Internal curing of ultra-high-performance concrete: A comprehensive overview

Abstract This article presents an overview of the research on the effects of internal curing (IC) on ultra-high-performance concrete (UHPC). The process of adding a curing ingredient to the concrete mixture to serve as a water reservoir is known as internal curing. IC is a viable technique for supplying additional water for curing cement-based material with lower water-to-binder concrete. It is distinct from externally applied curing. The water meant for internal water curing is dispersed within the concrete after it hardened and facilitated the hydration process. It was used to minimize self-desiccation and shrinkage in UHPC. Based on the reviewed literature, an exchange between mechanical characteristics and autogenous shrinkage for concrete was observed for internally cured UHPC. Even though IC affects the mechanical characteristics, after 28 days, it was possible to achieve a compressive strength of over 150 MPa. Thermal curing was found to exhibit a remarkable effect on the development of UHPC strength. Experimental findings revealed that using pre-saturated aggregates for IC improves the tensile strength of UHPC. The scanning electron microscope images revealed that the bulk of the voids within the super-absorbent polymer cavities are filled with portlandite.