Spalling corrosion product losses

For some materials, runoff and spalling losses are negligible in short-term exposures, e.g., Rj =Sj =0, so that m replaces in Equation 4. If, furthermore, the system of oxides, hydroxides, etc., which comprise the corrosion product are thermodynamically stable, i.e., relatively insensitive to changes in the environment so that the composition does not vary greatly, a plot of as a... 

In cases where runoff or spalling losses are significant, must be estimated from an analysis of the corrosion product retained on the corroding metal. This was done by wet chemical analysis of the stripping solutions that contain the corrosion product removed from exposed samples. Again, if the corrosion product is thermodynamically stable for a wide range of environmental... 

Consider now Equation 3 describing losses of corrosion product. Assuming that spalling does not occur, evidently true for most materials in this study except Cor-Ten A and carbon steel, and that dry deposition effects can be neglected, the principal effects leading to loss of corrosion product in runoff are (1) dissolution of the corrosion product in rainwater and (2) reaction of corrosion product with hydrogen ion in the rain to form a more soluble species. 

Figure 6.9 When membranes fail to bind to the concrete and water and chlorides get underneath, rapid local corrosion can lead to severe section loss without cracking or spalling of the concrete as the expansive corrosion product stays in solution.

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