Abstract

Calcium leaching degradation could be happened in RC members due to the contact with pure water in underground conditions. And it is used that concrete with improved durability by using mineral admixture in the underground structures. Thus, it is needed to evaluate the resistance of calcium leaching for underground concrete mixed with mineral admixtures. In this study to evaluate the effects of long-term calcium leaching on the RC members mixed with mineral admixture are investigated. From the test results, when the RC member is attacked by calcium leaching, the yield load decreased, and the deflection at this time increased. And, the moment at the time of the inflection point of curvature decreased as well. Also, while a continuous decrease in compressive strength occurred with leaching period, the yield point and deflection value of an RC member with relatively low water binder ratio and low replacement ratio of mineral admixture as binder did not show significant changes. Consequently, when the concrete is applied to the underground structure which is exposed to a calcium leaching environment, it is not desirable to use high water-binder ratio or a large amount of mineral admixture as binder.