Illustration of differen methods to assess the resistance of a X2CrNi12 against pitting corrosion in concrete
Source: BAM division Corrosion and Corrosion Protection
For modeling the service life of an infrastructure building, the corrosion-inducing chloride content (Ccrit) in concrete is relevant for ordinary reinforcing steels such as a B 500 A or B, and also for stainless steel reinforcement. In this article, different methods are used to determine the Ccrit, and the respective effect of the measurement methods on the result is discussed. In cooperation with the ETH Zurich, the Helmuth Schmidt University of the Federal Armed Forces in Hamburg, the TFB Wildegg and the Munich University of Applied Sciences, BAM has developed or modified two of the six investigated methods to determine the Ccrit. Innovative methods, such as laser induced breakdown spectroscopy (LIBS), were used to determine the chloride content in the mortar/concrete steel phase boundary and the existing standard test according to DIN 480-14 was modified to determine Ccrit.
The decisive difference between testing stainless steel reniforcement and testing unalloyed reinforcing steels is the possibility to use accelerated polarization tests for stainless steel.
This allows a drastically reduced test duration for comparative examinations from several weeks or months to a few days.
When comparing the results from different test methods, it becomes clear that the determined values for Ccrit can differ up to a factor of two. Comparative investigations of different stainless steel reinforcing steel grades must be carried out using the same test method and strictly observe the same boundary parameters.
For the determination of the Ccrit as an input parameter in the design of service life models, the capillary suction test carried out at BAM and the test method developed at ETH are recommended.
A comparison of methods to assess the resistance of reinforcing steel against chloride‐induced corrosion in concrete: Particular consideration of 12% chromium steel
C. Boschmann Käthler, Gino Ebell, S. Keßler, Y, Schiegg, C. Dauberschmidt, U. M. Angst
published in Materials and Corrosion, pages 1 -20, 2021
BAM division Corrosion and Corrosion Protection