Strengthening fire-damaged concrete with jute fiber-reinforced biopolymer: Experimental investigation and sustainability assessment

Abstract

Fire-induced damage significantly compromises the structural integrity of concrete, necessitating effective and sustainable repair solutions. This study investigates the effectiveness of jute fiber-reinforced biopolymer (JFRB) composites in restoring the compressive strength of fire-damaged concrete, with a focus on strength performance, predictive modeling, and sustainability. Concrete cylinders with compressive strengths of 35 MPa (S1) and 46 MPa (S2) were exposed to standard fire conditions for 30, 45, and 60 min. Subsequently, the fire-damaged specimens were strengthened with either 1–3 layers of jute fiber-reinforced biopolymer (JFRB) composites or a single layer of carbon fiber-reinforced biopolymer (CFRB) composites. Compression tests were conducted to evaluate the capacity of JFRB and CFRB in restoring the compressive strength of the damaged concrete. The results revealed that JFRB confinement significantly improved residual strength, particularly after 60 min of fire exposure. Strengthening with JFRB composites resulted in compressive strength gains of 2.02–3.69 times for S1 and 1.86–3.67 times for S2, depending on the number of layers applied. Notably, specimens wrapped with three layers of JFRB achieved strength recovery comparable to those reinforced with a single layer of CFRB, highlighting their potential for practical structural rehabilitation applications. Furthermore, an empirical model was developed to predict the compressive strength of both undamaged and fire-damaged concrete confined with JFRB. The model demonstrated superior accuracy compared to existing models, with prediction closely aligning with experimental results (R²=0.83), in estimating the compressive strength of JFRB-confined, fire-damaged concrete. These findings offer a strong experimental foundation and theoretical framework for the integration of JFRB composites into structural engineering practices. A sustainability assessment further highlighted the cost-effectiveness and environmental benefits of JFRB, demonstrating its potential as a practical and eco-friendly material for structural rehabilitation. Therefore, these findings emphasize the dual benefits of using JFRB composites to address both performance recovery and sustainability challenges in fire-damaged structures.