Thermal and pore structural characteristics of polymer-impregnated and superplasticized cement pastes

Abstract

Two sets of hardened cement pastes were prepared by (a) impregnation with polymethyl methacrylate and polystyrene or (b) admixing with water-soluble condensates (superplasticizers) such as Na-phenol sulphonate formaldehyde, Na-polystyrene sulphonate and Na-β-naphthol sulphonate formaldehyde. The pastes were hydrated for 180 days. The results of nitrogen adsorption indicated that polymer impregnation strongly affected the specific surface areas and the total pore volumes of the hardened cement pastes. XRD analysis, DTA and TG demonstrated (a) the formation of new phases as a result of the interactions involving the polymer within the pore system of the hydrated products of the impregnated cement pastes, and (b) no change in the phase composition of the hydrated products of the cement pastes admixed with superplasticizers.