Comprehensive analysis of Fiber Reinforced Concrete beams with conventional reinforcement

Abstract

The aim of this work is to analyze the failure and mechanical behavior of full-scale reinforced concrete beams elaborated with fiber reinforced concrete. Although several researches can be found in the literature related with the study of the mechanical behavior of fiber reinforced concrete, only few of them are related to real-scale structural elements. With the purpose of characterizing the material, in the first part of the paper experimental results corresponding to compressive tests and splitting tensile tests on cylindrical specimens, as well as three point bending tests on small notched beams considering plain and fiber reinforced concrete are addressed. Then, experimental results corresponding to four point bending tests on real-scale reinforced concrete beams, including different contents of industrial steel fibers in conjunction with different conventional reinforcement layouts, are presented and discussed. As expected, it was observed that fibers contribute to enhance structural integrity in post-peak behavior, both in small and structural elements. It was also observed that although the addition of fibers caused an increase in tensile strength on small samples, no evident differences were detected among cracking load values of full-scale beams with different fiber contents under bending. The evolution of crack widths with increasing loads was measured and analyzed in the experimental campaign in this work. In the last part of the paper, experimental results corresponding to ultimate bending and shear loads were compared with numerical estimations proposed in available international recommendations for structural design. It was detected that for the considered materials, current recommendations seem to be not enough conservative for predicting bending strength, contrary to the case of shear strength, where higher residual strengths were evidenced.