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Showing 1 to 20 of 27 for “"Water-Cement Ratio"”.
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Examination of Drying and Psychrometric Properties of High Water-Cement Ratio Concretes
Moisture from concrete has been estimated to be responsible for over $1 billion annually from damages in floor coverings. To prevent damages, flooring manufacturers require installers to test concrete moisture levels to determine if the concrete has dried sufficiently to receive flooring or …
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Thermal Conductivity of foamed concrete
… of (i) foam content (25%, 50% and 70 %), (ii) water-cement ratio (0.35- 0.55) and (iii) polymer content (5 to 20 % of cementitious material weight) is presented. Experiments were done using a heat flow meter according to ASTM C 518-02. The experimental results show that thermal conductivity …
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Rapid assessment of the potential chloride resistance of structural concrete
… the immersion test was carried out. At least two water-cement ratios were produced for each mix design to enable normalisation of the results. The performance of concrete was compared on the basis of equal compressive strength, i.e. 40 and 50 N/mm2 and an equal water-cement ratio of 0.45. In …
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Moisture permeability of mature concrete, cement mortar and cement paste
… tests were performed on specimens of concrete, cement mortar and cement paste with the bottom side in water or in moist air and the upper side in a relative humidity of 33 %. The distribution of the relative humidity within the specimen was measured, at stationary conditions, as well as the …
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Attainable Compressive Strength Of Pervious Concrete Paving Systems
… strength on pervious concrete as it relates to water-cement ratio, aggregate-cement ratio, aggregate size, and compaction and compare those results with results obtained in laboratory experiments conducted on samples of pervious concrete cylinders created for this purpose. The loadings and types …
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Freeze-thaw durability of high strength silica fume concrete
Specimens from 27 batches of concrete with water to cementitious (cement plus silica fume) ratio of 0.25 to 0.32, with and without entrained air, were tested for freeze-thaw durability in accordance with ASTM C666, procedure A (freezing and thawing in water). In addition, another set of similar …
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Accelerating the thaumasite form of sulfate attack and an investigation of its effects on skin friction
… and restrained conditions whereby the acceleration of TSA was observed at unrestrained conditions depending on water-cement ratio, cement content, casting face and aggressive solution. Restrained conditions simulated soil/concrete interface interactions and were applied to identify changes of …
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New developments in steel reinforcement protection from corrosion
Due to life-cycle costs considerations, the Federal Highway Administration has required that all their new bridge structures have a service life of more than 75 years. The practical use of adequate concrete cover, low water/cement ratio, and corrosion inhibitors and admixtures are not enough to …
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Effect of Admixtures, Chlorides, and Moisture on Dielectric Properties of Portland Cement Concrete in the Low Microwave Frequency Range
… evaluation technique to evaluate Portland cement concrete (PCC) structures is based on the principle that a change in the structure, composition, or properties of PCC results in a change in its dielectric properties. The coaxial transmission line is one of the few devices that can measure …
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Impact of Specification Changes on Chloride Induced Corrosion Service Life of Virginia Bridge Decks
… included for the time for corrosion deterioration after corrosion initiation. Data collected from ten bridge decks built in Virginia between 1981 and 1994 was used to model the surface chloride concentration, apparent diffusion coefficient, and clear cover depth. Several ranges of the …
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An experimental study of the effects of some commercial admixtures on the properties of concrete
… I. Three standard concrete mixtures at different water-cement ratios and approximately at constant slump were designed without the addition of admixtures to serve as a parameter for the test mixtures. Eighteen different test mixtures were made with local aggregates. Three test mixtures for each …
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Concrete Rheology
… that considers the effects of sand content, water/cement ratio, coarse aggregate type, fly ash content and the addition of a superplasticizer on the rheological parameters of yield stress, plastic viscosity, and apparent viscosity. The objective of this work was not only to measure the …
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The potential of porcelain waste as sand replacement to produce high strength concrete
… of using porcelain waste as sand replacement in the concrete production. Three different samples of concrete have been casted (cubes, cylinders and beams), with different sizes, the water cement ratio adopted is 0.5 and 0.37 when superplasticizer was added with mix proportion of …
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Utilization of coal bottom ash and fine coconut shell as partial sand replacement in concrete
… fine coconut shell (FCS) as partial sand replacement. Normal concrete design with compressive strength of 30 MPa strength at 28 days curing age and a water-cement ratio of 0.50 was used in this study. The percentages of CBA used were 5%, 10%, 15% and 20% while the percentages of FCS used were …
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Investigation of Reactive Electrokinetic Processes for Permeability Reduction in Hardened Cement Paste
… transporting chemical precursors into hardened cement paste pores using an electric field and causing them to undergo a chemical reaction that results in blocking the pores and reducing permeability. The chemical precursors, silicate and aluminate solutions and sols, were tested with simulated …
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Influence of Bridge Deck Concrete Parameters on the Reinforcing Steel Corrosion
… in concrete is one of the major forms of deterioration mechanisms found in reinforced concrete bridges. Early age corrosion damage reduces the lifespan of the bridges, which results in heavy economic losses. Research has been conducted to identify economic solutions for significantly delaying …
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Synthesis and nano-mechanical characterization of calcium silicate hydrate (C-S-H)
… (C-S-H) constitutes two-thirds of hydrated cement paste by volume. Having a better understanding of the mechanical properties of C-S-H will significantly aid in future effort for making concrete by design' for specific applications such as blast resistance. C-S-H is an amorphous compound …
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Performance of composite sand cement brick containing recycled concrete aggregate and waste polyethylene terepthalate
… (PET) waste bottles as sand aggregate replacement. RCA was obtained from crushed laboratory concrete cubes while PET bottles were collected around UTHM and Parit Raja areas. The objectives of this study are to determine the optimum cement-sand ratio (1:5, 1:6 and 1:7) for composite brick …
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Thermal Conductivity of Fiber-Reinforced Lightweight Cement Composites
… (ETC) of fiber-reinforced lightweight cement composites. At various stages in the development of the model, the results are compared to experimental values and the model is calibrated when appropriate. Additionally at each stage the proposed model and its results are compared to …
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Development, application and early-age monitoring of fiber-reinforced ‘crack-free’ cement-based overlays
… materials is of utmost importance. Fiber-reinforcement can be used to alleviate some of the issues related to plastic shrinkage. However, quantifying the performance of cement-based composites under restrained shrinkage conditions remains an issue. Various test techniques are available to measure …
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