Corrosion mapping · Laval
Corrosion mapping in Laval
Corrosion mapping locates the zones where reinforcing steel is likely corroding in a concrete slab or wall, so that repairs can be targeted in Laval. A single commercial or industrial slab may combine several exposure conditions: traffic, water, loading docks and joints.
Laval
Working in Laval
For a commercial or industrial structure in Laval, note the concrete’s exposure conditions: traffic, water, joints, loading docks and products used. The same slab may present several environments. Mapping must specify the areas covered and the conditions at the time of measurement. Samples or other tests may be needed to explain causes. Whether operations can continue and how the survey is phased must be studied with the manager.
When several exposure conditions coexist on one slab, the division into sectors follows those conditions rather than survey convenience. A traffic area, an area under a dock and a sheltered area compare poorly with one another once merged into a single sector.
That division is settled with whoever knows how the premises are run. They alone know where water stands, where vehicles turn and which portions have already been redone. That conversation, held before the survey, is worth more than rereading the map afterwards.
In Laval, permit requirements depend on the type of project, for example a residential renovation or the fit-out of a commercial space. The City describes each case in its “Trouver mon permis” section: check it before scheduling the survey.
Preparing your project in Laval
- Describe traffic areas, loading docks and exposed joints
- Indicate products used on the slab, if any
- Agree with the manager on keeping operations running during measurements
Île Jésus building stock and your concrete surveys
Until 1965, Île Jésus was made up of 14 municipalities, from Sainte-Rose to Chomedey by way of Duvernay and Saint-Vincent-de-Paul; the merger order is dated August 6, 1965. Laval is at once an administrative region, an RCM and a city, a unique case in Quebec, on a 246 km² territory, the smallest of Quebec’s regions. According to the Centre d’archives de Laval, postwar suburbanization transformed farmland: families of more modest means settled in Pont-Viau or Arèsville, and the bungalow spread through neighbourhoods such as Duvernay.
The older building stock rests on local stone. The Sainte-Rose-de-Lima church, a classified heritage building, was built from 1852 to 1856 on the bank of the Rivière des Mille Îles, using stone taken from nearby quarries. The island’s quarries also supplied stone for the Jacques Cartier Bridge and the Saint-Vincent-de-Paul penitentiary; one of them, after serving as a dump, became the Centre de la nature in 1970.
On the industrial side, a refinery once operated in Saint-François, and Laval’s manufacturing jobs are now concentrated in complex processing, such as printing and chemical products. The extension of the metro’s Orange Line added Cartier, De la Concorde and Montmorency stations, opened in April 2007.
The small neighbourhood shops that appeared to serve the new postwar neighbourhoods occupy buildings whose slabs, exterior steps and entrances may have received several layers of repairs. Before mapping, list these interventions and the coatings applied, since a patched area can respond differently from the original concrete. Point out the entrances exposed to de-icing salts and the moisture at the time of the survey; this information helps the professionals decide where additional samples would be useful.
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
Mapping method, process and limitations
How potential measurements work, how the survey runs, how to read the maps and their limitations are covered on our corrosion mapping in Quebec page. This page only covers what is specific to Laval.
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.
Can a slab be mapped without stopping operations?
It depends on the areas to be measured and their access. Phasing by sector can sometimes be considered; it is agreed with the manager based on the scope of the assignment.
Do loading dock areas need particular attention?
They may have exposure conditions that differ from the rest of the slab, such as water and traffic. Point them out in the request so the map distinguishes them.
Sources
- ASTM C876-22b, Standard Test Method for Corrosion Potentials of Uncoated Reinforcing Steel in Concrete
- Régie du bâtiment du Québec: Parking garages, maintenance and inspection
- Ville de Laval: Permis pour la rénovation et l’aménagement d’un espace commercial (in French)
- Centre d’archives de Laval (Community Stories): Se regrouper pour prospérer (in French)
- Centre d’archives de Laval (Community Stories): Banlieue, nouveau standard ! (in French)
- Centre d’archives de Laval (Community Stories): Les carrières, de moteur économique à souci écologique (in French)
- Centre d’archives de Laval (Community Stories): Industries et exportations (in French)
- Répertoire du patrimoine culturel du Québec: Église de Sainte-Rose-de-Lima (in French)
- Ministère de l’Économie, de l’Innovation et de l’Énergie: Portrait socioéconomique de Laval (in French)
- STM: Les stations de métro Cartier, de la Concorde et Montmorency ouvriront le 28 avril, 2007 (in French)
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