Compatibility of Polycarboxylate Superplasticizer with Cements of Different Freshness

In order to study the factors influencing the compatibility of polycarboxylate superplasticizer with cements, cement paste fluidity methods were used to evaluate the compatibility between the superplasticizer and cements with different freshness at different temperatures and moistures. The Zeta potential of cements was measured by Zeta potential analyzer, the mean particle sizes were measured by laser particle analyzer, and the cement clinker phases were investigated by X-ray diffraction. The results show that lower cement freshness, lower temperature and higher moisture would lead to lower saturation point of polycarboxylate superplasticizer in cement, higher initial fluidity and lower flow loss, namely, higher compatibility. Compared with the stale cement, the fresh cement was 1.86 mV higher in Zeta potential, 2.63 μm larger in particle size, and higher content of C3A and C4AF that would absorb more superplasticizer. It can be concluded that the possible factors that influence the compatibility of cements with the superplasticizer include temperature, moisture, Zeta potential and the clinker phases of cement.