Effects of sulfate and expansive clinker contents on expansion time of expansive-cement paste

The objective of this paper is to discuss the relationships between sulfate content and expansion time and between expansive-clinker content and expansion time in expansive-cement pastes. Generally, as the amount of sulfate increases, expansion time increases as well. In addition, sulfate content versus expansion time relationship depends on the size distribution of expansive-clinker particles. The increase is linear for monosize expansive-clinker particles and curvilinear for polysize particles. Increase in amount of expansive clinker up to a critical mass results in increase of expansion time. Addition of expansive clinker beyond the critical mass content results in reduction of expansion time. The above relationships serve as a basis for a model which can be used for optimizing mixture proportions. Such mixture proportioning will require only a small number of trial mixtures in order to achieve the optimum expansion strain, mechanical properties, and cost.