Potential accelerated test methods for physical sulfate attack on concrete

•Longer wetting times accelerate PSA damage in partially immersed specimens.•PSA damage principally occurs during the formation of mirabilite.•Lowering the w/c proved to be very effective against PSA.•5% sodium sulfate solution is not high enough for accelerated PSA tests.•Full immersion tests give higher mass loss but may cause combined sulfate attack. There is currently no standard test method to determine the physical salt attack (PSA) resistance of cement-based materials. In this study, several accelerated test methods for PSA were evaluated. This was accomplished by testing concrete mixtures in partial and full immersion in sodium sulfate solutions at different concentrations, temperature, and relative humidity cycling. A total of nine concrete mixtures made from three types of portland cement at three different water-to-cement ratios (w/c) were used in this research to compare each method with materials of different qualities. The results showed that a 5% sodium sulfate solution was too dilute to be used in accelerated PSA testing, whereas increasing the concentration to 10% showed better results. In addition, it was found that damage occurred during low temperatures at high relative humidity compared to high temperatures at low relative humidity. Testing fully immersed specimens in 30% sodium sulfate solution gave the highest mass loss, but the damage was located at the bottom third of the specimens because of a concentration gradient that formed in the solution.