Mechanical and Acoustic Performance of Lightweight Cementitious Composites Incorporating Pumice and Expanded Perlite

This study presents a comprehensive experimental investigation of lightweight cementitious composites incorporating pumice and expanded perlite as sustainable substitutes for conventional aggregate systems. Four replacement ratios (25%, 50%, 75%, and 100%) were evaluated to determine their effects on density, compressive strength, flexural strength, modulus of elasticity, and acoustic insulation properties, including the noise reduction coefficient (NRC) and frequency-dependent sound transmission loss (STL). The results showed that increasing the lightweight aggregate content generally reduced the strength-related mechanical properties while improving acoustic performance, particularly in the mid- and high-frequency ranges. Among all mixtures, the expanded perlite-based PRC-1.0 specimen exhibited the best overall acoustic performance, achieving the highest NRC value and the widest STL range. These findings demonstrate a clear trade-off between mechanical strength and acoustic efficiency, indicating that expanded perlite-based lightweight cementitious composites are promising materials for building applications requiring enhanced sound insulation performance.