Review on physical and chemical activation strategies for ultra-high performance concrete (UHPC)

This paper aims to investigate the latest advancement in physical and chemical activation strategies for ultra-high performance concrete (UHPC), addressing challenges such as high autogenous shrinkage, insufficient hydration, and inadequate steel fibers utilization, to further enhance its performance and achieve broader application. Firstly, an in-depth discussion is provided on physical activation strategies, encompassing design methodologies, nanomaterials, mixing, casting, and curing regimes. Subsequently, the discourse comprehensively covers chemical activation strategies, including active nanomaterials, multi-cementitious material systems, chemical admixtures and alkali-activator. Throughout this investigation, particular emphasis is placed on identifying research gaps within various activation strategies to foster more profound subsequent research and encourage innovative contributions to civil engineering. Finally, a focused discussion is provided on the influence of synergistic physical and chemical activation on UHPC performance. This comprehensive review serves as a crucial reference for deep research and broader application of UHPC in engineering, offering valuable insights for further exploration and optimization of the UHPC performance.