Effect of synthetic fibers on the quasi-static and blast behaviour of reinforced concrete beams

摘要

This paper presents the results of a study examining the effect of synthetic fibers on the flexural and shear behaviour of beams tested under quasi-static and blast loading. In total, ten beams built with normal-strength concrete and synthetic fibers are studied, with five specimens tested under quasi-static four-point bending and a companion set of five beams tested under simulated blast loads using a high-capacity shock-tube. Test parameters include the effect of concrete type (plain vs. fiber-reinforced concrete), fiber type (two types of macro-synthetic fibers) and transverse reinforcement (in plain and fiber-reinforced concrete beams). Under slowly applied loads, the provision of synthetic fibers is shown to improve the residual shear capacity of beams built without stirrups, while the combined use of synthetic fibers and stirrups is found to improve flexural ductility. The effect of synthetic fibers on blast capacity is examined by comparing the mid-span displacements, failure modes and damage of beams tested under gradually increasing blast pressures. The results show that the use of synthetic fibers increases the blast capacity of beams built without transverse reinforcement, delaying shear failure. When combined with stirrups the use of synthetic fibers is shown to enhance damage tolerance and allow for better control of residual mid-span displacements at equivalent blasts.