Effect of prevention for chloride ion using both of CA2 and expansive admixture to low heat Portland cement

Salt damage is one of the serious causes of deterioration in reinforced concrete. However, when building mass concrete under salt damage environment, we have to use cement with a heat suppression effect which has low resistance for chloride ion. In this research, we focused on the CA₂ which is admixture for salt damage prevention. CA₂ reacts with calcium hydroxide from cement hydration and makes hydrocalumite. Thus, the soluble chloride ion is reduced. Finally, concrete using CA₂ has high resistance for salt damage. LPC concrete using CA₂ has low resistance for chloride ion than OPC concrete using CA₂. After that, we had XRD measurement, and we have confirmed that hydration product is different in LPC and OPC when adding CA₂ and expansive admixture. We think that the difference of hydration product is reason for difference of salt damage prevention by difference of ability to immobilize chloride ion.