The Self-healing Behavior of Concrete Cracks Under Chloride Ion Environment and Its Impact on the Inhibitory Effect of Chloride Ion Transport

Abstract:

In order to study the self-healing behavior of concrete cracks in a chloride environment and its inhibitory effect on chloride ion transport, the dynamic self-healing process of concrete cracks was simulated. The self-healing behavior of concrete under different crack widths and various sodium chloride solutions was analyzed, as well as the inhibitory effect of crack self-healing on chloride ion transport in concrete. The relationship between crack width and sodium chloride solution concentration on crack healing rate was established. The results show that the healing rates of initial cracks with widths of 50, 150, and 250 μm after 60 days in water were 62.1%, 24.4%, and 15.1%, respectively, with the healing rate decreasing as crack width increased. The promoting effect of water on crack healing was limited, as it only effectively healed smaller cracks, generally with widths within 50 μm. The promotion of self-healing for cracks of different widths varied under chloride concentrations of 500, 1 000, and 2 000 mol/m³. When the chloride concentration was relatively low and the crack size was small, chloride ions exhibited a better promotion effect on crack self-healing. After healing for 12 hours in a 400 mol/m³ sodium chloride solution, the initial cracks with a width of 250 μm were completely healed, and the average chloride ion concentration at 5 mm around the cracks decreased by 2.6~5.0 mol/m³.