Experimental Investigation on the Cyclic Behaviour of Steel Fibre Reinforced Concrete Under Bending

Abstract

This paper presents the results of an experimental program investigating the monotonic and cyclic flexural behaviour of steel fibre reinforced concrete (SFRC). Three-point bending tests are assessed with acoustic emission (AE) monitoring to detect concrete micro-cracking and damage propagation during the different stages of cyclic loading. LVDTs over the prism’s height investigate the evolution of the neutral axis position. Three loading patterns are applied, namely monotonic, progressive cyclic and variable cyclic. 3D and 5D hooked end steel fibres are both used in a content of 20 kg/m3 and 40 kg/m3, representing a softening and a hardening behaviour respectively. By combining traditional and advanced measurement methods, the developed test setup allows a better understanding of the cyclic behaviour of SFRC. The monotonic envelope curves agree with the cyclic stress-CMOD curves. The neutral axis position appears to be independent of the SFRC classification. Fatigue damage development occurs for multiple load cycles at high load limits. Furthermore, AE monitoring proves to be complementary to mechanical testing for evaluating damage accumulation in SFRC under bending.