Date of Completion
This paper presents the results of a study on the effect of elevated temperatures on the compressive strength of ultra-high-performance fiber-reinforced concrete (UHPFRC). Two different mixtures of a commercially available UHPFRC were considered in this study. The standard mixture offered by the manufacturer incorporates only steel-fibers to improve the tensile properties of the concrete. The enhanced mixture, which is of primary focus in the study, incorporates additional polypropylene fibers to improve the fire-resistance behavior. Specimens from each mixture were cast into 76 mm (3 in.) diameter cylinders and 51 mm (2 in.) cubes. After exposure to elevated temperatures ranging from 200 to 600oC (392 to 1112oF) and for durations ranging from 5 minutes to 6 hours, the residual compressive strength was measured. The fire-resistant mixture exhibited no explosive spalling during heating but demonstrated reduced compressive strength at temperatures over 200oC (392oF). Durations greater than one hour had little effect on the residual compressive strength of the cylinders. Unlike the cylinders, the residual strength of the cubes was affected by the heating duration. The standard mixture exhibited explosive spalling at oven temperatures above 250oC (482oF) which demonstrates that incorporation of polypropylene fibers prevents the occurrence of explosive spalling in UHPFRC at temperatures up to 600oC.
Burke, Brian T., "Residual Strength of Ultra-High Performance Concrete After Exposure to Elevated Temperatures" (2011). Master's Theses. Paper 44.