Hydrogen embrittlement of steels for prestressing concrete: The FIP and DIBt tests

Two tests, the International Federation of Prestressed Concrete (FIP) and the Deutsches; Institut fur Bautechnik (DIBt) tests, are currently used for ascertaining the hydrogen embrittlement susceptibility of steels for prestressing concrete. Both tests have advantages and drawbacks and further research is needed. With this goal, two types of eutectoid cold-drawn steel wires, one more susceptible to hydrogen embrittlement than the other, were tested according to FIP and DIBt recommendations. Based on the obtained experimental results and on the analysis of the mentioned references, some conclusions have been deduced, among others that the FIP test is suited for quality control of a given type of steel (and for comparison purposes) of different grades of the same steel. Also, significant correlation was found between times to rupture in both tests and residual longitudinal stresses.