Journal of Materials in Civil Engineering

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November/December 2003

Volume 15, Issue 6, pp. 513-621

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Municipal Solid Waste Fly Ash as a Blended Cement Material

Chia-Chia Goh, Kuan-Yeow Show, and Hee-Kiat Cheong

J. Mater. Civ. Eng. 15, 513 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(513) (11 pages) | Cited 1 time

Online Publication Date: 14 November 2003

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Laboratory tests were carried out to characterize the properties of municipal fly ash (MFA) samples collected from an incineration plant in Singapore over a period of 12 months. The laboratory test results show that the major elements present in all MFA samples are Ca, K, Na, Si, Al, and Mg. The specific gravity of the ash samples lies in the range of 2.12–2.58, generally lower than the value of 3.2 for ordinary Portland cement (OPC). The Brunauer-Emmett-Teller (BET) surface area of the MFA was found to be 6.03 m2/g, about six times higher than OPC, which has a BET surface area of 1.03 m2/g. In the investigation on the use of MFA as a blended cement material, 50-mm mortar cubes were cast with various percentages of the OPC being replaced by an equivalent weight of MFA. Compressive strength results indicate that up to 10% by weight of OPC could be replaced by MFA, with higher mortar strength being achieved than in the control cubes. A seven-day strength activity index of 123.6% achieved by the MFA, which is almost 50% higher than the requirement of 75%, suggests its contribution toward the strength development of the blended cements. Mercury porosimetry performed on hardened cement pastes indicated a reduction in the average pore diameter with an increasing percentage of cement replacement, indicating a pore refining capability of MFA particles. Leaching tests conducted on the blended cement mortars showed that the contamination levels in all leachate complied with the maximum limit set in U.S. EPA drinking water standards after 120 days of stabilization.

Load-Duration Behavior of Wood-Plastic Composites

Christopher W. Brandt and Kenneth J. Fridley

J. Mater. Civ. Eng. 15, 524 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(524) (13 pages) | Cited 4 times

Online Publication Date: 14 November 2003

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The load-duration, or creep-rupture, behavior of wood and wood composite products has been studied extensively by numerous researchers, and simplified design procedures to account for creep effects are in place. However, the load-duration behavior of composite products made out of the combination of wood and plastic is not well understood or documented. Currently, wood-plastic composite (WPC) products are available on the commercial market, yet no standardized design procedures to account for creep or load-duration effects exist. Given the lack of understanding of the load-duration behavior of wood-plastic composites, a research effort was initiated to investigate the load-duration behavior of various wood-plastic composite formulations and to compare the observed behavior to that of solid sawn lumber. It was found that the wood-plastic composite formulations tested exhibited a more pronounced load-duration response than that of solid wood; however, the behavior trend was similar to that of solid wood and was successfully modeled using an exponential damage rate model originally developed for solid wood. Existing procedures for developing load-duration design adjustment factors for wood were used to develop load-duration design adjustment factors specifically for the WPC formulations tested.

Quantitative Description of the Pull-Out Behavior of Crimped Yarns from Cement Matrix

Alva Peled and Arnon Bentur, M.ASCE

J. Mater. Civ. Eng. 15, 537 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(537) (8 pages) | Cited 4 times

Online Publication Date: 14 November 2003

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The object of the present paper was to quantify the effect of crimping of a low modulus polymer yarn on the bonding with a cement paste matrix. Crimping of this kind has been evaluated within the context of optimizing the structure of woven fabric to obtain a strain hardening composite. The concept applied here was based on existing models developed for straight yarns. These models resolve between two stages: the elastic stage (adhesion) and the slip stage (friction). A similarity in the shape of the pull-out load versus slip curve of straight yarns and crimped yarns was found, suggesting that a modeling approach for straight fibers, which consider adhesional and frictional resistance, can also be applied for the crimped yarns. The effect of the yarn crimping on calculated adhesional and frictional components, τau and τfu, was estimated, showing a marked increase with yarn density for both types of bonding mechanisms. These values are considered as equivalent values since their physical significance is limited. Empirical linear correlations was found between the equivalent adhesional and frictional bond strengths and the crimp density. These empirical relations were combined with equation describing the shape of pull-out curves, to calculate the pull-out curves of the crimped yarns. The agreement with the experimental curve was reasonably good.

Thermal Movements in Concrete: Case Study of Multistory Underground Car Park

Walid Aboumoussa, P.E., A.M.ASCE and Magued Iskander, P.E., M.ASCE

J. Mater. Civ. Eng. 15, 545 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(545) (9 pages)

Online Publication Date: 14 November 2003

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An expansion joint in a concrete structure was instrumented and monitored for a period of one year. The structure is an open four-story car park, measuring 90 m (295.4 ft) in length and 71.62 m (235 ft) in width. It is a reinforced-concrete waffle-slab floor system with rectangular columns. The joint was instrumented using four vibrating-wire displacement transducers with integrated temperature sensors. Transducer measurements were recorded hourly. A description of the instrumentation and monitoring results of the expansion joint are presented, including annual, seasonal, and daily ranges of movements and the corresponding values of the apparent coefficient of thermal expansion (ACTE) of the constructed structure in service. In general, it was found that values of the annual ACTE of the joint ranged between 0.000586% per 100°C (0.00032% per 100°F) and 0.0757% per 100°C (0.041% per 100°F), depending on the type of structural restraint imposed on the expansion joint.

Polymer Effects on the Vibration Damping Behavior of Cement

W. G. Wong, Ping Fang, and J. K. Pan

J. Mater. Civ. Eng. 15, 554 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(554) (3 pages) | Cited 1 time

Online Publication Date: 14 November 2003

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In this paper, the vibration damping properties of polymer-modified-cement (PMC) have been studied. The storage modulus (E′) and loss tangent (tan δ) of PMC were studied by using a free vibration method. The propagation velocity of stress wave V and the scattered damping of stress wave in PMC were studied by using an ultrasonic testing method. When a suitable polymer is added in the cement, the storage modulus, the velocity of stress waves are decreased with an increase of the polymer/cement ratio (P/C), and the loss tangent is increased with an increase of P/C, thus the ability to vibration damping of PMC is improved. As the P/C is between 15 and 20%, the PMC demonstrates the best vibration damping within the adopted range of testing.

Nondestructive Evaluation of Tuned-Mass-Damper-Type Vibration Absorbers Using Vibration Signatures

F. Necati Catbas, Kirk A. Grimmelsman, Raymond A. Barrish, and A. Emin Aktan

J. Mater. Civ. Eng. 15, 557 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(557) (10 pages)

Online Publication Date: 14 November 2003

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Nondestructive evaluation methods are often essential in order to objectively assess the condition of structural and ancillary systems for bridges, particularly in cases where visual methods provide only limited or subjective data and the function of the systems being evaluated may not be disturbed using destructive evaluation techniques. This paper describes a nondestructive evaluation procedure that was developed to objectively assess the current condition of a system of 920 aged vibration absorbers installed on a long span cantilever truss bridge. The vibration absorbers, which are essentially tuned mass dampers consisting of a steel weight attached to the end of a viscoelastic rubber stem, were installed soon after the bridge was opened to mitigate the effects of excessive wind-induced vibrations that had occurred in many of the truss members. A nondestructive evaluation procedure was developed because the vibration absorbers had to remain in service during the evaluation process, and there were only a limited number of spare absorbers that could be used to replace any that might be destructively tested. The complete evaluation program included nondestructive vibration testing in the laboratory using impact methods to determine the current dynamic properties of the absorbers, and field testing to evaluate the energy dissipation characteristics of the installed vibration absorbers as they were actually operating. In addition, a limited number of destructive material tests were conducted in order to corroborate the results of the nondestructive tests. This evaluation program revealed that the current performance characteristics of the aged vibration absorbers were within the limits of the original design specifications, and that the synthetic rubber material used for the vibration absorbers had experienced no appreciable deterioration after nearly 25 years of continuous service.

Prepacked Grouting Process in Concrete Construction

Somsak Swaddiwudhipong, M.ASCE, Jing Zhang, and Seng Lip Lee, Hon.M.ASCE

J. Mater. Civ. Eng. 15, 567 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(567) (10 pages) | Cited 1 time

Online Publication Date: 14 November 2003

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Prediction of the prepacked grouting process provides useful information for site engineers to decide a proper spacing of injection point and foresee the injection pressure and flow rate to achieve a better quality control of concrete. Prediction methods based on both experimental and analytical work are proposed in this study to analyze the flow of cement grout through single-size aggregate media during the prepacked grouting process. Radial flow is employed to present a basic description of common cases in practice. Darcy’s law modified for Bingham fluid (Darcy approach) and Buckingham-Reiner equation modified for porous media (capillary approach) are developed to determine and analyze the flow. Evaluations of the viscosity of cement grout and permeability of the aggregate media are carefully designed and relevant parameters established for prediction analysis. Validation of the proposed analyses is confirmed by comparing the predicted results with monitored values from grouting tests.

Thermal Stabilization of Iron-Rich Sludge for High Strength Aggregates

Joo-Hwa Tay, Kuan-Yeow Show, Sze-Yunn Hong, Chao-Yu Chien, and Duu-Jong Lee

J. Mater. Civ. Eng. 15, 577 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(577) (9 pages) | Cited 4 times

Online Publication Date: 14 November 2003

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A key task in wastewater sludge management is preventing sludge from polluting the environment. Sludge invariably poses risks to both public health and the environment whether incinerated or landfilled. Alternative reuses need to be explored in order to solve the disposal problems of sludge in an environmentally sound manner. This investigation examines the potential of using an industrial sludge and marine clay to produce aggregates for replacement of regular coarse aggregate in concrete. The waste mixes were pressed into layers and sintered at elevated temperatures resulting in a fused hard solid mass. During the sintering process, the peak rates of weight loss occurred at temperatures of 80–90, 280–520, and 900°C, indicating mass loss through evaporation and volatilization of organic and metallic substances, respectively. The sintered materials were crushed into required sizes for a range of construction aggregates exhibiting varying characteristics. Laboratory test results indicated that sludge-clay aggregates of up to 20% clay content displayed better aggregate impact resistance of 23.1–28.8% Aggregate impact value (AIV) compared with 28.3–38.9% AIV for the control granite aggregate. Sodium salt and sintering temperature have significant influence on the product density. Concrete cast with the sludge-clay aggregates yielded compressive strengths ranging from 34.0 to 39.0 N/mm2, while the sludge aggregates of 0 and 20% clay content produced concrete stronger than those cast with conventional granite aggregate. Leaching test results showed that the concentrations of the toxic elements leached from the aggregates were within acceptable levels, suggesting that the sludge-clay materials could possibly be used as concrete aggregates without detrimental effects to the environment. The experimental study indicated that conversion of the sludge and clay into construction aggregates could offer a feasible technical solution for waste management.

Bond Geometry and Shear Strength of Steel Plates Bonded to Concrete on Heating

Fernando J. F. G. Branco, António J. B. Tadeu, and José A. D. Nogueira

J. Mater. Civ. Eng. 15, 586 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(586) (8 pages)

Online Publication Date: 14 November 2003

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As concrete deteriorates, rehabilitation work on construction elements is often needed. One of several techniques that restores, or even increases, the initial resistance of the element, is the bonding of steel plates to the original concrete element. In general, the new element behaves well under normal load conditions. However, the bonding agent may deteriorate when subjected to temperature increase, and failure may ensue. The present work reports laboratory tests that aim to analyze the influence of the geometry of the bonding on the shear resistance of the connection. The results are presented for different temperatures, two types of concrete and several bonding geometries.

Life Cycle Modeling of Corrosion Affected Concrete Structures—Initiation

C. Q. Li

J. Mater. Civ. Eng. 15, 594 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(594) (8 pages) | Cited 2 times

Online Publication Date: 14 November 2003

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Control and monitoring of reinforcement corrosion in concrete is of significant practical importance if premature failure of reinforced concrete structures is to be prevented. The detection of the initiation of reinforcement corrosion in concrete marks the beginning of whole life performance assessment for reinforced concrete structures. This paper attempts to present the concept of whole life performance assessment for structures and apply it to reinforced concrete structures located in a marine environment. Models used in the whole life assessment are developed and their statistics derived. A merit of the developed models is that they are derived from data representing concrete structures in real service conditions. The emphasis of the paper is to develop a reliability-based method to estimate the initiation time of reinforcement corrosion in concrete structures. This method can equip structural engineers and asset managers with confidence in decision making in regard to the maintenance and repairs of corroded reinforced concrete structures. It has been shown in the paper that the initiation time for reinforcement corrosion in concrete structures located in a marine environment is negligibly short for the service life consideration.
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Substitution of Fly Ash, Slag, and Chemical Admixtures in Concrete Mix Designs

Yingqin “Elaine” Jin and Nur Yazdani, P.E., F.ASCE

J. Mater. Civ. Eng. 15, 602 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(602) (7 pages) | Cited 1 time

Online Publication Date: 14 November 2003

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The Florida Department of Transportation (FDOT) requires contractors for FDOT’s projects to submit a proposed concrete mix design prior to the production of any concrete. The contractor must use mix designs approved by FDOT. Substitutions of ingredients other than coarse aggregate must be justified through trial mixtures, and authorized in writing by FDOT engineers. The study reported herein investigated whether substitutions of fly ash, slag, air-entraining admixtures, and Types A, D, and G admixtures could be performed and be allowed in FDOT approved concrete mix designs. Substitutions of the ingredients were performed on two typical FDOT hot weather mix designs in this study. The concrete properties considered were slump, air content, and compressive strength. Test data for substitution mix designs were compared with the data for the original mix design. Results show that the substitutions cause variability in concrete properties for both the fly ash and the slag mix designs. Statistically reliable conclusions cannot be made because of small sample sizes for test data sets. This study is preliminary in nature; more extensive research based on statistically significant sample sizes is needed to validate the findings from this study.

Biaxial Failure Model for Fiber Reinforced Concrete

Xiao Dong Hu, Robert Day, and Peter Dux

J. Mater. Civ. Eng. 15, 609 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(609) (7 pages) | Cited 2 times

Online Publication Date: 14 November 2003

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Steel fiber reinforced concrete (SFRC) is widely applied in the construction industry. Numerical elastoplastic analysis of the macroscopic behavior is complex. This typically involves a piecewise linear failure curve including corner singularities. This paper presents a single smooth biaxial failure curve for SFRC based on a semianalytical approximation. Convexity of the proposed model is guaranteed so that numerical problems are avoided. The model has sufficient flexibility to closely match experimental results. The failure curve is also suitable for modeling plain concrete under biaxial loading. Since this model is capable of simulating the failure states in all stress regimes with a single envelope, the elastoplastic formulation is very concise and simple. The finite element implementation is developed to demonstrate the conciseness and the effectiveness of the model. The computed results display good agreement with published experimental data.

Performance Characteristics of Soil-Cement from Industry Waste Binder

Juanrong Zheng and Weizu Qin

J. Mater. Civ. Eng. 15, 616 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(616) (3 pages) | Cited 1 time

Online Publication Date: 14 November 2003

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The performance characteristics of soil-cement with industry waste binder as the stabilizer (designated as industry waste soil-cement) were studied in terms of mix proportions, bulk density, and unconfined compressive strength (UCS). The industry waste binder in this study was prepared by blending ground granulated blast furnace slag (GGBS), fly-ash, dried lime sludge (DLS) from the acetylene industry, and natural anhydrite with certain specific surface areas in mix proportion. Soil-cement with ordinary Portland cement as the stabilizer (designated as OPC soil-cement) was used as the control sample. The aim of this study was to check the feasibility of substituting industry waste binder for ordinary Portland cement in stabilization of soft soils. The results of the laboratory tests indicated that the UCS of industry waste soil-cement was strongly dependent on the mix proportions of the binder (especially the content and fineness of GGBS and lime content) for a given soil, that the bulk density of industry waste soil-cement was nearly equal to that of OPC soil-cement, and that the industry waste binder optimized produced higher strengths than OPC under the same conditions. This result suggests that industry waste binder is promising for stabilization of soft soils in civil engineering construction.
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J. Mater. Civ. Eng. 15, 619 (2003); http://dx.doi.org/10.1061/(ASCE)0899-1561(2003)15:6(619) (3 pages)

Online Publication Date: 14 November 2003

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