Study on fracture characteristics of graphene oxide reinforced ultra high performance concrete using DIC technique

This study aims to investigate the effects of steel fiber geometry and graphene oxide (GO) on the fracture characteristics of ultra-high performance concrete (UHPC). Through fracture mechanics tests combined with digital image correlation technology (DIC), the evolution of the fracture process zone (FPZ) and crack propagation behavior in UHPC were dynamically monitored and quantitatively analyzed. The results indicate that both hooked-end steel fibers and GO significantly enhance the fracture performance of UHPC. More importantly, their bridging effects at different scales effectively restrain the rapid development of cracks during the fracture process of UHPC, leading to a delayed evolution of the FPZ and a reduction in its size under equivalent load levels. Additionally, they promote stress distribution along multiple pathways, driving the dissipation of externally input energy by triggering distributed micro-damage over a larger spatial range, resulting in a significant increase in both the length and width of the FPZ at peak load. This distributed damage mechanism effectively enhances the macroscopic deformation capacity of UHPC, enabling the material to maintain high load-bearing capacity even under substantially increased crack opening displacements.