min. The practicability of using equipment currently employed for the continuous placement of conventional portland cement concrete was proven. Field tests were performed under rainfall and dry conditions at temperatures ranging from -15/sup 0/ to 35/sup 0/C. The mixing and placement equipment performed well and the FA-PC slurries exhibited self-leveling characteristics. Test results from proxy samples prepared during the placement of the patches and cores taken after simulated aircraft trafficking, indicated that the property requirements at an age of 1 hr were attained.

  9. SA-based concrete seismic stress monitoring: a case study for normal strength concrete

    NASA Astrophysics Data System (ADS)

    Hou, S.; Zhang, H. B.; Ou, J. P.

    2016-09-01

    The stress history of concrete structures that have survived an earthquake can serve as a critical index to evaluate the health of the structure. There are currently few reliable monitoring methods to assess concrete stress after a seismic event. Piezoelectric-based smart aggregate (SA) provides an innovative experimental approach to monitor stress on concrete. The principle of SA-based concrete seismic stress monitoring is based on the assumption that concrete stress can be reliably predicted by the average output voltages of limited SAs with an acceptable margin of error. In this study, the meso-scale randomness of concrete was evaluated throughout the overall stress range of concrete and the influence of different load paths was considered. Four cylindrical specimens of normal strength concrete were embedded with a total of 24 SAs. The SA output sensitivity curve in the paths of loading-unloading with different amplitudes and monotonic loading up to failure was obtained. Monitoring errors were analyzed during pre- and post-peak stages from the experimental results. This research suggests that SA-based concrete seismic stress monitoring for normal strength concrete is reliable.

  10. Modeling the electrokinetic decontamination of concrete

    SciTech Connect

    Harris, M.T.; DePaoli, D.W.; Ally, M.R.

    1997-01-01

    The decontamination of concrete is a major concern in many Department of (DOE) facilities. Numerous techniques (abrasive methods, manual methods, ultrasonics, concrete surface layer removal, chemical extraction methods, etc.) have been used to remove radioactive contamination from the surface of concrete. Recently, processes that are based on electrokinetic phenomena have been developed to decontaminate concrete. Electrokinetic decontamination has been shown to remove from 70 to over 90% of the surface radioactivity. To evaluate and improve the electrokinetic processes, a model has been developed to simulate the transport of ionic radionuclei constituents through the pores of concrete and into the anolyte and catholyte. The model takes into account the adsorption and desorption kinetics of the radionuclei from the pore walls, and ion transport by electro-osmosis, electromigration, and diffusion. A numerical technique, orthogonal collocation, is used to simultaneously solve the governing convective diffusion equations for a porous concrete slab and the current density equation. This paper presents the theoretical framework of the model and the results from the computation of the dynamics of ion transport during electrokinetic treatment of concrete. The simulation results are in good agreement with experimental data.

  11. Nondestructive evaluation of thick concrete structures

    NASA Astrophysics Data System (ADS)

    Clayton, Dwight A.

    2015-03-01

    Concrete has been used in the construction of nuclear power plants (NPPs) due to three primary properties: its low cost, structural strength, and ability to shield radiation. Examples of concrete structures important to the safety of Light Water Reactor (LWR) plants include the containment building, spent fuel pool, and cooling towers. Use in these structures has made concrete's long-term performance crucial for the safe operation of commercial NPPs. Extending LWR operating period to 60 years and beyond will likely increase susceptibility and severity of known forms of degradation. New mechanisms of materials degradation are also possible. This creates the need to be able to nondestructively evaluate the current subsurface concrete condition of aging concrete material in NPP structures. The size and complexity of NPP containment structures and heterogeneity of Portland cement concrete make characterization of the degradation extent a difficult task. Specially designed and fabricated test specimens can provide realistic flaws that are similar to actual flaws in terms of how they interact with a particular nondestructive evaluation (NDE) technique. Artificial test blocks allow the isolation of certain testing problems as well as the variation of certain parameters. Representative large heavily reinforced concrete specimens would allow for comparative testing to evaluate the state-of-the-art NDE in this area and to identify additional developments necessary to address the challenges potentially found in NPPs.

  12. Self-cleaning geopolymer concrete - A review

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    Concrete is the most widely used construction materials for building technology. However, cement production releases high amounts of carbon dioxide (CO2) to the atmosphere that leads to increasing the global warming. Thus, an alternative, environmental friendly construction material such as geopolymer concrete has been developed. Geopolymer concrete applies greener alternative binder, which is an innovative construction material that replaces the Portland cement. This technology introduced nano-particles such as nanoclay into the cement paste in order to improve their mechanical properties. The concrete materials also have been developed to be functioned as self-cleaning construction materials. The self-cleaning properties of the concrete are induced by introducing the photocatalytic materials such as titania (TiO2) and zinc oxide (ZnO). Self-cleaning concrete that contains those photocatalysts will be energized by ultraviolet (UV) radiation and accelerates the decomposition of organic particulates. Thus, the cleanliness of the building surfaces can be maintained and the air surrounding air pollution can be reduced. This paper briefly reviews about self-cleaning concrete.

  13. Investigation of electrokinetic decontamination of concrete

    SciTech Connect

    DePaoli, D.W.; Harris, M.T.; Morgan, I.L.; Ally, M.R.

    1995-12-31

    Experiments have been conducted to investigate the capabilities of electrokinetic decontamination of concrete. Batch equilibration studies have determined that the loading of cesium and strontium on concrete may be decreased using electrolyte solutions containing competing cations, while solubilization of uranium and cobalt, that precipitate at high pH, will require lixiviants containing complexing agents. Dynamic electrokinetic experiments showed greater mobility of cesium than strontium, while some positive results were obtained for the transport of cobalt through concrete using EDTA and for uranium using carbonate.

  14. Development of refractory concrete for extreme conditions

    NASA Astrophysics Data System (ADS)

    Pundiene, I.; Antonovich, V.; Stonys, R.; Demidova-Buiziniene, I.

    2011-12-01

    Comparative analysis is provided for the properties of medium-cement refractory concrete with microsilica based on mullite filler in relation to different type of deflocculant. The effect of different deflocculants on refractory concrete structure formation, hydration, rheology, strength and heat resistance is discussed. Corrosion resistance test, determined that samples with hybrid deflocculant showed better resistance for slag penetration than samples with only the sodium tripolyphosphate or polycarboxylate ether deflocculant. Moreover, a composition of hybrid deflocculant let to control the rate of the hydration process and to get features of refractory refractory concrete.

  15. Reusing recycled aggregates in structural concrete

    NASA Astrophysics Data System (ADS)

    Kou, Shicong

    The utilization of recycled aggregates in concrete can minimize environmental impact and reduce the consumption of natural resources in concrete applications. The aim of this thesis is to provide a scientific basis for the possible use of recycled aggregates in structure concrete by conducting a comprehensive programme of laboratory study to gain a better understanding of the mechanical, microstructure and durability properties of concrete produced with recycled aggregates. The study also explored possible techniques to of improve the properties of recycled aggregate concrete that is produced with high percentages (≧ 50%) of recycled aggregates. These techniques included: (a) using lower water-to-cement ratios in the concrete mix design; (b) using fly ash as a cement replacement or as an additional mineral admixture in the concrete mixes, and (c) precasting recycled aggregate concrete with steam curing regimes. The characteristics of the recycled aggregates produced both from laboratory and a commercially operated pilot construction and demolition (C&D) waste recycling plant were first studied. A mix proportioning procedure was then established to produce six series of concrete mixtures using different percentages of recycled coarse aggregates with and without the use of fly ash. The water-to-cement (binder) ratios of 0.55, 0.50, 0.45 and 0.40 were used. The fresh properties (including slump and bleeding) of recycled aggregate concrete (RAC) were then quantified. The effects of fly ash on the fresh and hardened properties of RAC were then studied and compared with those RAC prepared with no fly ash addition. Furthermore, the effects of steam curing on the hardened properties of RAC were investigated. For micro-structural properties, the interfacial transition zones of the aggregates and the mortar/cement paste were analyzed by SEM and EDX-mapping. Moreover, a detailed set of results on the fracture properties for RAC were obtained. Based on the experimental

  16. Investigation of the Precipitates on the Concrete Surface due to Sulphate Exposure

    NASA Astrophysics Data System (ADS)

    Kovalčíková, Martina; Eštoková, Adriana; Oravec, Jozef; Luptáková, Alena

    2016-12-01

    The aim of this study is to investigate the durability of cement-based materials subjected to the effects of sulphuric acid in terms of surface deterioration. Damaged concrete surfaces and the samples' mass changes were studied during 270-day simulation of both chemical and biological attacks. Chemical corrosion was simulated by sulphuric acid with pH of 3.0 and 4.0, respectively, while biological corrosion was simulated by activity of bacteria Acidithiobacillus thiooxidans. XRD and SEM analyses confirmed a massive sulphate precipitate formation on the concrete surface due to chemical and biological sulphate corrosion.

  17. Molecular Survey of Concrete Sewer Biofilm Microbial Communities

    EPA Science Inventory

    Although bacteria are implicated in deteriorating concrete structures, there is very little information on the composition of concrete microbial communities. To this end, we studied different concrete biofilms by performing sequence analysis of 16S rDNA concrete clone libraries. ...

  18. 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..., 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...

  19. 76 FR 34890 - Track Safety Standards; Concrete Crossties

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-15

    ... Federal Railroad Administration 49 CFR Part 213 RIN 2130-AC01 Track Safety Standards; Concrete Crossties... mandates specific requirements for effective concrete crossties, for rail fastening systems connected to concrete crossties, and for automated inspections of track constructed with concrete crossties. The...

  20. 76 FR 55819 - Track Safety Standards; Concrete Crossties

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-09

    ... Federal Railroad Administration 49 CFR Part 213 RIN 2130-AC35 Track Safety Standards; Concrete Crossties... concrete crossties, for rail fastening systems connected to concrete crossties, and for automated inspections of track constructed with concrete crossties. This document amends and clarifies the final...

  1. 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..., 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...

  2. 76 FR 18073 - Track Safety Standards; Concrete Crossties

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-01

    ... Federal Railroad Administration 49 CFR Part 213 RIN 2130-AC01 Track Safety Standards; Concrete Crossties... over track constructed with concrete crossties. In particular, FRA is mandating specific requirements for effective concrete crossties, for rail fastening systems connected to concrete crossties, and...

  3. 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...

  4. 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..., 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...

  5. 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..., 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...

  6. Mechanical and Physical Properties of Polyester Polymer Concrete Using Recycled Aggregates from Concrete Sleepers

    PubMed Central

    Carrión, Francisco; Montalbán, Laura; Real, Julia I.

    2014-01-01

    Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior. PMID:25243213

  7. Mechanical and physical properties of polyester polymer concrete using recycled aggregates from concrete sleepers.

    PubMed

    Carrión, Francisco; Montalbán, Laura; Real, Julia I; Real, Teresa

    2014-01-01

    Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior.

  8. Simultaneous heat and mass transfer in a porous medium

    NASA Astrophysics Data System (ADS)

    Siang, H.

    1981-11-01

    Based upon the principle of irreversible thermodynamics, the macroscopic conservation laws of mass, momentum and energy, and equilibrium sorption of the porous concrete system, a set of basic equations for simultaneous mass and heat transfer is developed. An implicit finite difference technique is employed to solve this set of nonlinear partial differential equations. Numerical examples, using the theory developed, are illustrated to deepen the general understanding of the drying, thermal characteristics and related phenomena of hydrated concrete. The developed theoretical model is made nondimensional and an order of magnitude analysis is performed to elucidate the transport phenomenum of heat and mass occurring in a concrete body. In addition to diffusion, both the capillary and evaporation-condensation mechanisms, which are strongly affected by the topology of the porous concrete system, are important in the heat and mass transfer processes.

  9. Electro-osmotic techniques for removal of chloride from concrete and for emplacement of concrete sealants

    NASA Astrophysics Data System (ADS)

    Jayaprakash, G. P.; Bukovatz, J. E.; Ramamurti, K.; Gilliland, W. J.

    1982-08-01

    Chloride ion from bridge deck concrete can be removed by application of a direct current potential between bridge reinforcing steel (-) and a copper screen (+) conductor on the bridge surface. Soaring prices of all types of energy would make removal of all chloride prohibitatively expensive. The importance of verification of all electrical connections prior to the treatment is emphasized by the demonstration of concrete cracking when the steel was made a positive instead of a negative electrode. Data on effectiveness of calcium nitrite corrosion inhibitor added to the concrete overlay placed on electrotreated concrete is not extensive due to accidental damage to the test slabs.

  10. Exploring Floating Concrete and Beam Design.

    ERIC Educational Resources Information Center

    Snell, Billie G.; Snell, Luke M.

    2002-01-01

    Presents two construction activities that address both state and federal science standards and encourage students to consider career options in mathematics and science. Includes floating concrete and paper bridge activities. (YDS)

  11. Laboratory constitutive characterization of cellular concrete.

    SciTech Connect

    Hardy, Robert Douglas; Lee, Moo Yul; Bronowski, David R.

    2004-03-01

    To establish mechanical material properties of cellular concrete mixes, a series of quasi-static, compression and tension tests have been completed. This report summarizes the test methods, set-up, relevant observations, and results from the constitutive experimental efforts. Results from the uniaxial and triaxial compression tests established failure criteria for the cellular concrete in terms of stress invariants I{sub 1} and J{sub 2}. {radical}J{sub 2} (MPa) = 297.2 - 278.7 exp{sup -0.000455 I}{sub 1}{sup (MPa)} for the 90-pcf concrete {radical}J{sub 2} (MPa) = 211.4 - 204.2 exp {sup -0.000628 I}{sub 1}{sup (MPa)} for the 60-pcf concrete

  12. Seismic safety of high concrete dams

    NASA Astrophysics Data System (ADS)

    Chen, Houqun

    2014-08-01

    China is a country of high seismicity with many hydropower resources. Recently, a series of high arch dams have either been completed or are being constructed in seismic regions, of which most are concrete dams. The evaluation of seismic safety often becomes a critical problem in dam design. In this paper, a brief introduction to major progress in the research on seismic aspects of large concrete dams, conducted mainly at the Institute of Water Resources and Hydropower Research (IWHR) during the past 60 years, is presented. The dam site-specific ground motion input, improved response analysis, dynamic model test verification, field experiment investigations, dynamic behavior of dam concrete, and seismic monitoring and observation are described. Methods to prevent collapse of high concrete dams under maximum credible earthquakes are discussed.

  13. Pentek concrete scabbling system: Baseline report

    SciTech Connect

    1997-07-31

    The Pentek scabbling technology was tested at Florida International University (FIU) and is being evaluated as a baseline technology. This report evaluates it for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The Pentek concrete scabbling system consisted of the MOOSE{reg_sign}, SQUIRREL{reg_sign}-I, and SQUIRREL{reg_sign}-III scabblers. The scabblers are designed to scarify concrete floors and slabs using cross-section, tungsten carbide tipped bits. The bits are designed to remove concrete in 318 inch increments. The bits are either 9-tooth or demolition type. The scabblers are used with a vacuum system designed to collect and filter the concrete dust and contamination that is removed from the surface. The safety and health evaluation during the human factors assessment focused on two main areas: noise and dust.

  14. Sequestration of CO2 by concrete carbonation.

    PubMed

    Galan, Isabel; Andrade, Carmen; Mora, Pedro; Sanjuan, Miguel A

    2010-04-15

    Carbonation of reinforced concrete is one of the causes of corrosion, but it is also a way to sequester CO2. The characteristics of the concrete cover should ensure alkaline protection for the steel bars but should also be able to combine CO2 to a certain depth. This work attempts to advance the knowledge of the carbon footprint of cement. As it is one of the most commonly used materials worldwide, it is very important to assess its impact on the environment. In order to quantify the capacity of cement based materials to combine CO2 by means of the reaction with hydrated phases to produce calcium carbonate, Thermogravimetry and the phenolphthalein indicator have been used to characterize several cement pastes and concretes exposed to different environments. The combined effect of the main variables involved in this process is discussed. The moisture content of the concrete seems to be the most influential parameter.

  15. Concrete "Waffle" Provides Laser Beam Accuracy

    ERIC Educational Resources Information Center

    Building Design and Construction, 1978

    1978-01-01

    A massive concrete "waffle," riding on a bed of specially treated gravel and sand inside another building, provides the structural rigidity needed by the University of Rochester's Laboratory for Laser Energetics. (Author)

  16. Damage characterization in concrete using diffuse ultrasound

    NASA Astrophysics Data System (ADS)

    Shokouhi, Parisa; Niederleithinger, Ernst

    2012-05-01

    Diffuse ultrasonic measurements were used to characterize the state of stress-induced damage (volumetric microcracking) in concrete specimens. The test specimens were subjected to cycles of stepwise uniaxial compression. At each step, the loading (stress- or strain-controlled) was held constant and a series of ultrasonic measurements parallel and perpendicular to the loading were obtained. Unusually long signals were recorded, so that the diffuse ultrasonic regime tailing the coherent field could be studied. In the diffuse regime, the measured ultrasonic response is a superposition of reflections from scatters within concrete and thus, very sensitive to the changes in concrete microstructure. Using Coda Wave Interferometry (CWI), the evolution of diffuse velocity with the increasing load was monitored. The rate of change in the diffusion velocities was shown to be a good indication of the state of (low to medium intensity) damage in concrete.

  17. Cements for Structural Concrete in Cold Regions.

    DTIC Science & Technology

    1977-10-01

    setting-times than the Vicat test. Once the initial set has been reached, the high alumina cement will gain strength at a very rapid rate. This is not...the concrete becomes more permeable and decreases in strength . Neuman (1960) reports that high alumina cement concrete that has been affected by hot...conversion becomes more rapid and a serious loss of strength occurs which may take some months to develop (Building Research Establishment 1975). HIGH

  18. Evaluation and Repair of Concrete Slabs

    DTIC Science & Technology

    1992-01-01

    is duce a readily flowable concrete that is capable of listed in Table 1. completely filling the formed area. For large surface areas, it may be...Poor compaction, irregular surfaces, expansive soils , and the presence of mud or soft organic material can all result in a yielding subgrade. Again... fill all the spaces around the coarse aggregate. It is easily recognized by voids in the surface where the concrete appears as coarse aggregate

  19. Nonlinear Ultrasonic Evaluation of Concrete Microcracking

    NASA Astrophysics Data System (ADS)

    Woodward, C.; White, K. R.; Jauregui, D. V.; Stauffer, J.

    2004-02-01

    Microcracking is usually associated with most types of concrete deterioration. The nondestructive detection of deterioration in in-situ concrete in its early stages is not practical using current technology. In this project nonlinear ultrasound was used to evaluate the degree of microcracking changes resulting from increasing compression stresses. Second and third harmonic amplitudes were measured and correlated to the degree of microcracking induced in the specimen. These harmonics were found to increase with increasing levels of microcracking.

  20. Spall Repair of Wet Concrete Surfaces

    DTIC Science & Technology

    1990-01-01

    ILE COPY REPAIR, EVALUATION, MAINTENANCE, AND REHABILITATION RESEARCH PROGRAM TECHNICAL REPORT REMR-CS-25 SPALL REPAIR OF WET CONCRETE SURFACES by J...of the number designating technical reports of research published under the Repair, Evaluation. Maintenance. and Rehabilitation (REMR) Research ...Program identify the problem area under which the report was prepared Problem Area Problem Area CS Concrete and Steel Structures EM Electrical and

  1. Modeling of concrete response at high temperature

    SciTech Connect

    Pfeiffer, P.; Marchertas, A.

    1984-01-01

    A rate-type creep law is implemented into the computer code TEMP-STRESS for high temperature concrete analysis. The disposition of temperature, pore pressure and moisture for the particular structure in question is provided as input for the thermo-mechanical code. The loss of moisture from concrete also induces material shrinkage which is accounted for in the analytical model. Examples are given to illustrate the numerical results.

  2. Strain rate effects for spallation of concrete

    NASA Astrophysics Data System (ADS)

    Häussler-Combe, Ulrich; Panteki, Evmorfia; Kühn, Tino

    2015-09-01

    Appropriate triaxial constitutive laws are the key for a realistic simulation of high speed dynamics of concrete. The strain rate effect is still an open issue within this context. In particular the question whether it is a material property - which can be covered by rate dependent stress strain relations - or mainly an effect of inertia is still under discussion. Experimental and theoretical investigations of spallation of concrete specimen in a Hopkinson Bar setup may bring some evidence into this question. For this purpose the paper describes the VERD model, a newly developed constitutive law for concrete based on a damage approach with included strain rate effects [1]. In contrast to other approaches the dynamic strength increase is not directly coupled to strain rate values but related to physical mechanisms like the retarded movement of water in capillary systems and delayed microcracking. The constitutive law is fully triaxial and implemented into explicit finite element codes for the investigation of a wide range of concrete structures exposed to impact and explosions. The current setup models spallation experiments with concrete specimen [2]. The results of such experiments are mainly related to the dynamic tensile strength and the crack energy of concrete which may be derived from, e.g., the velocity of spalled concrete fragments. The experimental results are compared to the VERD model and two further constitutive laws implemented in LS-Dyna. The results indicate that both viscosity and retarded damage are required for a realistic description of the material behaviour of concrete exposed to high strain effects [3].

  3. Repairs to Concrete Port and Harbor Structures

    DTIC Science & Technology

    1991-11-18

    landmarks in the world is the Eddystone lighthouse which was constructed by the British engineer, John Smeaton , in 1756. The lighthouse is situated on the...west outlet of the English Channel and was constructed before the advent of portland cement. Smeaton invented a hydraulic (water-resisting) U lime by...Champion, S., Failure and Repair of Concrete Structures, John Wiley and Sons, New York, 1961 j [38] Gerwick, B. C., "Marine Concrete", Handbook of Ocean

  4. Behavior of Partially Restrained Reinforced Concrete Slabs.

    DTIC Science & Technology

    1986-09-01

    Experimental Deflections and Coupling Forces. ........ 72 3.4 Method of Approximating Support Rotations . . . 76 3.5 Free-Body Diagram Used in Computing...common types of structural elements. Slabs are found in practically every type of structural system, ’ whether steel or concrete, single -story or...Because of the nature of reinforced concrete slabs, accurate evaluations of stresses, strains, and deflections are difficult to make by elasticity

  5. Ulexite-galena intermediate-weight concrete as a novel design for overcoming space and weight limitations in the construction of efficient shields against neutrons and photons.

    PubMed

    Aghamiri, S M R; Mortazavi, S M J; Razi, Z; Mosleh-Shirazi, M A; Baradaran-Ghahfarokhi, M; Rahmani, F; Faeghi, F

    2013-01-01

    Recently, due to space and weight limitations, scientists have tried to design and produce concrete shields with increased attenuation of radiation but not increased mass density. Over the past years, the authors' had focused on the production of heavy concrete for radiation shielding, but this is the first experience of producing intermediate-weight concrete. In this study, ulexite (hydrated sodium calcium borate hydroxide) and galena (lead ore) have been used for the production of a special intermediate-weight concrete. Shielding properties of this intermediate-weight concrete against photons have been investigated by exposing the samples to narrow and broad beams of gamma rays emitted from a ⁶⁰Co radiotherapy unit. Densities of the intermediate-weight concrete samples ranged 3.64-3.90 g cm⁻³, based on the proportion of the ulexite in the mix design. The narrow-beam half-value layer (HVL) of the ulexite-galena concrete samples for 1.25 MeV ⁶⁰Co gamma rays was 2.84 cm, much less than that of ordinary concrete (6.0 cm). The Monte Carlo (MC) code MCNP4C was also used to model the attenuation of ⁶⁰Co gamma-ray photons and Am-Be neutrons of the ulexite-galena concrete with different thicknesses. The ⁶⁰Co HVL calculated by MCNP simulation was 2.87 cm, indicating a good agreement between experimental measurements and MC simulation. Furthermore, MC-calculated results showed that thick ulexite-galena concrete shields (60-cm thickness) had a 7.22 times (722 %) greater neutron attenuation compared with ordinary concrete. The intermediate-weight ulexite-galena concrete manufactured in this study may have many important applications in the construction of radiation shields with weight limitations such as the swing or sliding doors that are currently used for radiotherapy treatment rooms.

  6. Electromagnetic Metrology on Concrete and Corrosion*

    PubMed Central

    Kim, Sung; Surek, Jack; Baker-Jarvis, James

    2011-01-01

    To augment current methods for the evaluation of reinforcing bar (rebar) corrosion within concrete, we are exploring unique features in the dielectric and magnetic spectra of pure iron oxides and corrosion samples. Any signature needs to be both prominent and consistent in order to identify corrosion within concrete bridge deck or other structures. In order to measure the permittivity and propagation loss through concrete as a function of temperature and humidity, we cut and carefully fitted samples from residential concrete into three different waveguides. We also poured and cured a mortar sample within a waveguide that was later measured after curing 30 days. These measurements were performed from 45 MHz to 12 GHz. Our concrete measurements showed that the coarse granite aggregate that occupied about half the sample volume reduced the electromagnetic propagation loss in comparison to mortar. We also packed ground corrosion samples and commercially available iron-oxide powders into a transmission-line waveguide and found that magnetite and corrosion sample spectra are similar, with a feature between 0.5 GHz and 2 GHz that may prove useful for quantifying corrosion. We also performed reflection (S11) measurements at various corrosion surfaces and in loose powders from 45 MHz to 50 GHz. These results are a first step towards quantifying rebar corrosion in concrete. PMID:26989590

  7. 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.

  8. Electromagnetic Metrology on Concrete and Corrosion.

    PubMed

    Kim, Sung; Surek, Jack; Baker-Jarvis, James

    2011-01-01

    To augment current methods for the evaluation of reinforcing bar (rebar) corrosion within concrete, we are exploring unique features in the dielectric and magnetic spectra of pure iron oxides and corrosion samples. Any signature needs to be both prominent and consistent in order to identify corrosion within concrete bridge deck or other structures. In order to measure the permittivity and propagation loss through concrete as a function of temperature and humidity, we cut and carefully fitted samples from residential concrete into three different waveguides. We also poured and cured a mortar sample within a waveguide that was later measured after curing 30 days. These measurements were performed from 45 MHz to 12 GHz. Our concrete measurements showed that the coarse granite aggregate that occupied about half the sample volume reduced the electromagnetic propagation loss in comparison to mortar. We also packed ground corrosion samples and commercially available iron-oxide powders into a transmission-line waveguide and found that magnetite and corrosion sample spectra are similar, with a feature between 0.5 GHz and 2 GHz that may prove useful for quantifying corrosion. We also performed reflection (S 11) measurements at various corrosion surfaces and in loose powders from 45 MHz to 50 GHz. These results are a first step towards quantifying rebar corrosion in concrete.

  9. Ultrasonic testing of reactive powder concrete.

    PubMed

    Washer, Glenn; Fuchs, Paul; Graybeal, Benjamin A; Hartmann, Joseph Lawrence

    2004-02-01

    Concrete is a critical material for the construction of infrastructure facilities throughout the world. Traditional concretes consist of cement paste and aggregates ranging in size from 6 to 25 mm that form a heterogeneous material with substantial compressive strength and a very low tensile strength. Steel reinforcement is used to provide tensile strength for reinforced concrete structures and as a composite the material is useful for structural applications. A new material known as reactive powder concrete (RPC) is becoming available. It differs significantly from traditional concrete; RPC has no large aggregates, and contains small steel fibers that provide additional strength and, in some cases, can replace traditional steel reinforcement. Due to its high density and lack of aggregates, ultrasonic inspections at frequencies 10 to 20 times that of traditional concrete inspections are possible. This paper reports on the initial findings of research conducted to determine the applicability of ultrasonic testing techniques for the condition assessment of RPC. Pulse velocities for shear and longitudinal waves and ultrasonic measurement of the modulus of elasticity for RPC are reported. Ultrasonic crack detection for RPC also is investigated.

  10. Beta Bremsstrahlung dose in concrete shielding

    NASA Astrophysics Data System (ADS)

    Manjunatha, H. C.; Chandrika, B. M.; Rudraswamy, B.; Sankarshan, B. M.

    2012-05-01

    In a nuclear reactor, beta nuclides are released during nuclear reactions. These betas interact with shielding concrete and produces external Bremsstrahlung (EB) radiation. To estimate Bremsstrahlung dose and shield efficiency in concrete, it is essential to know Bremsstrahlung distribution or spectra. The present work formulated a new method to evaluate the EB spectrum and hence Bremsstrahlung dose of beta nuclides (32P, 89Sr, 90Sr-90Y, 90Y, 91Y, 208Tl, 210Bi, 234Pa and 40K) in concrete. The Bremsstrahlung yield of these beta nuclides in concrete is also estimated. The Bremsstrahlung yield in concrete due to 90Sr-90Y is higher than those of other given nuclides. This estimated spectrum is accurate because it is based on more accurate modified atomic number (Zmod) and Seltzer's data, where an electron-electron interaction is also included. Presented data in concrete provide a quick and convenient reference for radiation protection. The present methodology can be used to calculate the Bremsstrahlung dose in nuclear shielding materials. It can be quickly employed to give a first pass dose estimate prior to a more detailed experimental study.

  11. Enhancement of concrete properties for pavement slabs using waste metal drillings and silica fume.

    PubMed

    Hassani, Abolfazl; Arjmandi, Mohsen

    2010-01-01

    This paper presents a comparative study on the effects of steel fibres and waste metal drillings on the mechanical/physical behaviour of conventional and silica fume concrete. The amount of silica fume used was 10% of cement by mass and the amount of steel fibres and metal drillings used in both concrete mixtures was 0.5% by concrete volume for steel fibres and 0.0, 0.25, 0.50 and 0.75% for metal drillings, respectively. In total, 10 different mixtures were made and tested for compressive strength, modulus of elasticity, flexural strength and toughness. Our data reveal the significant impact of the effect of silica fume, steel fibres and industrial waste metal drillings on the mechanical and physical characteristics of concrete mixtures. The results also show that mixtures with steel fibres and waste metal drillings have comparable behaviour. Hence, there is a potential for use of waste metal drillings as an alternative to steel fibres for specific cases such as concrete pavement slabs.

  12. Moisture Transport Through Sprayed Concrete Tunnel Linings

    NASA Astrophysics Data System (ADS)

    Holter, Karl Gunnar; Geving, Stig

    2016-01-01

    Waterproofing of permanent sprayed concrete tunnel linings with sprayed membranes in a continuous sandwich structure has been attempted since 2000 and has seen increased use in some countries. The main function of a sprayed membrane from a waterproofing perspective is to provide crack bridging and hence prevent flow of liquid water into the tunnel through cracks and imperfections in the concrete material. However, moisture can migrate through the concrete and EVA-based membrane materials by capillary and vapor diffusion mechanisms. These moisture transport mechanisms can have an influence on the degree of saturation, and may influence the pore pressures in the concrete material as well as risk of freeze-thaw damage of the concrete and membrane. The paper describes a detailed study of moisture transport material parameters, moisture condition in tunnel linings and climatic conditions tunnels in hard rock in Norway. These data have been included in a hygrothermal simulation model in the software WUFI for moisture transport to substantiate moisture transport and long-term effects on saturation of the concrete and membrane material. The findings suggest that EVA-based membranes exhibit significant water absorption and vapor transport properties although they are impermeable to liquid water flow. State-of-the-art sprayed concrete material applied with the wet mix method exhibits very low hydraulic conductivities, lower than 10-14 m/s, thus saturated conductive water flow is a very unlikely dominant transport mechanism. Moisture transport through the lining structure by capillary flow and vapor diffusion are calculated to approximately 3 cm3/m2 per day for lining thicknesses in the range of 25-35 cm and seasonal Nordic climate variations. The calculated moisture contents in the tunnel linings from the hygrothermal simulations are largely in agreement with the measured moisture contents in the tunnel linings. The findings also indicate that the concrete material exhibits

  13. Low-energy broad-beam photon shielding data for constituents of concrete.

    PubMed

    Ogundare, Folorunso O; Ogundele, Samuel A; Akerele, Olumide O; Balogun, Fatai A

    2012-03-08

    The ability of concrete to attenuate ionizing radiation intensity is assessed using its linear or mass attenuation coefficient. In this work, the broad-beam linear and mass attenuation coefficients of different types of soils and cements used for making concrete were measured at different photon energies (60-1333 keV), nearly spanning the diagnostic photon energy range, using a NaI detector. The mass attenuation coefficients of cement decreased from 0.133 ± 0.002 at 60 keV to 0.047 ± 0.003 at 1332.5 keV. For soils, the mass attenuation coefficient of those collected from the beach was the highest, decreasing from 0.176 ± 0.003 cm²/g at 60 keV to 0.054 ± 0.001 cm²/g at 1332.5 keV. Land soils had the least value, decreasing from 0.124 ± 0.002 cm²/g at 60 keV to 0.044 ± 0.003 cm²/g at 1332.5 keV. Limestone had smaller mass attenuation coefficients than the cement produced using it. The implication of the above is that for making concrete, beach sand should be preferred as the sand component of the concrete. Models of the form μ(L) = A(E) exp[B(E)ρ] and μ(m) = αln(E)+β are proposed for fitting the linear attenuation coefficient and mass attenuation coefficient data, respectively.

  14. Curvature ductility of reinforced and prestressed concrete columns

    SciTech Connect

    Suprenant, B.A.

    1984-01-01

    Engineers are concerned with the survival of reinforced and prestressed concrete columns during earthquakes. The prediction of column survival can be deduced from moment-curvature curves of the column section. An analytical approach is incorporated into a computer model. The computer program is based on assumed stress-strain relations for confined and unconfined concrete, nonprestressed and prestressing steel. The results of studies on reinforced and prestressed concrete columns indicate that reinforced concrete columns may be designed to resist earthquakes, while prestressed concrete columns may not. The initial reduction in moment capacity, after concrete cover spalling, of a prestressed concrete column could be as much as 50%. Analyses indicate that the bond between concrete and prestressing strand after concrete cover spalling is not critical.

  15. Concrete shaver. Innovative technology summary report

    SciTech Connect

    1998-12-01

    The US Department of Energy (DOE) is in the process of decontamination and decommissioning (D and D) for many of its nuclear facilities throughout the United States. These facilities must be dismantled and the demolition waste sized into manageable pieces for handling and disposal. The facilities undergoing D and D are typically chemically and/or radiologically contaminated. To facilitate this work, DOE requires a tool capable of removing the surface of radiologically contaminated concrete floors. Operating requirements for the tool include simple and economical operation, the capability of operating in ambient temperatures from 3 C to 40 C (37 F to 104 F), and the ability to be easily decontaminated. The tool also must be safe for workers. The Marcrist Industries Limited concrete shaver is an electrically driven, self-propelled concrete and coating removal system. This technology consists of a 25-cm (10-in.)-wide diamond impregnated shaving drum powered by an electric motor and contains a vacuum port for dust extraction. The concrete shaver is ideal for use on open, flat, floor areas. The shaver may also be used on slightly curved surfaces. This shaver is self-propelled and produces a smooth, even surface with little vibration. The concrete shaver is an attractive alternative to traditional pneumatic scabbling tools, which were considered the baseline in this demonstration. The use of this tool reduces worker fatigue (compared to the baseline) due to lower vibration. The shaver is more than five times faster than the five-piston pneumatic scabbler at removing contamination from concrete. Because of this increased productivity, the shaver is 50% less costly to operate than baseline technologies. The DOE has successfully demonstrated the concrete shaver for decontaminating floors for free-release surveys prior to demolition work.

  16. Use of waste rubber as concrete additive.

    PubMed

    Chou, Liang Hsing; Lu, Chun-Ku; Chang, Jen-Ray; Lee, Maw Tien

    2007-02-01

    For resource reutilization, scrap tyres have long been investigated as an additive to concrete to form 'Rubcrete' for various applications and have shown promising results. However, the addition of rubber particles leads to the degradation of physical properties, particularly, the compressive strength of the concrete. In this study, a theoretical model was proposed to shed light on the mechanisms of decrease in compressive strength due to the addition of rubber particles as well as improvement in compressive strength through modification of particle surfaces. The literature suggests that the compressive strength can be improved by soaking the rubber particles in alkaline solution first to increase the inter-phase bonding between the rubber particles and cement. Instead, we discovered that the loss in compressive strength was due to local imperfections in the hydration of cement, induced by the addition of heterogeneous and hydrophobic rubber particles. Microscopic studies showed that the rubber particles disturbed the water transfer to create channels, which were prone to cracking and led to a loss in the compressive strength. Unexpectedly, no cracking was found along the surfaces of the rubber particles, indicating that the bonding strength between the rubber particles and cement phases was not the critical factor in determining the compressive strength. Therefore, a theoretical model was proposed to describe the water transfer in the Rubcrete specimens to explain the experimental data. In the model, the local water available for hydration (Q) is: Q = -A(slv)/6piv, where Q, A(slv), and v are mass flow rate (kg s(-1)), Hamaker constant (J), and dynamic viscosity (m2 s(-1)), respectively. By maximizing the quantity Q and, in turn, the Hamaker constant A(slv), the compressive strength could be improved. The Hamaker constant A(slv) for water film on rubber particle surfaces was smaller than that for the hydrated cement particles; the water transfer rate was lower in

  17. Nanomechanics and Multiscale Modeling of Sustainable Concretes

    NASA Astrophysics Data System (ADS)

    Zanjani Zadeh, Vahid

    The work presented in this dissertation is aimed to implement and further develop the recent advances in material characterization for porous and heterogeneous materials and apply these advances to sustainable concretes. The studied sustainable concretes were concrete containing fly ash and slag, Kenaf fiber reinforced concrete, and lightweight aggregate concrete. All these cement-based materials can be categorized as sustainable concrete, by achieving concrete with high strength while reducing cement consumption. The nanoindentation technique was used to infer the nanomechanical properties of the active hydration phases in bulk cement paste. Moreover, the interfacial transition zone (ITZ) of lightweight aggregate, normal aggregate, and Kenaf fibers were investigated using nanoindentation and imagine techniques, despite difficulties regarding characterizing this region. Samples were also tested after exposure to high temperature to evaluate the damage mechanics of sustainable concretes. It has been shown that there is a direct correlation between the nature of the nanoscale structure of a cement-based material with its macroscopic properties. This was addressed in two steps in this dissertation: (i) Nanoscale characterization of sustainable cementitious materials to understand the different role of fly ash, slag, lightweight aggregate, and Kenaf fibers on nanoscale (ii) Link the nanoscale mechanical properties to macroscale ones with multiscale modeling. The grid indentation technique originally developed for normal concrete was extended to sustainable concretes with more complex microstructure. The relation between morphology of cement paste materials and submicron mechanical properties, indentation modulus, hardness, and dissipated energy is explained in detail. Extensive experimental and analytical approaches were focused on description of the materials' heterogeneous microstructure as function of their composition and physical phenomenon. Quantitative

  18. SUSTAINABLE CONCRETE FOR WIND TURBINE FOUNDATIONS.

    SciTech Connect

    BERNDT,M.L.

    2004-06-01

    The use of wind power to generate electricity continues to grow, especially given commitments by various countries throughout the world to ensure that a significant percentage of energy comes from renewable sources. In order to meet such objectives, increasingly larger turbines with higher capacity are being developed. The engineering aspects of larger turbine development tend to focus on design and materials for blades and towers. However, foundations are also a critical component of large wind turbines and represent a significant cost of wind energy projects. Ongoing wind research at BNL is examining two areas: (a) structural response analysis of wind turbine-tower-foundation systems and (b) materials engineering of foundations. This work is investigating the dynamic interactions in wind turbine systems, which in turn assists the wind industry in achieving improved reliability and more cost efficient foundation designs. The results reported herein cover initial studies of concrete mix designs for large wind turbine foundations and how these may be tailored to reduce cost and incorporate sustainability and life cycle concepts. The approach taken was to investigate material substitutions so that the environmental, energy and CO{sub 2}-impact of concrete could be reduced. The use of high volumes of ''waste'' materials in concrete was examined. These materials included fly ash, blast furnace slag and recycled concrete aggregate. In addition, the use of steel fiber reinforcement as a means to improve mechanical properties and potentially reduce the amount of bar reinforcement in concrete foundations was studied. Four basic mixes were considered. These were: (1) conventional mix with no material substitutions, (2) 50% replacement of cement with fly ash, (3) 50% replacement of cement with blast furnace slag and (4) 25% replacement of cement with fly ash and 25% replacement with blast furnace slag. Variations on these mixes included the addition of 1% by volume steel

  19. Shrinkage deformation of cement foam concrete

    NASA Astrophysics Data System (ADS)

    Kudyakov, A. I.; Steshenko, A. B.

    2015-01-01

    The article presents the results of research of dispersion-reinforced cement foam concrete with chrysotile asbestos fibers. The goal was to study the patterns of influence of chrysotile asbestos fibers on drying shrinkage deformation of cement foam concrete of natural hardening. The chrysotile asbestos fiber contains cylindrical fiber shaped particles with a diameter of 0.55 micron to 8 microns, which are composed of nanostructures of the same form with diameters up to 55 nm and length up to 22 microns. Taking into account the wall thickness, effective reinforcement can be achieved only by microtube foam materials, the so- called carbon nanotubes, the dimensions of which are of power less that the wall pore diameter. The presence of not reinforced foam concrete pores with perforated walls causes a decrease in its strength, decreases the mechanical properties of the investigated material and increases its shrinkage. The microstructure investigation results have shown that introduction of chrysotile asbestos fibers in an amount of 2 % by weight of cement provides the finely porous foam concrete structure with more uniform size closed pores, which are uniformly distributed over the volume. This reduces the shrinkage deformation of foam concrete by 50%.

  20. Compressive strength of dune sand reinforced concrete

    NASA Astrophysics Data System (ADS)

    Mohammed, Mani; Abdelouahed, Kriker; Allaoua, Belferrag

    2017-02-01

    Many areas of south Algeria suffer from the problem of accumulation of sand on constructions. In fact, the phenomenon of sand silting causes technical and economical problems. Besides, these areas and other regions in Algeria suffer from the problem of unavailability of suitable sand for building. The use of dune sand offers an alternative solution for construction. In the same context, many researches confirm the possibility of using dune sand in the composition of concrete. In this paper, concrete made with dune sand was studied. For correction of the granulometry of dune sand by river sand, the rates of 50% DS+50% RS and 40% DS+60% RS were used. Also, two types of fibers were used, with 45 and 30 mm lengths, and diameters of 1 and 0.5 mm respectively. The percentage of the used fibers in the sand concrete was 1% and 1.5%. In this work an improvement of the compressive strength for the metal fibers reinforced sand concrete compared to plain concrete was obtained.

  1. Micromechanical Modeling of Concrete at Early Age

    NASA Astrophysics Data System (ADS)

    Tuleubekov, Kairat

    The focus of this research is a micromechanical characterization of Portland cement concrete at early age (less than 28 days). Concrete's viscoelastic properties change significantly at early age due to solidification of its matrix component. Bazant's solidification theory models concrete as a material solidifying in time. This approach is generalized to a three-dimensional characterization of a composite material with a solidifying matrix and elastic inclusions. An integral constitutive relationship was obtained using a generalized correspondence principle and homogenization techniques for elastic composite materials. In light of this approach, effective creep properties of composite spherical assemblage with an aging matrix are obtained. In addition, the elastic Hashin-Monteiro model is generalized to account for the effect of the interfacial transition zone properties on concrete creep. An effective computational platform was developed to evaluate operator expressions in order to obtain relaxation and creep functions numerically. Through numerical examples, it is shown that triaxial generalization of Bazant's solidification model enables robust and computationally efficient prediction of creep deformations in Portland cement concrete.

  2. Boric Acid Corrosion of Concrete Rebar

    NASA Astrophysics Data System (ADS)

    Pabalan, R. T.; Yang, L.; Chiang, K.–T.

    2013-07-01

    Borated water leakage through spent fuel pools (SFPs) at pressurized water reactors is a concern because it could cause corrosion of reinforcement steel in the concrete structure and compromise the integrity of the structure. Because corrosion rate of carbon steel in concrete in the presence of boric acid is lacking in published literature and available data are equivocal on the effect of boric acid on rebar corrosion, corrosion rate measurements were conducted in this study using several test methods. Rebar corrosion rates were measured in (i) borated water flowing in a simulated concrete crack, (ii) borated water flowing over a concrete surface, (iii) borated water that has reacted with concrete, and (iv) 2,400 ppm boric acid solutions with pH adjusted to a range of 6.0 to 7.7. The corrosion rates were measured using coupled multielectrode array sensor (CMAS) and linear polarization resistance (LPR) probes, both made using carbon steel. The results indicate that rebar corrosion rates are low (~1 μm/yr or less)when the solution pH is ~7.1 or higher. Below pH ~7.1, the corrosion rate increases with decreasing pH and can reach ~100 μm/yr in solutions with pH less than ~6.7. The threshold pH for carbon steel corrosion in borated solution is between 6.8 and 7.3.

  3. Predicting the remaining service life of concrete

    SciTech Connect

    Clifton, J.F.

    1991-11-01

    Nuclear power plants are providing, currently, about 17 percent of the U.S. electricity and many of these plants are approaching their licensed life of 40 years. The U.S. Nuclear Regulatory Commission and the Department of Energy`s Oak Ridge National Laboratory are carrying out a program to develop a methodology for assessing the remaining safe-life of the concrete components and structures in nuclear power plants. This program has the overall objective of identifying potential structural safety issues, as well as acceptance criteria, for use in evaluations of nuclear power plants for continued service. The National Institute of Standards and Technology (NIST) is contributing to this program by identifying and analyzing methods for predicting the remaining life of in-service concrete materials. This report examines the basis for predicting the remaining service lives of concrete materials of nuclear power facilities. Methods for predicting the service life of new and in-service concrete materials are analyzed. These methods include (1) estimates based on experience, (2) comparison of performance, (3) accelerated testing, (4) stochastic methods, and (5) mathematical modeling. New approaches for predicting the remaining service lives of concrete materials are proposed and recommendations for their further development given. Degradation processes are discussed based on considerations of their mechanisms, likelihood of occurrence, manifestations, and detection. They include corrosion, sulfate attack, alkali-aggregate reactions, frost attack, leaching, radiation, salt crystallization, and microbiological attack.

  4. Investigation of Radiation Attenuation Properties for Baryte Concrete

    NASA Astrophysics Data System (ADS)

    Abdo, A. El-Sayed; Kansouh, W. A.; Megahid, R. M.

    2002-12-01

    In the present work the authors have studied the attenuation properties of baryte concrete as a biological shield for nuclear power plants, particle accelerators, research reactors, laboratory hot cells and different radiation sources. Investigation has been performed by measuring the transmitted fast neutron and gamma ray spectra through cylindrical samples of baryte concrete (ρ=3.49 g\\cdotcm-3). A reactor-collimated beam and neutron-gamma spectrometer with stilbene scintillator were used during measurements. A pulse shape discriminating technique based on zero cross over method was used to discriminate between neutron and gamma pulses. Removal cross-section ΣR,eff and total attenuation coefficient μeff of neutrons and gamma rays were evaluated from the obtained results. Also, slow neutron fluxes have been measured using a collimated reactor beam and BF3 counter, where the macroscopic cross section Σ(En) has been evaluated using the attenuation relation. The total macroscopic cross sections ΣT(En) and total attenuation coefficient μ(Eg) of neutrons and gamma rays have been calculated based on the database cross sections. Also, the total mass attenuation coefficient μeff(Eg)/ρ and μ(Eg)/ρ of gamma ray have been estimated and calculated using the measured results and XCOM code respectively. Measured and calculated results were compared and a reasonable agreement was found.

  5. Flow conditions of fresh mortar and concrete in different pipes

    SciTech Connect

    Jacobsen, Stefan; Haugan, Lars; Hammer, Tor Arne; Kalogiannidis, Evangelos

    2009-11-15

    The variation in fresh concrete flow rate over the pipe cross section was investigated on differently coloured and highly flowable concrete mixes flowing through pipes of different materials (rubber, steel, acryl). First, uncoloured (gray) concrete was poured through the pipe and the pipe blocked. Similar but coloured (black) concrete was then poured into the pipe filled with gray concrete, flowing after the gray concrete for a while before being blocked and hardened. The advance of the colouring along the pipe wall (showing boundary flow rate) was observed on the moulded concrete surface appearing after removing the pipe from the hardened concrete. The shapes of the interfaces between uncoloured and coloured concrete (showing variation of flow rate over the pipe cross section) were observed on sawn surfaces of concrete half cylinders cut along the length axes of the concrete-filled pipe. Flow profiles over the pipe cross section were clearly seen with maximum flow rates near the centre of the pipe and low flow rate at the pipe wall (typically rubber pipe with reference concrete without silica fume and/or stabilizers). More plug-shaped profiles, with long slip layers and less variation of flow rate over the cross section, were also seen (typically in smooth acrylic pipes). Flow rate, amount of concrete sticking to the wall after flow and SEM-images of pipe surface roughness were observed, illustrating the problem of testing full scale pumping.

  6. Concrete Waste Recycling Process for High Quality Aggregate

    SciTech Connect

    Ishikura, Takeshi; Fujii, Shin-ichi

    2008-01-15

    Large amount of concrete waste generates during nuclear power plant (NPP) dismantling. Non-contaminated concrete waste is assumed to be disposed in a landfill site, but that will not be the solution especially in the future, because of decreasing tendency of the site availability and natural resources. Concerning concrete recycling, demand for roadbeds and backfill tends to be less than the amount of dismantled concrete generated in a single rural site, and conventional recycled aggregate is limited of its use to non-structural concrete, because of its inferior quality to ordinary natural aggregate. Therefore, it is vital to develop high quality recycled aggregate for general uses of dismantled concrete. If recycled aggregate is available for high structural concrete, the dismantling concrete is recyclable as aggregate for industry including nuclear field. Authors developed techniques on high quality aggregate reclamation for large amount of concrete generated during NPP decommissioning. Concrete of NPP buildings has good features for recycling aggregate; large quantity of high quality aggregate from same origin, record keeping of the aggregate origin, and little impurities in dismantled concrete such as wood and plastics. The target of recycled aggregate in this development is to meet the quality criteria for NPP concrete as prescribed in JASS 5N 'Specification for Nuclear Power Facility Reinforced Concrete' and JASS 5 'Specification for Reinforced Concrete Work'. The target of recycled aggregate concrete is to be comparable performance with ordinary aggregate concrete. The high quality recycled aggregate production techniques are assumed to apply for recycling for large amount of non-contaminated concrete. These techniques can also be applied for slightly contaminated concrete dismantled from radiological control area (RCA), together with free release survey. In conclusion: a technology on dismantled concrete recycling for high quality aggregate was developed

  7. An elastoplastic damage constitutive model for concrete

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Lin, Gao; Zhong, Hong

    2013-04-01

    An elastoplastic damage constitutive model to simulate nonlinear behavior of concrete is presented. Similar to traditional plastic theory, the irreversible deformation is modeled in effective stress space. In order to better describe different stiffness degradation mechanisms of concrete under tensile and compressive loading conditions, two damage variables, i.e., tension and compression are introduced, to quantitatively evaluate the degree of deterioration of concrete structure. The rate dependent behavior is taken into account, and this model is derived firmly in the framework of irreversible thermodynamics. Fully implicit backward-Euler algorithm is suggested to perform constitutive integration. Numerical results of the model accord well with the test results for specimens under uniaxial tension and compression, biaxial loading and triaxial loading. Failure processes of double-edge-notched (DEN) specimen are also simulated to further validate the proposed model.

  8. Concrete decontamination by electro-hydraulic scabbling

    SciTech Connect

    Goldfarb, V.; Gannon, R.

    1995-10-01

    Textron Defense Systems (TDS) is developing an electro-hydraulic device that has the potential for faster, safer, and less expensive scabbling of contaminated concrete surfaces. In the device, shock waves and cavitating bubbles are produced in water by the electric pulses, and the direct and reflected shock waves impinging on the concrete surface result in the crushing and cracking of the concrete. Pulse energy, frequency, and traverse speed control the depth of the scabbling action. Performance thus far has demonstrated the capability of a prototype unit to process a swath 24 inches wide, up to 3/4 inch deep at a linear velocity of up to 6 feet per hour, i.e., at a scabbling rate of 12 sq. ft. per hour.

  9. The feasibility of recycling contaminated concrete

    SciTech Connect

    Ayers, K.W,; Corroon, W.; Parker, F.L.

    1999-07-01

    The changing mission of the Department of Energy along with the aging of many of its facilities has resulted in renewed emphasis on decontaminating and decommissioning surplus structures. Currently DOE is decontaminating some concrete and sending the clean material to C and D disposal facilities. In other instance, DOE is sending contaminated concrete to LLW disposal facilities. This paper examines the economic feasibility of decontaminating the concrete and recycling the rubble as clean aggregate. A probabilistic cost model was used to examine six potential recycling and disposal scenarios. The model predicted potential costs saving across the DOE complex of nearly one billion dollars. The ability of local markets to assimilate the recycled material was estimated for Washington, Idaho, Tennessee, New Mexico, and South Carolina. The relationships between a number of the economic model's variables were examined to develop operating ranges for initial managerial evaluation of recycling.

  10. Concrete Slump Classification using GLCM Feature Extraction

    NASA Astrophysics Data System (ADS)

    Andayani, Relly; Madenda, Syarifudin

    2016-05-01

    Digital image processing technologies have been widely applies in analyzing concrete structure because the accuracy and real time result. The aim of this study is to classify concrete slump by using image processing technique. For this purpose, concrete mix design of 30 MPa compression strength designed with slump of 0-10 mm, 10-30 mm, 30-60 mm, and 60-180 mm were analysed. Image acquired by Nikon Camera D-7000 using high resolution was set up. In the first step RGB converted to greyimage than cropped to 1024 x 1024 pixel. With open-source program, cropped images to be analysed to extract GLCM feature. The result shows for the higher slump contrast getting lower, but higher correlation, energy, and homogeneity.

  11. Nuclear Concrete Materials Database Phase I Development

    SciTech Connect

    Ren, Weiju; Naus, Dan J

    2012-05-01

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

  12. Nonlinear fracture of concrete and ceramics

    NASA Technical Reports Server (NTRS)

    Kobayashi, Albert S.; Du, Jia-Ji; Hawkins, Niel M.; Bradt, Richard C.

    1989-01-01

    The nonlinear fracture process zones in an impacted unnotched concrete bend specimen, a prenotched ceramic bend specimen, and an unnotched ceramic/ceramic composite bend specimen were estimated through hybrid experimental numerical analysis. Aggregate bridging in concrete, particulate bridging in ceramics, and fiber bridging in ceramic/ceramic composite are modeled by Barenblatt-type cohesive zones which are incorporated into the finite-element models of the bend specimens. Both generation and propagation analyses are used to estimate the distribution of crack closure stresses in the nonlinear fracture process zones. The finite-element models are then used to simulate fracture tests consisting of rapid crack propagation in an impacted concrete bend specimen, and stable crack growth and strain softening in a ceramic and ceramic/ceramic composite bend specimens.

  13. Innovative technology summary report: Concrete grinder

    SciTech Connect

    1998-09-01

    The Flex concrete grinder is a lightweight, hand-held concrete and coating removal system used for decontaminating or stripping concrete surfaces. The US Department of Energy has successfully demonstrated it for decontaminating walls and floors for free release surveys prior to demolition work. The grinder is an electric-powered tool with a vacuum port for dust extraction and a diamond grinding wheel. The grinder is suitable for flat or slightly curved surfaces and results in a smooth surface, which makes release surveys more reliable. The grinder is lightweight and produces very little vibration, thus reducing worker fatigue. The grinder is more efficient than traditional baseline, tools at removing contamination from concrete surfaces (more than four times faster than hand-held pneumatic scabbling and scaling tools). Grinder consumables (i.e., replacement diamond grinding wheel) are more expensive than the replacement carbide parts for the scaler and scabbler. However, operating costs are outweighed by the lower purchase price of the grinder (50% of the price of the baseline scaler and 8% of the price of the baseline scabbler). Overall, the concrete grinder is an attractive alternative to traditional scabbling and scaling pneumatic tools. To this end, in July 1998, the outer rod room exposed walls of the Safe Storage Enclosure (SSE), an area measuring approximately 150 m{sup 2}, may be decontaminated with the hand-held grinder. This concrete grinder technology was demonstrated for the first time at the DOE`s Hanford Site. Decontamination of a sample room walls was performed at the C Reactor to free release the walls prior to demolition. The demonstration was conducted by onsite D and D workers, who were instructed by the vendor prior to and during the demonstration.

  14. Estimating crack growth in temperature damaged concrete

    NASA Astrophysics Data System (ADS)

    Recalde, Juan Jose

    2009-12-01

    Evaluation of the structural condition of deteriorated concrete infrastructure and evaluation of new sustainable cementitious materials require an understanding of how the material will respond to applied loads and environmental exposures. A fundamental understanding of how microstructural changes in these materials relate to changes in mechanical properties and changes in fluid penetrability is needed. The ability to provide rapid, inexpensive assessment of material characteristics and relevant engineering properties is valuable for decision making and asset management purposes. In this investigation, the effects of changes in dynamic elastic properties with water content and fluid penetrability properties before and after a 300°C exposure were investigated based on estimates of the crack density parameter from dry and saturated cracked media. The experimental and analytical techniques described in this dissertation allow calculation of a value for the crack density parameter using nondestructive determination of wet and dry dynamic shear modulus of relatively thin disks. The techniques were used to compare a conventional concrete mixture to several mixtures with enhanced sustainability characteristics. The three enhanced sustainable materials investigated were a very high fly ash mixture, a magnesium phosphate cement based mortar, and a magnesium phosphate cement based concrete, and were compared to a conventional concrete mixture. The analysis provided both quantitative assessment of changes with high temperature damage and autogenous healing, and estimates of changes in mean crack trace lengths. The results showed that water interaction, deterioration due to damage, and autogenous healing recovery were different for the magnesium phosphate cement based mixtures than the portland cement based concrete mixtures. A strong correlation was found between log-transformed Air Permeability Index, dynamic shear modulus, and crack density parameter. The findings imply

  15. TRANSPORT THROUGH CRACKED CONCRETE: LITERATURE REVIEW

    SciTech Connect

    Langton, C.

    2012-05-11

    Concrete containment structures and cement-based fills and waste forms are used at the Savannah River Site to enhance the performance of shallow land disposal systems designed for containment of low-level radioactive waste. Understanding and measuring transport through cracked concrete is important for describing the initial condition of radioactive waste containment structures at the Savannah River Site (SRS) and for predicting performance of these structures over time. This report transmits the results of a literature review on transport through cracked concrete which was performed by Professor Jason Weiss, Purdue University per SRR0000678 (RFP-RQ00001029-WY). This review complements the NRC-sponsored literature review and assessment of factors relevant to performance of grouted systems for radioactive waste disposal. This review was performed by The Center for Nuclear Waste Regulatory Analyses, San Antonio, TX, and The University of Aberdeen, Aberdeen Scotland and was focused on tank closure. The objective of the literature review on transport through cracked concrete was to identify information in the open literature which can be applied to SRS transport models for cementitious containment structures, fills, and waste forms. In addition, the literature review was intended to: (1) Provide a framework for describing and classifying cracks in containment structures and cementitious materials used in radioactive waste disposal, (2) Document the state of knowledge and research related to transport through cracks in concrete for various exposure conditions, (3) Provide information or methodology for answering several specific questions related to cracking and transport in concrete, and (4) Provide information that can be used to design experiments on transport through cracked samples and actual structures.

  16. 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.

  17. Evaluation of concrete recycling system efficiency for ready-mix concrete plants.

    PubMed

    Vieira, Luiz de Brito Prado; Figueiredo, Antonio Domingues de

    2016-10-01

    The volume of waste generated annually in concrete plants is quite large and has important environmental and economic consequences. The use of fresh concrete recyclers is an interesting way for the reuse of aggregates and water in new concrete production. This paper presents a study carried out for over one year by one of the largest ready-mix concrete producers in Brazil. This study focused on the evaluation of two recyclers with distinct material separation systems, herein referred to as drum-type and rotary sieve-type equipment. They were evaluated through characterization and monitoring test programs to verify the behaviour of recovered materials (aggregates, water, and slurry). The applicability of the recovered materials (water and aggregates) was also evaluated in the laboratory and at an industrial scale. The results obtained with the two types of recyclers used were equivalent and showed no significant differences. The only exception was in terms of workability. The drum-type recycler generated fewer cases that required increased pumping pressure. The analysis concluded that the use of untreated slurry is unfeasible because of its intense negative effects on the strength and workability of concrete. The reclaimed water, pre-treated to ensure that its density is less than 1.03g/cm(3), can be used on an industrial scale without causing any harm to the concrete. The use of recovered aggregates consequently induces an increase in water demand and cement consumption to ensure the workability conditions of concrete that is proportional to the concrete strength level. Therefore, the viability of their use is restricted to concretes with characteristic strengths lower than 25MPa.

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

    SciTech Connect

    Winkel, B.V.

    1995-03-03

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

  19. Comparative performance of various smart aggregates during strength gain and damage states of concrete

    NASA Astrophysics Data System (ADS)

    Jothi Saravanan, T.; Balamonica, K.; Bharathi Priya, C.; Likhith Reddy, A.; Gopalakrishnan, N.

    2015-08-01

    Information regarding the early strength gain of fresh concrete determines the time for the removal of form work and the transfer of pre-stressing forces for pre-stressed concrete. An ultrasonic based non-destructive evaluation of early strength gain may not work for concrete in fluid and semi-solid phases. A possible alternative is a lead zirconate titanate (PZT)-based smart aggregate embedded in concrete, which can evaluate the micro-structural and rheological properties right from the fluid phase. A set of five smart aggregates embedded in a concrete cube were investigated for their suitability to evaluate electromechanical impedance (EMI) signatures. Cubes were loaded to failure and the EMI during progressive strength loss under compressive loads was studied. To show the generalized applicability of this, experimental results for the performance of typical smart aggregates on a larger specimen, namely a concrete beam, are also discussed. Different statistical metrics were examined computationally on a three peak admittance curve with a parametric variation of stiffness, damping and simple scaling. The root mean square deviation (RMSD), mean absolute percentage deviation (MAPD), cross correlation (CC) and modified cross correlation (MCC) were investigated, in addition to the rate of change of the RMSD. Variations between the reference and modified states were studied. Both stiffness and mass gains occur for the smart aggregates, resulting in an increase or decrease of frequency and amplitude peaks due to progressive C-S-H gel formation. The trend of increasing stiffness and the consequent rightward shift of the resonant peaks and decrease of damping, with the consequent upward shift of amplitudes that happens during curing and strength gain, was observed to be reversed during the application of damaging loads.

  20. Lasers for the radioactive decontamination of concrete

    SciTech Connect

    Cannon, N.S.; Flesher, D.J.

    1993-10-01

    The use of lasers for removing radioactive contamination from concrete surfaces is being investigated at the US Department of Energy`s Hanford Site. A major advantage of a laser decontamination process is that no additional waste is generated. Test results using 50- and 600-W YAG (yttrium-aluminum-garnet) lasers have been extrapolated to more powerful commercially available units. The minimum removal rate for concrete in air is estimated at 420 cm{sup 2}/h (0.45 ft{sup 2}/h) to a depth of 0.64 cm (0.25 in.); underwater rates would be considerably reduced.

  1. Advanced Numerical Model for Irradiated Concrete

    SciTech Connect

    Giorla, Alain B.

    2015-03-01

    In this report, we establish a numerical model for concrete exposed to irradiation to address these three critical points. The model accounts for creep in the cement paste and its coupling with damage, temperature and relative humidity. The shift in failure mode with the loading rate is also properly represented. The numerical model for creep has been validated and calibrated against different experiments in the literature [Wittmann, 1970, Le Roy, 1995]. Results from a simplified model are shown to showcase the ability of numerical homogenization to simulate irradiation effects in concrete. In future works, the complete model will be applied to the analysis of the irradiation experiments of Elleuch et al. [1972] and Kelly et al. [1969]. This requires a careful examination of the experimental environmental conditions as in both cases certain critical information are missing, including the relative humidity history. A sensitivity analysis will be conducted to provide lower and upper bounds of the concrete expansion under irradiation, and check if the scatter in the simulated results matches the one found in experiments. The numerical and experimental results will be compared in terms of expansion and loss of mechanical stiffness and strength. Both effects should be captured accordingly by the model to validate it. Once the model has been validated on these two experiments, it can be applied to simulate concrete from nuclear power plants. To do so, the materials used in these concrete must be as well characterized as possible. The main parameters required are the mechanical properties of each constituent in the concrete (aggregates, cement paste), namely the elastic modulus, the creep properties, the tensile and compressive strength, the thermal expansion coefficient, and the drying shrinkage. These can be either measured experimentally, estimated from the initial composition in the case of cement paste, or back-calculated from mechanical tests on concrete. If some

  2. Prediction of creep of polymer concrete

    SciTech Connect

    Khristova, Yu.; Aniskevich, K.

    1995-11-01

    We studied the applicability of the phenomenological approach to the prediction of long-time creep of polymer concrete consisting of polyester binder with diabase filler and diabase aggregate. We discovered that the principles of temperature-time analogy, of moisture-time analogy, and of temperature-moisture-time analogy are applicable to the description of the diagrams of short-time creep and to the prediction of long-time creep of polymer concrete at different temperatures and constant moisture content of the material.

  3. Use of cactus in mortars and concrete

    SciTech Connect

    Chandra, S.; Eklund, L.; Villarreal, R.R.

    1998-01-01

    Natural polymers have been used in ancient times to improve the durability of lime-based mortars and concretes. The natural polymers used were locally available. In this work, cactus extract from Mexico has been tested in a Portland cement mortar. It is seen that cactus extract increases the plasticity of the mortar and improves water absorption and freeze-salt resistance. Calcium hydroxide produced by Portland cement hydration interacts with the components of cactus extract, polysaccharides or proteins, and forms complexes. It affects the crystallization process. Painting of the concrete with this extract has also shown improved water resistance.

  4. Concrete dam on the Bratsk hydroelectric station

    SciTech Connect

    Solov'eva, Z.I.

    1988-07-01

    The Bratsk concrete dam was designed and constructed with a sufficient degree of reliability. Settlement of the dam together with the powerhouse developed uniformly under the entire foundation. Two irreversible processes causing aging of the dam have been established by operating observations: leaching of the concrete and decompression of the contact zone of the foundation near the upstream face of the powerhouse sections. The decompression is due to the fact that the powerhouse sections are lighter than the spillway sections. At the present level this process can only be slowed by the combined use of grouting and drainage unloading.

  5. Detection Of Concrete Deterioration By Staining

    DOEpatents

    Guthrie, Jr., George D.; Carey, J. William

    1999-09-21

    A method using concentrated aqueous solutions of sodium cobaltinitrite and a rhodamine dye is described which can be used to identify concrete that contains gels formed by the alkali-silica reaction (ASR), and to identify degraded concrete which results in a porous or semi-permeable paste due to carbonation or leaching. These solutions present little health or environmental risk, are readily applied, and rapidly discriminate between two chemically distinct gels; K-rich, Na--K--Ca--Si gels are identified by yellow staining, and alkali-poor, Ca--Si gels are identified by pink staining.

  6. Repair and rehabilitation with polymer concrete

    SciTech Connect

    Kukacka, L.E.

    1988-09-01

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

  7. Occurrence and morphology of carbonate concretions in the Beulah-Zap coal bed, Williston basin, North Dakota

    USGS Publications Warehouse

    Keighin, C.W.M.; Flores, R.M.; Rowland, T.

    1996-01-01

    Carbonate concretionary bodies were encountered during mining of the Beulah-Zap lignite seam in the Coteau Properties' Freedom mine, Mercer County, North Dakota. Preliminary studies show that areal and vertical distribution of the concretions are variable. All concretions examined are composed almost entirely of calcite. They occur as thin tabular bodies, as more or less elliptical forms, or as tear shaped bodies, and may occur individually or as clusters of buff-colored, poorly consolidated to solidly crystalline material. The carbonate masses vary in size from a few millimeters to tens of centimeters. Bedding in the lignite may display some compactional folding over dense spheroidal to elliptical concretions, indicating formation of the concretions prior to compaction. Internal morphology of the concretions is complex, and includes cone-in-cone structure, cross-cutting calcite veinlets, and multiple generations of calcite. Carbon isotope values suggest the concretions are composed of biogenic carbonate, probably related to early diagenesis and decomposition of organic matter (peat); oxygen isotope values are light, and consistent with a freshwater origin.

  8. Strength Design of Reinforced Concrete Hydraulic Structures. Report 9. Analysis and Design of Reinforced Concrete Conduits

    DTIC Science & Technology

    1989-06-01

    American Concrete Pipe Association ( ACPA ) Approach 15. The "indirect method" of the ACPA (2-5) follows the D-load method of ASTM, but accounts for...been used on many occasions and is currently being converted from main frame to PC use. ACPA intends to distribute this program to designers, so there...Philadelphia, Pa., 1984. 2-5. American Concrete Pipe Association, "Concrete Pipe Handbook", Chap.4, ACPA , Vienna, Va. 1988. 2-6. Olander, H.C., U.S

  9. 31. VIEW OF CONCRETE SLAB AT WEST ENTRANCE OF WALKWAY. ...

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

    31. VIEW OF CONCRETE SLAB AT WEST ENTRANCE OF WALKWAY. '1944 JOE LANDETA' SCRATCHED INTO FRESH CONCRETE. March 1987 - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ

  10. DETAIL OF THE CONCRETE PAVING BLOCKS AT THE REAR OF ...

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

    DETAIL OF THE CONCRETE PAVING BLOCKS AT THE REAR OF THE BUILDING. SHOWING THE PIVOTING METAL LOOP RECESSED INTO THE CONCRETE. VIEW FACING EAST. - Hickam Field, Officers' Housing Type A, 601 Boquet Boulevard, Honolulu, Honolulu County, HI

  11. Application features of additives based on metakaolin in concrete

    NASA Astrophysics Data System (ADS)

    Kirsanova, A. A.; Kramar, L. Y.

    2015-01-01

    The present paper is devoted to the influence of additives based on metakaolin (U- YF, UM-YF and YF-UMD) on speed concrete strength development in the early stages of concrete hardening, as well as the strength increase in 28 days. The authors have proved that metakaolin gauging in concrete should not exceed 3%. Introduction of 5% of metakaolin or more entails the fault in concrete strength in the later stages of concrete hardening and decreases its resistance to the influence of sulfate and frosty environments. The most effective of the developed additives are UM-YF and UMD-YF which provide high sulfate and frost resistance to the concrete (up to 800 ... 1000 cycles). The above mentioned influence of additives on concrete properties is connected with an intended formation of structure of the cement matrix of concrete that is resistant to various aggressive environments.

  12. 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.

  13. Cohesive fracture model for functionally graded fiber reinforced concrete

    SciTech Connect

    Park, Kyoungsoo; Paulino, Glaucio H.; Roesler, Jeffery

    2010-06-15

    A simple, effective, and practical constitutive model for cohesive fracture of fiber reinforced concrete is proposed by differentiating the aggregate bridging zone and the fiber bridging zone. The aggregate bridging zone is related to the total fracture energy of plain concrete, while the fiber bridging zone is associated with the difference between the total fracture energy of fiber reinforced concrete and the total fracture energy of plain concrete. The cohesive fracture model is defined by experimental fracture parameters, which are obtained through three-point bending and split tensile tests. As expected, the model describes fracture behavior of plain concrete beams. In addition, it predicts the fracture behavior of either fiber reinforced concrete beams or a combination of plain and fiber reinforced concrete functionally layered in a single beam specimen. The validated model is also applied to investigate continuously, functionally graded fiber reinforced concrete composites.

  14. 7. Detail view of reinforced concrete archrings comprising dam's upstream ...

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

    7. Detail view of reinforced concrete arch-rings comprising dam's upstream face. Impressions of the wooden formwork used in construction are visible in the concrete. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

  15. 1. VIEW SHOWING REMAINS OF CAMOUFLAGE COVERING CONCRETE FOOTING FOR ...

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

    1. VIEW SHOWING REMAINS OF CAMOUFLAGE COVERING CONCRETE FOOTING FOR A GENERATOR PAD - Fort Cronkhite, Anti-Aircraft Battery No. 1, Concrete Footing-Generator Pad, Wolf Road, Sausalito, Marin County, CA

  16. Effect of exposure delay of concrete into aggressive environment

    NASA Astrophysics Data System (ADS)

    Abimouloud, Youcef; Kriker, Abdelouahed

    2016-07-01

    Some regions in the world suffered since several years from environmental problems such as underground level water rising. Water table effects durability of concrete implantation in the underground by the ease of luckless chemical elements ingress mainly through concrete the foundations of structures such as sulfate, chloride, and acids. For that reason a lot of foundations structures were made with SRPC (sulfate resisting Portland cement). This study is a contribution to assess the effect of exposure delay of concrete into aggressive fields, as a kind of cure which protects concrete from aggressive factors and allows it to acquire the needed strength. The study has shown that concrete exposure delay into aggressive environment is not a kind of cure mainly for concrete made with SRPC. Concrete with SRPC immediately exposed to aggressive environment shows a better mechanical resistance than concrete that has known exposure delay.

  17. Small Displacement Coupled Analysis of Concrete Gravity Dam Foundations: Static and Dynamic Conditions

    NASA Astrophysics Data System (ADS)

    Farinha, Maria Luísa Braga; Azevedo, Nuno Monteiro; Candeias, Mariline

    2017-02-01

    The explicit formulation of a small displacement model for the coupled hydro-mechanical analysis of concrete gravity dam foundations based on joint finite elements is presented. The proposed coupled model requires a thorough pre-processing stage in order to ensure that the interaction between the various blocks which represent both the rock mass foundation and the dam is always edge to edge. The mechanical part of the model, though limited to small displacements, has the advantage of allowing an accurate representation of the stress distribution along the interfaces, such as rock mass joints. The hydraulic part and the mechanical part of the model are fully compatible. The coupled model is validated using a real case of a dam in operation, by comparison of the results with those obtained with a large displacement discrete model. It is shown that it is possible to assess the sliding stability of concrete gravity dams using small displacement models under both static and dynamic conditions.

  18. Patio Stone Project Gives Students a Concrete Learning Experience

    ERIC Educational Resources Information Center

    Fitzgerald, Mike

    2005-01-01

    In this article, the author presents an overview of concrete as a building material and as an example of a particle composite, and discusses the origins of concrete in ancient Rome. He then describes an activity in which students can cast a concrete patio stone. Students can apply the technological design process, as well as the elements of…

  19. 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

  20. 13. VIEW EAST OF NORTHEAST CONCRETE PIER AND WING WALL. ...

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

    13. VIEW EAST OF NORTHEAST CONCRETE PIER AND WING WALL. NOTE DETAIL OF 1920 CONCRETE PIER WHICH WAS CAST IN PLACE AROUND A VERTICAL POST, AND STOP LOCK NOTCH TO LEFT OF CONCRETE PIER. - Chesapeake & Ohio Canal, Conococheague Creek Aqueduct, Milepost 99.80, Williamsport, Washington County, MD

  1. 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...

  2. 7 CFR 3201.36 - Concrete and asphalt release fluids.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Concrete and asphalt release fluids. 3201.36 Section... PROCUREMENT Designated Items § 3201.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete...

  3. 7 CFR 3201.65 - Concrete and asphalt cleaners.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Concrete and asphalt cleaners. 3201.65 Section 3201... PROCUREMENT Designated Items § 3201.65 Concrete and asphalt cleaners. (a) Definition. Chemicals used in concrete etching as well as to remove petroleum-based soils, lubricants, paints, mastics, organic...

  4. 75 FR 4104 - Prestressed Concrete Steel Wire Strand From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-26

    ... COMMISSION Prestressed Concrete Steel Wire Strand From China AGENCY: United States International Trade... concrete steel wire strand, provided for in subheading 7312.10.30 of the Harmonized Tariff Schedule of the... suitable for use in prestressed concrete (both pre-tensioned and post- tensioned) applications. The...

  5. 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...

  6. 7 CFR 2902.36 - Concrete and asphalt release fluids.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Concrete and asphalt release fluids. 2902.36 Section... PROCUREMENT Designated Items § 2902.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete...

  7. 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...

  8. 7 CFR 3201.36 - Concrete and asphalt release fluids.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Concrete and asphalt release fluids. 3201.36 Section... PROCUREMENT Designated Items § 3201.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete...

  9. 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...

  10. 7 CFR 3201.65 - Concrete and asphalt cleaners.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Concrete and asphalt cleaners. 3201.65 Section 3201... PROCUREMENT Designated Items § 3201.65 Concrete and asphalt cleaners. (a) Definition. Chemicals used in concrete etching as well as to remove petroleum-based soils, lubricants, paints, mastics, organic...

  11. 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...

  12. 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...

  13. 7 CFR 3201.65 - Concrete and asphalt cleaners.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Concrete and asphalt cleaners. 3201.65 Section 3201... PROCUREMENT Designated Items § 3201.65 Concrete and asphalt cleaners. (a) Definition. Chemicals used in concrete etching as well as to remove petroleum-based soils, lubricants, paints, mastics, organic...

  14. 7 CFR 3201.36 - Concrete and asphalt release fluids.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Concrete and asphalt release fluids. 3201.36 Section... PROCUREMENT Designated Items § 3201.36 Concrete and asphalt release fluids. (a) Definition. Products that are designed to provide a lubricating barrier between the composite surface materials (e.g., concrete...

  15. 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...

  16. 75 FR 52490 - Track Safety Standards; Concrete Crossties

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-26

    ... Federal Railroad Administration 49 CFR Part 213 RIN 2130-AC01 Track Safety Standards; Concrete Crossties... promote the safety of railroad operations over track constructed with concrete crossties. In particular, FRA is proposing specific requirements for effective concrete crossties, for rail fastening...

  17. 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...

  18. 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...

  19. 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.

  20. Mathematical modeling of steel fiber concrete under dynamic impact

    NASA Astrophysics Data System (ADS)

    Belov, N. N.; Yugov, N. T.; Kopanitsa, D. G.; Kopanitsa, G. D.; Yugov, A. A.; Shashkov, V. V.

    2015-01-01

    This paper introduces a continuum mechanics mathematical model that describes the processes of deformation and destruction of steel-fiber-concrete under a shock wave impact. A computer modeling method was applied to study the processes of shock wave impact of a steel cylindrical rod and concrete and steel fiber concrete plates. The impact speeds were within 100-500 m/s.

  1. Corrosion in prestressed concrete: Pipes, piles, and decks

    SciTech Connect

    Szeliga, M.

    1995-12-31

    This is the first compilation or book focusing on prestressed concrete. It features 21 classic NACE papers on prestressed concrete piping, piles, bridge decks, and cathodic protection. It includes basic corrosion mechanisms of prestressed concrete structures with detailed case histories of corrosion failures and corrective measures.

  2. Aspects Concerning the Use of Recycled Concrete Aggregates

    NASA Astrophysics Data System (ADS)

    Robu, I.; Mazilu, C.; Deju, R.

    2016-11-01

    Natural aggregates (gravel and crushed) are essential non-renewable resources which are used for infrastructure works and civil engineering. Using recycled concrete aggregates (RCA) is a matter of high priority in the construction industry worldwide. This paper presents a study on the use of recycled aggregates, from a concrete of specified class, to acquire new cement concrete with different percentages of recycled aggregates.

  3. Intermediate-scale sodium-concrete reaction tests with basalt and limestone concrete

    SciTech Connect

    Hassberger, J.A.; Muhlestein, L.D.

    1981-01-01

    Ten tests were performed to investigate the chemical reactions and rate and extent of attack between sodium and basalt and limestone concretes. Test temperatures ranged from 510 to 870/sup 0/C (950 to 1600/sup 0/F) and test times from 2 to 24 hours. Sodium hydroxide was added to some of the tests to assess the impact of a sodium hydroxide-aided reaction on the overall penetration characteristics. Data suggest that the sodium penetration of concrete surfaces is limited. Penetration of basalt concrete in the presence of sodium hydroxide is shown to be less severe than attack by the metallic sodium alone. Presence of sodium hydroxide changes the characteristics of sodium penetration of limestone concrete, but no major differences in bulk penetration were observed as compared to penetration by metallic sodium.

  4. Assessing relationships among properties of demolished concrete, recycled aggregate and recycled aggregate concrete using regression analysis.

    PubMed

    Tam, Vivian W Y; Wang, K; Tam, C M

    2008-04-01

    Recycled demolished concrete (DC) as recycled aggregate (RA) and recycled aggregate concrete (RAC) is generally suitable for most construction applications. Low-grade applications, including sub-base and roadwork, have been implemented in many countries; however, higher-grade activities are rarely considered. This paper examines relationships among DC characteristics, properties of their RA and strength of their RAC using regression analysis. Ten samples collected from demolition sites are examined. The results show strong correlation among the DC samples, properties of RA and RAC. It should be highlighted that inferior quality of DC will lower the quality of RA and thus their RAC. Prediction of RAC strength is also formulated from the DC characteristics and the RA properties. From that, the RAC performance from DC and RA can be estimated. In addition, RAC design requirements can also be developed at the initial stage of concrete demolition. Recommendations are also given to improve the future concreting practice.

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

    PubMed

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

    2009-02-01

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

  6. Concrete Property and Radionuclide Migration Tests

    SciTech Connect

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

    2008-10-01

    The Waste Management Project provides safe, compliant, and cost-effective waste management services for the Hanford Site and the DOE Complex. Part of theses services includes safe disposal of LLW and MLLW at the Hanford Low-Level Waste Burial Grounds (LLBG) in accordance with the requirements listed in DOE Order 435.1, Radioactive Waste Management. To partially satisfy these requirements, a Performance Assessment (PA) analyses were completed and approved. DOE Order 435.1 also requires that continuing data collection be conducted to enhance confidence in the critical assumptions used in these analyses to characterize the operational features of the disposal facility that are relied upon to satisfy the performance objectives identified in the Order. One critical assumption is that concrete will frequently be used as waste form or container material to control and minimize the release of radionuclide constituents in waste into the surrounding environment. Data was collected to (1) quantify radionuclide migration through concrete materials similar to those used to encapsulate waste in the LLBG, (2) measure the properties of the concrete materials, especially those likely to influence radionuclide migration, and (3) quantify the stability of U-bearing solid phases of limited solubility in concrete.

  7. Training Guidelines. Operatives-Precast Concrete.

    ERIC Educational Resources Information Center

    Ceramics, Glass, and Mineral Products Industry Training Board, Harrow (England).

    This manual is intended to provide guidelines for firms in the precast concrete industry in planning their training programs particularly with reference to new entrants into the industry. Details for preparing training syllabuses for various job specifications are given--mould makers in timber, steel, and glass fiber; makers; finishers; site…

  8. Fractal characterization of fracture surfaces in concrete

    USGS Publications Warehouse

    Saouma, V.E.; Barton, C.C.; Gamaleldin, N.A.

    1990-01-01

    Fractal geometry is used to characterize the roughness of cracked concrete surfaces through a specially built profilometer, and the fractal dimension is subsequently correlated to the fracture toughness and direction of crack propagation. Preliminary results indicate that the fracture surface is indeed fractal over two orders of magnitudes with a dimension of approximately 1.20. ?? 1990.

  9. GPR measurements of attenuation in concrete

    SciTech Connect

    Eisenmann, David Margetan, Frank J. Pavel, Brittney

    2015-03-31

    Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

  10. Sulfur 'Concrete' for Lunar Applications - Environmental Considerations

    NASA Technical Reports Server (NTRS)

    Grugel, R. N.

    2008-01-01

    Commercial use of sulfur concrete on Earth is well established, particularly in corrosive, e.g., acid and salt, environments. Having found troilite (FeS) on the Moon raises the question of using extracted sulfur as a lunar construction material, an attractive alternative to conventional concrete as it does not require water. For the purpose of this Technical Memorandum, it is assumed that lunar ore is mined, refined, and the raw sulfur processed with appropriate lunar regolith to form, for example, bricks. With this stipulation, it is then noted that the viability of sulfur concrete in a lunar environment, which is characterized by lack of an atmosphere and extreme temperatures, is not well understood. The work presented here evaluates two sets of small sulfur concrete samples that have been prepared using JSC-1 lunar simulant as an aggregate addition. One set was subjected to extended periods in high vacuum to evaluate sublimation issues, and the other was cycled between room and liquid nitrogen temperatures to investigate their subsequent mechanical integrity. Results are presented from both investigations, discussed, and put into the context of the lunar environment.

  11. Improving Representational Competence with Concrete Models

    ERIC Educational Resources Information Center

    Stieff, Mike; Scopelitis, Stephanie; Lira, Matthew E.; DeSutter, Dane

    2016-01-01

    Representational competence is a primary contributor to student learning in science, technology, engineering, and math (STEM) disciplines and an optimal target for instruction at all educational levels. We describe the design and implementation of a learning activity that uses concrete models to improve students' representational competence and…

  12. Sulfur "Concrete" for Lunar Applications - Sublimation Concerns

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N.; Toutanji, Houssam

    2006-01-01

    Melting sulfur and mixing it with an aggregate to form "concrete" is commercially well established and constitutes a material that is particularly well-suited for use in corrosive environments. Discovery of the mineral troilite (FeS) on the moon poses the question of extracting the sulfur for use as a lunar construction material. This would be an attractive alternative to conventional concrete as it does not require water. However, the viability of sulfur concrete in a lunar environment, which is characterized by lack of an atmosphere and extreme temperatures, is not well understood. Here it is assumed that the lunar ore can be mined, refined, and the raw sulfur melded with appropriate lunar regolith to form, for example, bricks. This study evaluates pure sulfur and two sets of small sulfur concrete samples that have been prepared using JSC-1 lunar stimulant and SiO2 powder as aggregate additions. Each set was subjected to extended periods in a vacuum environment to evaluate sublimation issues. Results from these experiments are presented and discussed within the context of the lunar environment.

  13. Anodes for cathodic protection of reinforced concrete

    SciTech Connect

    S.J. Bullard; B.S. Covino, Jr.; S.D. Cramer; G.R. Holcomb; J.H. Russell

    2000-03-01

    Consumable anodes were evaluated in the laboratory for use in cathodic protection systems for steel reinforced concrete bridges in coastal environments and in areas where de-icing salts are employed. The anode materials include Zn-hydrogel and thermal-sprayed Zn, Zn-15Al, and Al-12Zn-0.2In. These anodes were evaluated for service in both galvanic (GCP) and impressed current (ICCP) cathodic protection systems. ICCP anodes were electrochemically aged at a factor of 15 times greater than used by the Oregon Department of Transportation in typical coastal ICCP systems (2.2 mA/m{sup 2} based on anode area). Increasing moisture at the anode-concrete interface reduced the operating voltage of all the anodes. The pH at the anode-concrete interface fell to 7 to 8.5 with electrochemical age. Bond strength between the anodes and concrete decreased with electrochemical aging. Interfacial chemistry was the critical link between long-term anode performance and electrochemical age. Zn-hydrogel and the rmal-sprayed Zn and Al-12Zn-0.2In GCP anodes appear to supply adequate protection current to rebar in the Cape Perpetua Viaduct.

  14. Inspection of prestressed concrete pressure pipe

    NASA Astrophysics Data System (ADS)

    Atherton, D. L.; Morton, K. J.; Mergelas, B. J.; Kong, X.

    2000-05-01

    A new electromagnetic technique for inspecting prestressed concrete pressure pipe (CPP) for broken prestressing wires is described. CPP is used for water supply lines, power station cooling loops and waste water force lines. The smaller lined cylinder pipes have diameters 400-1200 mm. They have a thin steel cylinder with an inner centrifugally cast concrete core 25-50 mm thick. After curing, high strength prestressing wire is spirally wound, under high tension, onto the steel cylinder. A protective mortar coating is then impacted. Embedded-cylinder pipes have diameters 1.2-7 m. Their construction is similar but they have an additional 80-130 mm layers of concrete cast outside the steel cylinder before the prestressing wire is wound on. The pitch and gage of the wire is chosen to ensure that the concrete is always under compression. The new inspection technique uses a combination of remote field eddy current and transformer coupling effects to detect broken prestressing wires. The tools can access large pipes through small diameter man holes. They can detect single or multiple breaks in the prestressing wire at any point on the circumference and are drawn through a pipe at walking speed. The principles of operation and inspection results are described.

  15. Acoustic Emission Analysis of Prestressed Concrete Structures

    NASA Astrophysics Data System (ADS)

    Elfergani, H. A.; Pullin, R.; Holford, K. M.

    2011-07-01

    Corrosion is a substantial problem in numerous structures and in particular corrosion is very serious in reinforced and prestressed concrete and must, in certain applications, be given special consideration because failure may result in loss of life and high financial cost. Furthermore corrosion cannot only be considered a long term problem with many studies reporting failure of bridges and concrete pipes due to corrosion within a short period after they were constructed. The concrete pipes which transport water are examples of structures that have suffered from corrosion; for example, the pipes of The Great Man-Made River Project of Libya. Five pipe failures due to corrosion have occurred since their installation. The main reason for the damage is corrosion of prestressed wires in the pipes due to the attack of chloride ions from the surrounding soil. Detection of the corrosion in initial stages has been very important to avoid other failures and the interruption of water flow. Even though most non-destructive methods which are used in the project are able to detect wire breaks, they cannot detect the presence of corrosion. Hence in areas where no excavation has been completed, areas of serious damage can go undetected. Therefore, the major problem which faces engineers is to find the best way to detect the corrosion and prevent the pipes from deteriorating. This paper reports on the use of the Acoustic Emission (AE) technique to detect the early stages of corrosion prior to deterioration of concrete structures.

  16. Concrete. Course in Carpentry. Workbook and Tests.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento. Bureau of Publications.

    This workbook is one of a series of individually bound units of instruction for carpentry apprenticeship classes in a four-year apprenticeship program. It consists of two sections--the workbook section and a test section. The workbook section provides instructional materials on 10 topics: introduction to cement and concrete, specifications for…

  17. Concrete structure construction on the Moon

    NASA Technical Reports Server (NTRS)

    Matsumoto, Shinji; Namba, Haruyuki; Kai, Yoshiro; Yoshida, Tetsuji

    1992-01-01

    This paper describes a precast prestressed concrete structure system on the Moon and erection methods for this system. The horizontal section of the structural module is hexagonal so that various layouts of the modules are possible by connecting the adjacent modules to each other. For erection of the modules, specially designed mobile cranes are used.

  18. Fracture Toughness of Fiber Reinforced Concrete.

    DTIC Science & Technology

    1983-06-01

    14, 1979, pp. 443-449. 5 Mindess , S., Lawrence, F. V., and Kesler, C. E., "The J-Integral as a Fracture Criterion for Fiber Reinforced Concrete...34 Cement and Con- crete Research, Vol. 7, 1977 , pp. 731-742. 6 Velazco, G., Visalvanich, K., and Shah, S. P., "Fracture Behavior and Analysis of Fiber

  19. Self Healing Concrete: A Biological Approach

    NASA Astrophysics Data System (ADS)

    Jonkers, Henk M.

    Concrete can be considered as a kind of artificial rock with properties more or less similar to certain natural rocks. As it is strong, durable, and relatively cheap, concrete is, since almost two centuries, the most used construction material worldwide, which can easily be recognized as it has changed the physiognomy of rural areas. However, due to the heterogeneity of the composition of its principle components, cement, water, and a variety of aggregates, the properties of the final product can widely vary. The structural designer therefore must previously establish which properties are important for a specific application and must choose the correct composition of the concrete ingredients in order to ensure that the final product applies to the previously set standards. Concrete is typically characterized by a high-compressive strength, but unfortunately also by a rather low-tensile strength. However, through the application of steel or other material reinforcements, the latter can be compensated for as such reinforcements can take over tensile forces.

  20. The Paradox of Abstraction: Precision Versus Concreteness.

    PubMed

    Iliev, Rumen; Axelrod, Robert

    2016-11-22

    We introduce a novel measure of abstractness based on the amount of information of a concept computed from its position in a semantic taxonomy. We refer to this measure as precision. We propose two alternative ways to measure precision, one based on the path length from a concept to the root of the taxonomic tree, and another one based on the number of direct and indirect descendants. Since more information implies greater processing load, we hypothesize that nouns higher in precision will have a processing disadvantage in a lexical decision task. We contrast precision to concreteness, a common measure of abstractness based on the proportion of sensory-based information associated with a concept. Since concreteness facilitates cognitive processing, we predict that while both concreteness and precision are measures of abstractness, they will have opposite effects on performance. In two studies we found empirical support for our hypothesis. Precision and concreteness had opposite effects on latency and accuracy in a lexical decision task, and these opposite effects were observable while controlling for word length, word frequency, affective content and semantic diversity. Our results support the view that concepts organization includes amodal semantic structures which are independent of sensory information. They also suggest that we should distinguish between sensory-based and amount-of-information-based abstractness.

  1. Identifying Concrete and Formal Operational Children.

    ERIC Educational Resources Information Center

    Docherty, Edward M.

    This paper presents a study designed to determine if groups of concrete and formal operational children can be identified through the technique of cluster analysis, using a battery of Piagetian tasks. A Total of 64 subjects, 8 boys and 8 girls from each of the second, fourth, sixth, and eighth grade levels, were selected from a public elementary…

  2. Math & the Dyslexic: Making the Abstract Concrete.

    ERIC Educational Resources Information Center

    Kitzen, Kay

    1983-01-01

    Math historian Morris Kline suggests that math instruction should be made concrete and that teachers should not turn kids off by making intuitively understood concepts complex through the use of fancy language. He advocates using pictorial representations and examples of actual physical occurrences. The dyslexic student has special difficulties in…

  3. Hydraulic design of pervious concrete highway shoulders

    NASA Astrophysics Data System (ADS)

    Grahl, Nathan Andrew

    Stormwater drainage has been a factor in roadway design for years. Now stormwater quantity and quality are also becoming regulated for roadways. As regulations of stormwater management continue to increase so does the need for more viable and effect management practices. The research presented and discussed in this thesis presents the option of using pervious concrete in highway shoulders as a best management practice for stormwater management. Research focused on the hydraulic response of pervious concrete pavements exposed to sheet flowing water. Pervious concrete samples were placed in a hydraulic flume to determine capture discharges, infiltration rates, and by-pass flowrates for a broad range of void contents, across a broad range of pavement cross slopes. The results demonstrate that the capture discharge and infiltration rates are inversely related to the cross slope of the pavement. Results also showed the infiltration rate of the permeable pavement exposed to sheet flowing water, in the model, is significantly lower than the measured infiltration rate. Pervious concrete samples were also tested to determine hydraulic response when exposed to clogging associated with sand used in roadway de-icing. The results of the clogging of the permeable pavements followed similar trends as the unclogged samples, with the only difference being a more significant reduction in infiltration rates at higher applications of sand. Preliminary discussion of a design methodology is included with a design example.

  4. Bridge concrete deteriorating diagnosis by infrared thermography

    NASA Astrophysics Data System (ADS)

    Shibata, Hiroki; Fukuyama, Nobuhiro; Sakuma, Joji; Mochizuki, Jun; Kimura, Yukinori

    2006-04-01

    Bridge is indispensable as social overhead capital. In the past, concrete construction was believed to be semi-permanent. Actually, however, concrete is deteriorated by various factors including seawater damage, annual temperature change, etc. Therefore, it is now obvious that maintenance and management are essential to keep performance of the bridge. In Japan, we had many reports of using infrared thermography for diagnosis of building, mainly for delamination of tile and mortar used for surface of the building for more than 10 years. In recent years, infrared thermogrephy is more actively used for delamination of surface of the bridge. Passive method is usually used for open-air concrete structure diagnosis, which utilizes intraday environmental temperature change and/or radiation energy emitted from the sun which create delta-T of delamination portion of the concrete structure. It is very important to take thermal image at right conditions. Otherwise, you may easily fall onto false diagnosis. In our presentation, many case examples and study of thermal data will be shown, which are taken at the right condition.

  5. Strain Rate Effects for Concrete and Fiber Reinforced Concrete Subjected to Impact Loading

    DTIC Science & Technology

    1987-10-01

    S. Mindess and S. P. Shah) MRS Symposia Proceedings, V67. 64, pp. 21-37, 1986. 9. Shah, S. P., "Concrete and Fiber Reinforced Concrete Subjected to...Impact Loading," in Cement Based Composites: Strain Rate Effects on Fracture (eds. S. Mindess and S. P. Shah) MRS Symposia Proceedings, Vol. 64, pp... Mindess (11), Sierakowski (12), aAd Reinhardt (13). Many investigators (see for example Ref. 6) have studied the rate sensitivity of fracture strength

  6. Mechanical Properties and Durability of "Waterless Concrete"

    NASA Technical Reports Server (NTRS)

    Toutanji, Houssam; Grugel, Richard N.

    2008-01-01

    Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and by oxidation soil iron and sulfur can be produced. Iron can be used to reinforce the sulfur concrete. Sulfur concrete specimens were cycled between liquid nitrogen (approximately 191 C) and room temperature (approximately 21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (approximately 21 C) and approximately 101 C. Test results showed that due to temperature cycling, compressive strength of cycled specimens was 20% of those non-cycled. Microscopic examination of the fracture surfaces from the cycled samples showed clear de-bonding of the sulfur from the aggregate material whereas it was seen well bonded in those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibers. The glass fibers from lunar regolith simulant was melted in a 25 cc Pt-Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to 1 hour. Glass fibers were cast from the melt into graphite crucibles and were annealed for a couple of hours at 600 C. Glass fibers and small rods were pulled from the melt. The glass melt wets the ceramic rod and long continuous glass fibers were easily hand drawn. The glass fibers were immediately coated with a protective polymer to maintain the mechanical strength. The glass fibers were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Prisms beams strengthened with glass fibers were tested in 4-point bending test. Beams strengthened with glass fiber showed to

  7. Characterization and genesis interpretation of charcoal-bearing concretions from the early Eocene Ione Formation, CA

    NASA Astrophysics Data System (ADS)

    Bair, D.; Aburto, F.

    2013-12-01

    Charcoal core concretions have been discovered in the kaolinitic soil horizons of the Ione formation (early Eocene epoch ~52Ma BP). It is thought that the Ione Formation in the Ione Basin was deposited in delta and estuarine waters that were subsequently exhumed and exposed to a warmer, humid, tropical-like environment during the early Eocene. The formation of concretions is indicative of seasonal dryness, and the charcoal cores are evidence of wildfires and of the existence of a forest ecosystem. The mineral outer shells of the concretions have been characterized by powder X-ray diffraction, Electron Microprobe and Laser Ablation Quadruple Mass Spectrometry (LA-ICP-MS). Micro-computed tomography (MCT) scans indicate that these concretions have at least three distinct shells and a inner core with fragments of charcoal without apparent internal organization. The outer shell is mainly composed of a layered mix of kaolinite, quartz, goethite, hematite and birnessite. Some pyrite and jarosite have also been found, which could indicate that goethite may be post-depositional and a product of the bacteria-mediated oxidation of pyrite. The central shell has a similar composition, but with a higher content of iron oxyhydroxides and jarosite. The inner cores of the concretions are mainly composed of a mixture of kaolinite and quartz which correspond to the layer in which the concretions were found. The concretion cores contain loose charcoal fragments in a unsolidified kaolinite matrix. The charcoal fragments have been characterized by Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), C/N isotope analysis, and Synchrotron radiation FTIR (SR-FTIR). Analysis of the ATR-FTIR spectra showed significant absorbance peaks at wavenumbers that coincided with the chemical functionality of other wood biochars. Charcoal from different concretions display (n =12) extremely similar spectra which suggest that they were originated from similar species and

  8. Radiation resistant concrete for applications in nuclear power and radioactive waste industries

    NASA Astrophysics Data System (ADS)

    Burnham, Steven Robert

    Elemental components of ordinary concrete contain a variety of metals and rare earth elements that are susceptible to neutron activation. This activation occurs by means of radiative capture, a neutron interaction that results in formation of radioisotopes such as Co-60, Eu-152, and Eu-154. Studies have shown that these three radioisotopes are responsible for the residual radioactivity found in nuclear power plant concrete reactor dome and shielding walls. Such concrete is classified as Low Level Radioactive Waste (LLRW) and Very Low Level Waste (VLLW) by International Atomic Energy Agency (IAEA) standards and requires disposal at appropriate disposal sites. There are only three such sites in the USA, and every nuclear power plant will produce at the time of decommissioning approximately 1,500 tonnes of activated concrete classified as LLRW and VLLW. NAVA ALIGA (ancient word for a new stone) is a new concrete mixture developed mainly by research as presented in this thesis. The purpose of NAVA ALIGA is to satisfy IAEA clearance levels if used as a material for reactor dome, spent fuel pool, or radioactive waste canisters. NAVA ALIGA will never be activated above the IAEA clearance level after long-term exposure to neutron radiation when used as a material for reactor dome, spent fuel pool, and radioactive waste canisters. Components of NAVA ALIGA were identified using Instrumental Neutron Activation Analysis (INAA) and Inductively Coupled Plasma Mass Spectrometry (ISP-MS) to determine trace element composition. In addition, it was tested for compressive strength and permeability, important for nuclear infrastructure. The studied mixture had a high water to cement ratio of 0.56, which likely resulted in the high measured permeability, yet the mixture also showed a compressive strength greater than 6 000 psi after 28 days. In addition to this experimental analysis, which goal was to develop a standard approach to define the concrete mixtures in satisfying the IAEA

  9. 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.

  10. Diagnosing delayed ettringite formation in concrete structures

    SciTech Connect

    Thomas, Michael Folliard, Kevin Drimalas, Thano Ramlochan, Terry

    2008-06-15

    There has been a number of cases involving deteriorated concrete structures in North America where there has been considerable controversy surrounding the respective contributions of alkali-silica reaction (ASR) and delayed ettringite formation (DEF) to the observed damage. The problem arises because the macroscopic symptoms of distress are not unequivocal and microscopical examinations of field samples often reveal evidence of both processes making it difficult to separate the individual contributions. This paper presents the results of an investigation of a number of concrete columns carrying a raised expressway in North America; prior studies had implicated both DEF and ASR as possible causes of deterioration. Although the columns were not deliberately heat-cured, it is estimated that the peak internal temperature would have exceeded 70 deg. C and perhaps even 80 deg. C, in some cases. The forensic investigation included scanning electron microscopy with energy-dispersive X-ray analysis and expansion testing of cores extracted from the structure. Small-diameter cores stored in limewater expanded significantly (0.3 to 1.3%) and on the basis of supplementary tests on laboratory-produced concrete specimens it was concluded that expansion under such conditions is caused by DEF as the conditions of the test will not sustain ASR. In at least one column, DEF was diagnosed as the sole contributory cause of damage with no evidence of any contribution from ASR or any other deterioration process. In other cases, both ASR and DEF were observed to have contributed to the apparent damage. Of the columns examined, only concrete containing fly ash appeared to be undamaged. The results of this study confirm that, under certain conditions, the process of DEF (acting in isolation of other processes) can result in significant deterioration of cast-in-place reinforced concrete structures.

  11. Electrical resistance tomography for imaging concrete structures

    SciTech Connect

    Buettner, M.; Ramirez, A.; Daily, W.

    1995-11-08

    Electrical Resistance Tomography (ERT) has been used to non-destructively examine the interior of reinforced concrete pillars in the laboratory during a water infiltration experiment. ERT is a technique for determining the electrical resistivity distribution within a volume from measurement of injected currents and the resulting electrical potential distribution on the surface. The transfer resistance (ratio of potential to injected current) data are inverted using an algorithm based on a finite element forward solution which is iteratively adjusted in a least squares sense until the measured and calculated transfer resistances agree to within some predetermined value. Laboratory specimens of concrete pillars, 61.0 cm (24 in) in length and 20.3 cm (8 in) on a side, were prepared with various combinations of steel reinforcing bars and voids (1.27 cm diameter) which ran along the length of the pillars. An array of electrodes was placed around the pillar to allow for injecting current and measuring the resulting potentials. After the baseline resistivity distribution was determined, water was added to a void near one comer of the pillar. ERT was used to determine the resistivity distribution of the pillar at regular time intervals as water was added. The ERT images show very clearly that the water was gradually imbibed into the concrete pillar during the course of the experiment. The resistivity decreased by nearly an order of magnitude near the point of water addition in the first hour, and by nearly two orders of magnitude by the end of the experiment. Other applications for this technology include monitoring of curing in concrete structures, detecting cracks in concrete structures, detecting rebar location and corrosion state, monitoring slope stability and the stability of footings, detecting and monitoring leaks from storage tanks, monitoring thermal processes during environmental remediation, and for detecting and monitoring contaminants in soil and groundwater.

  12. Understanding the scabbling of concrete using microwave energy

    SciTech Connect

    Buttress, A.J.; Jones, D.A.; Dodds, C.; Dimitrakis, G.; Campbell, C.J.; Dawson, A.; Kingman, S.W.

    2015-09-15

    Concrete blocks supplied by the UK Sellafield nuclear site were treated with microwave energy using a 15 kW system operating at 2.45 GHz. The effect of aggregate type (Whinstone, Gravel and Limestone); standoff distance; and effect of surface coating were studied to determine their influence on the systems performance in terms of mass and area removal rates and evaluate the controllability of the process. All blocks were scabbled successfully, with mass and area removal rates averaging 11.3 g s{sup −} {sup 1} and 3 cm s{sup −} {sup 1} respectively on treating large areas to a depth of 25 mm. The use of a Kevlar barrier between the block and applicator was found to significantly reduce the generation of dust as only 1.6% of the scabbled mass was in the < 106 μm — that generally considered to be airborne. Importantly Brazilian disc testing of the scabbled block showed that the process did not adversely affect structural properties of the test blocks after treatment.

  13. Effect of Surrogate Aggregates on the Thermal Conductivity of Concrete at Ambient and Elevated Temperatures

    PubMed Central

    Yun, Tae Sup; Jeong, Yeon Jong; Youm, Kwang-Soo

    2014-01-01

    The accurate assessment of the thermal conductivity of concretes is an important part of building design in terms of thermal efficiency and thermal performance of materials at various temperatures. We present an experimental assessment of the thermal conductivity of five thermally insulated concrete specimens made using lightweight aggregates and glass bubbles in place of normal aggregates. Four different measurement methods are used to assess the reliability of the thermal data and to evaluate the effects of the various sensor types. The concrete specimens are also assessed at every 100°C during heating to ~800°C. Normal concrete is shown to have a thermal conductivity of ~2.25 W m−1 K−1. The surrogate aggregates effectively reduce the conductivity to ~1.25 W m−1 K−1 at room temperature. The aggregate size is shown not to affect thermal conduction: fine and coarse aggregates each lead to similar results. Surface contact methods of assessment tend to underestimate thermal conductivity, presumably owing to high thermal resistance between the transducers and the specimens. Thermogravimetric analysis shows that the stages of mass loss of the cement paste correspond to the evolution of thermal conductivity upon heating. PMID:24696666

  14. Effect of surrogate aggregates on the thermal conductivity of concrete at ambient and elevated temperatures.

    PubMed

    Yun, Tae Sup; Jeong, Yeon Jong; Youm, Kwang-Soo

    2014-01-01

    The accurate assessment of the thermal conductivity of concretes is an important part of building design in terms of thermal efficiency and thermal performance of materials at various temperatures. We present an experimental assessment of the thermal conductivity of five thermally insulated concrete specimens made using lightweight aggregates and glass bubbles in place of normal aggregates. Four different measurement methods are used to assess the reliability of the thermal data and to evaluate the effects of the various sensor types. The concrete specimens are also assessed at every 100 °C during heating to ~800 °C. Normal concrete is shown to have a thermal conductivity of ~2.25 W m(-1) K(-1). The surrogate aggregates effectively reduce the conductivity to ~1.25 W m(-1) K(-1) at room temperature. The aggregate size is shown not to affect thermal conduction: fine and coarse aggregates each lead to similar results. Surface contact methods of assessment tend to underestimate thermal conductivity, presumably owing to high thermal resistance between the transducers and the specimens. Thermogravimetric analysis shows that the stages of mass loss of the cement paste correspond to the evolution of thermal conductivity upon heating.

  15. Pavement management and rehabilitation of portland cement concrete pavements

    NASA Astrophysics Data System (ADS)

    Zegeer, C. V.; Agent, K. R.; Rizenbergs, R. L.; Curtayne, P. C.; Scullion, T.; Pedigo, R. D.; Hudson, W. R.; Roberts, F. L.; Karan, M. A.; Haas, R.

    Pavement management and rehabilitation projects and techniques are discussed. The following topics are discussed: economic analyses and dynamic programming in resurfacing project selection; implementation of an urban pavement management system; pavement performance modeling for pavement management; illustration of pavement management: from data inventory to priority analysis; rehabilitation of concrete pavements by using portland cement concrete overlays; pavement management study: Illinois tollway pavement overlays; resurfacing of plain jointed-concrete pavements; design procedure for premium composite pavement; model study of anchored pavement; prestressed concrete overlay at O'Hare International Airport: in-service evaluation; and, bonded portland cement concrete resurfacing.

  16. Concrete decontamination by Electro-Hydraulic Scabbling (EHS)

    SciTech Connect

    1994-11-01

    EHS is being developed for decontaminating concrete structures from radionuclides, organic substances, and hazardous metals. EHS involves the generation of powerful shock waves and intense cavitation by a strong pulsed electric discharge in a water layer at the concrete surface; high impulse pressure results in stresses which crack and peel off a concrete layer of controllable thickness. Scabbling produces contaminated debris of relatively small volume which can be easily removed, leaving clean bulk concrete. Objective of Phase I was to prove the technical feasibility of EH for controlled scabbling and decontamination of concrete. Phase I is complete.

  17. A quantitative empirical analysis of the abstract/concrete distinction.

    PubMed

    Hill, Felix; Korhonen, Anna; Bentz, Christian

    2014-01-01

    This study presents original evidence that abstract and concrete concepts are organized and represented differently in the mind, based on analyses of thousands of concepts in publicly available data sets and computational resources. First, we show that abstract and concrete concepts have differing patterns of association with other concepts. Second, we test recent hypotheses that abstract concepts are organized according to association, whereas concrete concepts are organized according to (semantic) similarity. Third, we present evidence suggesting that concrete representations are more strongly feature-based than abstract concepts. We argue that degree of feature-based structure may fundamentally determine concreteness, and we discuss implications for cognitive and computational models of meaning.

  18. Microbiologically induced deterioration of concrete--a review.

    PubMed

    Wei, Shiping; Jiang, Zhenglong; Liu, Hao; Zhou, Dongsheng; Sanchez-Silva, Mauricio

    2013-12-01

    Microbiologically induced deterioration (MID) causes corrosion of concrete by producing acids (including organic and inorganic acids) that degrade concrete components and thus compromise the integrity of sewer pipelines and other structures, creating significant problems worldwide. Understanding of the fundamental corrosion process and the causal agents will help us develop an appropriate strategy to minimize the costs in repairs. This review presents how microorganisms induce the deterioration of concrete, including the organisms involved and their colonization and succession on concrete, the microbial deterioration mechanism, the approaches of studying MID and safeguards against concrete biodeterioration. In addition, the uninvestigated research area of MID is also proposed.

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

    SciTech Connect

    Naus, D.J.

    1981-05-01

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

  20. Infiltration and Evaporation of Diesel and Gasoline Droplets Spilled onto Concrete Pavement

    NASA Astrophysics Data System (ADS)

    Hilpert, M.; Adria-Mora, B.

    2015-12-01

    Pollution at gas stations due to small spills that occur during refueling of customer vehicles has received little attention. We have performed laboratory experiments in order to assess the processes of evaporation and infiltration of fuel spilled onto concrete samples. Changes in mass of both spilled diesel and gasoline droplets as a function of time have been analyzed. The infiltrated mass is affected by variations in humidity, among other parameters, which influence the amount of water condensed onto the concrete. Therefore, we used a humidity data logger and statistical tools to predict the evolution of the real mass of infiltrated fuel. The infiltrated mass roughly decreases exponentially, but the difference in behavior between both fuel types is important. The percentage of evaporated mass is much larger for gasoline, while infiltration is more significant for diesel. Also, the percentage of infiltrated liquid depends on the initial droplet mass. We also developed a multiphysics model, which couples pore-scale infiltration to turbulent atmospheric transport, to explain the experimental data. In conclusion, a substantial amount of fuel could both seep into the ground to contaminate groundwater and be released to the atmosphere. More studies are needed to quantify the public health implications of the released pollutants.

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

    NASA Astrophysics Data System (ADS)

    Helminger, Nicholas P.

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

  2. Durability of styrene-butadiene latex modified concrete

    SciTech Connect

    Shaker, F.A.; El-Dieb, A.S.; Reda, M.M.

    1997-05-01

    The durability of reinforced concrete structures represents a major concern to many investigators. The use of latex modified concrete (LMC) in construction has urged researchers to review and investigate its different properties. This study is part of a comprehensive investigation carried on the use of polymers in concrete. The main objective of this study to investigate and evaluate the main durability aspects of Styrene-Butadiene latex modified concrete (LMC) compared to those of conventional concrete. Also, the main microstructural characteristics of LMC were studied using a Scanning Electron Microscope (SEM). The SEM investigation of the LMC showed major differences in its microstructure compared to that of the conventional concrete. The LMC proved to be superior in its durability compared to the durability of conventional concrete especially its water tightness (measured by water penetration, absorption, and sorptivity tests), abrasion, corrosion, and sulphate resistance.

  3. An Alternative Mechanism for Accelerated Carbon Sequestration in Concrete

    SciTech Connect

    Haselbach, Liv M.; Thomle, Jonathan N.

    2014-07-01

    The increased rate of carbon dioxide sequestration (carbonation) is desired in many primary and secondary life applications of concrete in order to make the life cycle of concrete structures more carbon neutral. Most carbonation rate studies have focused on concrete exposed to air under various conditions. An alternative mechanism for accelerated carbon sequestration in concrete was investigated in this research based on the pH change of waters in contact with pervious concrete which have been submerged in carbonate laden waters. The results indicate that the concrete exposed to high levels of carbonate species in water may carbonate faster than when exposed to ambient air, and that the rate is higher with higher concentrations. Validation of increased carbon dioxide sequestration was also performed via thermogravimetric analysis (TGA). It is theorized that the proposed alternative mechanism reduces a limiting rate effect of carbon dioxide dissolution in water in the micro pores of the concrete.

  4. Surface treated polypropylene (PP) fibres for reinforced concrete

    SciTech Connect

    López-Buendía, Angel M.; Romero-Sánchez, María Dolores; Climent, Verónica

    2013-12-15

    Surface treatments on a polypropylene (PP) fibre have contributed to the improvement of fibre/concrete adhesion in fibre-reinforced concrete. The treatments to the PP fibre were characterized by contact angle measurements, ATR-IR and XPS to analyse chemical alterations. The surface topography and fibre/concrete interaction were analysed by several microscopic techniques, namely optical petrographic, and scanning electron microscopy. Treatment modified the surface chemistry and topography of the fibre by introducing sodium moieties and created additional fibre surface roughness. Modifications in the fibre surface led to an increase in the adhesion properties between the treated fibres and concrete and an improvement in the mechanical properties of the fibre-reinforced concrete composite as compared to the concrete containing untreated PP fibres. Compatibility with the concrete and increased roughness and mineral surface was also improved by nucleated portlandite and ettringite mineral association anchored on the alkaline PP fibre surface, which is induced during treatment.

  5. Recycling of PET bottles as fine aggregate in concrete.

    PubMed

    Frigione, Mariaenrica

    2010-06-01

    An attempt to substitute in concrete the 5% by weight of fine aggregate (natural sand) with an equal weight of PET aggregates manufactured from the waste un-washed PET bottles (WPET), is presented. The WPET particles possessed a granulometry similar to that of the substituted sand. Specimens with different cement content and water/cement ratio were manufactured. Rheological characterization on fresh concrete and mechanical tests at the ages of 28 and 365days were performed on the WPET/concretes as well as on reference concretes containing only natural fine aggregate in order to investigate the influence of the substitution of WPET to the fine aggregate in concrete. It was found that the WPET concretes display similar workability characteristics, compressive strength and splitting tensile strength slightly lower that the reference concrete and a moderately higher ductility.

  6. Innovative process routes for a high-quality concrete recycling.

    PubMed

    Menard, Y; Bru, K; Touze, S; Lemoign, A; Poirier, J E; Ruffie, G; Bonnaudin, F; Von Der Weid, F

    2013-06-01

    This study presents alternative methods for the processing of concrete waste. The mechanical stresses needed for the embrittlement of the mortar matrix and further selective crushing of concrete were generated by either electric impulses or microwaves heating. Tests were carried out on lab-made concrete samples representative of concrete waste from concrete mixer trucks and on concrete waste collected on a French demolition site. The results obtained so far show that both techniques can be used to weaken concrete samples and to enhance aggregate selective liberation (that is the production of cement paste-free aggregates) during crushing and grinding. Electric pulses treatment seems to appear more efficient, more robust and less energy consuming (1-3 kWh t(-1)) than microwave treatment (10-40 kWh t(-1)) but it can only be applied on samples in water leading to a major drawback for recycling aggregates or cement paste in the cement production process.

  7. An Investigation of Tendon Corrosion-Inhibitor Leakage into Concrete

    SciTech Connect

    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 the 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.

  8. Recycling of PET bottles as fine aggregate in concrete

    SciTech Connect

    Frigione, Mariaenrica

    2010-06-15

    An attempt to substitute in concrete the 5% by weight of fine aggregate (natural sand) with an equal weight of PET aggregates manufactured from the waste un-washed PET bottles (WPET), is presented. The WPET particles possessed a granulometry similar to that of the substituted sand. Specimens with different cement content and water/cement ratio were manufactured. Rheological characterization on fresh concrete and mechanical tests at the ages of 28 and 365 days were performed on the WPET/concretes as well as on reference concretes containing only natural fine aggregate in order to investigate the influence of the substitution of WPET to the fine aggregate in concrete. It was found that the WPET concretes display similar workability characteristics, compressive strength and splitting tensile strength slightly lower that the reference concrete and a moderately higher ductility.

  9. Molecular survey of concrete sewer biofilm microbial communities.

    PubMed

    Santo Domingo, Jorge W; Revetta, Randy P; Iker, Brandon; Gomez-Alvarez, Vicente; Garcia, Jarissa; Sullivan, John; Weast, James

    2011-10-01

    The microbial composition of concrete biofilms within wastewater collection systems was studied using molecular assays. SSU rDNA clone libraries were generated from 16 concrete surfaces of manholes, a combined sewer overflow, and sections of a corroded sewer pipe. Of the 2457 sequences analyzed, α-, β-, γ-, and δ-Proteobacteria represented 15%, 22%, 11%, and 4% of the clones, respectively. β-Proteobacteria (47%) sequences were more abundant in the pipe crown than any of the other concrete surfaces. While 178 to 493 Operational Taxonomic Units (OTUs) were associated with the different concrete samples, only four sequences were shared among the different clone libraries. Bacteria implicated in concrete corrosion were found in the clone libraries while archaea, fungi, and several bacterial groups were also detected using group-specific assays. The results showed that concrete sewer biofilms are more diverse than previously reported. A more comprehensive molecular database will be needed to better study the dynamics of concrete biofilms.

  10. Monte Carlo simulations for optimization of neutron shielding concrete

    NASA Astrophysics Data System (ADS)

    Piotrowski, Tomasz; Tefelski, Dariusz B.; Polański, Aleksander; Skubalski, Janusz

    2012-06-01

    Concrete is one of the main materials used for gamma and neutron shielding. While in case of gamma rays an increase in density is usually efficient enough, protection against neutrons is more complex. The aim of this paper is to show the possibility of using the Monte Carlo codes for evaluation and optimization of concrete mix to reach better neutron shielding. Two codes (MCNPX and SPOT — written by authors) were used to simulate neutron transport through a wall made of different concretes. It is showed that concrete of higher compressive strength attenuates neutrons more effectively. The advantage of heavyweight concrete (with barite aggregate), usually used for gamma shielding, over the ordinary concrete was not so clear. Neutron shielding depends on many factors e.g. neutron energy, barrier thickness and atomic composition. All this makes a proper design of concrete as a very important issue for nuclear power plant safety assurance.

  11. 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

  12. Numerical Study Of The Effects Of Preloading, Axial Loading And Concrete Shrinkage On Reinforced Concrete Elements Strengthened By Concrete Layers And Jackets

    NASA Astrophysics Data System (ADS)

    Lampropoulos, A. P.; Dritsos, S. E.

    2008-07-01

    In this study, the technique of seismic strengthening existing reinforced concrete columns and beams using additional concrete layers and jackets is examined. The finite element method and the finite element program ATENA is used in this investigation. When a reinforced jacket or layer is being constructed around a column it is already preloaded due to existing service loads. This effect has been examined for different values of the axial load normalized to the strengthened column. The techniques of strengthening with a concrete jacket or a reinforced concrete layer on the compressive side of the column are examined. Another phenomenon that is examined in this study is the shrinkage of the new concrete of an additional layer used to strengthen an existing member. For this investigation, a simply supported beam with an additional reinforced concrete layer on the tensile side is examined. The results demonstrate that the effect of preloading is important when a reinforced concrete layer is being used with shear connectors between the old and the new reinforcement. It was also found that the shrinkage of the new concrete reduces the strength of the strengthened beam and induces an initial sliding between the old and the new concrete.

  13. Retention of Lead and Total Suspended Solids in Pervious Concrete

    NASA Astrophysics Data System (ADS)

    Nolin, Spring

    Pervious concrete, an alternative to conventional concrete, is a material with an increased amount of void space that allows water to pass through the concrete versus ponding and/or running off into catchment systems. This study examines the retention capabilities of lead and Total Suspended Solids (TSS) within an entire pervious concrete system and the effects of different fly ash compositions for pervious concrete along with two different types of crushed stones and a soil layer. A complete pervious concrete system consisted of one formulation of pervious concrete along with one type of crushed stone and the soil layer used in the individual trials of TSS removal and lead retention to determine if a complete pervious concrete system would equal the sum of its parts. The retention of lead by the complete pervious concrete system was compared against the individual results from the parts of the complete pervious concrete system. Among the different formulations of pervious concrete, the specimens with a high loss on ignition showed a higher removal rate of lead but not TSS than those with low loss on ignition, yet the difference in the percentage of fly ash did not show an effect on the removal or retention of either lead or TSS. Of the two types of crushed stone tested, the 3/8" crushed stone retained more TSS than the #57 crushed stone. The amount of lead retained by the #57 crushed stone was not significantly different from the 3/8" crushed stone after the crushed stone was flushed. The dirt layer showed a complete removal rate of lead as did the complete pervious concrete system. The sum of the parts of the pervious concrete system indicate that for maximum removal of TSS and lead, a high loss on ignition fly ash pervious concrete cylinder should be used in conjunction with a 3/8" crushed stone layer.

  14. COIN Project: Towards a zero-waste technology for concrete aggregate production in Norway

    NASA Astrophysics Data System (ADS)

    Cepuritis, Rolands; Willy Danielsen, Svein

    2014-05-01

    COIN Project: Towards a zero-waste technology for concrete aggregate production in Norway Rolands Cepuritis, Norcem/NTNU and Svein Willy Danielsen, SINTEF Aggregate production is a mining operation where no purification of the "ore" is necessary. Still it is extremely rare that an aggregate production plant is operating on the basis of zero-waste concept. This is since historically the fine crushed aggregate (particles with a size of less than 2, 4 or sometimes 8 mm) has been regarded as a by-product or waste of the more valuable coarse aggregate production. The reason is that the crushed coarse aggregates can easily replace coarse rounded natural stones in almost any concrete composition; while, the situation with the sand is different. The production of coarse aggregate normally yields fine fractions with rough surface texture, flaky or elongated particles an inadequate gradation. When such a material replaces smooth and rounded natural sand grains in a concrete mix, the result is usually poor and much more water and cement has to be used to achieve adequate concrete flow. The consequences are huge stockpiles of the crushed fine fractions that can't be sold (mass balance problems) for the aggregate producers, sustainability problems for the whole industry and environmental issues for society due to dumping and storing of the fine co-generated material. There have been attempts of utilising the material in concrete before; however, they have mostly ended up in failure. There have been attempts to adjust the crushed sand to the properties of the natural sand, which would still give a lot of waste, especially if the grading would have to be adjusted and the high amounts of fines abundantly present in the crushed sand would have to be removed. Another fundamental reason for failure has been that historically such attempts have mainly ended up in a research carried out by people (both industrial and academic) with aggregate background (= parties willing to find market

  15. Isolation and Identification of Concrete Environment Bacteria

    NASA Astrophysics Data System (ADS)

    Irwan, J. M.; Anneza, L. H.; Othman, N.; Husnul, T.; Alshalif, A. F.

    2016-07-01

    This paper presents the isolation and molecular method for bacteria identification through PCR and DNA sequencing. Identification of the bacteria species is required in order to fully utilize the bacterium capability for precipitation of calcium carbonate in concrete. This process is to enable the addition of suitable catalyst according to the bacterium enzymatic pathway that is known through the bacteria species used. The objective of this study is to isolate, enriched and identify the bacteria species. The bacteria in this study was isolated from fresh urine and acid mine drainage water, Kota Tinggi, Johor. Enrichment of the isolated bacteria was conducted to ensure the bacteria survivability in concrete. The identification of bacteria species was done through polymerase chain reaction (PCR) and rRDNA sequencing. The isolation and enrichment of the bacteria was done successfully. Whereas, the results for bacteria identification showed that the isolated bacteria strains are Bacillus sp and Enterococus faecalis.

  16. Mechanical properties of high-strength concrete

    NASA Astrophysics Data System (ADS)

    Mokhtarzadeh, Alireza

    This report summarizes an experimental program conducted to investigate production techniques and mechanical properties of high strength concrete in general and to provide recommendations for using these concretes in manufacturing precast/prestressed bridge girders. Test variables included total amount and composition of cementitious material (portland cement, fly ash, and silica fume), type and brand of cement, type of silica fume (dry densified and slurry), type and brand of high-range water-reducing admixture, type of aggregate, aggregate gradation, maximum aggregate size, and curing. Tests were conducted to determine the effects of these variables on changes in compressive strength and modulus of elasticity over time, splitting tensile strength, modulus of rupture, creep, shrinkage, and absorption potential (as an indirect indicator of permeability). Also investigated were the effects of test parameters such as mold size, mold material, and end condition. Over 6,300 specimens were cast from approximately 140 mixes over a period of 3 years.

  17. High-strength concrete for Peacekeeper facilities

    NASA Astrophysics Data System (ADS)

    Saucier, K. L.

    1984-03-01

    An investigation is described which was conducted to determine the processes and techniques required to produce portland-cement concrete with a compressive strength of 15,000 psi or greater using conventional concreting methods and equipment, and to develop physical property data on the mixtures. It was permitted that special materials and admixtures be used, but a requirement was set that the aggregates and cements be selected from those available in the Cheyenne, Wyoming, area. Results indicated that it is feasible to achieve the 15,000-psi compressive strengths but that workability may decrease over a 2-hour period, and this latter development should be studied under job conditions. It is recommended that: (1) all materials and procedures to be used on a specific project be tested in the laboratory for basic property information, and (2) selected mixtures be tested in the field under expected environmental conditions prior to actual job use.

  18. Overlays for plain jointed concrete pavements

    NASA Astrophysics Data System (ADS)

    Gulden, W.; Brown, D.

    1984-09-01

    This report describes the construction and performance of 4 concrete and 16 asphalt overlay test sections after nine years of traffic. The test sections were placed on I-85 which carries a substantial number of heavy trucks to determine what treatments and overlay type and thickness would give acceptable performance. The concrete overlay sections were placed in 1975 and consisted of 3 inch, 4 1/2 inch, and 6 inch CRC and 6 inch jointed PCC with 15 ft. and 30 ft. joint spacing. The asphalt sections were placed in 1976 with the variables being overlay thickness of 2 inches, 4 inches, and 6 inches and the placement of two geotextiles and strips of a waterproofing membrane for each overlay thickness. An Arkansas base test section was also included in the experiment.

  19. Nonlinear pushover analysis of infilled concrete frames

    NASA Astrophysics Data System (ADS)

    Huang, Chao Hsun; Tuan, Yungting Alex; Hsu, Ruo Yun

    2006-12-01

    Six reinforced concrete frames with or without masonry infills were constructed and tested under horizontal cyclic loads. All six frames had identical details in which the transverse reinforcement in columns was provided by rectangular hoops that did not meet current ACI specifications for ductile frames. For comparison purposes, the columns in three of these frames were jacketed by carbon-fiber-reinforced-polymer (CFRP) sheets to avoid possible shear failure. A nonlinear pushover analysis, in which the force-deformation relationships of individual elements were developed based on ACI 318, FEMA 356, and Chen’s model, was carried out for these frames and compared to test results. Both the failure mechanisms and impact of infills on the behaviors of these frames were examined in the study. Conclusions from the present analysis provide structural engineers with valuable information for evaluation and design of infilled concrete frame building structures.

  20. Nondestructive Evaluation of Thick Concrete Structures

    SciTech Connect

    Clayton, Dwight A

    2015-01-01

    Materials issues are a key concern for the existing nuclear reactor fleet in the United States as material degradation can lead to increased maintenance, increased downtime, and increased risk. Extending reactor life to 60 years and beyond will likely increase susceptibility and severity of both known and new forms of degradation. A multitude of concrete-based structures are typically part of a light water reactor plant to provide foundation, support, shielding, and containment functions. The size and complexity of nuclear power plant containment structures and the heterogeneity of Portland cement concrete make characterization of the degradation extent a difficult task. This paper examines the benefits of using time-frequency analysis with Synthetic Aperture Focusing Technique (SAFT). By using wavelet packet decomposition, the original ultrasound signals are decomposed into various frequency bands that facilitates highly selective analysis of the signal’s frequency content and can be visualized using the familiar SAFT image reconstruction algorithm.

  1. Cathodic protection on concrete offshore platforms

    SciTech Connect

    Heuze, B.

    1980-05-01

    Experience with five cathodically protected North Sea concrete platforms has demonstrated the value of interconnecting the concrete-reinforcement steel with cathodically protected metal items on the structure (rather than insulating the steel from them) as a means of bringing the entire structure under the protection of the corrosion-control system. Lessons learned from this experience point out the importance of the duct material in safeguarding the prestressing tendons, the limitations of cathodic protection in cases of coating cracking and disbondment, and the precautions to be taken against stray welding currents. An improved approach to corrosion prevention focuses on the design philosophy, the current required by the reinforcing bar and well casing, the corrosion protection inside piping shafts and risers, and the required monitoring systems.

  2. Electrical resistance tomography of concrete structures

    SciTech Connect

    Daily, W.; Ramirez, A.; Binley, A.; Henry-Poulter, S.

    1993-10-01

    The purpose of this work is to determine the feasibility of using Electrical resistance tomography (ERT) to nondestructively examine the interior of concrete structures such as bridge pillars and roadways. We report the results of experiments wherein ERT is used to image the two concrete specimens in the laboratory. Each specimen is 5 inches square and 12 inches long and contained steel reinforcing rods along its length. Twenty electrodes were placed on each sample and an-image of electrical resistivity distribution was generated from current and voltage measurements. We found that the images show the general location of the reinforcing steel and, what`s more important, delineate the absence of the steel. The method may therefore be useful for determining if such steel has been destroyed by corrosion, however to make it useful, the technique must have better resolution so that individual reinforcing steel units are resolved.

  3. CP systems for steel reinforced concrete bridges

    SciTech Connect

    Bullard, Sophie J.; Cramer, Stephen D.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Ziomek-Moroz, Margaret; Soltesz, Steven M.

    2004-01-01

    Thermal-sprayed zinc anodes are used for cathodic protection (CP) systems in Oregon?s reinforced concrete coastal bridges to prevent chloride-induced corrosion damage. Thermal-sprayed zinc performs well as an ICCP anode but the service life of the zinc anode is directly related to the average current density used to operate the systems. Oregon Department of Transportation (DOT) is investigating ways of monitoring the rebar corrosion in reinforced concrete bridges to identify conditions when protection of the rebar is needed. This approach reflects the fact that external protection may not be needed for all environmental conditions, leading Oregon DOT to examine the use of intermittent, galvanic, and constant voltage cathodic protection systems. Results from these types of systems are reported.

  4. Composite binders for concrete with reduced permeability

    NASA Astrophysics Data System (ADS)

    Fediuk, R.; Yushin, A.

    2016-02-01

    Composite binder consisting of cement (55%), acid fly ash (40%) and limestone (5%) has been designed. It is obtained by co-milling to a specific surface of 550 kg/m2, it has an activity of 77.3 MPa and can produce a more dense cement stone structure. Integrated study revealed that the concrete on the composite binder basis provides an effective diffusion coefficient D. So we can conclude that the concrete layer protects buildings from toxic effects of expanded polystyrene. Low water absorption of the material (2.5% by weight) is due to the structure of its cement stone pore space. Besides lime powder prevents the penetration of moisture, reduces water saturation of the coverage that has a positive effect on useful life period. It also explains rather low water vapor permeability of the material - 0.021 mg/(m- hour-Pa).

  5. Engineering properties of inorganic polymer concretes (IPCs)

    SciTech Connect

    Sofi, M.; Deventer, J.S.J. van . E-mail: jannie@unimelb.edu.au; Mendis, P.A. . E-mail: pamendis@unimelb.edu.au; Lukey, G.C.

    2007-02-15

    This paper presents the engineering properties of inorganic polymer concretes (IPCs) with a compressive strength of 50 MPa. The study includes a determination of the modulus of elasticity, Poisson's ratio, compressive strength, and the splitting tensile strength and flexural strength of IPCs, formulated using three different sources of Class-F fly ash. Six IPC mix designs were adopted to evaluate the effects of the inclusion of coarse aggregates and granulated blast furnace slag into the mixes. A total of 90 cylindrical and 24 small beam specimens were investigated, and all tests were carried out pursuant to the relevant Australian Standards. Although some variability between the mixes was observed, the results show that, in most cases, the engineering properties of IPCs compare favorably to those predicted by the relevant Australian Standards for concrete mixtures.

  6. Behaviour of concrete beams reinforced withFRP prestressed concrete prisms

    NASA Astrophysics Data System (ADS)

    Svecova, Dagmar

    The use of fibre reinforced plastics (FRP) to reinforce concrete is gaining acceptance. However, due to the relatively low modulus of FRP, in comparison to steel, such structures may, if sufficient amount of reinforcement is not used, suffer from large deformations and wide cracks. FRP is generally more suited for prestressing. Since it is not feasible to prestress all concrete structures to eliminate the large deflections of FRP reinforced concrete flexural members, researchers are focusing on other strategies. A simple method for avoiding excessive deflections is to provide sufficiently high amount of FRP reinforcement to limit its stress (strain) to acceptable levels under service loads. This approach will not be able to take advantage of the high strength of FRP and will be generally uneconomical. The current investigation focuses on the feasibility of an alternative strategy. This thesis deals with the flexural and shear behaviour of concrete beams reinforced with FRP prestressed concrete prisms. FRP prestressed concrete prisms (PCP) are new reinforcing bars, made by pretensioning FRP and embedding it in high strength grout/concrete. The purpose of the research is to investigate the feasibility of using such pretensioned rebars, and their effect on the flexural and shear behaviour of reinforced concrete beams over the entire loading range. Due to the prestress in the prisms, deflection of concrete beams reinforced with this product is substantially reduced, and is comparable to similarly steel reinforced beams. The thesis comprises both theoretical and experimental investigations. In the experimental part, nine beams reinforced with FRP prestressed concrete prisms, and two companion beams, one steel and one FRP reinforced were tested. All the beams were designed to carry the same ultimate moment. Excellent flexural and shear behaviour of beams reinforced with higher prestressed prisms is reported. When comparing deflections of three beams designed to have the

  7. Sulfate resistance of high calcium fly ash concrete

    NASA Astrophysics Data System (ADS)

    Dhole, Rajaram

    Sulfate attack is one of the mechanisms which can cause deterioration of concrete. In general, Class C fly ash mixtures are reported to provide poor sulfate resistance. Fly ashes, mainly those belonging to the Class C, were tested as per the ASTM C 1012 procedure to evaluate chemical sulfate resistance. Overall the Class C fly ashes showed poor resistance in the sulfate environment. Different strategies were used in this research work to improve the sulfate resistance of Class C fly ash mixes. The study revealed that some of the strategies such as use of low W/CM (water to cementing materials by mass ratio), silica fume or ultra fine fly ash, high volumes of fly ash and, ternary or quaternary mixes with suitable supplementary cementing materials, can successfully improve the sulfate resistance of the Class C fly ash mixes. Combined sulfate attack, involving physical and chemical action, was studied using sodium sulfate and calcium sulfate solutions. The specimens were subjected to wetting-drying cycles and temperature changes. These conditions were found to accelerate the rate of degradation of concrete placed in a sodium sulfate environment. W/CM was found to be the main governing factor in providing sulfate resistance to mixes. Calcium sulfate did not reveal damage as a result of mainly physical action. Characterization of the selected fly ashes was undertaken by using SEM, XRD and the Rietveld analysis techniques, to determine the relation between the composition of fly ashes and resistance to sulfate attack. The chemical composition of glass represented on the ternary diagram was the main factor which had a significant influence on the sulfate resistance of fly ash mixtures. Mixes prepared with fly ashes containing significant amounts of vulnerable crystalline phases offered poor sulfate resistance. Comparatively, fly ash mixes containing inert crystalline phases such as quartz, mullite and hematite offered good sulfate resistance. The analysis of hydrated lime

  8. Precast concrete sandwich panels subjected to impact loading

    NASA Astrophysics Data System (ADS)

    Runge, Matthew W.

    Precast concrete sandwich panels are a relatively new product in the construction industry. The design of these panels incorporates properties that allow for great resilience against temperature fluctuation as well as the very rapid and precise construction of facilities. The concrete sandwich panels investigated in this study represent the second generation of an ongoing research and development project. This second generation of panels have been engineered to construct midsized commercial buildings up to three stories in height as well as residential dwellings. The panels consist of a double-tee structural wythe, a foam core and a fascia wythe, joined by shear connectors. Structures constructed from these panels may be subjected to extreme loading including the effects of seismic and blast loading in addition to wind. The aim of this work was to investigate the behaviour of this particular sandwich panel when subjected to structural impact events. The experimental program consisted of fourteen concrete sandwich panels, five of which were considered full-sized specimens (2700 mm X 1200mm X 270 mm) and nine half-sized specimens (2700mm X 600mm X 270 mm) The panels were subjected to impact loads from a pendulum impact hammer where the total energy applied to the panels was varied by changing the mass of the hammer. The applied loads, displacements, accelerations, and strains at the mid-span of the panel as well as the reaction point forces were monitored during the impact. The behaviour of the panels was determined primarily from the experimental results. The applied loads at low energy levels that caused little to no residual deflection as well as the applied loads at high energy levels that represent catastrophic events and thus caused immediate failure were determined from an impact on the structural and the fascia wythes. Applied loads at intermediate energy levels representing extreme events were also used to determine whether or not the panels could withstand

  9. Environmental evaluation of green concretes versus conventional concrete by means of LCA.

    PubMed

    Turk, Janez; Cotič, Zvonko; Mladenovič, Ana; Šajna, Aljoša

    2015-11-01

    A number of green concrete mixes having similar basic properties were evaluated from the environmental point of view by means of the Life Cycle Assessment method, and compared with a corresponding conventional concrete mix. The investigated green concrete mixes were prepared from three different types of industrial by-products, i.e. (1) foundry sand, and (2) steel slag, both of which were used as manufactured aggregates, and (3) fly ash, which was used as a mineral admixture. Some green concrete mixes were also prepared from a recycled aggregate, which was obtained from reinforced concrete waste. In some of the green concrete mixes the recycled aggregate was used in combination with the above-mentioned types of manufactured aggregate and fly ash. All of these materials are able, to some extent, to replace natural aggregate or Portland cement in concrete mixes, thus providing an environmental benefit from the point of view of the saving of natural resources. Taking into account consequential modelling, the credit related to the avoidance of the need to dispose of the waste materials is considered as a benefit. In case of the recycling of waste concrete into aggregate, credit is attributed to the recovery of scrap iron from the steel reinforcement. In the case of the use of steel slag, credit is attributed to the recovery of metals, which are extracted from the slag before being used as an alternative material. The disadvantage of using alternative materials and recycled aggregates can sometimes be their relatively long delivery distance. For this reason, a transport sensitivity analysis was carried out. The results indicate that the use of the discussed alternative and recycled materials is beneficial in the concrete production industry. Preference is given to the fly ash and foundry sand scenarios, and especially to those scenarios which are based on the combined use of recycled aggregate with these two alternative materials. It was found that longer delivery

  10. Terrestrial Fe-oxide Concretions and Mars Blueberries: Comparisons of Similar Advective and Diffusive Chemical Infiltration Reaction Mechanisms

    NASA Astrophysics Data System (ADS)

    Park, A. J.; Chan, M. A.

    2006-12-01

    Abundant iron oxide concretions occurring in Navajo Sandstone of southern Utah and those discovered at Meridiani Planum, Mars share many common observable physical traits such as their spheriodal shapes, occurrence, and distribution patterns in sediments. Terrestrial concretions are products of interaction between oxygen-rich aquifer water and basin-derived reducing (iron-rich) water. Water-rock interaction simulations show that diffusion of oxygen and iron supplied by slow-moving water is a reasonable mechanism for producing observed concretion patterns. In short, southern Utah iron oxide concretions are results of Liesegang-type diffusive infiltration reactions in sediments. We propose that the formation of blueberry hematite concretions in Mars sediments followed a similar diagenetic mechanism where iron was derived from the alteration of volcanic substrate and oxygen was provided by the early Martian atmosphere. Although the terrestrial analog differs in the original host rock composition, both the terrestrial and Mars iron-oxide precipitation mechanisms utilize iron and oxygen interactions in sedimentary host rock with diffusive infiltration of solutes from two opposite sources. For the terrestrial model, slow advection of iron-rich water is an important factor that allowed pervasive and in places massive precipitation of iron-oxide concretions. In Mars, evaporative flux of water at the top of the sediment column may have produced a slow advective mass-transfer mechanism that provided a steady source and the right quantity of iron. The similarities of the terrestrial and Martian systems are demonstrated using a water-rock interaction simulator Sym.8, initially in one-dimensional systems. Boundary conditions such as oxygen content of water, partial pressure of oxygen, and supply rate of iron were varied. The results demonstrate the importance of slow advection of water and diffusive processes for producing diagenetic iron oxide concretions.

  11. Dynamic Fracture of Concrete. Part 1

    DTIC Science & Technology

    1990-02-14

    real reference grating, and other experimental measurements . For the first time, the crack closure stres versus COD relation of a fracture process zone...fracture process zones simulated the measured crack propagation histories within the I. DISTRIBUTION /AVAILABILITY OF ABSTRACT 21. AB)TRACT SECURITY...grating, and other experimental measurements . For the first time, the crack closure stress versus COD relation of a fracture process zone in concrete

  12. Fate of Nerve Agent Simulants on Concrete

    DTIC Science & Technology

    2005-10-01

    2.0 µL range was detected. INTRODUCTION The rate of decomposition of chemical warfare agents on substrates commonly present in a...Edgewood Chemical Biological Center (ECBC) ABSTRACT The nerve agent VX (O-ethyl S-[2-(diisopropylamino)ethyl]methylphosphonothiolate) has...from Aldrich Chemical Company and used as received. 31P NMR of the starting materials indicated that it was the correct compound. Concrete samples

  13. Concrete Durability: A Multibillion-Dollar Opportunity

    DTIC Science & Technology

    1987-01-01

    1985. Durability of building materials: Durability research in the United States and the influence of RILEM on durability research. Materiaux et...the porosity, microstructure. and permeability of the final concrete and, to a large * extent, its resistance to environmental attack. This is well...to resist dilation induced by freezing. Large-sized aggregate pieces are far more susceptible than small-sized pieces of aggregate of the same type and

  14. Rapid Polymer Concrete Repairs Using Available Fillers

    DTIC Science & Technology

    2006-02-01

    report was reviewed and cleared for public release by the Air Force Research Laboratory Tyndall Site (AFRL/MLQ) Public Affairs Office (PAO) and is...AFRL-ML-TY-TP-2005-4544 RAPID POLYMER CONCRETE REPAIRS USING AVAILABLE FILLERS David W. Fowler, Ph. D, P.E., Chul Suh, P.E., and...February 2006 DISTRIBUTION STATEMENT A: Approved for public release; distribution unlimited. Air Force Research Laboratory Materials and

  15. Production of Lunar Concrete Using Molten Sulfur

    NASA Technical Reports Server (NTRS)

    Omar, Husam A.

    1993-01-01

    The United States has made a commitment to go back to the moon to stay in the early part of the next century. In order to achieve this objective it became evident to NASA that a Lunar Outpost will be needed to house scientists and astronauts who will be living on the moon for extended periods of time. A study has been undertaken by the authors and supported by NASA to study the feasibility of using lunar regolith with different binders such as molten sulfur, epoxy or hydraulic cement as a construction material for different lunar structures. The basic premise of this study is that it will be more logical and cost effective to manufacture lunar construction materials utilizing indigenous resources rather than transporting needed materials from earth. Lunar concrete (made from Hydraulic Cement and lunar soil) has been studied and suggested as the construction material of choice for some of the lunar projects. Unfortunately, its hydration requires water which is going to be a precious commodity on the moon. Therefore this study explores the feasibility of using binders other than hydraulic cement such as sulfur or epoxy with lunar regolith as a construction material. This report describes findings of this study which deals specifically with using molten sulfur as a binder for Lunar concrete. It describes laboratory experiments in which the sulfur to lunar soil simulant ratios by weight were varied to study the minimum amount of sulfur required to produce a particular strength. The compressive and tensile strengths of these mixes were evaluated. Metal and fiber glass fibers were added to some of the mixes to study their effects on the compressive and tensile strengths. This report also describes experiments where the sulfur is melted and mixed with the lunar regolith in a specially designed vacuum chamber. The properties of the produced concrete were compared to those of concrete produced under normal pressure.

  16. Mix design and pollution control potential of pervious concrete with non-compliant waste fly ash.

    PubMed

    Soto-Pérez, Linoshka; Hwang, Sangchul

    2016-07-01

    Pervious concrete mix was optimized for the maximum compressive strength and the desired permeability at 7 mm/s with varying percentages of water-to-binder (W/B), fly ash-to-binder (FA/B), nano-iron oxide-to-binder (NI/B) and water reducer-to-binder (WR/B). The mass ratio of coarse aggregates in sizes of 4.75-9.5 mm to the binder was fixed at 4:1. Waste FA used in the study was not compliant with a standard specification for use as a mineral admixture in concrete. One optimum pervious concrete (Opt A) targeting high volume FA utilization had a 28-day compressive strength of 22.8 MPa and a permeability of 5.6 mm/s with a mix design at 36% W/B, 35% FA/B, 6% NI/B and 1.2% WR/B. The other (Opt B) targeting a less use of admixtures had a 28-day compressive strength and a permeability of 21.4 MPa and 7.6 mm/s, respectively, at 32% W/B, 10% FA/B, 0.5% NI/B and 0.8% WR/B. During 10 loads at a 2-h contact time each, the Opt A and Opt B achieved the average fecal coliform removals of 72.4% and 77.9% and phosphorus removals of 49.8% and 40.5%, respectively. Therefore, non-compliant waste FA could be utilized for a cleaner production of pervious concrete possessing a greater structural strength and compatible hydrological property and pollution control potential, compared to the ordinary pervious concrete.

  17. An investigation on the use of shredded waste PET bottles as aggregate in lightweight concrete.

    PubMed

    Akçaözoğlu, Semiha; Atiş, Cengiz Duran; Akçaözoğlu, Kubilay

    2010-02-01

    In this work, the utilization of shredded waste Poly-ethylene Terephthalate (PET) bottle granules as a lightweight aggregate in mortar was investigated. Investigation was carried out on two groups of mortar samples, one made with only PET aggregates and, second made with PET and sand aggregates together. Additionally, blast-furnace slag was also used as the replacement of cement on mass basis at the replacement ratio of 50% to reduce the amount of cement used and provide savings. The water-binder (w/b) ratio and PET-binder (PET/b) ratio used in the mixtures were 0.45 and 0.50, respectively. The size of shredded PET granules used in the preparation of mortar mixtures were between 0 and 4 mm. The results of the laboratory study and testing carried out showed that mortar containing only PET aggregate, mortar containing PET and sand aggregate, and mortars modified with slag as cement replacement can be drop into structural lightweight concrete category in terms of unit weight and strength properties. Therefore, it was concluded that there is a potential for the use of shredded waste PET granules as aggregate in the production of structural lightweight concrete. The use of shredded waste PET granules due to its low unit weight reduces the unit weight of concrete which results in a reduction in the death weight of a structural concrete member of a building. Reduction in the death weight of a building will help to reduce the seismic risk of the building since the earthquake forces linearly dependent on the dead-weight. Furthermore, it was also concluded that the use of industrial wastes such as PET granules and blast-furnace slag in concrete provides some advantages, i.e., reduction in the use of natural resources, disposal of wastes, prevention of environmental pollution, and energy saving.

  18. An investigation on the use of shredded waste PET bottles as aggregate in lightweight concrete

    SciTech Connect

    Akcaoezoglu, Semiha; Atis, Cengiz Duran; Akcaoezoglu, Kubilay

    2010-02-15

    In this work, the utilization of shredded waste Poly-ethylene Terephthalate (PET) bottle granules as a lightweight aggregate in mortar was investigated. Investigation was carried out on two groups of mortar samples, one made with only PET aggregates and, second made with PET and sand aggregates together. Additionally, blast-furnace slag was also used as the replacement of cement on mass basis at the replacement ratio of 50% to reduce the amount of cement used and provide savings. The water-binder (w/b) ratio and PET-binder (PET/b) ratio used in the mixtures were 0.45 and 0.50, respectively. The size of shredded PET granules used in the preparation of mortar mixtures were between 0 and 4 mm. The results of the laboratory study and testing carried out showed that mortar containing only PET aggregate, mortar containing PET and sand aggregate, and mortars modified with slag as cement replacement can be drop into structural lightweight concrete category in terms of unit weight and strength properties. Therefore, it was concluded that there is a potential for the use of shredded waste PET granules as aggregate in the production of structural lightweight concrete. The use of shredded waste PET granules due to its low unit weight reduces the unit weight of concrete which results in a reduction in the death weight of a structural concrete member of a building. Reduction in the death weight of a building will help to reduce the seismic risk of the building since the earthquake forces linearly dependant on the dead-weight. Furthermore, it was also concluded that the use of industrial wastes such as PET granules and blast-furnace slag in concrete provides some advantages, i.e., reduction in the use of natural resources, disposal of wastes, prevention of environmental pollution, and energy saving.

  19. Seismic retrofitting of reinforced concrete frame structures using GFRP-tube-confined-concrete composite braces

    NASA Astrophysics Data System (ADS)

    Moghaddasi B., Nasim S.; Zhang, Yunfeng; Hu, Xiaobin

    2012-03-01

    This paper presents a new type of structural bracing intended for seismic retrofitting use in framed structures. This special composite brace, termed glass-fiber-reinforced-polymer (GFRP)-tube-confined-concrete composite brace, is comprised of concrete confined by a GFRP tube and an inner steel core for energy dissipation. Together with a contribution from the GFRP-tube confined concrete, the composite brace shows a substantially increased stiffness to control story drift, which is often a preferred feature in seismic retrofitting. An analysis model is established and implemented in a general finite element analysis program — OpenSees, for simulating the load-displacement behavior of the composite brace. Using this model, a parametric study of the hysteretic behavior (energy dissipation, stiffness, ductility and strength) of the composite brace was conducted under static cyclic loading and it was found that the area ratio of steel core to concrete has the greatest influence among all the parameters considered. To demonstrate the application of the composite brace in seismic retrofitting, a three-story nonductile reinforced concrete (RC) frame structure was retrofitted with the composite braces. Pushover analysis and nonlinear time-history analyses of the retrofitted RC frame structure was performed by employing a suite of 20 strong ground motion earthquake records. The analysis results show that the composite braces can effectively reduce the peak seismic responses of the RC frame structure without significantly increasing the base shear demand.

  20. Behaviour of Recycled Coarse Aggregate Concrete: Age and Successive Recycling

    NASA Astrophysics Data System (ADS)

    Sahoo, Kirtikanta; Pathappilly, Robin Davis; Sarkar, Pradip

    2016-06-01

    Recycled Coarse Aggregate (RCA) concrete construction technique can be called as `green concrete', as it minimizes the environmental hazard of the concrete waste disposal. Indian standard recommends target mean compressive strength of the conventional concrete in terms of water cement ratio ( w/ c). The present work is an attempt to study the behaviour of RCA concrete from two samples of parent concrete having different age group with regard to the relationship of compressive strength with water cement ratios. Number of recycling may influence the mechanical properties of RCA concrete. The influence of age and successive recycling on the properties such as capillary water absorption, drying shrinkage strain, air content, flexural strength and tensile splitting strength of the RCA concrete are examined. The relationship between compressive strength at different w/ c ratios obtained experimentally is investigated for the two parameters such as age of parent concrete and successive recycling. The recycled concrete using older recycled aggregate shows poor quality. While the compressive strength reduces with successive recycling gradually, the capillary water absorption increases abruptly, which leads to the conclusion that further recycling may not be advisable.

  1. Review of concrete biodeterioration in relation to nuclear waste.

    PubMed

    Turick, Charles E; Berry, Christopher J

    2016-01-01

    Storage of radioactive waste in concrete structures is a means of containing wastes and related radionuclides generated from nuclear operations in many countries. Previous efforts related to microbial impacts on concrete structures that are used to contain radioactive waste showed that microbial activity can play a significant role in the process of concrete degradation and ultimately structural deterioration. This literature review examines the research in this field and is focused on specific parameters that are applicable to modeling and prediction of the fate of concrete structures used to store or dispose of radioactive waste. Rates of concrete biodegradation vary with the environmental conditions, illustrating a need to understand the bioavailability of key compounds involved in microbial activity. Specific parameters require pH and osmotic pressure to be within a certain range to allow for microbial growth as well as the availability and abundance of energy sources such as components involved in sulfur, iron and nitrogen oxidation. Carbon flow and availability are also factors to consider in predicting concrete biodegradation. The microbial contribution to degradation of the concrete structures containing radioactive waste is a constant possibility. The rate and degree of concrete biodegradation is dependent on numerous physical, chemical and biological parameters. Parameters to focus on for modeling activities and possible options for mitigation that would minimize concrete biodegradation are discussed and include key conditions that drive microbial activity on concrete surfaces.

  2. Phenomena of Foamed Concrete under Rolling of Aircraft Wheels

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  3. Prompt gamma analysis of chlorine in concrete for corrosion study.

    PubMed

    Naqvi, A A; Nagadi, M M; Al-Amoudi, O S B

    2006-02-01

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine gamma-rays and calcium gamma-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine gamma-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  4. Mechanical Model for Dynamic Behavior of Concrete Under Impact Loading

    NASA Astrophysics Data System (ADS)

    Sun, Yuanxiang

    Concrete is a geo-material which is used substantively in the civil building and military safeguard. One coupled model of damage and plasticity to describe the complex behavior of concrete subjected to impact loading is proposed in this research work. The concrete is assumed as homogeneous continuum with pre-existing micro-cracks and micro-voids. Damage to concrete is caused due to micro-crack nucleation, growth and coalescence, and defined as the probability of fracture at a given crack density. It induces a decrease of strength and stiffness of concrete. Compaction of concrete is physically a collapse of the material voids. It produces the plastic strain in the concrete and, at the same time, an increase of the bulk modulus. In terms of crack growth model, micro-cracks are activated, and begin to propagate gradually. When crack density reaches a critical value, concrete takes place the smashing destroy. The model parameters for mortar are determined using plate impact experiment with uni-axial strain state. Comparison with the test results shows that the proposed model can give consistent prediction of the impact behavior of concrete. The proposed model may be used to design and analysis of concrete structures under impact and shock loading. This work is supported by State Key Laboratory of Explosion science and Technology, Beijing Institute of Technology (YBKT14-02).

  5. Composition of Meridiani Hematite-rich Spherules: A Mass-Balance Mixing-Model Approach

    NASA Astrophysics Data System (ADS)

    Jolliff, B. L.; Athena Science Team

    2005-03-01

    A mass-balance model using APXS data and microscopic images indicates that the composition of spherules ("blueberries"), found at the Meridiani site by the Mars Exploration Rover Opportunity and thought to be concretions, contain ~45-60 wt% hematite.

  6. Radionuclide Retention in Concrete Waste Forms

    SciTech Connect

    Mattigod, Shas V.; Bovaird, Chase C.; Wellman, Dawn M.; Wood, Marcus I.

    2010-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how waste form performance is affected by the full range of environmental conditions within the disposal facility; the process of waste form aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of waste form aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the waste forms come in contact with groundwater. The information presented in the report provides data that 1) quantify radionuclide retention within concrete waste form materials similar to those used to encapsulate waste in the Low-Level Waste Burial Grounds (LLBG); 2) measure the effect of concrete waste form properties likely to influence radionuclide migration; and 3) quantify the stability of uranium-bearing solid phases of limited solubility in concrete.

  7. Sonic inspection of concrete bridge decks

    NASA Astrophysics Data System (ADS)

    Costley, R. Daniel; Boudreaux, Gary; Ramsey, William Gene

    2003-10-01

    One technique for determining the integrity of concrete structures, such as bridge decks, involves dragging a chain across it and listening to the audible response. A distinctive, hollow sound is produced when a chain is dragged over a section of concrete containing a delamination. This technique has been automated by recording the sound produced by a dragging chain with a suitable microphone and processing these signals with a minicomputer to distinguish between ``good'' and ``bad'' sections of concrete. The equipment is mounted on a hand-pushed cart with chains attached so that they drag along the surface of the deck. In addition, the microphone is mounted in such a way, using standard noise control techniques, so that external noise is minimized. Traffic noise is filtered electronically. These improvements make the technique operator independent and allow inspections to be made in noisy environments. Another advantage is that this approach produces an objective record of the inspection, available both electronically and in hardcopy. These records can be compared to past and future inspections, allowing the inspectors to monitor the health of the structure. Results from bridge deck inspections will be presented, along with a description of the device and the signal processing techniques.

  8. Monitoring corrosion in reinforced concrete structures

    NASA Astrophysics Data System (ADS)

    Kung, Peter; Comanici, Maria I.

    2014-06-01

    Many defects can cause deterioration and cracks in concrete; these are results of poor concrete mix, poor workmanship, inadequate design, shrinkage, chemical and environmental attack, physical or mechanical damage, and corrosion of reinforcing steel (RS). We want to develop a suite of sensors and systems that can detect that corrosion is taking place in RS and inform owners how serious the problem is. By understanding the stages of the corrosion process, we can develop special a sensor that detects each transition. First, moisture ingress can be monitored by a fiber optics humidity sensor, then ingress of Chloride, which acts as a catalyst and accelerates the corrosion process by converting iron into ferrous compounds. We need a fiber optics sensor which can quantify Chloride ingress over time. Converting ferric to ferrous causes large volume expansion and cracks. Such pressure build-up can be detected by a fiber optic pressure sensor. Finally, cracks emit acoustic waves, which can be detected by a high frequency sensor made with phase-shifted gratings. This paper will discuss the progress in our development of these special sensors and also our plan for a field test by the end of 2014. We recommend that we deploy these sensors by visually inspecting the affected area and by identifying locations of corrosion; then, work with the designers to identify spots that would compromise the integrity of the structure; finally, drill a small hole in the concrete and insert these sensors. Interrogation can be done at fixed intervals with a portable unit.

  9. Room air conditioning by means of overnight cooling of the concrete ceiling

    SciTech Connect

    Meierhans, R.A.

    1996-11-01

    Active control of the storage mass of an office building in Horgen, Switzerland, by means of a water-carrying pipe system installed in the core of the concrete ceilings has already proven successful over a period of three summers. Comfort measurements in practice and under load-simulated operating conditions have confirmed the suitability of the system for small and medium loads. During the day, only the supply air volume of the mechanical ventilation system is cooled to a temperature of 19 C (66.2 F); the heat stored in the concrete mass is discharged overnight. However, the proportion of cooling water generated in the free-cooling mode remained below expectations. This is attributable to the clearly lower inner thermal loads and the facade insulation, which is no longer up-to-date. Since the building already dispenses a part of its heat via the facade on cooler summer nights, the utilization efficiency of the free concrete core-cooling system diminishes somewhat in importance. The experience gained, however, is recommendation enough for the employment of the embedded pipework system, not only for the cooling but also for the heating of well-insulated buildings with small and medium cooling loads.

  10. Assessment of corrosion rate in prestressed concrete with acoustic emission

    NASA Astrophysics Data System (ADS)

    Mangual, Jesé; ElBatanouny, Mohamed K.; Vélez, William; Ziehl, Paul; Matta, Fabio; González, Miguel

    2011-04-01

    Acoustic Emission (AE) sensing was employed to assess the rate of corrosion of steel strands in small scale concrete block specimens. The corrosion process was accelerated in a laboratory environment using a potentiostat to supply a constant potential difference with a 3% NaCl solution as the electrolyte. The embedded prestressing steel strand served as the anode, and a copper plate served as the cathode. Corrosion rate, half-cell potential measurements, and AE activity were recorded continuously throughout each test and examined to assess the development of corrosion and its rate. At the end of each test the steel strands were cleaned and re-weighed to determine the mass loss and evaluate it vis-á-vis the AE data. The initiation and propagation phases of corrosion were correlated with the percentage mass loss of steel and the acquired AE signals. Results indicate that AE monitoring may be a useful aid in the detection and differentiation of the steel deterioration phases, and estimation of the locations of corroded areas.

  11. Application of microorganisms in concrete: a promising sustainable strategy to improve concrete durability.

    PubMed

    Wang, Jianyun; Ersan, Yusuf Cagatay; Boon, Nico; De Belie, Nele

    2016-04-01

    The beneficial effect of microbially induced carbonate precipitation on building materials has been gradually disclosed in the last decade. After the first applications of on historical stones, promising results were obtained with the respect of improved durability. An extensive study then followed on the application of this environmentally friendly and compatible material on a currently widely used construction material, concrete. This review is focused on the discussion of the impact of the two main applications, bacterial surface treatment and bacteria based crack repair, on concrete durability. Special attention was paid to the choice of suitable bacteria and the metabolic pathway aiming at their functionality in concrete environment. Interactions between bacterial cells and cementitious matrix were also elaborated. Furthermore, recommendations to improve the effectiveness of bacterial treatment are provided. Limitations of current studies, updated applications and future application perspectives are shortly outlined.

  12. Detection and Identification of Concrete Cracking in Reinforced Concrete by Acoustic Emission

    NASA Astrophysics Data System (ADS)

    Ohtsu, Masayasu

    2003-03-01

    Cracking in concrete due to corrosion of rebars in reinforced concrete is one of critical problems in concrete structures. To clarify cracking process, acoustic emission (AE) measurement is applied. In an accelerated corrosion test, AE events are detected and monitored continuously. Comparing with permeation of chloride ions, it is found that onset of corrosion and nucleation of cracking can be qualified from AE activity. Applying SiGMA procedure, nucleation mechanisms of cracks due to expansion of corrosive product are identified. During extension of the surface crack, tensile cracks are nucleated dominantly. For the spalling crack, both the tensile and the shear cracks are generated, as the former dominates the latter approaching to a stress-free surface. In contrast, it is found that the internal crack is nucleated mainly due to shear-crack motion.

  13. Passivation and electrochemical behavior of 316L stainless steel in chlorinated simulated concrete pore solution

    NASA Astrophysics Data System (ADS)

    Luo, Hong; Su, Huaizhi; Dong, Chaofang; Li, Xiaogang

    2017-04-01

    In this paper, the passivation and electrochemical behavior of 316L stainless steel in chlorinated simulated concrete pore solutions at different pH was evaluated by potentiodynamic measurements, electrochemical impedance spectroscopy. The composition of the passive film and surface morphology were investigated by X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and scanning electron microscopy, respectively. The results reveal that metastable pitting susceptibility, stable pitting corrosion, and composition of the passive film are influenced by pH value. After long time immersion, a bilayer structure passive film can be formed in this environment. The appearance of molybdates on the outermost surface layer, further enhancing the stability of the passive film. Moreover, the good pitting corrosion resistance of 316L stainless steel in simulated concrete pore solution without carbonated is mainly due to the presence of high Cr/Fe ratio and molybdates ions within the passive film.

  14. Concrete decontamination by Electro-Hydraulic Scabbling (EHS). Topical report

    SciTech Connect

    1996-03-30

    Electro-Hydraulic Scabbling (EHS) technology and equipment for decontaminating concrete structures from radionuclides, organic substances, and hazardous metals is being developed by Textron Systems Division (TSD). This wet scabbling technique involves the generation of powerful shock waves and intense cavitation by a strong pulsed electric discharge in a water layer at the concrete surface. The high pressure impulse results in stresses which crack and peel off a concrete layer of a controllable thickness. Scabbling produces contaminated debris of relatively small volume which can be easily removed, leaving clean bulk concrete. This new technology is being developed under Contract No. DE-AC21-93MC30164. The project objective is to develop and demonstrate a cost-efficient, rapid, controllable process to remove the surface layer of contaminated concrete while generating minimal secondary waste. The primary target of this program is uranium-contaminated concrete floors which constitute a substantial part of the contaminated area at DOE weapon facilities.

  15. Relationship between liquid sorptivity and capillarity in concrete

    SciTech Connect

    Hanzic, L.; Ilic, R

    2003-09-01

    Neutron radiography (NR) was applied to study liquid transport processes in concrete. With this method, it is possible to monitor the liquid distribution inside specimens and to measure the height of the liquid front for liquids of high hydrogen content inside concrete. The experiment was performed with water and fuel oil for three different types of concrete. The results are compared with the sorptivity measured by the gravimetric method. It is shown that the ratio between the capillarity coefficient and sorptivity depends upon the combination of liquid and solid phases. For water, this value was found to be 5.5{+-}0.6, 5.8{+-}0.6 and 7.1{+-}0.7 in concrete without additives, concrete with an air-entraining agent and concrete with a plasticizer, respectively. For fuel oil, the value is about 50% higher than that for water.

  16. Hydrothermal alteration of concrete: Yucca Mountain repository analogues

    SciTech Connect

    Myers, K.B.; Meike, A.

    1997-10-01

    Concrete could comprise a major share of construction materials present in the potential Yucca Mountain high-level radioactive waste repository. Concrete and shotcrete would be used as mechanical support (precast concrete liners), or road bed (invert) in repository emplacement drifts. These drifts could reach at least 150 to 200{degrees}C for extended periods of time, possibly in the presence of fluids. This study characterizes chemical and structural transformations in concrete that may occur as a result of a repository hydrothermal cycle. The specific concrete formulation to be used in the potential Yucca Mountain repository had not been determined at the time of the experiment. Invert and Fibercrete{sup TM} materials from the Exploratory Studies Facility (ESF) were chosen for these experiments as representatives of standard construction concrete used in this setting.

  17. Behaviour of reinforced concrete beams with confined concrete related to ultimate bending and shear strength

    NASA Astrophysics Data System (ADS)

    Tee, Horng Hean; Al-Sanjery, Kousay; Chiang, Jeffrey Choong Luin

    2017-03-01

    This research is to investigate the behaviour of over-balanced High Strength Reinforced Concrete Beams with the compression zone confined with spiral / helical steel reinforcements. The study covered beam behaviour with respect to flexural strength, shear strength, deflection and cracking related to confined concrete. Six 200mm (width) X 300mm (depth) X 3000mm (length) Reinforced Concrete (RC) Beams, the first three beams incorporating steel ratio of 1.42ρb and the remaining 1.64ρb were tested under a four point static load test. The confinement of the concrete was carried out using spiral reinforcements of diameter 6mm and yield stress of 406N/mm2 with pitches of 50mm and 100mm. Measurements of deflection, cracking, and strains on both main reinforcements and concrete of the beams were taken. At the same level of stress, beams with confined concrete strained less than control beams without confinement for both tensile strain at the main steel reinforcement and compressive strain across the compression zone of concrete. Deflections of beams with helical confinement were less than the control beams. All beams failed in shear / flexural mode and gave fair warning against failure, more specifically beams with 1.42ρb, which is not normally associated with shear-type failure of beams which are over reinforced. The early shear failure prevented the beams from achieving its full utilisation of the ultimate strength. It is recommended that for over-reinforced confined concrete beams, the shear strength of beams should be based on using the diagonal compressive strut angle (θ) of more than 22 degrees recommended in Eurocode 2 (EC2), hence giving the beam higher safety factor against shear failure. All samples exhibited flexure and shear cracks in a manner which gave a good warning against failure. The ratio of the failure load to the theoretical ultimate load for shear ranged between 0.98 and 1.25 while the ratio of the failure load to the ultimate flexural load ranged

  18. The effects of utilizing silica fume in Portland Cement Pervious Concrete

    NASA Astrophysics Data System (ADS)

    Mann, Daniel Allen

    Silica fume has long been used as a supplementary cementing material to provide a high density, high strength, and durable building material. Silica fume has a particle size a fraction of any conventional cement, which allows it to increase concrete strength by decreasing the porosity especially near the aggregates surface. Because Portland Cement Pervious Concrete (PCPC) has a smaller bond area between aggregate and paste, silica fume has significant impacts on the properties of the PCPC. The research in this paper studies the workability of a cement paste containing silica fume in addition to analyzing the results of testing on Portland Cement Pervious Concrete mixtures that also contained silica fume. Testing conducted included a study of the effects of silica fume on cement's rheological properties at various dosage rates ranging from zero to ten percent by mass. It was determined that silica fume has negligible effects on the viscosity of cement paste until a dosage rate of five percent, at which point the viscosity increases rapidly. In addition to the rheological testing of the cement paste, trials were also conducted on the pervious concrete samples. Sample groups included mixes with river gravel and chipped limestone as aggregate, washed and unwashed, and two different void contents. Workability tests showed that mixtures containing a silica fume dosage rate of 5 percent or less had comparable or slightly improved workability when compared to control groups. Workability was found to decrease at a 7 percent dosage rate. Samples were tested for compressive strength at 7 and 28 days and splitting tensile strength at 28 days. It was found in most sample groups, strength increased with dosage rates of 3 to 5 percent but often decreased when the dosage reached 7 percent. Abrasion testing showed that both samples containing washed aggregate and samples containing silica fume exhibited a reduced mass loss.

  19. Evaluation of Concrete Mixtures for Use in Underwater Repairs

    DTIC Science & Technology

    1988-04-01

    Review ....... . of This Study Scope ••••••••••••••••••• PART II: EXPERIMENTAL PROGRAM Phase I: Concrete Mixture Proportions ....... Phase I...to determine the combination of materials necessary to produce concrete with the desired properties. Significant correlations that exist between...Test Procedures . . . . . . . . . . . . . . ...... Phase II: Concrete Mixture Proportions Phase II: Test Procedures . . . . . . . ..... PART III

  20. Precast/Prestressed Concrete Experiments - Series 1 (Volume 1)

    DTIC Science & Technology

    2008-11-01

    specific retrofit. To illustrate this concept, the blast resistances of non-load bearing precast , prestressed concrete sandwich wall panels (WP) are...resistances of non-load bearing precast , prestressed concrete sandwich wall panels (WP) are examined. These components are used extensively in...are examined for each facet of the Portland Cement Associations’ membership. This includes Prestressed/ Precast Concrete Wall Panels for the

  1. 19. Virginia Route 605 grade separation structure. This reinforced concrete ...

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

    19. Virginia Route 605 grade separation structure. This reinforced concrete rigid frame structure. This reinforced concrete rigid frame structure was built in 1950. It is an example of the most common ornament used on the parkway where the headwall, wingwalls, and railing is faced rusticated stone, but not the interior abutment walls and the bottom of the arch are plain concrete. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  2. Residual Strength of Blast Damaged Reinforced Concrete Columns

    DTIC Science & Technology

    2010-07-01

    both reinforced concrete columns and shear walls during seismic investigations [14]. 4.2.3. Effect of longitudinal reinforcement ratio As the...Residual strength of blast damaged reinforced concrete columns Xiaoli Bao, Bing Li* School of Civil and Environmental Engineering, Nanyang...DATES COVERED - 4. TITLE AND SUBTITLE Residual strength of blast damaged reinforced concrete columns 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  3. Radiation shielding properties of concretes including quiclime (CaO)

    NASA Astrophysics Data System (ADS)

    Özavcı, S.; ćetin, B.

    2017-02-01

    Lime is one of the oldest binder material used for concrete production. In this study, the shielding properties of γ-rays by Quicklime concretes have been investigated for concretes containing different rates of wood ash, küfenki stones, disbudak tree leaf juice and water. Measurements performed using a gamma spectrometer that contains an NaI(Tl) detector and MCA at 662, 1173 and 1332 keV.

  4. Underwater Nondestructive Testing of Concrete: An Evaluation of Techniques.

    DTIC Science & Technology

    1986-02-01

    waterfront facilities, concrete, Schmidt hammer, rebar location, ultrasonic testing 20 ABSTRACT (Co,id irn. r1.0,e id* it necessary and idenlty by...construction material used by the Navy in waterfront structures. It is estimated that more than 40% of Navy piers consist of a concrete deck supported...concrete, pile-supported, waterfront structure, located at the North Island Naval Air Station in Zan Diego. The pier is supported by 791 piles and

  5. Failure of underground concrete structures subjected to blast loadings

    NASA Technical Reports Server (NTRS)

    Ross, C. A.; Nash, P. T.; Griner, G. R.

    1979-01-01

    The response and failure of two edges of free reinforced concrete slabs subjected to intermediate blast loadings are examined. The failure of the reinforced concrete structures is defined as a condition where actual separation or fracture of the reinforcing elements has occurred. Approximate theoretical methods using stationary and moving plastic hinge mechanisms with linearly varying and time dependent loadings are developed. Equations developed to predict deflection and failure of reinforced concrete beams are presented and compared with the experimental results.

  6. Porous Portland Cement Concrete; The State of the Art.

    DTIC Science & Technology

    This study investigates the current state of the art relating to the production and use of those porous portland cement concretes that may be...suitable for the construction of porous portland cement friction courses. Porous concretes produced by gap grading or elimination of the fine aggregate...applications discussed include: a no-fines pavement layer, porous portland cement concrete pavements, and porous pavement edge drains or porous hard shoulders

  7. Durability of high performance concrete in magnesium brine

    SciTech Connect

    Tumidajski, P.J.; Chan, G.W.

    1996-04-01

    The durability of six concretes exposed to magnesium brine was monitored for 24 months. These concretes incorporated ground granulated blast furnace slag, silica fume, and fly ash. The Young`s moduli, chloride penetrations, and median pore diameters were measured. There was a cyclic nature to these properties due to the complicated interaction of hydration with magnesium, chloride and sulfate attack. Mineral admixtures, in combination with a long initial cure, provided the most durable concrete. Concrete with 65% slag had the best overall durability to the brines tested.

  8. Carbonate concretions: an ideal sedimentary host for microfossils.

    USGS Publications Warehouse

    Blome, C.D.; Albert, N.R.

    1985-01-01

    Enhanced preservation correlates with early diagenetic concretion formation at or near the sediment-water interface and with higher carbonate, organic material, and metallic cation content than in surrounding rocks. Early diagenetic growth is inferred by diverging sedimentary laminations and small-scale sedimentary structures in fossiliferous carbonate concretions. High initial concentration of microorganisms or fecal pellets may commonly be responsible for incipient carbonate-concretion growth. Excellent preservation is demonstrated by radiolarians and palynomorphs extracted from a carbonate concretion from the Middle Jurassic Shelikof Formation, S Alaska.-from Authors

  9. Performance Enhancement of the Automated Concrete Evaluation System (ACES)

    SciTech Connect

    Baumgart,C.W.; Cave,S.P.; Linder,K.E.

    2002-02-14

    The objective of this proposed research is to improve and expand the detection and analysis capabilities of the automated, concrete evaluation (ACE) system. MoDOT and Honeywell jointly developed this system. The focus of this proposed research will be on the following: Coordination of concrete imaging efforts with other states, Validation and testing of the ACE system on a broad range of concrete samples, and Identification and development of software and hardware enhancements. These enhancements will meet the needs of diverse users in the field of concrete materials, construction, and research.

  10. Development of ultrasonic methods for the nondestructive inspection of concrete

    NASA Astrophysics Data System (ADS)

    Claytor, T. M.; Ellingson, W. A.

    1983-08-01

    Nondestructive inspection of Portland cement and refractory concrete is conducted to determine strength, thickness, presence of voids or foreign matter, presence of cracks, amount of degradation due to chemical attack, and other properties without the necessity of coring the structure (which is usually accomplished by destructively removing a sample). The state of the art of acoustic nondestructive testing methods for Portland cement and refractory concrete is reviewed. Most nondestructive work on concrete has concentrated on measuring acoustic velocity by through transmission methods. Development of a reliable pitch-catch or pulse-echo system would provide a method of measuring thickness with access from only one side of the concrete.

  11. Protecting steel in concrete in the Persian Gulf

    SciTech Connect

    Matta, Z.G. )

    1994-06-01

    The climate and geomorphology of the Persian Gulf make it one of the world's most severe environments for reinforced concrete. The concrete mix ingredients are usually contaminated with chloride, and the environment around reinforced concrete structures also contains salts, both under- and above-ground. Prevailing high temperatures also promote rapid rates of corrosion. Fusion-bonded epoxy-coated rebar, polyvinyl butyral-based coated rebar, calcium nitrile corrosion-inhibiting admixture, and microsilica are reviewed as corrosion prevention measures for steel in concrete for Persian Gulf service. Detrimental effects and user-friendliness are discussed.

  12. Life Cycle Cost Analysis of Ready Mix Concrete Plant

    NASA Astrophysics Data System (ADS)

    Topkar, V. M.; Duggar, A. R.; Kumar, A.; Bonde, P. P.; Girwalkar, R. S.; Gade, S. B.

    2013-11-01

    India, being a developing nation is experiencing major growth in its infrastructural sector. Concrete is the major component in construction. The requirement of good quality of concrete in large quantities can be fulfilled by ready mix concrete batching and mixing plants. The paper presents a technique of applying the value engineering tool life cycle cost analysis to a ready mix concrete plant. This will help an investor or an organization to take investment decisions regarding a ready mix concrete facility. No economic alternatives are compared in this study. A cost breakdown structure is prepared for the ready mix concrete plant. A market survey has been conducted to collect realistic costs for the ready mix concrete facility. The study establishes the cash flow for the ready mix concrete facility helpful in investment and capital generation related decisions. Transit mixers form an important component of the facility and are included in the calculations. A fleet size for transit mixers has been assumed for this purpose. The life cycle cost has been calculated for the system of the ready mix concrete plant and transit mixers.

  13. Microstructural characterization of concrete prepared with recycled aggregates.

    PubMed

    Guedes, Mafalda; Evangelista, Luís; de Brito, Jorge; Ferro, Alberto C

    2013-10-01

    Several authors have reported the workability, mechanical properties, and durability of concrete produced with construction waste replacing the natural aggregate. However, a systematic microstructural characterization of recycled aggregate concrete has not been reported. This work studies the use of fine recycled aggregate to replace fine natural aggregate in the production of concrete and reports the resulting microstructures. The used raw materials were natural aggregate, recycled aggregate obtained from a standard concrete, and Portland cement. The substitution extent was 0, 10, 50, and 100 vol%; hydration was stopped at 9, 24, and 96 h and 28 days. Microscopy was focused on the cement/aggregate interfacial transition zone, enlightening the effect of incorporating recycled aggregate on the formation and morphology of the different concrete hydration products. The results show that concretes with recycled aggregates exhibit typical microstructural features of the transition zone in normal strength concrete. Although overall porosity increases with increasing replacement, the interfacial bond is apparently stronger when recycled aggregates are used. An addition of 10 vol% results in a decrease in porosity at the interface with a corresponding increase of the material hardness. This provides an opportunity for development of increased strength Portland cement concretes using controlled amounts of concrete waste.

  14. Dynamic Impact Analyses and Tests of Concrete Overpacks - 13638

    SciTech Connect

    Lee, Sanghoon; Cho, Sang-Soon; Kim, Ki-Young; Jeon, Je-Eon; Seo, Ki-Seog

    2013-07-01

    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 while 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)

  15. Properties of Refractory Concrete in Tension and Compression

    NASA Technical Reports Server (NTRS)

    Sampson, Jeffrey

    2009-01-01

    Refractory concrete on the LC-39A Flame Deflector has been damaged during multiple Space Shuttle launches (e.g. STS-124, STS-126, STS-119, and STS-125, STS-127). These events have prompted a better understanding of the system via an analytical model of the Flame Deflector assembly to include the Fondu Fyre refractory concrete. This model requires test data inputs of the refractory concrete's mechanical properties, which include stress versus strain curves in tension and compression, modulus of elasticity, and Poisson's ratio. Sections of Fondu Fyre refractory concrete removed from the LC-39A Flame Deflector were provided for this testing.

  16. Modification in Cay Concrete Properties During Fluid Flow Permeability Measurement

    NASA Astrophysics Data System (ADS)

    Solomon, F.; Ekolu, S. O.

    2015-11-01

    In this paper, two methods consisting of triaxial water permeability and water penetration were used to evaluate the changes occurring in the pores of clay concretes during the tests. Triaxial permeability is generally used for concrete with higher permeability while concretes with very low permeability are suited for the penetration method. Clay concrete specimens of 0 to 40% clay content were used in the study. The concrete mixes had water-to-cement ratios (w/c) of 0.70, 0.75, 0.80, 0.85, and the cementitious content 380 and 450 kg/m3. Results show that concrete gains moisture during wetting at a much faster rate than loses it during subsequent drying. This could be explained by the contribution of suction pressure created upon drying. When water penetration pressure is applied, more water is driven into pore space that could be responsible for changing the network of the voids. Pore structure during drying may certainly be different in size and shape than its form during wetting, leading to a consequent effect on the permeability of the clay concretes. The modification could be one reason why the moisture gain percentage in clay concretes was higher than in normal concretes.

  17. An investigation of tendon sheathing filler migration into concrete

    SciTech Connect

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

    1998-03-01

    During some of the inspections at nuclear power plants with prestressed concrete containments, it was observed that the containments has experienced leakage of the tendon sheathing filler (i.e., streaks). The objective of this activity was to provide an indication of the extent of tendon sheathing filler leakage into the concrete and its affects on concrete properties. Literature was reviewed and concrete core samples were obtained from the Trojan Nuclear Plant and tested. The literature primarily addressed effects of crude or lubricating oils that are known to cause concrete damage. However, these materials have significantly different characteristics relative to the materials used as tendon sheathing fillers. Examination and testing of the concrete cores indicated that the appearance of tendon sheathing filler on the concrete surface was due to leakage from the conduits and its subsequent migration through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks and there was no perceptible movement into the concrete. Results of compressive strength testing indicated that the concrete quality was consistent in the containment and that the strength had increased over 40% in 25.4 years relative to the average compressive strength at 28-days age.

  18. Prestressed concrete for the storage of liquefied gases

    SciTech Connect

    Bruggeling, A.S.G.

    1981-01-01

    Both concrete and prestressing-steel materials retain their strengths at cryogenic temperatures, making them ideal for LNG storage tanks and similar structures. Prestressed concrete lends itself to a wide variety of configurations, from containment dikes to integrated tank systems in which the steel, insulation, and concrete must interact efficiently. Of major importance in building prestressed-concrete storage tanks are the design loads and load factors to be adopted, especially the so-called special loads that depend on the nature and quantity of the product to be stored, the type of installation involved, the siting of the storage facilities, and the tank construction (flexible or rigid).

  19. The interaction between the atmosphere and curing concrete bridge decks

    NASA Astrophysics Data System (ADS)

    Wojcik, Gary S.

    The long-term durability of concrete can be compromised by excessive concrete temperatures or temperature gradients and lack of moisture during the first few days after placement. Because the concrete binder components undergo temperature-dependent hydration reactions during this period, atmospheric and construction conditions influence the ultimate concrete quality. To understand this interaction, curing concrete bridge energy balances were estimated with meteorological techniques and calorimetry and model experiments were performed. The agreement of concrete hydration heat estimates from the energy balances, calorimetry experiments, and model simulations validates our methodology and results. In Chapter 2, we estimate from meteorological measurements and techniques the energy balances of four curing concrete bridge decks. One challenge is to determine fluxes from small surfaces (largest horizontal dimension <50 m) in a heterogeneous landscape with methods that are best suited for larger, more homogeneous areas. Estimating the concrete heat generation provides the means to successfully meet this challenge. The energy balance and calorimetry estimates of 24 h concrete heat generation agree within 20%. Between 70--85% of the concrete's heat transfer occurs at its top surface and heat transfer through steel support beams can be significant. A new parameterization for computing bulk exchange coefficients for small areas is developed. Chapter 3, we improve with calorimetry experiments a simple bimolecular heat generation expression for hydrating binder. We show that this expression, with a new parameterization accounting for retarder effects on hydration rates, simulates temperatures to within 2°C and 72 h heat generation (˜265 kJ kg-1) to within 10% of the observed. In Chapter 4, we present models developed with the field and laboratory work and show that the highest concrete temperatures occur at high initial concrete temperatures and air temperatures and

  20. Deterioration of concrete structures in coastal environment due to carbonation.

    PubMed

    Balaji, K V G D; Gopalaraju, S S S V; Trilochan, Jena

    2010-07-01

    Failure of existing concrete structures takes place due to lack of durability, and not due to less structural strength. One of the important aspects of durability is carbonation depth. The rate of carbonation in concrete is influenced by both its physical properties and exposure conditions. Rebar corrodes when carbonation reaches to a depth of concrete cover provided. In the present work, various concrete structures with different life periods and exposed to different weather conditions have been considered to study the carbonation effect. It is observed that the effect of carbonation is more in the structures located near to the sea coast and on windward face of the structure.

  1. Delamination detection in reinforced concrete using thermal inertia

    SciTech Connect

    Del Grande, N K; Durbin, P F

    1998-11-30

    We investigated the feasibility of thermal inertia mapping for bridge deck inspections. Using pulsed thermal imaging, we heat-stimulated surrogate delaminations in reinforced concrete and asphalt-concrete slabs. Using a dual-band infrared camera system, we measured thermal inertia responses of Styrofoam implants under 5 cm of asphalt, 5 cm of concrete, and 10 cm of asphalt and concrete. We compared thermal maps from solar-heated concrete and asphalt-concrete slabs with thermal inertia maps from flash-heated concrete and asphalt-concrete slabs. Thermal inertia mapping is a tool for visualizing and quantifying subsurface defects. Physically, thermal inertia is a measure of the resistance of the bridge deck to temperature change. Experimentally, it is determined from the inverse slope of the surface temperature versus the inverse square root of time. Mathematically, thermal inertia is the square root of the product of thermal conductivity, density, and heat capacity. Thermal inertia mapping distinguishes delaminated decks which have below-average thermal inertias from normal or shaded decks. Key Words: Pulsed Thermal Imaging, Thermal Inertia, Detection Of Concrete Bridgedeck Delaminations

  2. 56. photographer unknown 14 October 1935 CONCRETE BLOCKS OF SOUTH ...

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

    56. photographer unknown 14 October 1935 CONCRETE BLOCKS OF SOUTH HALF OF SPILLWAY SHOWING STEEL REINFORCING OF BAFFLES. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  3. Development of ultrasonic methods for the nondestructive inspection of concrete

    SciTech Connect

    Claytor, T.N.; Ellingson, W.A.

    1983-08-01

    Nondestructive inspection of Portland cement and refractory concrete is conducted to determine strength, thickness, presence of voids or foreign matter, presence of cracks, amount of degradation due to chemical attack, and other properties without the necessity of coring the structure (which is usually accomplished by destructively removing a sample). This paper reviews the state of the art of acoustic nondestructive testing methods for Portland cement and refractory concrete. Most nondestructive work on concrete has concentrated on measuring acoustic velocity by through transmission methods. Development of a reliable pitch-catch or pulse-echo system would provide a method of measuring thickness with access from only one side of the concrete.

  4. Some engineering properties of heavy concrete added silica fume

    NASA Astrophysics Data System (ADS)

    Akkaş, Ayşe; Başyiǧit, Celalettin; Esen, Serap

    2013-12-01

    Many different types of building materials have been used in building construction for years. Heavy concretes can be used as a building material for critical building as it can contain a mixture of many heavy elements. The barite itself for radiation shielding can be used and also in concrete to produce the workable concrete with a maximum density and adequate structural strength. In this study, some engineering properties like compressive strength, elasticity modules and flexure strength of heavy concretes' added Silica fume have been investigated.

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

    SciTech Connect

    Oland, C.B.; Frohnsdorff, G.

    1995-12-31

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

  6. The effect of recycled concrete aggregate properties on the bond strength between RCA concrete and steel reinforcement

    SciTech Connect

    Butler, L. West, J.S.; Tighe, S.L.

    2011-10-15

    The purpose of this study was to investigate the influence that replacing natural coarse aggregate with recycled concrete aggregate (RCA) has on concrete bond strength with reinforcing steel. Two sources of RCA were used along with one natural aggregate source. Numerous aggregate properties were measured for all aggregate sources. Two types of concrete mixture proportions were developed replacing 100% of the natural aggregate with RCA. The first type maintained the same water-cement ratios while the second type was designed to achieve the same compressive strengths. Beam-end specimens were tested to determine the relative bond strength of RCA and natural aggregate concrete. On average, natural aggregate concrete specimens had bond strengths that were 9 to 19% higher than the equivalent RCA specimens. Bond strength and the aggregate crushing value seemed to correlate well for all concrete types.

  7. Resin systems for producing polymer concrete

    SciTech Connect

    Kukacka, L.E.

    1988-09-01

    When plastics are combined with mixtures of inorganic materials, high-strength, durable, fast-setting composites are produced. These materials are used in structural engineering and other applications, and as a result of the many commercial successes that have been achieved, considerable research and development work is in progress throughout the world. One family of polymer-based composites receiving considerable attention is called polymer concrete. Work in this area is directed toward developing new high-strength durable materials by combining cement and concrete technology with that of polymer chemistry. The purpose of this paper is to discuss the types of resins that can be used to form polymer concretes. Resin selection is normally based upon the desired properties for the composite and cost. However, the physical and chemical properties of the resins before and during curing are also important, particularly for field-applied materials. Currently, for normal temperature (0/degree/ to 30/degree/C) applications, epoxy resins, vinyl monomers such as polyester-styrene, methylmethacrylate, furfuryl alcohol, furan derivatives, urethane, and styrene, are being used. Styrene-trimethylolpropane trimethacrylate (TMPTMA) mixtures and styrene-acrylamide-TMPTMA mixtures yield composites with excellent hydrothermal stability at temperatures up to 150/degree/ and 250/degree/C, respectively, and organosiloxane resins have been successfully tested at 300/degree/C. Of equal importance is the selection of the composition of the inorganic phase of the composite, since chemical interactions between the two phases can significantly enhance the final properties. Further work to elucidate the mechanisms of these interactions is needed. 6 refs.

  8. Prestressed concrete using KEVLAR reinforced tendons

    SciTech Connect

    Dolan, C.W.

    1989-01-01

    KEVLAR is a high strength, high modulus synthetic fiber manufactured by the E.I. DuPont de Nemours Company. The fiber is resistant to chloride and alkali attack. The resistance is enhanced when the fibers are assembled into a resin matrix and fabricated as rods. These properties suggest that KEVLAR reinforced rods may be a substitute for high strength steel prestress tendons in certain applications such as bridge decks and parking structures. This dissertation presents the background, theoretical development, and experimental investigations of KEVLAR reinforced rod strength, anchorage, fabrication and performance in prestressed concrete structures. The study concludes that KEVLAR has significant potential for these prestressed concrete applications. However, the reliability of the long term anchorage of the KEVLAR reinforced rods must be improved before production applications are undertaken. KEVLAR has a low shear strength compared to its tensile capacity. The anchorage of KEVLAR reinforced rods is sensitive to the shear forces generated in the anchorage assembly. Finite element analyses, using interface elements to simulate the addition of a mold release agent in a conic anchor, predict the behavior of resin socketed anchors. Test results confirm that mold release agents reduce the anchor shear stresses and suggest that moderate strength resins may be used in the anchor. KEVLAR is nearly linearly elastic to failure, yet ductility of a structure is an important design concern. Prestressed concrete beam tests using both bonded and unbonded tendons demonstrated that ductile structural behavior is obtained. Methods of predicting the strength and deflection behavior of the prestressed beams are presented and the theoretical predictions are compared to the experimental results. The overall correlation between predicted and theoretical results is satisfactory.

  9. Durability of an inorganic polymer concrete coating

    NASA Astrophysics Data System (ADS)

    Wasserman, Kenneth

    The objective of the research program reported in this thesis is to evaluate the durability of an inorganic polymer composite coating exposed to freeze/thaw cycling and wet-dry cycling. Freeze/thaw cycling is performed following ASTM D6944-09 Standard Practice for Resistance of Cured Coatings to Thermal Cycling and wet/dry cycling is performed following guidelines set forth in a thesis written by Ronald Garon at Rutgers University. For both sets of experiments, four coating mixture proportions were evaluated. The variables were: silica/alumina ratio, mixing protocol using high shear and normal shear mixing, curing temperatures of 70 and 120 degrees Fahrenheit and use of nano size constituent materials. The mix with highest silica/alumina ratio was designated as Mix 1 and mixes with lower ratios were designated as Mix 2 and Mix 3. Mix 4 had nano silica particles. Four prisms were used for each variable including control that had no coating. The performance of the coating was evaluated using adhesion strength measured using: ASTM D7234 Test Method for Pull-Off Strength of Coatings on Concrete Using Portable Adhesion Testers. Tests were performed after every five consecutive cycles of thermal conditioning and six consecutive cycles of wet-dry exposure. Results from the thermal cycling and wet-dry testing demonstrate that all coating formulations are durable. The minimum adhesion strength was 300 psi even though a relatively weak base concrete surface was chosen for the study. The weak surface was chosen to simulate aged concrete surfaces present in actual field conditions. Due to the inherent nature of the test procedure the variation in test results is high. However, based on the test results, high shear mixer and high temperature curing are not recommended. As expected nano size constituent materials provide better performance.

  10. Innovative reuse of concrete slurry waste from ready-mixed concrete plants in construction products.

    PubMed

    Xuan, Dongxing; Zhan, Baojian; Poon, Chi Sun; Zheng, Wei

    2016-07-15

    Concrete slurry waste (CSW) is generated from ready-mixed concrete plants during concrete production and is classified as a corrosive hazardous material. If it is disposed of at landfills, it would cause detrimental effects for our surrounding environment and ecosystems due to its high pH value as well as heavy metal contamination and accumulation. A new method in this study has been introduced to effectively reuse CSW in new construction products. In this method, the calcium-silicate rich CSW in the fresh state was considered as a cementitious paste as well as a CO2 capture medium. The experimental results showed that the pH values of the collected CSWs stored for 28 days ranged from 12.5 to 13.0 and a drastic decrease of pH value was detected after accelerated mineral carbonation. The theoretically calculated CO2 sequestration extent of CSWs was from 27.05% to 31.23%. The practical water to solid ratio in the fresh CSW varied from 0.76 to 1.12, which had a significant impact on the compressive strength of the mixture with CSWs. After subjecting to accelerated mineral carbonation, rapid initial strength development and lower drying shrinkage for the prepared concrete mixture were achieved.

  11. Improving the bond strength between steel rebar and concrete by ozone treatment of rebar and polymer addition to concrete

    SciTech Connect

    Fu, X.; Chung, D.D.L.

    1997-05-01

    Ozone treatment of steel rebar, together with latex addition (20% by weight of cement) to concrete, resulted in a 39% increase in the shear bond strength between rebar and concrete, compared to a 25% increase resulted from either ozone treatment alone or latex addition alone. Ozone treatment and latex addition resulted in similarly small increases in the contact electrical resistivity between rebar and concrete. Methylcellulose addition (0.4% by weight of cement) to concrete gave slightly less bond strength increase than the latex addition, but did not affect the contact resistivity.

  12. Studies of detailed biofilm characterization on fly ash concrete in comparison with normal and superplasticizer concrete in seawater environments.

    PubMed

    Vishwakarmaa, Vinita; George, R P; Ramachandran, D; Anandkumar, B; Mudalib, U Kamachi

    2014-01-01

    In cooling water systems, many concrete structures in the form of tanks, pillars and reservoirs that come in contact with aggressive seawater are being deteriorated by chemical and biological factors. The nuclear industry has decided to partially replace the Portland cement with appropriate pozzolans such as fly ash, which could densify the matrix and make the concrete impermeable. Three types of concrete mixes, viz., normal concrete (NC), concrete with fly ash and superplasticizer (FA) and concrete with only superplasticizer (SP) were fabricated for short- and long-term exposure studies and for screening out the better concrete in seawater environments. Biofilm characterization studies and microscopic studies showed excellent performance of FA concrete compared to the other two. Laboratory exposure studies in pure cultures of Thiobacillus thiooxidans and Fusarium oxysporum were demonstrated for the inhibition of microbial growth on fly ash. Epifluorescence and scanning electron microscopic studies supported the better performance of the FA specimen. Thus, the present study clearly showed that FA concrete is less prone to biofilm formation and biodeterioration.

  13. Environmental performance and mechanical analysis of concrete containing recycled asphalt pavement (RAP) and waste precast concrete as aggregate.

    PubMed

    Erdem, Savaş; Blankson, Marva Angela

    2014-01-15

    The overall objective of this research project was to investigate the feasibility of incorporating 100% recycled aggregates, either waste precast concrete or waste asphalt planning, as replacements for virgin aggregates in structural concrete and to determine the mechanical and environmental performance of concrete containing these aggregates. Four different types of concrete mixtures were designed with the same total water cement ratio (w/c=0.74) either by using natural aggregate as reference or by totally replacing the natural aggregate with recycled material. Ground granulated blast furnace slag (GGBS) was used as a mineral addition (35%) in all mixtures. The test results showed that it is possible to obtain satisfactory performance for strength characteristics of concrete containing recycled aggregates, if these aggregates are sourced from old precast concrete. However, from the perspective of the mechanical properties, the test results indicated that concrete with RAP aggregate cannot be used for structural applications. In terms of leaching, the results also showed that the environmental behaviour of the recycled aggregate concrete is similar to that of the natural aggregate concrete.

  14. Concrete Infill Monitoring in Concrete-Filled FRP Tubes Using a PZT-Based Ultrasonic Time-of-Flight Method.

    PubMed

    Luo, Mingzhang; Li, Weijie; Hei, Chuang; Song, Gangbing

    2016-12-07

    Concrete-filled fiber-reinforced polymer tubes (CFFTs) have attracted interest for their structural applications in corrosive environments. However, a weak interfacial strength between the fiber-reinforced polymer (FRP) tube and the concrete infill may develop due to concrete shrinkage and inadequate concrete compaction during concrete casting, which will destroy the confinement effect and thereby reduce the load bearing capacity of a CFFT. In this paper, the lead zirconate titanate (PZT)-based ultrasonic time-of-flight (TOF) method was adopted to assess the concrete infill condition of CFFTs. The basic idea of this method is that the velocity of the ultrasonic wave propagation in the FRP material is about half of that in concrete material. Any voids or debonding created along the interface between the FRP tube and the concrete will delay the arrival time between the pairs of PZT transducers. A comparison of the arrival times of the PZT pairs between the intact and the defected CFFT was made to assess the severity of the voids or the debonding. The feasibility of the methodology was analyzed using a finite-difference time-domain-based numerical simulation. Experiments were setup to validate the numerical results, which showed good agreement with the numerical findings. The results showed that the ultrasonic time-of-flight method is able to detect the concrete infill condition of CFFTs.

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

    SciTech Connect

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

    2007-07-01

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

  16. Concrete Infill Monitoring in Concrete-Filled FRP Tubes Using a PZT-Based Ultrasonic Time-of-Flight Method

    PubMed Central

    Luo, Mingzhang; Li, Weijie; Hei, Chuang; Song, Gangbing

    2016-01-01

    Concrete-filled fiber-reinforced polymer tubes (CFFTs) have attracted interest for their structural applications in corrosive environments. However, a weak interfacial strength between the fiber-reinforced polymer (FRP) tube and the concrete infill may develop due to concrete shrinkage and inadequate concrete compaction during concrete casting, which will destroy the confinement effect and thereby reduce the load bearing capacity of a CFFT. In this paper, the lead zirconate titanate (PZT)-based ultrasonic time-of-flight (TOF) method was adopted to assess the concrete infill condition of CFFTs. The basic idea of this method is that the velocity of the ultrasonic wave propagation in the FRP material is about half of that in concrete material. Any voids or debonding created along the interface between the FRP tube and the concrete will delay the arrival time between the pairs of PZT transducers. A comparison of the arrival times of the PZT pairs between the intact and the defected CFFT was made to assess the severity of the voids or the debonding. The feasibility of the methodology was analyzed using a finite-difference time-domain-based numerical simulation. Experiments were setup to validate the numerical results, which showed good agreement with the numerical findings. The results showed that the ultrasonic time-of-flight method is able to detect the concrete infill condition of CFFTs. PMID:27941617

  17. CONCRETE SUPPORT DESIGN FOR MISCELLANEOUS ESF UTILITIES

    SciTech Connect

    T.A. Misiak

    1999-06-21

    The purpose and objective of this analysis is to design concrete supports for the miscellaneous utility equipment used at the Exploratory Studies Facility (ESF). Two utility systems are analyzed: (1) the surface collection tanks of the Waste Water System, and (2) the chemical tracer mixing and storage tanks of the Non-Potable Water System. This analysis satisfies design recommended in the Title III Evaluation Reports for the Subsurface Fire Water System and Subsurface Portion of the Non-Potable Water System (CRWMS M&O 1998a) and Waste Water Systems (CRWMS M&O 1998b).

  18. Reliability evaluation of prestressed concrete containment structures

    SciTech Connect

    Pires, J.; Hwang, H.; Reich, M.

    1985-01-01

    The probabilistic safety evaluation of a realistic unbonded prestressed concrete containment building subjected to combinations of static and dynamic loads is presented. Loads considered include dead load, prestressing, accidental internal pressure, tornado and earthquake loads. Pertinent load parameters are the occurrence rate, duration and intensity. These parameters are treated as random variables for most of the loads. Limit state probabilities conditional on a specific load combination are calculated using the analytical procedure developed at BNL, which makes use of the finite element method and random vibration theory. Lifetime limit state probabilities are calculated using a load coincidence formulation. 3 refs., 2 figs., 2 tabs.

  19. The curing of high-performance concrete

    NASA Astrophysics Data System (ADS)

    Meeks, Kenneth Wayne

    This dissertation describes the latest information, technology, and research on the curing of high performance concrete (HPC). Expanded somewhat beyond the scope of HPC, it examines the current body of knowledge on the effects of various curing regimes on concrete. The significance and importance of curing are discussed as well as the various definitions of HPC. The current curing requirements, standards, and criteria as proposed by ACI, as well as those of other countries, are reviewed and discussed. The current prescriptive curing requirements may not be applicable to high performance concrete. The research program reported in this dissertation looked at one approach to development of curing criteria for this relatively new class of concrete. The program applies some of the basic concepts of the methodology developed by the German researcher, H. K. Hilsdorf, to the curing of HPC with the objective to determine minimum curing durations for adequate strength development. The approach is to determine what fraction of the standard-cured 28-day strength has to be attained at the end of the curing period to assure that the design strength is attained in the interior of the member. An innovative direct tension test was developed to measure the strength at specific depths from the drying surface of small mortar cylinders (50 x 127 mm (2 x 5 in.)). Two mortar mixtures were investigated, w/c = 0.30 and w/c = 0.45, and three different moist curing regimes, 1-day, 3-day, and 7-day. Specimens were stored in two environmental chambers at 25sp°C, 50% RH; and 25sp°C, 70% RH, until testing at the age of 28 days. Direct tensile tests were conducted using steel disks epoxied to the ends of the specimens. Also, the penetration of the drying front was calculated from the drying data using porosity and degree of hydration relationships. The major observation from these tests was that adequate strength is attained in both mortar mixtures with only one day of moist curing. The drying

  20. Strength of concrete structures under dynamic loading

    SciTech Connect

    Kumpyak, O. G. Galyautdinov, Z. R. Kokorin, D. N.

    2016-01-15

    The use of elastic supports is one the efficient methods of decreasing the dynamic loading. The paper describes the influence of elastic supports on the stress-strain state of steel concrete structures exposed to one-time dynamic loading resulting in failure. Oblique bending beams on elastic supports and their elastic, elastoplastic, and elastoplastic consolidation behavior are considered in this paper. For numerical calculations the developed computer program is used based on the finite element method. Research findings prove high efficiency of elastic supports under dynamic loading conditions. The most effective behavior of elastic supports is demonstrated at the elastoplastic stage. A good agreement is observed between the theoretical and experimental results.

  1. Development of thermally stable polymer concrete

    SciTech Connect

    Megahed, T.N.E.D., Kukacka, L.E.; Fontana, J.J.

    1989-10-01

    This work pertains to the development of a polymer concrete type that is thermally stable under working temperatures of 200{degree} to 300{degree}F. This material is highly durable and thermally stable with high flexural strength and ductility. Its consistency, while fresh, is suitable for both casting in place or precasting techniques. Several optimization stages were applied ranging from mixing ratios and type of aggregate to resin formulation itself. An optimized range of mixing ratios is developed along with optimized mix ingredients, relating mechanical performance to elevated temperature at various degrees of workability.

  2. Use of waste ash from palm oil industry in concrete.

    PubMed

    Tangchirapat, Weerachart; Saeting, Tirasit; Jaturapitakkul, Chai; Kiattikomol, Kraiwood; Siripanichgorn, Anek

    2007-01-01

    Palm oil fuel ash (POFA), a by-product from the palm oil industry, is disposed of as waste in landfills. In this study, POFA was utilized as a pozzolan in concrete. The original size POFA (termed OP) was ground until the median particle sizes were 15.9 microm (termed MP) and 7.4 microm (termed SP). Portland cement Type I was replaced by OP, MP, and SP of 10%, 20%, 30%, and 40% by weight of binder. The properties of concrete, such as setting time, compressive strength, and expansion due to magnesium sulfate attack were investigated. The results revealed that the use of POFA in concretes caused delay in both initial and final setting times, depending on the fineness and degree of replacement of POFA. The compressive strength of concrete containing OP was much lower than that of Portland cement Type I concrete. Thus, OP is not suitable to be used as a pozzolanic material in concrete. However, the replacement of Portland cement Type I by 10% of MP and 20% of SP gave the compressive strengths of concrete at 90 days higher than that of concrete made from Portland cement Type I. After being immersed in 5% of magnesium sulfate solution for 364 days, the concrete bar mixed with 30% of SP had the same expansion level as that of the concrete bar made from Portland cement Type V. The above results suggest that ground POFA is an excellent pozzolanic material and can be used as a cement replacement in concrete. It is recommended that the optimum replacement levels of Portland cement Type I by MP and SP are 20% and 30%, respectively.

  3. Strength Characteristics of Groundnut Leaf/Stem Ash (GLSA) Concrete

    NASA Astrophysics Data System (ADS)

    Oseni, O. W.; Audu, M. T.

    2016-09-01

    The compressive strength properties of concrete are substantial factors in the design and construction of concrete structures. Compressive strength directly affects the degree to which the concrete can be able to carry a load over time. These changes are complemented by deflections, cracks etc., in the structural elements of concrete. This research investigated the effect of groundnut leaf/stem ash (GLSA) on the compressive strength of concrete at 0%, 5 %, 10 % and 15 % replacements of cement. The effect of the water-cement ratio on properties such as the compressive strength, slump, flow and workability properties of groundnut leaf/stem ash (GLSA) mixes with OPC were evaluated to determine whether they are acceptable for use in concrete structural elements. A normal concrete mix with cement at 100 % (i.e., GLSA at 0%) with concrete grade C25 that can attain an average strength of 25 N/mm2 at 28 days was used as a control at design water-cement ratios of 0.65 and grading of (0.5-32) mm from fine to coarse aggregates was tested for: (1) compressive strength, and the (2) slump and flow Test. The results and observations showed that the concrete mixes from GLSA at 5 - 15 % ratios exhibit: pozzolanic properties and GLSA could be used as a partial replacement for cement at these percentage mix ratios compared with the control concrete; an increase in the water-cement ratio showed a significant decrease in the compressive strength and an increase in workability. Therefore, it is important that all concrete mixes exude an acceptably designed water-cement ratio for compressive strength characteristics for use in structures, water-cement ratio is a significant factor.

  4. 77 FR 18973 - Reinforced Concrete in Construction, and Preventing Backover Injuries and Fatalities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-29

    ... Reinforced Concrete in Construction, and Preventing Backover Injuries and Fatalities AGENCY: Occupational... aware of employee safety risks in two areas, reinforcing operations in concrete work (construction only... following methods (submissions relating to Reinforced Concrete in Construction to Docket No....

  5. Preliminary tests of silicon carbide based concretes for hybrid rocket nozzles in a solar furnace

    NASA Astrophysics Data System (ADS)

    D'Elia, Raffaele; Bernhart, Gérard; Cutard, Thierry; Peraudeau, Gilles; Balat-Pichelin, Marianne

    2014-06-01

    This research is part of the PERSEUS project, a space program concerning hybrid propulsion and supported by CNES. The main goal of this study is to characterise silicon carbide based micro-concrete with a maximum aggregates size of 800 μm, in a hybrid propulsion environment. The nozzle throat has to resist to a highly oxidising polyethylene (PE)/N2O hybrid environment, under temperatures ranging up to 2980 K. The study is divided into two main parts: the first one deals with the thermo-mechanical characterisation of the material up to 1500 K and the second one with an investigation on the oxidation behaviour in a standard atmosphere, under a solar flux up to 13.5 MW/m2. Young's modulus was determined by resonant frequency method: results show an increase with the stabilisation temperature. Four point bending tests have shown a rupture tensile strength increasing with stabilisation temperature, up to 1473 K. Sintering and densification processes are primary causes of this phenomenon. Visco-plastic behaviour appears at 1373 K, due to the formation of liquid phases in cement ternary system. High-temperature oxidation in ambient air was carried out at PROMES-CNRS laboratory, on a 2 kW solar furnace, with a concentration factor of 15,000. A maximum 13.5 MW/m2 incident solar flux and a 7-90 s exposure times have been chosen. Optical microscopy, SEM, EDS analyses were used to determine the microstructure evolution and the mass loss kinetics. During these tests, silicon carbide undergoes active oxidation with production of SiO and CO smokes and ablation. A linear relation between mass loss and time is found. Oxidation tests performed at 13.5 MW/m2 solar flux have shown a mass loss of 10 mg/cm2 after 15 s. After 90 s, the mass loss reaches 60 mg/cm2. Surface temperature measurement is a main point in this study, because of necessity of a thermo-mechanical-ablative model for the material. Smokes appear at around 5.9 MW/m2, leading to the impossibility of useful temperature

  6. High Modulus Asphalt Concrete with Dolomite Aggregates

    NASA Astrophysics Data System (ADS)

    Haritonovs, V.; Tihonovs, J.; Smirnovs, J.

    2015-11-01

    Dolomite is one of the most widely available sedimentary rocks in the territory of Latvia. Dolomite quarries contain about 1,000 million tons of this material. However, according to Latvian Road Specifications, this dolomite cannot be used for average and high intensity roads because of its low quality, mainly, its LA index (The Los Angeles abrasion test). Therefore, mostly the imported magmatic rocks (granite, diabase, gabbro, basalt) or imported dolomite are used, which makes asphalt expensive. However, practical experience shows that even with these high quality materials roads exhibit rutting, fatigue, and thermal cracks. The aim of the research is to develop a high performance asphalt concrete for base and binder courses using only locally available aggregates. In order to achieve resistance against deformations at a high ambient temperature, a hard grade binder was used. Workability, fatigue and thermal cracking resistance, as well as sufficient water resistance is achieved by low porosity (3-5%) and higher binder content compared to traditional asphalt mixtures. The design of the asphalt includes a combination of empirical and performance based tests, which in laboratory circumstances allow simulating traffic and environmental loads. High performance AC 16 base asphalt concrete was created using local dolomite aggregate with polymer modified (PMB 10/40-65) and hard grade (B20/30) bitumen. The mixtures were specified based on fundamental properties in accordance with EN 13108-1 standard.

  7. Evaluation of concrete containing photocatalytic titanium dioxide

    NASA Astrophysics Data System (ADS)

    Hanson, Shannon

    The air pollution inversions in the mountain west are a societal problem that require a large-scale solution. With the more stringent Environmental Protection Agency (EPA) regulations established in 2010, and the recent discovery of the photocatalytic pollution reduction capabilities of titanium dioxide (TiO2), interest has developed to create pollution-reducing construction materials. Over the last decade, a number of laboratory studies have been performed and a few field studies have occurred around the world. There are commercially available photocatalytic materials that can be used in concrete construction; however, the materials are often cost prohibitive. This study investigated both practical application techniques and the effects of the climatic environment around the specimens. When concrete specimens were exposed to the weather for 120-days, the specimen's photocatalytic efficiency decreased significantly. Rejuvenation methods were investigated; however, no methods tested were able to increase the photocatalytic efficiency of the specimens to preweathered condition. The final element of this study focused on identifying practical and cost-effective methods of adding TiO2 to current production methods by working with a local precast manufacturer. This research is a stepping stone to develop methodologies to minimize the decline of photocatalytic efficiency due to the exposure to the environment. This element is critical in understanding this complex technology and identifying problems that need to be addressed before products are ready for widespread use.

  8. Radionuclide Retention in Concrete Wasteforms - FY13

    SciTech Connect

    Snyder, Michelle MV; Golovich, Elizabeth C.; Wellman, Dawn M.; Crum, Jarrod V.; Lapierre, Robert; Dage, Denomy C.; Parker, Kent E.; Cordova, Elsa A.

    2013-10-15

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of low-level waste and mixed low-level waste, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  9. CREATION OF MUSIC WITH FIBER REINFORCED CONCRETE

    NASA Astrophysics Data System (ADS)

    Kato, Hayato; Takeuchi, Masaki; Ogura, Naoyuki; Kitahara, Yukiko; Okamoto, Takahisa

    This research focuses on the Fiber Reinforcement Concrete(FRC) and its performance on musical tones. Thepossibility of future musical instruments made of this concrete is discussed. Recently, the technical properties of FRC had been improved and the different production styles, such as unit weight of binding material and volume of fiber in the structure, hardly affects the results of the acoustics. However, the board thickness in the FRC instruments is directly related with the variety of musical tone. The FRC musical effects were compared with those produced with wood on wind instruments. The sounds were compared with those produced with woodwind instruments. The sound pressure level was affected by the material and it becomes remarkably notorious in the high frequency levels. These differences had great influence on the spectrum analysis of the tone in the wind instruments and the sensory test. The results from the sensory test show dominant performances of brightness, beauty and power in the FRC instruments compared with those made of wood.

  10. Thermal inertia properties of autoclaved aerated concrete

    SciTech Connect

    Ropelewski, L.; Neufeld, R.D.

    1999-08-01

    Autoclaved aerated concrete (AAC) is a lightweight, porous concrete with advanced thermal properties. AAC is unique among construction materials in combining excellent thermal resistance and thermal inertia. Generally, low-density construction materials do not provide good thermal inertia, while heavier ones commonly have poor thermal resistance. Five different 10.2 cm (4 in.) AAC samples made from US electric utility fly ash as the silica source, along with three 10.2 cm (4 in.) conventional building material specimens, were tested for thermal inertia properties. Three primary issues addressed by these experiments were: (1) to develop and compare AAC thermal inertia to conventional building materials; (2) to document differences in thermal inertia characteristics of the AAC blocks produced by the various utilities; and (3) to determine if a periodic heat flow model using the thermal inertia approach adequately predicts the observed thermal inertia parameters of a material. A theoretical periodic heat flow model in the literature for thermal inertia did an adequate job of predicting the observed thermal inertia parameters for the AAC and conventional construction samples.

  11. Structural properties of autoclaved aerated concrete masonry

    SciTech Connect

    Matthys, J.H.; Nelson, R.L.

    1999-07-01

    Autoclaved aerated concrete masonry units are manufactured from portland cement, quartz sand, water, lime, gypsum and a gas forming agent. The units are steam cured under pressure in an autoclave transforming the material into a hard calcium silicate. The autoclaved aerated concrete masonry units are large-size solid rectangular prisms which are laid using thin-bed mortar layers into masonry assemblages. The system and product are not new--patented in 1924 by Swedish architect Johan Eriksson. Over a period of 60 years this product has been used in all areas of residential and industrial construction and in virtually all climates. However, the principal locations of application have been generally outside the US Little information in the US is available on the structural properties of this product. Due to the interest in use of this product in the construction industry and the construction of production plants in the US, the Construction Research Center at the University of Texas at Arlington and Robert L. Nelson & Associates conducted a series of tests to determine some of the basic structural properties of this product. This paper presents the findings of those investigations.

  12. Impact echo scanning of concrete and wood

    NASA Astrophysics Data System (ADS)

    Sack, Dennis A.; Olson, Larry D.; Aouad, Marwan F.

    1995-05-01

    This paper presents an overview of a new nondestructive testing (NDT) system that allows rapid nondestructive assessment of many types of structural materials. The new system is based on scanning impact echo (IE), using a rolling receiver, digitally controlled impact source, and a distance measurement wheel integrated into a system that is capable of performing over 3000 IE tests per hour. The system has been successfully used on both concrete and wood for condition assessment. Previously, impact echo testing has been limited to point-by-point testing at rates of typically 30 - 60 points per hour. The new system is usable on any flat, relatively smooth surface such as floor slabs, pavements, walls, columns, beams, etc. In addition to IE scanning, the new system has recently been expanded to allow the performance of spectral analysis of surface waves (SASW) scanning on concrete and wood. The SASW method allows the measurement of material stiffness (modulus) versus depth, and therefore can give a profile of the material condition versus depth. Included in this paper are brief discussions of the IE and SASW methods, the scanner system hardware, and the software which was developed to enable efficient processing, analysis, and display of the test data and results. Also included are sample data plots and a case history presentation of the use of the system in the field, including one in which 23,000 IE tests were performed on an elevated floor slab in approximately 16 hours of testing time.

  13. Multiscale Concrete Modeling of Aging Degradation

    SciTech Connect

    Hammi, Yousseff; Gullett, Philipp; Horstemeyer, Mark F.

    2015-07-31

    In this work a numerical finite element framework is implemented to enable the integration of coupled multiscale and multiphysics transport processes. A User Element subroutine (UEL) in Abaqus is used to simultaneously solve stress equilibrium, heat conduction, and multiple diffusion equations for 2D and 3D linear and quadratic elements. Transport processes in concrete structures and their degradation mechanisms are presented along with the discretization of the governing equations. The multiphysics modeling framework is theoretically extended to the linear elastic fracture mechanics (LEFM) by introducing the eXtended Finite Element Method (XFEM) and based on the XFEM user element implementation of Giner et al. [2009]. A damage model that takes into account the damage contribution from the different degradation mechanisms is theoretically developed. The total contribution of damage is forwarded to a Multi-Stage Fatigue (MSF) model to enable the assessment of the fatigue life and the deterioration of reinforced concrete structures in a nuclear power plant. Finally, two examples are presented to illustrate the developed multiphysics user element implementation and the XFEM implementation of Giner et al. [2009].

  14. Durability and Behavior of Prestressed Concrete Beams. Report 6. Posttensioned Concrete Beam Investigation, Supplemental Laboratory Tests of Beams Exposed from 1961 to 1982.

    DTIC Science & Technology

    1984-10-01

    rD-Ai4. 82. DURABILITY AND BEHAVIOR OF PRESTRESSED CONCRETE BEAMS i/i REPORT 6 POSTTENSIO..(U) ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG... REPORT NO. 6-570 US A.my Cc. DURABILITY AND BEHAVIOR OF of Engineers PRESTRESSED CONCRETE BEAMS Report 6 " POSTTENSIONED CONCRETE BEAM 00...PERIOD COVERED DURAB ILITY AND BEHAVIOR OF PRESTRESSED CONCRETE BEAMS; Report 6: Posttensioned Concrete Beam Report 6 of a series Investigation

  15. A study of the coupling relationship between concrete surface temperature and concrete surface emissivity in natural conditions.

    PubMed

    Tang, Lin-Ling; Chen, Xiao-Ling; Wang, Jia-Ning; Zhao, Hong-Mei; Huang, Qi-Ting

    2014-07-01

    Land surface emissivity (LSE) has already been recognized as a crucial parameter for the determination of land surface temperature (LST). There is an ill-posed problem for the retrieval of LST and LSE. And laboratory-based emissivity is measured in natural constant conditions, which is limited in the application in thermal remote sensing. To solve the above problems, the coupling of LST and LSE is explored to eliminate temperature effects and improve the accuracy of LES. And then, the estimation accuracy of LST from passive remote sensing images will be improved. For different land surface materials, the coupling of land surface emissivity and land surface temperature is various. This paper focuses on studying concrete surface that is one of the typical man-made materials in urban. First the experiments of measuring concrete surface emissivity and concrete surface temperature in natural conditions are arranged reasonably and the suitable data are selected under ideal atmosphere conductions. Then to improve the determination accuracy of concrete surface emissivity, the algorithm worked on the computer of Fourier Transform Infrared Spectroradiometer (FTIR) has been improved by the most adapted temperature and emissivity separation algorithm. Finally the coupling of concrete surface temperature and concrete surface emissivity is analyzed and the coupling model of concrete surface temperature and concrete surface emissivity is established. The results show that there is a highest correlation coefficient between the second derivative of emissivity spectra and concrete surface temperature, and the correlation coefficient is -0.925 1. The best coupling model is the stepwise regression model, whose determination coefficient (R2) is 0.886. The determination coefficient (R2) is 0.905 and the root mean squares error (RMSE) is 0.292 1 in the validation of the model. The coupling model of concrete surface temperature and concrete surface emissivity under natural conditions

  16. WEST FACADE. THREESTORY BRICK AND STEEL BUILDING WITH CONCRETE ADDITION ...

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

    WEST FACADE. THREE-STORY BRICK AND STEEL BUILDING WITH CONCRETE ADDITION AT SOUTH FACE. NOTE OPENINGS INTO BUILDING ARE BOARDED OR BRICKED UP WITH WOODEN BOARDS OR CONCRETE BLOCK. (Duplicate color view of HAER MI-352-1) - National Can Company, 2566 East Grand Boulevard, Detroit, MI

  17. VIEW OF GUN EMPLACEMENT AND THE TABLELIKE CAST CONCRETE STRUCTURE ...

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

    VIEW OF GUN EMPLACEMENT AND THE TABLE-LIKE CAST CONCRETE STRUCTURE SHOWING THE SPALLED AREA ON ITS EAST SIDE (LEFT) WHERE THE SECOND PROJECTING ARM WAS BROKEN OFF. NOTE THE SLOPED CONCRETE PAD IN THE BACKGROUND. VIEW FACING SOUTHWEST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, East Gun Emplacement, Ford Island, Pearl City, Honolulu County, HI

  18. DETAIL OF THE SLOPING CONCRETE PAD AT THE SOUTH SIDE ...

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

    DETAIL OF THE SLOPING CONCRETE PAD AT THE SOUTH SIDE OF THE GUN EMPLACEMENT. NOTE ADDED BLOCK OF CAST CONCRETE AT THE LOW (RIGHT) END OF SLOPED PAD. VIEW FACING SOUTHWEST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, East Gun Emplacement, Ford Island, Pearl City, Honolulu County, HI

  19. Functional characterization of two concrete biofilms using pyrosequencing data

    EPA Science Inventory

    Phylogenetic studies of concrete biofilms using 16SrRNA-based approaches have demonstrated that concrete surfaces harbor a diverse microbial community. These approaches can provide information on the general taxonomical groups present in a sample but cannot shed light on the func...

  20. Influence of Elevated Temperatures on Pet-Concrete Properties

    NASA Astrophysics Data System (ADS)

    Albano, C.; Camacho, N.; Hernández, M.; Matheus, A.; Gutiérrez, A.

    2008-08-01

    Lightweight aggregate is an important material in reducing the unit weight of concrete complying with special concrete structures of large high-rise buildings. Besides, the use of recycled PET bottles as lightweight aggregate in concrete is an effective contribution for environment preservation. So, the objective of the present work was to study experimentally the flexural strength of the PET -concrete blends and the thermal degradation of the PET in the concrete, when the blends with 10 and 20% in volume of PET were exposed to different temperatures (200, 400, 600 °C). The flexural strength of concrete-PET exposed to a heat source is strongly dependent on the temperature, water/cement ratio, as well as the content and particle size of PET. However, the activation energy is affected by the temperature, location of the PET particles on the slabs and the water/cement ratio. Higher water content originates thermal and hydrolytic degradation on the PET, while on the concrete, a higher vapor pressure which causes an increase in crack formation. The values of the activation energy are higher on the center of the slabs than on the surface, since concrete is a poor heat conductor.

  1. Use of recycled fine aggregate in concretes with durable requirements.

    PubMed

    Zega, Claudio Javier; Di Maio, Angel Antonio

    2011-11-01

    The use of construction waste materials as aggregates for concrete production is highly attractive compared to the use of non-renewable natural resources, promoting environmental protection and allowing the development of a new raw material. Several countries have recommendations for the use of recycled coarse aggregate in structural concrete, whereas the use of the fine fraction is limited because it may produce significant changes in some properties of concrete. However, during the last decade the use of recycled fine aggregates (RFA) has achieved a great international interest, mainly because of economic implications related to the shortage of natural sands suitable for the production of concrete, besides to allow an integral use of this type of waste. In this study, the durable behaviour of structural concretes made with different percentage of RFA (0%, 20%, and 30%) is evaluated. Different properties related to the durability of concretes such as absorption, sorptivity, water penetration under pressure, and carbonation are determined. In addition, the results of compressive strength, static modulus of elasticity and drying shrinkage are presented. The obtained results indicate that the recycled concretes have a suitable resistant and durable behaviour, according to the limits indicated by different international codes for structural concrete.

  2. Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete

    DOEpatents

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

    1981-11-04

    Quick setting polymer concrete compositions which are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate which may be wet and a source of bivalent metallic ions which will set to polymer concrete with excellent structural properties.

  3. Effects of Abstract and Concrete Simulation Elements on Science Learning

    ERIC Educational Resources Information Center

    Jaakkola, T.; Veermans, K.

    2015-01-01

    Contemporary evidence on the effectiveness of concrete and abstract representations in science education is based solely on studies conducted in college context. There it has been found that learning with abstract representations produces predominantly better outcomes than learning with concrete representations and combining the representations…

  4. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, G.A.; Smith, J.W.; Ihle, N.C.

    1982-07-08

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH)/sub 2/ to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with Portland cement to form concrete.

  5. Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete

    DOEpatents

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

    1983-05-13

    Quick setting polymer concrete compositions are described which are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate which may be wet and a source of bivalent metallic ions which will set to polymer concrete with excellent structural properties.

  6. 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.

  7. [Characteristic of Particulate Emissions from Concrete Batching in Beijing].

    PubMed

    Xue, Yi-feng; Zhou, Zhen; Zhong, Lian-hong; Yan, Jing; Qu, Song; Huang, Yu-hu; Tian, He- zhong; Pan, Tao

    2016-01-15

    With the economic development and population growth in Beijing, there is a strong need for construction and housing, which leads to the increase of the construction areas. Meanwhile, as a local provided material, the production of concrete has been raised. In the process of concrete production by concrete batching, there are numerous particulates emitted, which have large effect on the atmospheric environment, however, systematic study about the tempo-spatial characteristics of pollutant emission from concrete batching is still rare. In this study, we estimated the emission of particulates from concrete batching from 1991 to 2012 using emission factor method, analyzed the tempo-spatial characteristics of pollutant emission, established the uncertainty range by adopting Monte-Carlo method, and predicted the future emission in 2020 based on the relative environmental and economical policies. The results showed that: (1) the emissions of particulates from concrete batching showed a trend of "first increase and then decrease", reaching the maximum in 2005, and then decreased due to stricter emission standard and enhanced environmental management. (2) according to spatial distribution, the emission of particulates from concrete batch mainly concentrated in the urban area with more human activities, and the area between the fifth ring and the sixth ring contributed the most. (3) through scenarios analysis, for further reducing the emission from concrete batching in 2020, more stricter standard for green production as well as powerful supervision is needed.

  8. Concreteness Fading in Mathematics and Science Instruction: A Systematic Review

    ERIC Educational Resources Information Center

    Fyfe, Emily R.; McNeil, Nicole M.; Son, Ji Y.; Goldstone, Robert L.

    2014-01-01

    A longstanding debate concerns the use of concrete versus abstract instructional materials, particularly in domains such as mathematics and science. Although decades of research have focused on the advantages and disadvantages of concrete and abstract materials considered independently, we argue for an approach that moves beyond this dichotomy and…

  9. Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete

    DOEpatents

    Sugama, Toshifumi; Kukacka, Lawrence E.; Horn, William H.

    1985-01-01

    Quick setting polymer concrete compositions with excellent structural properties are disclosed; these polymer concrete compositions are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate, which may be wet, and with a source of bivalent metallic ions.

  10. A Quantitative Empirical Analysis of the Abstract/Concrete Distinction

    ERIC Educational Resources Information Center

    Hill, Felix; Korhonen, Anna; Bentz, Christian

    2014-01-01

    This study presents original evidence that abstract and concrete concepts are organized and represented differently in the mind, based on analyses of thousands of concepts in publicly available data sets and computational resources. First, we show that abstract and concrete concepts have differing patterns of association with other concepts.…

  11. Use of recycled plastics in concrete: A critical review.

    PubMed

    Gu, Lei; Ozbakkaloglu, Togay

    2016-05-01

    Plastics have become an essential part of our modern lifestyle, and the global plastic production has increased immensely during the past 50years. This has contributed greatly to the production of plastic-related waste. Reuse of waste and recycled plastic materials in concrete mix as an environmental friendly construction material has drawn attention of researchers in recent times, and a large number of studies reporting the behavior of concrete containing waste and recycled plastic materials have been published. This paper summarizes the current published literature until 2015, discussing the material properties and recycling methods of plastic and the influence of plastic materials on the properties of concrete. To provide a comprehensive review, a total of 84 studies were considered, and they were classified into sub categories based on whether they dealt with concrete containing plastic aggregates or plastic fibers. Furthermore, the morphology of concrete containing plastic materials is described in this paper to explain the influence of plastic aggregates and plastic fibers on the properties of concrete. The properties of concretes containing virgin plastic materials were also reviewed to establish their similarities and differences with concrete containing recycled plastics.

  12. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, Gary A [Kennewick, WA; Smith, Jeffrey W [Lancaster, OH; Ihle, Nathan C [Walla Walla, WA

    1984-01-01

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH).sub.2 to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with portland cement to form concrete.

  13. Self-assembling particle-siloxane coatings for superhydrophobic concrete.

    PubMed

    Flores-Vivian, Ismael; Hejazi, Vahid; Kozhukhova, Marina I; Nosonovsky, Michael; Sobolev, Konstantin

    2013-12-26

    We report here, for the first time in the literature, a method to synthesize hydrophobic and superhydrophobic concrete. Concrete is normally a hydrophilic material, which significantly reduces the durability of concrete structures and pavements. To synthesize water-repellent concrete, hydrophobic emulsions were fabricated and applied on portland cement mortar tiles. The emulsion was enriched with the polymethyl-hydrogen siloxane oil hydrophobic agent as well as metakaolin (MK) or silica fume (SF) to induce the microroughness and polyvinyl alcohol (PVA) fibers to create hierarchical surfaces. Various emulsion types were investigated by using different mixing procedures, and single- and double-layer hydrophobic coatings were applied. The emulsions and coatings were characterized with optical microscope and scanning electron microscope (SEM), and their wetting properties, including the water contact angle (CA) and roll-off angle, were measured. A theoretical model for coated and non-coated concrete, which can be generalized for other types of materials, was developed to predict the effect of surface roughness and composition on the CA. An optimized distance between the aggregates was found where the CA has the highest value. The maximal CA measured was 156° for the specimen with PVA fibers treated with MK based emulsion. Since water penetration is the main factor leading to concrete deterioration, hydrophobic water-repellent concretes have much longer durability then regular concretes and can have a broad range of applications in civil and materials engineering.

  14. 13. DETAIL: A CLOSEUP VIEW OF TWO UNEQUAL WIDTH CONCRETE ...

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

    13. DETAIL: A CLOSE-UP VIEW OF TWO UNEQUAL WIDTH CONCRETE BRACKETS AND THE LARGE CAST ANCONE WHICH SUPPORTS A QUIRK IN THE CONCRETE BALUSTRADE. - Delphi Bridge on U.S. Route 421, Spanning Deer Creek at U.S. Route 421, Delphi, Carroll County, IN

  15. Performance of Lightweight Concrete based on Granulated Foamglass

    NASA Astrophysics Data System (ADS)

    Popov, M.; Zakrevskaya, L.; Vaganov, V.; Hempel, S.; Mechtcherine, V.

    2015-11-01

    The paper presents an investigation of lightweight concretes properties, based on granulated foamglass (GFG-LWC) aggregates. The application of granulated foamglass (GFG) in concrete might significantly reduce the volume of waste glass and enhance the recycling industry in order to improve environmental performance. The conducted experiments showed high strength and thermal properties for GFG-LWC. However, the use of GFG in concrete is associated with the risk of harmful alkali-silica reactions (ASR). Thus, one of the main aims was to study ASR manifestation in GFG-LWC. It was found that the lightweight concrete based on porous aggregates, and ordinary concrete, have different a mechanism of ASR. In GFG-LWC, microstructural changes, partial destruction of granules, and accumulation of silica hydro-gel in pores were observed. According to the existing methods of analysis of ASR manifestation in concrete, sample expansion was measured, however, this method was found to be not appropriate to indicate ASR in concrete with porous aggregates. Microstructural analysis and testing of the concrete strength are needed to evaluate the damage degree due to ASR. Low-alkali cement and various pozzolanic additives as preventive measures against ASR were chosen. The final composition of the GFG-LWC provides very good characteristics with respect to compressive strength, thermal conductivity and durability. On the whole, the potential for GFG-LWC has been identified.

  16. Concrete decontamination by electro-hydraulic scabbling (EHS). Final report

    SciTech Connect

    1997-10-01

    Contamination of concrete structures by radionuclides, hazardous metals and organic substances (including PCB`s) occurs at many DOE sites. The contamination of concrete structures (walls, floors, ceilings, etc.) varies in type, concentration, and especially depth of penetration into the concrete. In many instances, only the surface layer of concrete is contaminated, up to a depth of one inch, according to estimates provided in the R and D ID document. Then, removal of the concrete surface layer (scabbling) is considered to be the most effective decontamination method. Textron Systems Corp. (TSC) has developed a scabbling concept based on electro-mechanical phenomena accompanying strong electric pulses generated by applying high voltage at the concrete/water interface. Depending on the conditions, the electric discharge may occur either through a waste layer or through the concrete body itself. This report describes the development, testing, and results of this electro-mechanical process. Phase 1 demonstrated the feasibility of the process for the controlled removal of a thin layer of contaminated concrete. Phase 2 designed, fabricated, and tested an integrated subscale unit. This was tested at Fernald. In Phase 3, the scabbling unit was reconfigured to increase its power and processing rate. Technology transfer to an engineering contracting company is continuing.

  17. 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

  18. 1. CONTEXTUAL VIEW, LOOKING DOWNSTREAM (NORTHERLY) OF THE CONCRETE ARCH ...

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

    1. CONTEXTUAL VIEW, LOOKING DOWNSTREAM (NORTHERLY) OF THE CONCRETE ARCH ('ONE-WAY BRIDGE') THAT PROVIDES PRIVATE (WWP) ACCESS TO THE MIDDLE CHANNEL OF THE POST FALLS POWER PLANT. - Washington Water Power Company Post Falls Power Plant, Concrete Arch Bridge, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  19. 3. PORTAL VIEW OF THE CONCRETE ARCH (ONEWAY BRIDGE) THAT ...

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

    3. PORTAL VIEW OF THE CONCRETE ARCH (ONE-WAY BRIDGE) THAT PROVIDES ACCESS TO THE MIDDLE CHANNEL DAM AND POWER PLANT, LOOKING WEST. - Washington Water Power Company Post Falls Power Plant, Concrete Arch Bridge, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  20. 4. PORTAL VIEW OF THE CONCRETE ARCH (ONEWAY BRIDGE) THAT ...

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

    4. PORTAL VIEW OF THE CONCRETE ARCH (ONE-WAY BRIDGE) THAT EXITS THE MIDDLE CHANNEL ISLAND AND POST FALLS POWER PLANT, LOOKING EAST. - Washington Water Power Company Post Falls Power Plant, Concrete Arch Bridge, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID