Strength and absorption characteristics of fly ash based geopolymer composite reinforced with glass fiber

This thesis presents results of an experimental program to determine mechanical properties of glass fiber reinforced geopolymer mortar which is a mixture of fly ash, alkaline liquids, fine aggregates, and glass fibers. The effects of inclusion of glass fibers on density, compressive strength, splitting tensile strength, absorption and sorptivity of hardened geopolymer mortar composite (GPMC) was studied. Alkaline liquid to fly ash ratio was fixed as 0.33. NaOH and Na2SiO3 solutions were used as alkaline liquids for activation of fly ash. The alkaline liquid combination ratios of 2.5 to 1 were accounted for Na2SiO3 solution and NaOH solution, respectively. Glass fiber was added to the mixes in 0.2%, 0.4%, 0.6%, 0.8%, 1.0% and 1.2% by volume of mortar. Curing regime of 48 hours with 60 oC temperature was applied. The experimental results indicated that inclusion of the glass fibers resulted in decrease of the workability but improvement in compressive strength, splitting tensile strength, of the fly ash based GPM with increased fiber content. However, inclusion of glass fiber did not indicate a remarkable change in the water absorption and sorptivity of the geopolymer mortars.