Experimental and numerical investigation of fracture behavior of ultra high performance concrete

Abstract

The fracture behavior of ultra-high performance concrete (UHPC) with different depths of notches and curing ages were investigated using a three-point bending test. The ratio of total fracture energy to initial fracture energy raises from 5.9 to 8.3, and then drops to 7.8 with the increases of depth of notch. The fracture energy of UHPC beams with different depths of notches has size effect based on comprehensive analysis. Furthermore, the ratio of total fracture energy to initial fracture energy diminishes from 17.9 to 8.2. The two types of fracture energy of UHPC grow rapidly as the curing age increases, and the influence of curing ages on the fracture energy is mainly reflected in the energy growth within 14 days. In addition, a more suitable improved softening curve model for UHPC is proposed based on the above experimental results and analysis of fracture process. The model could not only better predict the peak load in the rising section of the crack mouth open displacement (CMOD) curve, but also simulate the failure process in the descending section curve.