Fundamental engineering properties of cement-based fiber-reinforced composites exposed to elevated temperature

The main purpose of the current MSc thesis is to examine the effect of high temperature on fundamental engineering properties of cement-based fiber-reinforced composites depending on the mixing parameters. For this purpose, 36 different mixtures were designed. Brass coated steel fiber and polypropylene fiber were used in these mixtures. Produced samples were kept in three different curing regimes as water curing, air curing and impermeable bag curing until the testing age. The samples were exposed to 250 °C at the curing ages of 7, 28 and 90 days and then basic engineering properties such as compressive strength and ultrasonic pulse velocity were investigated for before and after exposure to fire. In the design, air entrained admixture ratio, the water to binder ratio and aggregate to binder ratio were kept constant at 0.6%, 0.3 and 1.5, respectively, for all mixtures. The experimental results showed that the utilization of polypropylene fiber in cementitious material has little effect on the fundamental mechanical properties such as compressive strength under the influence of high temperature, and the resudial mechanical properties are improved in the use of steel fibers compared to polypropylene fibers. The performance properties of the samples produced with the utilization of hybrid fibers were better than the fiber reinforced composites produced with the use of PP fiber, while it was worse than that of produced with the use of brass coated steel fiber.