Abstract
This study presents experimental work on bending strength and fracture energy of hybrid fibres reinforced high-strength concrete (HFRHSC) which were conducted during and after heating (i.e. hot and residual tests). It was observed that hot test results showed lower bending strength compared to residual one. This is considered to be mainly due to deterioration of ITZ during heating which significantly affects the bending strength of HSC. As for the fracture toughness, notably HFRHSC in hot test showed lower fracture energy compared to residual test. This is considered to be mainly due to the decrease of the bond strength between steel fibre and concrete matrix during heating. Additionally, hybrid fibre reinforcement is efficient in maintaining the bending strength, and is importantly effective to improve the fracture toughness of HSC both during and after heating. Thus, the hot test should be conducted for evaluating fractural properties of HSC due to its severity compared to residual test.
