Enhancing Fire Performance of Steel Reinforcement in RCC Structures: A Comprehensive Investigation

Abstract

The assessment, repair, and rehabilitation of fire-damaged structures have become crucial due to the rise in significant building fires.This particular field necessitates proficiency in various domains including concrete technology, material science and testing, structural engineering, and repair materials and processes. Researchers and developers are currently engaged in extensive efforts to tackle the challenges related to improving the fire resistance of steel reinforcement in reinforced concrete (RCC) structures. These endeavors involve comprehensive research and development to overcome these challenges and ensure originality of the work. This comprehensive investigation aims to contribute to the knowledge and strategies for improving the fire resistance and durability of steel reinforcement in RCC structures.To evaluate the impact of fire on reinforcement steel bars, a series of experiments were conducted. The bars were subjected to temperatures ranging from 100°C to 900°C, with six samples tested at each temperature level. The heated samples underwent rapid cooling through quenching in water, and in some cases, air chilling was also employed. Mechanical characteristics were assessed using a universal testing machine, while the grain size and structure were analyzed using a scanning electron microscope (SEM) at a microscopic level. The research outcomes reveal that a significant proportion of fire-affected RCC structures can be successfully restored and repaired. However, exposure to temperatures exceeding 900°C and rapid quenching in water resulted in a significant reduction in the ductility of the reinforcing bars. On the other hand, minimal effects on ductility were observed when the bars were air-chilled. This highlights the importance of the cooling method employed after exposure to fire in preserving the ductile behavior of the reinforcement. Moreover, controlled heating was found to be a viable method for modifying the properties of the reinforcing bars without altering their chemical composition. This presents an opportunity to enhance the fire performance of steel reinforcement through targeted heat treatment, thereby improving its fire resistance and overall structural integrity.  In conclusion, this comprehensive investigation underscores the significance of assessing, repairing, and rehabilitating fire-damaged structures. The research outcomes contribute to the development of strategies for enhancing the fire performance of steel reinforcement in RCC structures. The findings emphasize the importance of appropriate cooling methods and controlled heating techniques in mitigating the detrimental effects of fire on the ductility of reinforcing bars. By implementing the knowledge gained from this study, safer and more resilient RCC structures can be achieved in the face of fire incidents.