Effect of gypsum content on some properties of blast furnace slag cement

Abstract

The objective of the study is to evaluate the influence of gypsum content on certain properties of blast furnace slag cement (with 40% blast furnace slag) at gypsum levels ranging from 2% to 5%. The properties of the cement investigated include water of consistency, initial and final setting times, compressive strength at ages of 1, 3, 7, and 28 days, and heat of hydration of the cement paste within the first 24 hours. Experimental results indicate that increasing the gypsum content has minimal impact on the water of consistency but prolongs the setting time, while still meeting the technical requirements according to TCVN 6260:2020. The optimal gypsum content, in terms of strength, for blast furnace slag cement is 4%, providing compressive strength comparable to the control sample of ordinary Portland cement at 3 and 28 days of age.