Strength behavior of fly ash geopolymer with microwave pre-radiation curing

Abstract

Abstract

This research studied on the effect of microwave energy on the compressive strength of geopolymer and compared
with that of geopolymer curing with the conventional heat system. Geopolymer was produced by the reaction between a pozzolan and the highly concentrated alkali and sodium silicate solutions, and then cured at the temperature of 65oC. Pre–radiation of microwave energy was applied before heat curing. Microwave energy helped the geopolymerization reaction resulting in the increase in leaching of silica and alumina on the fly ash surfaces and development of compressive strength. System with 90 watt microwave pre – radiation for 5 min plus 6 h heat curing gave a compressive strength of 34 MPa, which was higher than that of system with 65oC heat curing for 24 h (31 MPa). Therefore, the microwave energy could reduce the curing time and save energy obtaining the higher strength of geopolymer.