CORROSION OF HARDENED CEMENT PASTE BY ACETIC AND NITRIC-ACIDS .2. FORMATION AND CHEMICAL-COMPOSITION OF THE CORROSION PRODUCTS LAYER

Nitric and acetic acids attack cement paste. Layers of corrosion produ cts covering the undamaged cement paste were chemically analyzed as a whole as well as across the layer. Analysis of the corrosion process t aking place in nitric acid enabled us to calculate the thickness of th e brown colored zone in the layer of corrosion products which containe d an increased content of hydrated Fe2O3, and thus verify various zone formation theories. After about a year of exposure of the cement past e to solutions of lower concentrations, an additional zone in the appa rently uncorroded core was seen to form. This so-called ''core layer'' contains almost no portlandite and in addition it contains an increas ed content of SO3.