PENETRATION OF CHLORIDE IONS INTO HARDENED CEMENT CONSIDERING MULTIPLE IONS IN SEAWATER

Abstract

 To understand the effects of multiple ions in seawater on the penetration of chloride ions and the alteration of the solid phase of hardened cement, immersion tests were conducted with four different solutions. In the case of mortar, chloride penetration was accelerated in NaCl+MgSO₄ solution and suppressed in artificial seawater, as indicated by the results of the immersion test for 1736 days. This was thought to be due to the influence of aragonite brucite gypsum, and ettringite formed, and leaching of CSH on the mortar surface. For concrete, the results of 1008 days of immersion test showed that regardless of the type of immersion solution, there was no portlandite in the area up to 10 mm of the concrete, suggesting that changes in the pore structure due to leaching affected the penetration of chloride ions.