Hybrid effects of polyvinyl alcohol (PVA) and basalt fibers on microwave absorption of cement composites with fly ash

Polyvinyl alcohol (PVA) and basalt fibers have been overlooked in the microwave absorption enhancement due to their low electromagnetic parameters. In this study, we examined the hybrid effects of PVA and basalt fibers on the microwave absorption of cement composites with high-volume fly ash. The mechanisms of the enhanced absorption were explored by investigating microstructures, phase compositions, and chemical bonds. It was found that reflection loss is significantly enhanced with variation in fiber proportion. Also, the fibers affect the dielectric properties using the Debye relaxation. In addition, in this paper, the relationship between the microstructure and electromagnetic parameters is established. It was also found that, in cement composites with high-volume fly ash, the hybrid effects of PVA and basalt fibers can improve the polymerization of the C–A–S–H gel, which influences these cement composites’ microstructures, and in turn, their Debye relaxation.