Find in Library

This paper presents an experimental investigation consisting of casting and testing in flexure twenty four rectangular simply supported reinforced concrete beams.Three of the tested beams are made with conventional concrete (CC), five with reactive powder concrete (RPC) and sixteen as hybrid beams of the two concretes. RPC is used in tension in ten hybrid beams and in compression in the other six beams. Experimental results have generally shown that higher ultimate loads (Pu) are obtained with the increase of RPC layer thickness (hR/h), steel fibers volumetric ratio (Vf) and longitudinal steel ratio (ρ) for hybrid beams with RPC in tension as well as in compression. However, the effect of (ρ) is more pronounced than the other factors. Using RPC in compression is found to be more effective than using RPC in tension. The increasing ratios for ultimate loads of hybrid beams with RPC in compression, ρ=3.36% and Vf= 1% (compared to CC beams) are 47.13% and 71.97% for (hR/h) of 0.25 and 0.5, respectively. These ratios are higher than those for hybrid beams with RPC in tension, ρ=3.36% and Vf= 1%, for hR/h of 0.25 and 0.5 by 35.67% and 37.58%, respectively.