FPrimeC was engaged by ECHO- Environmental Consulting Occupational Health to perform corrosion inspection of school building in Milton, ON. The client was interested to evaluate the likelihood of active corrosion. The basement is located under the kitchen area which can increase the risk of moisture penetration, which can result in steel corrosion. The main objective of the project was to measure the likelihood of corrosion of steel bars in the concrete slab by means of a non-destructive test namely, Half-cell corrosion potential test.
Solution: Half-Cell Corrosion Potential Mapping
Following communication with the client, and initial site visit, a comprehensive test plan was designed and proposed to the client. The proposed methodology involved three major steps:
- Visual Inspection
- Ground Penetrating Radar – GPR (Learn more)
- Half-Cell Corrosion Potential Mapping (Learn More)
A walk-through Visual Inspection was performed. The goal is to identify areas of concern such as cracking and visible signs of corrosion. This helped the FPrimeC engineers conduct the Nondestructive tests on these areas.
GPR scanning was used to determine the location of embedded rebar in concrete prior to removing the concrete cover at the reference points. Concrete line scan was used to verify the precise location of reinforcement in concrete slab, and to avoid unnecessary damages to the concrete slab.
At each reference point, the concrete was scanned on multiple lines in two directions, to ensure the precise location of the rebar. Reference points were selected at the intersection of two bars (in 2D space), to increase the chances of success.
Half-Cell corrosion mapping was used to determine the probability (likelihood) of active corrosion in the steel rebar. The Half-Cell test was conducted according to the recommendations of the ASTM C876 on a systematic test grid and the measurements were used to create comprehensive contour map of corrosion activity for select test areas.
The comprehensive test plan allowed the FPrimeC engineers to identify the source of the problem and develop solutions on how to address it. In this project, the GPR scanning helped identify the precise location of the steel bars without unnecessary damage and the Half-Cell Corrosion test helped identify where active corrosion is occurring in the areas of concern.