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An experimental investigation was conducted on the shear behavior of deep beams made with steel fiber reinforced high performance concrete (HPC). Twenty-six beam specimens with various shear span-effective depth ratios, steel fiber contents, amounts of vertical and horizontal web reinforcements were tested under static loads. In addition to the strength test, extensive instrumentations were designed for the measurements of average strains of reinforced concrete in the shear span and strains of web reinforcements. The web-shear cracking initiated as the first inclined shear crack. About 30% increase in the inclined shear strength and 25% increase in the ultimate shear strength can be achieved with addition of 1 .O% steel fiber for specimens having a/d= 1 .5. The strain of vertical web reinforcements became negative and the horizontal web reinforcements were stretched to yield state for specimens having a/d ratios approach 0.5. The measured load-deformation relationships of reinforced concrete and strains of web reinforcements were compared with the prediction of the softened truss model of steel fiber reinforced concrete proposed by other investigators. Good correlation was found from the comparisons.

A 4-year study, conducted by a consortium of three universities, on the use of high-performance concrete in highway applications was recently completed. A major goal of this research project was to determine if high-performance concrete mixes could be successfully produced in the field. In addition, an evaluation was to be made of the long-term performance of this concrete under field service conditions. Field installations were constructed in five states for this purpose. Paper provides potential users of high-performance concrete with general recommendations and guidelines for production and placement.

The use of high-strength lightweight concrete (HSLWC) in offshore oil and gas platforms is becoming more common. The constant wave action on these structures imposes continual fatigue loading on the concrete. Paper reviews previous research on both compressive and flexural fatigue behavior of HSLWC. The fatigue behavior of HSLWC is comparable or somewhat better than high-strength normal-density concrete (HSNDC) tested under the same conditions. The cyclic strain behavior of HSLWC is significantly different than for HSNDC and there is little change in strain behavior with increasing cycles of load until failure occurs. The fatigue life is reduced when the concrete is tested in submerged conditions. There is no significant difference between the S-N curves for reinforced and nonreinforced concrete. The mechanism that causes HSLWC to have comparable or better performance than HSNDC is attributed to the improved microstructure of the matrix-aggregate interface. This improvement reduces microcracking that typically leads to fatigue damage. The effect of crack blocking by sea salt depositions is discussed.

Besides high workability (high filling capacity and high resistance to segregation), little drying shrinkage and high resistance to cracking are important properties required for high-performance concrete. Addition of expansive admixture by appropriate proportion is an efficient way to compensate drying shrinkage for conventional concrete. By experimental investigations, it is confirmed that there is a very similar effect for high-performance concrete (HPC). But the effects of different types of expansive admixture for improving properties of high-performance concrete are various. As distinguished from using silica fume to produce HPC, fly ash is adopted in tests. It is found that appropriate amount of fly ash can not only avoid segregation, but also helps regulate unfavorable expansion of concrete caused by excessive content of expansive admixtures. Four types of expansive admixture are used in tests. Their effects on workability, deformation, and strength of HPC are discussed in this paper.

Presents the results of an investigation on the long-term deformation of steel fiber reinforced concrete containing silica fume. The influence of loading ages on the creep and ages of curing on the shrinkage of specimens was investigated. The volume fraction of steel fibers used in concrete is 0, 1, and 2 percent. The addition of silica fume is 0, 5, and 10 percent by weight of cement. Test results indicate that the combined effect of fibers and silica fume reduces the creep and shrinkage and enhances the development of compressive strength of concrete. At specific silica fume content (10 percent), the effect of increasing fiber content to reduce creep and shrinkage decreases gradually as the fiber content increases. This phenomena is similar to the addition of silica fume in concrete with 1 percent volume fraction of steel fibers.