Microstructural and mechanical behavior of jute fiber-reinforced high-performance concrete at elevated temperatures

Abstract

ABSTRACT This study evaluates the thermal and mechanical performance of high-performance concrete (HPC) reinforced with jute fibers under elevated temperatures up to 650°C. Different fiber-reinforced mixes, including steel and polypropylene, were compared in terms of compressive strength, flexural strength, elastic modulus, mass loss, ultrasonic pulse velocity (UPV), and spalling resistance. Results showed a progressive reduction in mechanical properties with increasing temperature. Jute fiber-reinforced concrete exhibited a compressive strength loss of about 60%, comparable to polypropylene-based mixes, while maintaining relatively better flexural performance. It also demonstrated lower mass loss within the 250–450°C range. The gradual thermal degradation of jute fibers improved permeability, allowing effective vapor release and reducing internal pressure, thereby minimizing spalling. Microstructural observations confirmed the formation of a porous network that enhanced thermal stability. Compared to synthetic fibers, jute fibers provided a balanced performance in terms of strength retention and fire resistance. In addition to mechanical benefits, jute fibers offer advantages such as low cost, biodegradability, and wide availability. These findings highlight the potential of jute fibers as a sustainable alternative for improving the fire resistance of HPC.