UBC Theses and Dissertations
Corrosion behavior of galvanized steel reinforcements in MSE walls in the presence of soil organics Soriano Vazquez, Claudia Aide
Mechanically Stabilized Earth is a civil infrastructure technology that is widely used in retaining walls. Although the structures are designed for a service life of 75 years, early distress has been reported. Corrosion of the galvanized steel reinforcements has been pointed as one of the major causes that jeopardize their long-term performance. The corrosion behavior of galvanized steel in the presence of organics found in soil is studied through electrochemical techniques as PDP, EIS and LPR in two types of solutions at various concentrations below 1 wt%. The first type of solutions aims to determine the corrosion behavior in the presence of individual organic reagents: humic acid, dextrose, citric acid and oxalic acid. The second type of solutions is prepared with a system that combines the organic reagents in proportions that simulate the typical composition of organic matter in soil and is called Simulated Soil Organic Matter (SSOM). Subsequently, the surface is analyzed using SEM and EDX. The data shows that the corrosion effect of organic matter on galvanized steel depends on its composition. The comparison of the highest current density produced by the individual organics, allows ranging them in terms of their aggressiveness on galvanized steel in the following order: citric acid > oxalic acid > humic acid > dextrose. The Simulated Soil Organic Matter was able to corrode the zinc coating and the base steel.
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