PERFORMANCE OF CONCRETE MIXED WITH FLY ASH AND PLASTIC WHEN EXPOSED TO FIRE

Abstract

Due to the negative environmental impacts of concrete production, several studies have explored
other concrete materials, specifically plastic aggregates and fly ash. However, previous studies have focused on
evaluating the alternative concrete for its strength properties and none for its performance during extreme events,
such as a fire. Thus, this study sought to further validate the feasibility of alternative concrete by investigating its
strength properties in conjunction with its post-fire performance. The concrete specimens were made by replacing
sand with HDPE pellets by volume of fine aggregates, and cement with class F fly ash by weight of the binder.
The parameters investigated were Compressive Strength (Fc’), Post-Fire Relative Residual Strength (RRS), and
Fire Resistance Rating (FRR). The compressive strength tests were done on cylindrical specimens at varying
curing periods (7,14,28, and 120 days), while fire performance tests were done on specimens cured for 28 days.
The specimens were fired on one surface in a small-scale furnace. The fired cubes were then tested for compressive
strength to obtain the RRS. The results show that to have comparable or increased strength than conventional
concrete. Using the optimization model, response surface method, the optimum mix was garnered. This study is a
stepping stone towards acceptance of the alternative concrete in the Philippines.