Chloride Corrosion and Earth Retaining Systems: Measurement and Calibration Techniques to Track Chloride Movements in Soils

Chloride-based deicers are commonly applied at the soil surface. The migration of these chlorides through soils can lead to corrosion and ultimately failure of buried infrastructure such as earth retaining systems. State Department of Transportation and engineering practice have typically performed laboratory tests on soil samples recovered from sites and/or only the pore fluid removed from the soil. The current study focuses on developing a laboratory-scale technique to enable the continuous tracking of chloride movements in situ. The novel use of electrical probes to correlate electrical conductivity and dielectric permittivity to the mass concentration of chlorides in soil is discussed. Testing to control for the probes’ sensitivity to factors other than the chloride concentration, such as soil type or void ratio, is discussed. Overall, the potential to quantify the evolving distributions of chlorides through various soil backfill conditions and better understand the risk to buried infrastructure is illustrated.