EXPERIMENTAL INVESTIGATION OF CONCRETE WITH GLASS FIBER EXPOSED TO FIRE

Abstract

This research intention is to investigate the compressive, tensile as well as flexural strength of concrete that mixed with E-glass fiber and then exposed to fire under different magnitude of temperature for different durations. A total of 192 specimens were cast; including 129 for compression strength test and the rest 63 for split tensile strength test with the concrete grade C25/30 with the percentage of glass fiber 0%, 0.09%, 0.18%, 0.27% and 0.36% by weight of concrete. Also, 6 beams with and without E-glass fiber, cast to investigating flexural strength of concrete. The furnace temperature adjusted for 1500C, 3000C, 4500C and 6000C for 2 and 4 hours of firing time. From the result, adding glass fiber in concrete improves the compressive and tensile strength of conventional concrete as well as concrete which is exposed to fire at different level of temperature and firing hour. However, the workability of concrete decreases as the addition of E-glass fiber in concrete mix increase. The optimum percentage of fiber for the concrete grade considered in this study for compressive strength is 0.18% and for tensile strength is 0.27%. At optimum point, the compressive strength has increased by 29.7% and the tensile strength by 31.5% from plain concrete. For flexural strength, percentage of glass fiber 0.27% has shown a great result on failure load and has a great impact on load vs deformation. It makes the failure of concrete more ductile than it used to be. For lower temperature 1500C with 2hr, at the optimum percentage of glass fiber, the compressive strength increased by 35.2% and the tensile strength by 39.8%. Whereas for higher temperature 6000C with 4hr, at the optimum percentage of glass fiber, the compressive strength increased by 78.4% and the tensile strength by 84.8%. Time vs Temperature of furnace used for this study has similarity to the ISO standard curve. However, somehow the equation of this ISO standard curve is changed to meet the curve for this specific furnace. Spalling, cracking, weight loss and color change was observed during fire exposure. It is commonly observed that adding of glass fiber has shown a greater effect on resisting fire damage on concrete