Interparticle Potential and Sedimentation Behavior of Cement Suspensions: Effects of Admixtures

DLVO theory has been applied to cement suspensions containing admixtures. Two different batches of the same cement, different only in storage history, are compared. It is found that, although their general sedimentation behavior is similar, differences exist in the zeta potential and basic chemistry. Both the superplasticizer and water-reducing admixture result in all cases in a stable dispersion, contrary to the theoretical prediction that only a coagulated suspension should exist. This finding suggests that steric hindrance plays a larger role compared to electric repulsion in the deflocculation of cement pastes than previously believed. Zeta potential and sedimentation data for CaCl₂ and sugar are also presented.