Acoustic, Thermal, and Mechanical Performance of Polymer-Coated Pumice Aggregate Lightweight Concretes.

Pumice aggregate, with its highly porous structure, offers excellent lightweight and insulating characteristics; however, its excessive water absorption and weak interfacial bonding often limit its mechanical and durability performance in concrete applications. To overcome these drawbacks, this study developed a polymer-coated pumice aggregate (PCPA) concrete by applying a thin polyester layer onto the aggregate surface to enhance matrix-aggregate adhesion and reduce permeability. The mechanical, thermal, and acoustic performances of PCPA were systematically evaluated. Results revealed that polyester coating led to a notable improvement in compressive strength (up to 25%) and significantly reduced weight loss after freeze-thaw cycles. Furthermore, PCPA samples exhibited enhanced resistance to thermal degradation, maintaining structural stability even at 600 °C, and achieved a 40% higher sound absorption coefficient at 630 Hz compared to uncoated pumice concrete. These findings demonstrate that polyester coating effectively addresses the inherent limitations of pumice concrete, offering a promising approach for producing lightweight concretes with superior durability and multifunctional performance.