Evaluation of the effect of natural and expanded perlite aggregates on the durability properties of vinylester and polyester resin polymer concretes

This study investigates the durability performance of lightweight polymer concretes produced with natural and expanded perlite aggregates. The effects of perlite incorporation on the macroscopic behavior and microstructural characteristics of polyester- and vinylester-based polymer concrete matrices were examined through a comparative and integrated approach. Quartz aggregates were replaced by 5% and 10% natural or expanded perlite by volume, and capillary water absorption, acid and sulfate attack, high-temperature exposure, and freeze–thaw tests were performed at 28, 56, and 90 days. Microstructural changes after high-temperature and freeze–thaw conditioning were analyzed using SEM. The results showed that perlite type and replacement level significantly influenced durability. Natural perlite provided stronger adhesion with both resin systems, lowering water absorption and enhancing resistance to chemical attack, freeze–thaw cycles, and elevated temperatures. Conversely, the high porosity of expanded perlite increased matrix permeability and reduced mechanical stability. Among all mixes, the vinylester-based polymer concrete containing 5% natural perlite exhibited the lowest durability losses and the most stable internal structure. Overall, natural perlite proved to be a promising local and sustainable lightweight aggregate for improving the environmental and durability performance of polymer concretes.