Shear Strength of Fiber Reinforced Recycled Aggregate Concrete

Abstract

In this research, the shear strength of fiber reinforced recycled concrete was investigated. A High-strength Self Consolidated Concrete (SCC) matrix with 100% coarse recycled aggregate and different types/configurations of fibers were used in the study. Steel (3D and 5D), synthetic and hybrid fibers (mix of steel 5D and synthetic fibers) with a volume fraction of 0.75 % were added to the concrete matrix to prepare eight beams. In addition, four beams were prepared without fibers as control specimens. The aim of the experimental program is to evaluate the effect of: 1) recycled coarse-aggregate replacement; 2) addition of fibers and 3) the steel fiber configuration on the shear strength of recycled aggregate concrete. The results show that recycled aggregate concrete resulted in an improvement in the average concrete shear strength of about 14.4% compared to that of the normal weight aggregate concrete. In addition, the fiber-reinforced beams showed significant improvement in the average concrete shear capacity in the range of 23.44 – 64.48% when compared to that of the control specimen. The highest improvement was achieved by the 3D steel fiber beams. The addition of the fiber delayed the crack initiation, and improved the post-cracking and ductile behavior of all beams. Moreover, the experimental results were compared to that predicted by codes and proposed equations found in the literature for concrete strength with and without fiber. It was found that the ACI simplified equation predicts the closest results for both types of aggregates; while the fib model code 2010 equation predicted the most conservative results.