Abstract:
While a lot of research has been conducted under on sustainable building materials towards exploring the mechanical and physical properties of fly ash as a recycled material that replaces ordinary portland cement in concrete, little has been directed towards testing its fire resistance properties. Due to the growing need to use fly ash based concrete and the severity of fire, the third most reason for casualties in building inhabitants, this research is directed into exploring the fire resistance properties of fly ash based concrete. After conducting the literature review, the following hypothesis was formulated: not only does fly ash affect the behavior of the concrete, but also other test variables like the oven temperature, the curing period and several others. Therefore, an experimental program was formulated based on the literature findings in order to validate this hypothesis. Four hundred and eighty specimens were prepared to see whether the change in fly ash percentage, oven temperature, coarse aggregate size, curing time, curing method and steel reinforcement affects the fire resistance of concrete. Within the limitations of the experimental testing program, the following main findings can be stated; a) Concrete fire resistance property could be measured by a strength reduction index (Beta) that measures the decrease in compressive strength before and after being exposed to elevated temperatures, b) 30% FA samples has 20-25% higher Beta values than OPC Concrete in the early curing days (3 and 7), c) 30% FA samples has 10% higher Beta values on average in all tested oven temperatures, and d) concrete cured manually has higher Beta values than the ones in the curing room at 200 and 800 degrees.
