Strength Enhancement and Deformability of Confined High-Strength Steel Fiber Concrete After Burning

Abstract

This study investigates post-burning steel fibrous concrete that aims to identify the mechanical quantities affecting the behavior of confined steel fibrous concrete after burning. A total of 72 specimens of unconfined concrete and confined concrete were made by reviewing design parameters, namely concrete compressive strength (fc ’), fiber fraction and duration of combustion (1 hour, 2 hours and 3 hours). All specimens were monotonically compressed with a deformation control testing system. The parameters discussed from the experimental results represent the strength of the confined concrete (fccf ’), the peak strain of the confined concrete (εccf ′), and the strain of the confined concrete after the peak stress is exceeded and decreases by 50% (εcc50f ). The experimental results showed that for concrete with higher volume fractions of fiber (0%, 1% and 2%), the relative strength enhancement of confined concrete (K value) indicates an increase in the value of K although it is not significant. On the other hand, in general, the values of εccf′ and εcc50f tend to increase significantly at post peak response, if the confined steel fiber concrete specimen is burned for a longer time and volume fraction of fiber were higher. The increase in the strain of confined concrete is one indication that the specimen is more ductile with increasing burning time.