Macroscopic Kelvin Probe for contactless corrosion assessment of structures buried in soil

A pioneering application of a Kelvin Probe (KP) sensor for surface potential mapping of soil and cementitious soil fill to assess corrosion of embedded steel reinforcement is presented. The KP potential measurements were rapid, stable and adequately reproducible, for constructing surface maps to serve for corrosion assessments without any disturbance of the surface. Results are promising for mobile deployment. The KP successfully operated under dynamic conditions representative of a cathodic protection installation, showing capability for electrochemical diagnostic operations. Operation of a dual sensor array was demonstrated as well.

I. Introduction

Building foundations, highway tunnels, pipelines, and many other areas of the nation's infrastructure rely on adequate corrosion performance of buried metal. A representative example is provided by mechanically stabilized earth walls (MSEW), which are a critical structural component in many highways. The walls are often reinforced with galvanized steel buried in the soil. Voids sometimes occur in the soil and are typically filled with cement-based hardened controlled low strength material (CLSM). Soil/CLSM electrochemical macrocells may develop and aggravate reinforcement corrosion. [1].