Effect of amorphous metallic fiber on mechanical properties of high-strength concrete exposed to high-temperature

This study experimentally examined the effect of amorphous metallic fiber on the mechanical properties of heated high-strength concrete with compressive strengths of 100 and 120 MPa. The mixing ratios of amorphous metallic fiber were 0.3 and 0.5 vol%. Polypropylene fiber was added at the ratios of 0.15 and 0.25 vol% according to the compressive strength of concrete. Specimens were prepared at six levels depending on the compressive strength of concrete and the mixing condition of the fiber. Specimens were heated up to the target temperatures of 100, 200, 300, 500, and 700 degrees C at the rate of 1 degrees C /min, and the respective compressive strength and elastic modulus were measured after 24 h cooling periods. The thermal expansion strain was experimentally measured while the specimen was heated (maximum temperature of 700 degrees C). The addition of amorphous metallic fiber can improve the degradation of compressive strength and elastic modulus of high-strength concrete (which was heated at temperatures above 300 degrees C). This effect could be confirmed by measurements of the thermal expansion and the peak strains. The addition of amorphous metallic fiber was effective in suppressing cracks that occurred owing to the expansion of aggregate and the shrinkage of cement paste. (C) 2019 Elsevier Ltd. All rights reserved.