Thermal and Microstructural Performance of Fire Resistance Concrete Using Vermiculite Aggregates

Abstract

The need for fire-resistant concrete has become more and more critical to enhance the thermal resistance and structural safety of buildings under high temperature exposure. But, experimental studies to assess its thermal and microstructural performance can be expensive and time-consuming. In this work, a numerical framework is proposed which integrates the aspect of fire-resistance performance with thermal and microstructural characteristics of concrete using vermiculite as aggregate. In this framework, mathematical models for the effective thermal conductivity, transient heat transfer, residual compressive strength, and a microstructural damage index were included to predict the material behavior under various levels of fire exposure. Numerical simulations are carried out with vermiculite replacement percentage varying from 0% to 20% and with a temperature range from 25 to 800°C. The prediction of the simulation is a 37.8% reduction in the thermal conductivity, a 22.5% reduction in the internal temperature of the material, a 32.4% increase in residual compressive strength, and a 36.2% decrease in microstructural damage at optimal replacement level. The proposed framework would offer an efficient numerical method to assess the performance of the concrete to resist fire.