Single and synergistic enhancement on durability of geopolymer mortar by Polyvinyl Alcohol fiber and Nano-SiO2

Abstract To determine the optimal dosage of polyvinyl alcohol (PVA) fiber and Nano-SiO2 (NS) in metakaolin (MK) and fly ash (FA) based geopolymer mortar from the perspective of enhancement on durability of geopolymer mortar, the single and binary effects of PVA fiber and NS was explored. The compressive strength tests, rapid chloride permeability (RCP) tests, freezing-thawing cycle tests, sulfate wet-dry cycle tests, and scanning electron microscope (SEM) observation were conducted to evaluate the enhancement of PVA fiber and NS on compressive strength and durability of MK-FA based geopolymer mortar. The results showed that the application of PVA fiber and NS in appropriate dosage had significant improvement on compressive strength and durability of MK and FA based geopolymer mortar no matter they were used in single or blended addition. The best modification effect can be achieved when PVA fiber and NS were used together. The optimal mixing contents of PVA fiber and NS were 0.6-0.8 v% and 1.0-2.0 wt%, respectively. The results obtained in this study will enrich the knowledge system on properties of PVA fiber and NS modified geopolymer composites, which can provide guidance for the further promotion application of MK-FA based geopolymer mortar.