Influence of fire severity and concrete properties on the thermo-hygral behavior of concrete during fire exposure

Since the world is transitioning toward performance based design, the study of thermo-hygral behavior of concrete when subjected to real fire becomes crucial. Fire accidents have revealed that nominal fire curves cannot be applied because of varying severity of real fire. In 2008, traveling fire concept was developed in which severity is dependent on heat release rate and fire size. This study explores the effect of fire severity and other concrete properties like strength, aggregate type, and relative humidity. The proposed model has been developed by combining the principles of mechanics and thermodynamics and upon validation with the experimental results, a reasonable agreement has been observed. It can be concluded that severity of fire is directly related to thermo-hygral behavior of concrete. On the other hand, this study also highlights the influence of type of aggregate and moisture content in addition to the traditional variables like volume fraction of solid and permeability. On studying the influence of type of aggregate, it can be concluded that recycled aggregate concrete performed better than conventional concrete. The integration of proposed model in the performance based design is a leap toward development of resilient structure subjected to dynamic fire conditions.