Abstract
Excessive expansion (overexpansion) may occur in a relatively short period of time when hardened paste of rapid hardening cement is subjected to water absorption after heating. In this study, hardened specimens of rapid hardening cement were prepared in different sizes, heated under different temperatures between 65°C and 120°C, and then immersed in water to investigate their expansion behavior, as well as cracks in appearance and changes in the strength of the hardened cement. It was found that overexpansion was likely to occur when the heating temperature was above 100°C, and that the effect of overexpansion was more significant in the smaller specimens. In the specimens with larger sizes and restrained by steel reinforcement, even when heated at above 100°C, the effect of overexpansion was found to be limited to the vicinity of the surface of the hardened cement, with no significant impairment to the mechanical properties as a structural member.
