Methods for Accelerating Physical Salt Attack on Cement-Based Materials in Laboratory Testing: Effects of Curing Age and Water-to-Cement Ratio

In marine environments, chloride salt ingress into concrete having a porous structure can lead to physical salt attack (PSA) deterioration. However, the slow deterioration of cement-based materials caused by PSA under current laboratory conditions limits the understanding of the mechanisms of PSA. To improve the efficiency of accelerated testing for PSA in a laboratory, this study investigates the accelerated methods for PSA deterioration of cement-based specimens exposed to NaCl solution by adjusting curing ages and water-to-cement ratios. The results indicate that specimens with shorter curing age exhibit accelerated damage due to insufficient hydration, while specimens with higher water-to-cement ratios experience expedited surface scaling due to increased porosity. Reducing curing age from 28 to 7 days shortened the deterioration time of specimens by 50%. For the 28-day-cured specimens, increasing the w/c ratio from 0.4 to 0.5 accelerated the initial damage by 25%. Despite the variations in the curing age and water-to-cement ratio, the fundamental deterioration mechanism remained consistent across specimens. Notably, deterioration predominantly occurred in regions with relatively reduced external salt crystallization, which can serve as an indicator for predicting potential deterioration locations. The findings provide a theoretical basis for enhancing the efficiency of accelerated PSA testing protocols in a laboratory environment.