Prediction of the Effect of GGBFS on the Hydration of Cement Using Extended CEMHYD3D Model

The study presents important findings on predicting the behavior of a Portland cement-based mixture, specifically regarding hydration. Supplementary cementitious materials (SCMs) such as ground granulated blast furnace slag (GGBFS), often called slag cement, fly ash (FA), and silica fume (SF) are widely used in cementitious composites due to their durability, environmental friendliness, and minimal cost. Portland cement is usually substituted with granulated blast furnace slag (GGBFS) to make a blended cement. A slag-blended cement has a more complicated hydration process than Portland cement due to the interactions between the slag reaction and the hydration of Portland cement in the cementitious systems. Understanding the effect of slag substitution on the hydration of cement is still challenging. To achieve this, the extended CEMHYD3D model was employed to predict the hydration of a slag-blended cement. An OPC as a reference cement confirmed to ASTM C 150 and a slag confirmed to ASTM C 989 standard requirements were used in this study. The simulation was done with cement paste samples made with various w/c ratios and different slag substitution levels, in which the interaction between the hydration of Portland cement and the reaction of slag was considered. The prediction model has been validated with experimental results and verified to be successful in predicting the hydration of slag-blended cement. The consideration of the chemical composition of slag improves the predictability of hydration in cement, and the same method was applied in this model. Both in the early age and up to the age of 90 days, the hydration of slag-blended cement can be predicted with the proposed model.