Assessment of mechanical properties of fiber reinforced cementitious system exposed to high temperature

Abstract

In this study, it was aimed to determine the optimum fiber type and usage ratio by examining the effect of fiber type and usage rate on the properties of mortar mixtures exposed to high temperatures such as 300°C, 450°C, and 600°C. For this purpose, mixtures were prepared by substituting polypropylene (PP), polyamide (PA) and basalt (B) fibers in proportions as 0.25%, 0.50%, 0.75%, and 1% instead of aggregate. Unit weight, compressive-flexural strength, ultrasonic pulse velocity (UPV), and permeability properties of mixtures were determined. Regardless of fiber type, flexural strength and permeability increased, UPV decreased with the addition of fiber. Basalt fiber mixtures exhibited the highest performance in terms of flexural strength. PP fiber mixtures exhibited the best performance in terms of permeability, ultrasonic pulse velocity and dynamic modulus of elasticity. SEM analyzes showed that PP fibers exposed to 600°C melted, leading to the formation of channel voids. According to TGA result, approximately 15% mass loss was observed in the control sample at 600°C.