Title : EFFECT OF CHLORIDE ION DIFFUSION IN MORTAR MIXED WITH ION-EXCHANGE RESIN
Authors : Osamu Sanada, Hiroshi Mutsuyoshi, Atsushi Sumita, and Yao Luan
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Price : 250
Abstract : In Japan, a number of concrete structures constructed a few decades ago are suffering deterioration due to chloride attack, especially those at coastal regions. In order to effectively repair or strengthen those deteriorated structures, high performance materials with relatively low cost are requisite for repair and rehabilitation. A new repair material, which is made by mixing ion-exchange resin (IER) into cement mortar, has been developed in the authors’ group. In previous studies, using potentiometric titration method, it has been confirmed that the repair mortar can absorb chloride ions from the substrate mortar, alleviating the concentration of total chloride ions in the substrate. In this paper, EPMA analysis is conducted to visualize the state of chloride ions diffusion in the inverse diffusion test. The result of EPMA confirms that chloride ions can be absorbed from the substrate mortar into the repair mortar, which is consistent with the result of potentiometric titration. Furthermore, micro-cell and macro-cell corrosion tests of steel bar in mortar are carried out. Repair mortar mixed with IER is cast at the surface of substrate mortar, in which sodium chloride is added and steel bar is embedded preliminarily. The corrosion of steel bar is evaluated by measuring natural potentials. The result shows that the corrosive environment of steel bar can be alleviated due to the absorption of chloride ions by the repair mortar.