Some aspects on improvement of water resistant perfornace of gypsum binders

Abstract

The study reports that control of water resistant and strength performance of composite binder can be accomplished by using nanostructured gypsum silicate binder and portland cement and reduction of calcium sulfate dihydrate. Formation of an arranged more dense packing in crystal matrix of binder structure can be achieved through polydispersity of nanostructured silicon component. Highly reactive silica particles participate in synthesis of microcrystalline compounds such as hydroxylellestadite and serve as nucleation sites providing an increase of surface contact area between crystal structures. Cement in the system provides conditions to synthesis of stable flat-like hydroxysulfoaluminates. Upon hydration of a binder crystals of calcium sulfate dihydrate impound to a mass of water resistant crystalhydrate new formations, type and morphology of which promotes decreasing of intercrystal porosity followed by density, strength and water resistance increase of the composite.