The influence of elevated temperatures on the mechanical properties of polypropylene fiber reinforced concrete

Abstract

This paper describes the strength of Polypropylene Fiber Reinforced Concrete (PFRC) exposed to the elevated temperatures. In the study, control specimens without any fibers and the concrete specimens with the ratios of 0.30, 0.60, 0.90 and 1.20 kg/m³ polypropylene fibers both in woolen and bar shape fiber have been produced. The specimens have been kept in the laboratory conditions for 28 days. Shortly after the curing period was completed, every group was heated at 23, 150, 300, 450, 600 and 750°C for two hours then the compressive strengths of them were determined. The maximum compressive strength was obtained by the specimens including 0.30 kg/m³ woolen polypropylene. For this group, the compressive strength increase was 8% according to the control specimens. The compressive strengths of bar polypropylene fiber concrete were higher than the wool fibers under elevated temperatures. On the other hand, more compressive strength values are obtained from the control specimens than fiber groups at 600°C temperature. Melting the polypropylene fiber at 500°C formed some pore spaces in concrete and caused reduction of the compressive strength.