Enhancement of compressive strength and thermal shock resistance of fly ash-based geopolymer composites

This study presented the effect of 0-5 wt% TiO2 addition on compressive strength and thermal shock resistance of fly ash based geopolymer composites, which were prepared by activating high calcium fly ash reinforced with basalt fibers. The compressive strength of the composites after aging 28 days increased to 52 MPa when 5 wt% TiO2 was added. The retained compressive strength as 5 wt% TiO2 was added after 15 thermal cycles (800 degrees C) was 26 MPa, which was increased by 44% compared to TiO2 free composites. Such an enhancement was ascribed to the acceleration of hydration reactions in geopolymer structures resulting more C-H-S phases which resulted in a denser matrix with increased strength. (C) 2016 Elsevier Ltd. All rights reserved.