Bond-slip response of steel fibers after exposure to elevated temperatures: Experimental program and design-oriented constitutive equation

摘要

This study aimed to evaluate the effect of elevated temperatures on the bond-slip behavior of hooked-end steel fibers. A total of 180 pullout specimens were tested in post-cooling conditions using a double-sided pullout test with multiple embedded fibers for target temperatures between 25 and 750 degrees C. Results proved that the bond strength significantly increases for temperatures up to 450 degrees C, and drastically decreases for temperatures of 600 and 750 degrees C. The contribution of hooks reduced with temperature and is negligible for temperatures higher than 600 degrees C, while the fiber-matrix frictional interaction seems to improve for all temperatures evaluated. A temperature-sensitive constitutive equation that allows simulating the bond-slip behavior of hooked-end steel fibers is proposed and its suitability confirmed through a numerical model.