Properties of lightweight aerated geopolymer synthesis from high-calcium fly ash and aluminium powder

Abstract

In the present work, efforts to decrease unit weighs of the geopolymer mortar around 2,400 kilograms per cubic meter to be lightweight aerated geopolymer which density lower than 1,800 kilograms per cubic meter and study the properties of lightweight aerated geopolymer based on binders composed of high calcium fly ash, and the aluminum powder was studied. Compressive strengths and densities of lightweight geopolymers with aluminium powder contents of 0-0.20%wt, NaOH concentrations of 7.5-12.5 molars, liquid to fly ash ratios of 0.45-0.65, Na2SiO3 to NaOH ratios of 0.33-1.5, sand to fly ash ratio of 0.6-1.4, curing temperatures of 25-100 degree Celsius, and curing period of 1-24 hours. were tested. In addition, SEM and ultrasonic pulse velocity of lightweight aerated geopolymer were determined. Results showed that the lightweight aerated geopolymer high calcium fly ash and aluminum powder with the 28-day compressive strength of 1.2-12.6 MPa and densities of 770-1,560 kilogram per cubic meter, with satisfactory strength, could be made.