Evaluation and regulation of Ultra-High Performance Concrete (UHPC) crack resistance based on physicochemical multi-factor coupling approach

•The effect of low cement amount on UHPC crack resistance is studied.•The effect of steel fiber on UHPC crack resistance is studied.•The effect of expansive agent on UHPC crack resistance is studied.•The multi-factor coupling effects on UHPC crack resistance are studied.•An optimized recipe for the UHPC with advanced crack resistance is proposed. This study attempts to evaluate and regulate the crack resistance of UHPC mainly based on physicochemical multi-factor coupling methods. First of all, the effects of cement content, steel fibers and expansive agent on UHPC crack resistance are studied. Then, the response surface method is further utilized to investigate physicochemical multi-factor coupling effects on UHPC crack resistance. Based on the obtained results, it shows that using low cement content, adding steel fibers and adding expansive agent all can effectively improve crack resistance of UHPC. In particular, the effect of adding steel fibers is the most remarkable. Besides, the coupling effect among the three factors is explored based on response surface method, and the predicted values and actual values are in good agreement. Among them, there is a good interaction between steel fibers and expansive agent for the UHPC crack resistance improvement. Finally, based on the optimized approach proposed in this study, the crack resistance of UHPC can be effectively evaluated and regulated.