DefinePK

Abstract

An experimental program was carried out to study the effect of water absorption, apparent porosity and sorptivity on durability of fly ash based geopolymer mortar specimens in Sulfuric acid solution. Low calcium Class F fly ash was activated by a mixture of NaOH and Na2SiO3 containing 5% to 8% Na2O with water to fly ash ratio of 0.33. The durability of geopolymer mortar specimens was evaluated on the basis of reduction in compressive strength when exposed in 10% Sulfuric acid solution for 24 weeks. Specimens containing lesser alkali were found to possess higher apparent porosity, water absorption and water sorptivity. After 24 weeks in sulfuric acid solution, specimens still had substantial residual compressive strength ranging from 29.4% to 54.8%. Specimens with higher water absorption, porosity and water sorptivity lost more strength than those with lesser corresponding values. Results obtained in the experimental program indicate that porosity, sorptivity and water absorption of geopolymer mortar specimens influences the durability of geopolymer mortars in sulfuric acid.