LAUSR

This paper aims to investigate the mechanical performance of high-strength concrete (HSC) made with polypropylene fiber at various high temperatures. In this study, five different concrete compositions having three contents of polypropylene fiber were prepared. Polypropylene fibers were incorporated at 0.5, 1.0 and 1.5 kg/m3 in concrete and the samples were exposed to 25, 150, 350, 550 and 750 °C temperature, respectively. Fresh properties tests, including slump, density, compacting factor and Kelly ball penetration were conducted for fresh concrete. Mechanical properties, such as compressive strength and splitting tensile strength of HSC were investigated for 14 and 28 days at all high temperatures. In addition, scanning electron microscopy analysis was conducted to examine the changes in the microstructure of optimum fiber content HSC mixture. Experimental results exhibited a reduction in fresh properties and improvement in mechanical properties with the incorporation of polypropylene fiber in HSC. High temperature substantially decreased the compressive and tensile strength of all HSC mixtures; however, the inclusion of polypropylene fiber in HSC reduced the relative compressive and tensile strength loss than the control HSC at all high temperatures. The optimum addition of polypropylene fiber content in HSC was found 1.0 kg/m3, which reduced the strength loss at all high temperatures than other fiber contents.