Effect of fiber content on fracture behavior of UHPFRCC by acoustic emission technique

Abstract

The paper aims to study strain-harden and strain-soften fracture behavior of ultra-high performance fiber reinforced cementitious composites (UHPFRCC) with different fiber content based on acoustic emission (AE) technology. Three-point bending fracture test was performed on UHPFRC with 0 %, 1 %, and 2 % fiber content, and the fracture mechanical properties of UHPFRCC were analyzed. Meanwhile, the AE cumulative parameters, location, b-value, and crack mode were used to identify the fracture behavior of UHPFRCC. The result showed that with the increase of fiber content, the peak load and toughness of UHPFRCC increase, but the fiber content has little effect on the peak load displacement and ductility. Furthermore, cumulative AE parameters can distinguish strain-harden stage directly of UHPFRCC. And there is an exponential relationship between cumulative AE parameters and fiber content. Additionally, with the increase of fiber content, the width of fracture process zone and width of damage zone increases, and the reduction of b-value gradually decreases. The tensile crack mode is dominant in the fracture process of UHPFRCC by the k-means method, but the fiber content has little effect on the fracture mode of UHPFCC. This research can provide a theoretical basis for crack propagation and non-destructive testing of UHPFRCC in practical engineering.