Preparation methods and comprehensive performance of desulfurized gypsum–rubber particles lightweight composites

Industrial solid waste recycling into building materials still faces challenges from inefficient processing and sparse durability data. This study optimizes the preparation and assesses the long-term performance of desulfurized gypsum – rubber composites. Specimens were cast with NaOH-treated rubber particles (4–20 wt%; 20-, 40-, and 60-mesh) using three mixing sequences. We measured compressive and flexural strength, density, thermal conductivity, and thermal resistance, and conducted 40-cycle freeze – thaw, water absorption, SEM, XRD, and mercury intrusion porosimetry tests. At 20 wt% 20-mesh rubber – using a dry gypsum – rubber premix – the compressive strength fell from 11.1 to 4.93 MPa, flexural strength from 3.96 to 1.18 MPa; density decreased by 12.4%, thermal conductivity by 34.9%, and thermal resistance increased by 52.8%. After 40 freeze – thaw cycles, mass and strength losses remained below 5% and 25%, respectively, satisfying GB 50,574-2010. SEM, XRD, and porosimetry data confirm that enhanced interfacial bonding and controlled porosity underpin these durable, thermally efficient composites. These results demonstrate a viable route to lightweight, insulating wall panels from industrial by-products. Future work will explore hybrid fiber reinforcements and functional additives to further improve toughness, hydrophobicity, and durability, Provides a practical solution for lightweight, durable, and insulating wall materials in Xinjiang’s severe cold regions.