Effects of test procedures on critical chloride threshold of steel

The critical chloride threshold of embedded steel reinforcement is an important service life parameter and is defined as the concentration of chlorides required at the interface between the steel and cementitious materials interface to initiate chloride-induced corrosion. This paper presents experimental data on the critical chloride threshold of ASTM A706, ASTM A615, and ASTM A1035 steels, collected using the Accelerated Chloride Threshold (ACT) test and ASTM G109 tests. The durations of the ACT and ASTM G109 tests were approximately two months and seven years, respectively. The ASTM G109 test uses integrated macrocell charge for corrosion evaluation, whereas the ACT test uses a significant change in linear polarization resistance values to assess corrosion initiation. The critical chloride threshold values of ASTM A706, ASTM A615 steels determined using the ACT and ASTM G109 tests were found to be statistically different. However, the critical chloride threshold values of the corrosion resistant ASTM A1035 steel determined using the ACT and ASTM G109 tests were found to be statistically similar.