Corrosion mapping in Trois-Rivières

What the Trois-Rivières building stock means for your concrete surveys

Founded in 1634, Trois-Rivières retains a heritage site declared in 1964, where the Ursuline monastery stands alongside middle-class and workers’ houses from the second half of the 19th century, boomtown-style houses and apartment buildings from the early 20th century. On June 22, 1908, a fire razed nearly 800 buildings. According to the City, the downtown area was rebuilt, its streets were widened, and the district still shows strong architectural consistency.

The forest shaped the riverbank. The Répertoire du patrimoine culturel du Québec places the city’s first sawmill in the mid-1850s, at the confluence of the Saint-Maurice River and the St. Lawrence. Around 1919, Canadian International Paper built a pulp and paper mill there that became, by the late 1920s, the largest newsprint mill in the world. Closed in 2000, the complex was demolished in 2001, except for the filtration plant, whose brick load-bearing walls support reinforced concrete beams and a concrete roof.

In the late 1960s, the city broadened its economic base toward college and university education, and the Université du Québec à Trois-Rivières was founded in 1969. The Laviolette Bridge, completed in 1967, is the only road link spanning the St. Lawrence between Montreal and Quebec City. From 2023 to 2025, the Government of Québec replaced the original deck of its central section using 680 precast panels.

The Auditor General of Québec notes that the use of road salt became widespread from the 1960s onward and that heavy use affects road infrastructure, notably through corrosion of reinforced concrete. A parking deck or ramp in Trois-Rivières from that era may therefore have been exposed to salt for more than half a century.

For this type of structure, gather the known dates of construction, repairs and membranes, and identify the sectors exposed to vehicles or meltwater. This information makes it possible to separate, on the map, original portions from portions already repaired.