Mechanical properties of ambient cured fly ash-slag-based engineered geopolymer composites with different types of fibers

In this paper, low-strength polyvinyl alcohol (L-PVA) fibers, high-strength polyvinyl alcohol (H-PVA) fibers, and polyethylene (PE) fibers were used to prepare ambient cured fly ash-slag-based engineered geopolymer composites (EGC). The effects of fiber types and fiber volume fractions (1.5%, 1.75%, 2.0%, 2.25%, and 2.5%) on the compressive strength and tensile performance of EGC were evaluated. It was found that by increasing the fiber volume fraction from 1.5% to 2.5%, L-PVA fibers had the lowest influence, whereas PE fibers had the highest influence on the compressive strength of EGC. The optimum fiber volume fractions of L-PVA, H-PVA, and PE fibers were 1.75%, 2.25%, and 1.5%, respectively, for EGC to achieve the best tensile performance. Scanning electron microscope (SEM) investigations showed that the bonding performance of PE fibers to the EGC matrix was higher than those of L-PVA and H-PVA fibers to the EGC matrix.