Introduction
Effects of styrene acrylic (SA) latex on the hydration and mechanical properties of metakaolin blended cement (MKC) were systematically evaluated through the combined techniques of calorimetry, flow table test, Vicat test, mechanical measurement, QXRD, TGA and SEM. The results show that the presence of metakaolin (MK) greatly changes the interaction of SA polymer with cement grains and then modifies the properties of cement paste and mortar. Specifically, the retardation effect of SA latex on cement hydration can be alleviated through the addition of MK due to its strong adsorption ability to polymer particles, which is beneficial to shorten the setting time of cement paste. The addition of SA latex not only retards the hydration process of cement but also the pozzolanic reaction of MK with portlandite. Contrary to the adverse effect of SA latex on compressive strength, improved strength of hardened MKC mortar was observed with the increased polymer dosage from 4 % to 8 %, which is believed to be caused by the modified microstructure of the matrix through the film formation of SA polymer.