Laboratory simulation on airborne chloride transport behaviors in cracked mortar under drying-wetting conditions

Airborne chloride deteriorates the durability of reinforced concrete structures, with cracks accelerating this decay process. The salt spray chamber (SSC) has been employed to simulate chloride transport in cementitious materials but falls short of quantitatively correlating the laboratory and field results. This study investigated airborne chloride penetration in cracked mortar under simulated drying-wetting alternation using the SSC. Results revealed that the cracks transform chloride transport from one-dimensional to two-dimensional, resulting in higher surface chloride concentrations and diffusion coefficients. This study linked the laboratory and field airborne chloride transports by establishing a logarithmic equation correlating surface chloride concentration with chloride deposition rate. An empirical equation incorporating cumulative chloride deposition and crack widths is proposed. The simulated initial corrosion time of mortar and mortar with 30% fly ash is 15.5 a and 19.64 a, respectively. However, this time shortens to 2.75 a and 6.19 a when the crack width extends to 0.4 mm. This study offers new insights into understanding airborne chloride transport in cracked mortar and the connection between laboratory simulation and field results.