CHLORIDE INGRESS INTO CRACKING IN EXISTING CONCRETE STRUCTURES

Abstract

The paper discusses behavior of chloride ions at cracking in existing concrete structures in coastal areas. Two-dimensional distribution of chloride ions in fifteen cores taken from various cracking areas on a bridge pier, a bridge abutment and concrete blocks for strengthening a prestressed concrete beam were obtained by EPMA. It was found that in spite of much chloride ingress into concrete, chloride concentration was not observed at cracking area. Besides, most of cores definitely showed reduction of chloride ions around cracking in concrete regardless of causes and degree of the cracking. While many unknown factors remain to identify the mechanism of the chloride reduction, it was recognized that carbonation around cracking influenced the chloride behavior.