The influence of curing regimes on hydration, microstructure and compressive strength of ultra-high performance concrete: A review

Abstract

Accelerated curing regimes, such as high temperature curing, can lead to significant improvements in the hydration and early mechanical properties of ultra-high performance concrete (UHPC). The curing regime can greatly influence the hydration products and pore structure of UHPC, ultimately impacting its mechanical properties and durability. This paper provides a review of the various types of curing regimes utilized for UHPC. The analysis focuses on the impact of thermal curing on the hydration and microstructure of UHPC. Additionally, the effects of curing regimes on compressive strength at different ages are examined, along with the suggested relationship between hydration, pore structure, and compressive strength. The findings demonstrate that 1) thermal curing significantly enhances compressive strength, although later strength may slightly decrease; 2) higher 28-day compressive strength is associated with lower content of portlandite, as well as the morphology and Ca/Si ratio of C-(A)-S-H are closely linked to mechanical properties; 3) compressive strength is strongly and positively correlated with both the degree of hydration (DOH) of cement and the overall reaction degree (ORD) of binders at the same ratio; 4) there is a relatively strong correlation between compressive strength and porosity, while the effect of other pore structure parameters requires further experimentation to establish a mathematical relationship between microstructure and compressive strength of UHPC.