Impact resistance of heated and unheated two-way slab reinforced with basalt fiber

Abstract

This research investigates the effect of using basalt fiber with different ratios on the impact resistance of heated and unheated two-way slab. Twelve heated and unheated two-way slab specimens of (1.05 m x 1.05 m x 0.07 m) were cast with different basalt fiber ratios of (0.25, 0.50, 0.75, 1.00, and 1.25) % by weight of cement and two fiber lengths of 12 and 24 mm have been exposed to ambient temperature and elevated temperature of (600 °C). This experiment investigates the effect of basalt fiber on the behavior of two-way slab in terms of compressive strength of concrete, punching shear failure, deflection, stiffness, and induced strain. The results showed that adding basalt fibers with different ratios experienced minor improvements in the concrete compressive strength for all specimens. The application of the impact load resulted in the formation of radial and conic cracks originating at the center of the specimen. These cracks indicated that the primary mode of failure is punching shear. Additionally, in this study, it was observed that a gradual increase in the proportion of basalt fibers led to a reduction in both the length and number of cracks. Moreover, for the pattern of the cracks due to static load, it was observed that the development of conical cracks was a result of overloading. The specimen incorporating a 24 mm basalt fiber at a 1 % ratio under unheated conditions demonstrated the significant improvement in performance regarding cracking compared to control. The stiffness and deflection of the specimens were improved by increasing the proportion of basalt fiber. Additionally, employing 24 mm fibers resulted in reduced deflection and increased stiffness compared to using 12 mm fibers.