The influence of high-temperature curing on the hydration characteristics of a cement–GGBS binder

Abstract

The influence of high temperature curing at early ages on the hydration characteristics of a complex binder containing ground granulated blast furnace slag (GGBS) was investigated. High-temperature curing at early ages promotes the early hydration of cement, but it hinders the later hydration, and leads to large pores in the microstructure. So the long-term strength of cement mortar cured under high temperature at early ages is lower than that cured at under 20°C. The hydration of a cement–GGBS complex binder is more sensitive to temperature than is cement, and the strength gain rate of a cement–GGBS mortar is higher than that of cement mortar under high temperature curing at early ages. After high temperature curing at early ages, the later hydration of the cement fraction of the complex binder is hindered, but the later reaction of GGBS fraction is not influenced. The further reaction of GGBS increases the C–S–H gel quantity and improves the pore structure. Therefore, the cement–GGBS mortar gains a high early strength under high temperature curing at early ages, and its strength has a considerable increment at later ages due to the contribution of the reaction of GGBS.