Effects of PVA fibers on microstructures and hydration products of cementitious composites with and without fly ash

This study explores the effects of poly(vinyl alcohol) (PVA) fibers on the microstructures and hydration products of cementitious composites with and without high-volume fly ash. To this end, the prepared composites are systematically characterized. The results indicate significant differences in the effect of PVA fibers on the cementitious composites with different fly ash contents. In the cementitious composites with high-volume fly ash, the PVA fibers give rise to the decalcification and polymerization of calcium (alumino) silicate hydrate (C (-A)-S-H) gels and a looser gel pore structure. In the composites without fly ash, PVA fibers promote the formation of Ca(OH)2 on the surface of fibers, increase the calcium-to-silicon ratio, and refine the gel pore structure. Furthermore, this study provides new insights into the influence of PVA fibers on the pore structure and molecular structure of the cementitious composites with different fly ash contents associated with their durability and dielectric properties.