Refluxed rice husk ash/NaOH suspension for preparing alkali activated binders

Geopolymers simultaneously containing two waste materials have been developed: fluid catalytic cracking catalyst (FCC) as mineral admixture and rice husk ash (RHA) for preparing an alkaline activator. Alkaline activators were prepared by refluxing aqueous mixtures of ground or original RHA with NaOH. All mortars with alkaline activator containing RHA show compressive strength (cured at 65°C for 1 day) in the range of 31–41MPa, which is similar to control mortar prepared using an equivalent mixture of NaOH and water glass. Refluxing times between 30 and 240min yielded good performance mortars. This new way of valorisation would imply economic and environmental benefits in geopolymer production.