Corrosion mapping · Saguenay
Corrosion mapping in Saguenay
Corrosion mapping locates the zones where reinforcing steel is likely corroding in a concrete slab or wall, so that repairs can be targeted in Saguenay. Covering a surface by sector, to follow a change rather than record it once.
Saguenay
Working in Saguenay
A corrosion map makes sense when it can be repeated later on the same division. In Saguenay, on a structure in use, that means fixing the sectors, their naming and the drawing format from the first pass. Indicate the areas already repaired, those in doubt and the use that will be made of the result. A survey whose division changes at every pass compares poorly with itself.
Saguenay directs permit requests to two separate counters, Info-permis résidentiel and Info-permis commercial. A survey that supports work in a commercial or institutional building is therefore not prepared in the same place as a residential project. Identifying the right counter before planning avoids a round trip when the application is filed.
Preparing your project in Saguenay
- Fix the division into sectors and their naming from the first pass
- Locate the areas already repaired and those in doubt
- Agree on the drawing format that later passes will reuse
Measuring corrosion activity
The ASTM C876 test method covers the estimation of the corrosion potential of uncoated reinforcing steel in concrete, for the purpose of determining its corrosion activity. Taken on a grid, these measurements produce a map of the surveyed surface.
Exposed slabs and parking garages
Parking garages are subject to specific obligations in Quebec: an annual visual verification and an in-depth verification report by an engineer every five years, according to the Régie du bâtiment du Québec. A corrosion map helps locate the zones to watch between these verifications.
- On a cracked or spalled parking slab
- Before planning concrete repairs
- To monitor an area that has already been repaired
Reading a corrosion map
Read colours with the legend, method, measurement conditions and limitations. A probability class is not a percentage of steel section loss.
Potential measurements do not determine the structural properties of steel or reinforced concrete. Additional data may be needed to interpret activity and consequences.
Deliverables and repair planning
Agree on plans, coverage, presentation and the engineer’s requirements before the survey. Located findings support comparisons and additional investigation.
Repair quantities, specifications and cost estimates require appropriate diagnosis. Visible deterioration alone does not establish the repair scope.
When to request mapping
Describe observed conditions and the decision you need to make.
- Before parking garage repairs
- After observing rust stains or spalling
- When documenting changes in a structure
- Alongside structural assessment
Frequently asked questions
Does corrosion mapping indicate the strength of the structure?
Not directly. It provides information on the corrosion activity of the rebar; assessing structural capacity is an engineer’s responsibility.
Why combine it with a concrete scan?
Ground-penetrating radar locates the rebar and estimates its depth, which helps position corrosion measurements on the steel.
Why fix the division at the first survey?
Because a comparison only means something on the same division. Changing sectors between passes makes it impossible to say whether an area changed or only the way it was outlined.
Can the result support a call for tenders?
It can document the extent to consider, provided the report states the method, the areas covered and the limits. The expected content is settled when the request is made.
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