Experimental and numerical study on post-fire self-healing concrete for enhanced durability
Ajitanshu Vedrtnam, Martin T. Palou, Hugo Varela, Dheeraj Gunwant, Kishor Kalauni, Gonzalo Barluenga
Abstract
Fire hazards pose significant risks to civil infrastructure, leading to concrete degradation. This study explores the development of post-fire self-healing concrete incorporating encapsulated or immobilized bacteria to restore structural integrity after fire exposure. Key challenges addressed include protecting bacteria during fire exposure and activating them post-fire. Innovative encapsulation techniques were developed to shield bacteria within concrete samples during fires, enabling their activation afterward to enhance structural strength. A finite element model simulated the time-temperature profile within the concrete and cement-based composites, replicating experimental conditions. Concrete samples underwent customized ISO 834 standard testing for a shorter period, open fire tests, and ultrasonic assessments to evaluate residual properties post-heating. A novel surface treatment was devised to protect embedded bacteria during fire exposure, proving effective in maintaining bacterial viability and enabling post-fire self-healing. A finite element model was employed to simulate the internal temperature profiles and assess the effectiveness of bacterial activation post-fire. The results confirm that the encapsulated bacteria can survive fire exposure and subsequently enhance the concrete's mechanical properties, marking a significant advance in fire-resistant construction materials. The research establishes critical time-temperature thresholds for the feasibility of post-fire self-healing in concrete, presenting a significant advancement in fire-resistant construction materials.