Corrosion of hardened cement paste by acetic and nitric acids part II: Formation and chemical composition of the corrosion products layer

Abstract Nitric and acetic acids attack cement paste. Layers of corrosion products covering the undamaged cement paste were chemically analyzed as a whole as well as across the layer. Analysis of the corrosion process taking place in nitric acid enabled us to calculate the thickness of the brown colored zone in the layer of corrosion products which contained an increased content of hydrated Fe 2 O 3 , and thus verify various zone formation theories. After about a year of exposure of the cement paste to solutions of lower concentrations, an additional zone in the apparently uncorroded core was seen to form. This so-called “core layer” contains almost no portlandite and in addition it contains an increased content of SO 3 .