Corrosion resistance of steel fibre reinforced concrete – a literature review

Steel fibre reinforced concrete (SFRC) is increasingly being used in the construction of prefabricated segmental linings for bored tunnels, since it entails simplified production processes and higher quality standards. However, international standards and guidelines are not consistent regarding the consideration of steel fibres for the structural verification of SFRC elements exposed to corrosive environments, hampering the development of civil infrastructure built of SFRC. In particular, the long-term effect of exposure to chlorides is in focus and under discussion. This paper reviews the existing literature concerning chloride-induced corrosion on steel fibres, as well as the impact of steel fibre corrosion on the residual-tensile strength of SFRC. The review confirms the agreement among academics and regulators regarding the superior durability of un-cracked SFRC exposed to chlorides, relative to conventional reinforcement. However, the durability of cracked SFRC is still under discussion, as the mechanisms governing the corrosion of carbon-steel fibres in cracks and its effects on the fracture behaviour of SFRC are still unclear. Nevertheless, there is insight among several researchers concerning the existence of a critical crack width, below 0.20 mm, where corrosion of carbon-steel fibres is not critical and the structural integrity of the exposed SFRC can be ensured over the long-term. A doctoral project investigating chloride-induced corrosion of steel fibres on cracked SFRC has been initiated, in order to explore the governing deterioration mechanisms.