In this study, a new concept on self healing of cracks that the ingressive ions in the crack is chemically bound to improve the self-healing efficiency was proposed for cracked cementitious materials in a marine environment. Thermodynamic modeling was performed to determine the appropriate masses and ratio of Ca2+ and Al3+ provided by chemical agents for a good efficiency of self-healing and chemical binding of Cl-, SO4 2-, and Mg2+ ions from sea water. It was found that when CaO-NaAlO2 and CaO-metakaolin are used as self-healing agents, Friedel’s salt, kuzel’s salt, ettringite and hydrotalcite can be formed and, thus, Cl-, SO4 2- and Mg2+ from sea water are chemically bound. Moreover, the volume of phase assemblages becomes larger, which facilitates the self-healing of cracks. For a ratio of 0.3 between the mass of self-healing agent to the mass of sea water, the removal efficiency of Clions for CaO-NaAlO2 agent with a Ca/Al of 5 reaches the maximum value, i.e. 87%, while for CaO-metakaolin agent the removal efficiency of Cl- ions reaches the maximum when the Ca/Al is 3. The chemical binding of Mg2+ and SO4 2- ions is hardly influenced by Ca/Al when it is larger than 2 and the removal efficiency approximates 100%.