The effect of high temperature on concrete containing fibers from recycled plastic bottles

Abstract

High consumption of plastic based products has increased the volume of polymeric waste leading to several environmental problems. Utilizing plastic waste fiber is believed to offer benefits such as waste reduction and resource conservation. The properties of concrete exposed to elevated temperature are of importance in terms of structural stability and assessment of serviceability state of the structure. This study shows the behavior of concrete incorporating Polyethylene Terephthalate (PET) fibers at elevated temperature. Concrete samples with PET fibers at 0%, 0.5% and 1% are thermally treated in an electric furnace for a period of 1 hour at elevated temperatures of 200, 400, 600 and 800° C. Specimen are water cured for 28 days and tested for visual inspection, ultrasonic pulse velocity (UPV) and residual compressive strength. It is found out that the workability decreases with the increment of PET fibers. Furthermore, an increment in compressive strength is witnessed for concrete incorporating PET fibers with PET-FRC (0.5% fibers) showing maximum strength gain up to temperature of 400°C. A drastic drop in residual compressive strength and UPV for all specimen is witnessed at temperatures of 600°C and 800°C. Vaporizing of PET fibers at elevated temperatures led to the formation of channels and air voids which reduced the strength of FRC more than PC. It is concluded that PET-FRC with 0.5% fiber volume increases the strength of concrete at lower temperatures however, at elevated temperatures the strength is significantly reduced.