An experimental investigation on tensile behaviour of corroded ultra-high-performance concrete

When UHPFRC is exposed to a corrosive environment, steel fibres may undergo corrosion which may affect the interfacial bond and therefore the overall tensile behaviour of UHPFRC. Previous studies have predominately investigated the influence of fibre corrosion on the tensile behaviour of UHPFRC using the flexural test method. In this approach, the significant variation in crack width may lead to variation in the level of corrosion, making it more difficult to develop material models. In this study, the influence of corrosion on the tensile resistance of UHPFRC has been studied using direct tensile test of thirty-nine grooved prisms with a range of different precracking conditions and corrosion levels. The results show that even when crack widths are large, fibre corrosion has a relatively minor impact on the tensile performance of UHPFRC, and the expected level of deterioration is reduced due to self-healing of cracks and continued hydration of the cement when immersed in the chloride solution. When uncracked specimens are subjected to corrosive environments it was shown that the tensile strength was significantly increased due to enhanced hydration of the binder and associated pozzolanic reaction with silica fume. Despite the degree of experimental scatter and the competing mechanisms of corrosion and self-healing, the residual response of the corroded specimens has been found similar to that of the control specimens.