Experimental assessment of steel fibre reinforced concretes with different concentrations of fibres

Abstract

At present, steel fibre reinforced concrete can be classified as a composite material commonly used for load-bearing building structures. Adding steel fibers to fresh mixture improves its mechanical properties in comparison to plain concrete. The problem is, however, the production technology, which has not been standardized by regulations so far, and thus, proposals for the amount of steel fibers added to the mixture are still based on the long-term experience and performed tests. The paper describes an experiment focused on the determination and assessment of mechanical properties of steel fibre reinforced concretes with high concentrations of fibres (40 kg/m3, 80 kg/m3 and 120 kg/m3). To better understand the behavior of test specimens during the three-point bending test, the acoustic emission method was used, which is able to capture active defects. The results show that the increasing amount of fibers has the influence on values of FRk,0.5 and FRk,res,1 (e.g. for concentration 40 kg/m3 is FRk, 0.5 = 13.27 kN and for 120 kg/m3 is FRk, 0.5 = 21.18 kN).