Experimental Investigation on Shrinkage in High Strength Fiber-Reinforced Concrete and Its Influence on the Shear Capacity of RC Beams Having Shear Reinforcement
The present study includes the experimental investigation on the structural mechanism of reinforced concrete (RC) beams using high strength reactive powder concrete (RPC) and containing high-strength steel short fibers. The steel fiber reinforced high-strength RPC beams was design lightly reinforced with shear reinforcement but to still fail in shear in the loading tests. The parameter was set as shear reinforcement ratio (0, 0.3%, and 0.6%), volume fraction of fiber (0, 1%, and 2%) and volume change due to mainly shrinkage which was controlled by the water dissipation during the curing with drying or sealed sequences until the loading test for the beams. The strains of the concrete and reinforcing bars in the RC beams and the strain in the reference specimen were measured during the curing. In the loading test, an image analysis using a digital image correlation method was carried out in order to detect the micro- and macro-cracks in the RC beams. We have confirmed from the loading experiments that the increase in the shear capacity of the RC beams by containing the shear reinforcement and steel fibers even when the amount of shear reinforcement was set close to the minimum requirement. The interval of the diagonal cracks in the RC beams at the ultimate stage was changed according to the amount of the shear reinforcement and the volume fraction of fiber. In addition, the results of loading tests indicate that the initiation and propagation of a diagonal crack in the RC beams was changed and finally the shear capacity of the beams was influenced by the parameters, especially in the case of high shrinkage condition.
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