A study of the effect of light-burnt dolomite on the hydration of alkali-activated Portland blast-furnace slag cement

•In Na2SO4-activated Portland blast-furnace slag cement, the hydration heat increased with the addition of LBD.•A delay of the initial setting time was observed with the addition of LBD.•The compressive strength improved with the addition of LBD.•The pore structure of the paste became dense after 28 days of aging. This study used the typical powder alkaline material anhydrous sodium sulfate (Na2SO4) as an activator in a system in which Portland cement (10–20%) and ground granulated blast-furnace slag (GGBS, 80–90%) are generally mixed and added to light-burnt dolomite (LBD), one of the economical lime materials. Their effect on the hydration and strength of the cement was then analyzed. According to the analysis, the 1st peak of the minute heat of hydration increased after mixing the LBD. On the other hand, for the 2nd peak, a slight delay was observed. As a result of the mixing, the cumulative heat of hydration increased. Although the rate of setting decreased, the strength of the material improved after the 3rd, 7th and 28th days. In other words, it was confirmed that the pore structure of the paste became dense after 28days of aging.