Modeling of Hydration, Strength Development, and Optimum Combinations of Cement-Slag-Limestone Ternary Concrete

Slag can increase late age strength of concrete, but impairs the concrete early-age strength due to low reactivity. Limestone powder can increase early-age strength, but impairs late-age strength due to dilution effect. The combination of slag and limestone powder can produce a composite concrete with adequate strength at both early ages and late ages. This study shows an integrated hydration-strength-optimization model for cement-slag-limestone ternary blends. First, a blended hydration model is put forward for simulating the hydration of composite binder containing slag and limestone powder. Reaction degrees of individual component of binders are calculated using this hydration model. Second, the gel-space ratio of ternary blended concrete is determined based on reaction degrees of composite binder and mixing proportions. Moreover concrete compressive strength is calculated using gel-space ratio. Third, based on parameters analysis, the isoresponse curves regarding strength of concrete are calculated. The optimum combinations of cement, slag, and limestone powder at different ages are calculated. The proposed numerical procedure is valuable for optimum strength design of cement-slag-limestone ternary concrete.