Factors Affecting Carbonation of Railway Rigid-Frame Viaducts

Abstract

Recent years have seen a considerable amount of research on the carbonation of concrete. The standard specifications for concrete structures, outlined by the Japan Society of Civil Engineers (JSCE), prescribe a method to verify the durability of concrete structures in relation to carbonation. However, as the carbonation rate is largely governed by environmental conditions, it is important to quantitatively assess the effect of these conditions on the carbonation of concrete structures by applying the method to actual structures.The factors affecting the progress of carbonation in different members were investigated based on the results of a survey on a rigid-frame railway viaduct in service since its construction several decades before. The study results indicate that the carbonation rate of columns varies with height and depends on the exposure condition to rainwater. In contrast, the dis-persion of the carbonation depth on beams and slabs is small when compared to that of the carbonation depth on columns.