Pre- and post-fire behavior of modern construction and building materials

Purpose The purpose of this study is to investigate the performance and durability of commonly used construction and building materials when subjected to elevated temperatures. The research aims to understand the degradation behavior and assess key physical and mechanical properties post-fire exposure, which are crucial for designing thermally resilient and fire-safe structures. Design/methodology/approach This study evaluates six widely used masonry units – clay brick, fly ash brick, cement brick, autoclaved aerated concrete (AAC) block, porotherm block and solid concrete block – under fire conditions based on International Organization for Standardization 834 standard fire curves. The materials were exposed to heating durations of 1 and 2 h. Parameters such as dry and wet density, water absorption, compressive strength, porosity, mass loss and residual strength were comprehensively analyzed before and after fire exposure. Findings The results reveal significant variation in fire performance across different materials. Clay bricks retained the highest residual strength (74.4%) and exhibited the lowest porosity increase (1.8%) after 2 h of heating, indicating superior fire resilience. Fly ash bricks, while initially strong (11.48 MPa), suffered a 47.7% strength loss post-fire. Cement bricks showed a high mass loss (35.7%) and strength reduction (37.6%), limiting their post-fire reuse. AAC blocks displayed the highest water absorption (26.2%) and porosity (8.75%), compromising their structural reliability after exposure. Porotherm blocks showed a balanced performance with moderate strength loss (27.6%) and good thermal stability, suggesting suitability for fire-prone environments. Solid blocks, though dense, experienced the greatest strength degradation (52.3%) and porosity increase (8.88%), indicating poor thermal durability. Originality/value The novelty of this work lies in its holistic experimental comparison of both traditional and modern masonry units under standardized fire conditions. By integrating mass loss, residual strength and porosity as post-fire durability indicators, the study offers valuable insights for material selection in fire-prone and safety-critical structures. These findings also serve as a foundation for sustainability assessment and life cycle-based decision-making in resilient construction.