Effect of Curing Temperature on Volume Changes of Alkali-Activated Slag Pastes

This study investigates the influence of curing temperature (explored at 10 °C, 20 °C, and 30 °C) on the volume changes of alkali-activated slag (AAS) pastes with the aim of expanding existing knowledge on alkali-activated materials (AAMs). The focus was on autogenous and thermal strains, internal relative humidity (IRH), heat flow and cumulative heat, setting times, and workability. The results indicate that increasing the curing temperature to 30 °C reduces autogenous shrinkage, likely due to changes in the elastic modulus and viscoelastic properties, while promoting swelling, especially for higher molarities. The coefficient of thermal expansion (CTE), related to thermal strains, is higher when the curing temperature is increased, but its development is delayed. The IRH is influenced more by the activating solution's molarity than by curing temperature, although temperature does affect the initial IRH. The study also revealed that higher curing temperatures accelerate chemical reactions and reduce setting times. The initial workability was significantly affected by the solution-to-binder ratio, while higher temperatures decreased workability, especially at higher molarities. These findings contribute to the understanding of how curing temperature influences the durability of AAS pastes, offering insights into optimized construction practices under varying environmental conditions.