Principles of polymer film in tile adhesive mortars at early ages

Principles of polymer film in tile adhesive mortars at early ages had been investigated by three redispersible polymer powders under SEM and CT. Morphology and distributions of polymer film of these redispersible polymer powders(EVA, E/VA/VE and E/VCVL) both in fresh cement pastes after natural stratification and in hardened C₃S pastes were random and regional. Intergrowth relationship between polymer film and hydrates was universal and this intergrowth in microzones should be regarded as one unique microstructure which named 'hybrid intergrowth zone, HIZ'. Inside these HIZs, there were two types of polymer film, 'pure type' only containing polymer particles and 'hybrid type' containing both polymer particles and inorganic particles. There were enlargement effects of redispersible polymer powders on porosity, average pore diameter and mean pore diameter of pores in cement mortars. Based on mean sphericity of CT, the connectivity of pores in cement mortars had been improved by redispersible polymer powders. 3D shapes of pores had also been changed by redisperisble polymer powders. Effects of redispersible polymer powders were quite different. (paper)