The interface between polymer-modified cement paste and aggregates

The effects of polymer dispersions on the structure of the interfacial zone between portland cement paste and aggregates (limestone and granite) have been investigated. EDAX analyses of the polymer modified composites showed that a relatively high polymer content is present at the paste-aggregate interface. Scanning electron microscope (SEM) observations of fractured surfaces of the plain cement paste-aggregate interface revealed large calcium hydroxide crystals which are orientated with their c-axes perpendicular to the interface. With increasing polymer content cement hydration products become indistinct, and microcracks appeared to be bridged-up by the polymer film.