Formation Process of Steel Corrosion Products in Alkaline Environment and Corrosion Environment of Reinforcement in Concrete

Abstract

When reinforcement in concrete corrodes, cracks are induced in cover concrete because volume of corrosion products are much larger than that of original steel. Because these cracks can be the index of corrosion grade, many researchers have studied about the relationship between crack width and corrosion weight loss. Recently, it was reported that corrosion products have large influence on the relationship because each corrosion products have its own density and volumetric expansion ratio. However, formation process of corrosion products in alkaline environment have not been made clear and at this point it is difficult to predict corrosion products formed in concrete in various environment. Then in this study, in order to make clear formation process of corrosion products in alkaline environment, corrosion products formed in solution of various OH^- and Cl^- concentration were evaluated by Raman spectroscopy. And additionally, influence of dissolved oxygen on corrosion products was also investigated. Furthermore, arrangement of corrosion environment of reinforcement in concrete was tried, based on field study.