Temperature distribution within polypropylene fiber-mixed reinforced concrete slabs exposed to an ISO 834 standard fire

Abstract

In this research, we have developed formulas for calculating sectional temperature of Reinforced Concrete (RC) slabs exposed to an ISO 834 standard fire based on depth measures of the fire-exposed surface and duration of the exposure. Our derivations are from multiple regression analyses using experimentally acquired temperature data from a previous research on Polypropylene (PP) fibers embedded in concrete. In this context, PP fibers serve to suppress explosive spalling of concrete under fire, and consequently diminish the temperature elevation of concrete and the likelihood of explosive spalling. In the previous research, the optimal volume fraction of PP fiber for temperature control and spalling suppression was reported to be 0.1 vol.%. Thus in our study a formula for RC slabs mixed with 0.1 vol.% of PP fiber is proposed, along with a formula for ‘normal’ RC slabs, with no PP fiber, for comparison. The proposed temperature formulas and contours can be effectively applied to designing fire-resistant PP fiber-mixed RC slabs.