Effects of types and surface areas of activated materials on compressive strength of GGBS cement

Abstract

This study investigated the effects of changing the type and surface area per unit mass (Sa) of activated materials on the compressive strength of ground granulated blast-furnace slag (GGBS) cement (GGBS > 60%). This study is divided into two parts. The first part involved the selection of activated materials. Compressive strength results show that gypsum improves the early strength of GGBS cement more effectively than does sodium silicate or sodium hydroxide. The gypsum activators increase GGBS activity through sulfates, generating ettringites and C–S–H to increase compressive strength. Chemical analysis shows that the sulfite (SO3) in GGBS cement has more stable compressive strength at 6–8%. The second part of this study investigated the influence of Sa. Gypsum was used as a strength activator. The sulfite in GGBS cement was controlled at 6.5% ± 0.5%, and Sa was adjusted as the variable. Linear regression analysis shows that the change in GGBS cement Sa (Msa) is positively correlated with compressive strength. The value of Msa can be estimated according to the value of Sa and the quantity of ingredients used for the study results (cement, GGBS and gypsum). The compressive strengths of GGBS cement at various curing ages can be predicted using Msa.