DEGRADATION AND CORROSION OF REINFORCED CONCRETE IN ACID SULFATE SOIL

摘要

Reinforced concrete specimens with water-cement ratios of 45%, 55%, and 65% were exposed to a soil of Myoban Spa, Beppu, Japan. The analytical results of chemical compositions and degradation of the specimens indicate that the severest corrosion environment of the hot-spring soil is represented by the surface layer, where hot-spring ingredients are concentrated. Internal rebars were corroded before the concrete degradation indicated by the phenolphthalein method was extended to the rebar area. The distribution of elements investigated by EPMA revealed the presence of sulfide without an indication of degradation in the rebar area. It is concluded that rebars are affected by sulfate ions even in an alkaline environment of concrete.