Test Methods for Assessing the Susceptibility of Prestressing Steel to Hydrogen Induced SCC

The high-strength pre-stressing steels used to strengthen concrete structures may be susceptible to hydrogen-induced stress corrosion cracking when exposed to corrosive conditions during service. This form of attack can lead to the sudden failure of pre-stressed concrete structures without forewarning, posing a real risk of death or severe injury to those in the vicinity. In order to ensure that the steels used for pre-stressed concrete possess sufficient resistance to hydrogen-induced stress corrosion cracking, a number of test methods have been developed over the past twenty-five years. This report begins by outlining the requirements and properties of pre-stressing steels before reviewing the fundamental processes by which crack initiation and propagation can occur in corrosive environments. Following a general overview of the various test methods available for assessing stress corrosion cracking tendencies, attention is focused on the particular case of test methods for hydrogen-induced stress corrosion cracking of pre-stressing steels. The advantages and disadvantages of the most frequently used test methods are discussed and the importance of close simulation of the environmental and loading conditions encountered in service is emphasised. The publication will be of value to all those working on pre-stressing steels and pre-stressed concrete structures.