Stratlingite and Hydrogarnet from Calcium Aluminosilicate Glass Cements

Abstract

AbstractCalcium aluminosilicate glass cements that hydrate directly to stratlingite (2CaO·Al2 O3 SiO2 · 8H2 O) and/or hydrogamet solid solution (3CaO·Al2 O3·XsiO2 ·[16–2X]H2O) are described.Hydrogamet develops rapidly during curing of pastes containing between 12 and 16 wt.% SiO2, while stratlingite grows more slowly in bladed radial spherulites in compositions containing 18 to 25% SiO2Compressive strengths between 35 and 70 MPa, 20–35% porosity, and excellent thermal and chemical stability are characteristic of the cured hydrogamet cements, while the stratlingite pastes have strengths between 70 and 140 MPa and 1–10% porosity.A preferred composition area is described that yields mixtures of the two hydrated phases, resulting in a useful combination of low porosity and high early strength.