Geopolymer synthesis using silica fume and sodium aluminate

Monoliths that set rapidly and harden at ambient temperature have been prepared by exploiting sol–gel type condensation reactions between sodium silicate, formed in-situ by alkaline dissolution of silica fume, and a solution of sodium aluminate. Structural characterisation of the product was carried out by XRD, 27Al and 29Si MAS NMR spectroscopy) and the samples showed reproducibly good compressive strengths, indicating that the products display all the characteristics of typical aluminosilicate geopolymers