Pseudo strain hardening model of ultra high performance cementitious composites under flexural loading

According to Tjiptobroto's research, the multiple cracking failure mechanism of cementitious composites was studied based on the energy dissipation equilibrium criterion between the initial cracking and non-initial cracking. The partial debonding energy at non-initial cracking and the number of random effective fibers were inserted with the assumption of the initial crack as the final failure crack of the structure. All the energy terms related in the model were modified and simplified according to the properties of ultra high performance cementitious composites (UHPCC) and a theoretical model of multiple cracking propagation of UHPCC was constructed to predict the crack propagation based on energy equilibrium criterion. The number of cracks and energy dissipation terms of Tjiptobroto experiment specimens were predicted. The comparison with the test results showed good agreement. It is suggested that the partial debonding energy term is necessary for UHPCC with high modulus of elasticity of steel fiber. The model can be a theoretical reference for predicting the initial cracking loading capacity and the ultimate limit loading capacity of UHPCC.