Performance and Integrity of Calcined Perlite Concrete at Varied Thermal Conditions: Mechanical and Microstructural Insights

This study evaluates the mechanical, durability, and thermal characteristics of perlite binary concrete (PBC) for potential use in contemporary large-scale structures. This novel concrete is prepared by partial replacement of cement with calcined perlite powder (PP) in proportions ranging from 1% to 7%, with 5% PP found to be the optimal mix inar room temperature (27°C) and at 200°C to 800°C in increments of 200°C. A compressive strength of 47.8 MPa at 400°C was achieved for 5% PBC mix, with increases observed for split tensile strength (24%) and flexural strength (32%) compared with control concrete (CC) at 400°C, as confirmed by regression analysis. Further, the resilience of the 5% PBC mix was demonstrated by its high modulus of elasticity at room temperature and elevated temperatures. Load deflection curves demonstrated that 5% PBC performed more consistently in terms of strength and thermal stability. Additionally, for all combinations except CC, PBC exhibited comparable performance at room temperature and 600°C for all mixes. With the exception of CC at 600°C, crack formation began as the cement paste dehydrated. Overall, the addition of calcined PP enhances the mechanical performance, lightweight characteristics, and thermal resistance, making 5% PBC a promising option for applications requiring high-temperature endurance.