NBCC 2020 and CSA A23.3 define the structural and material requirements for flexible pavement design in Trois-Rivières. The city sits on the north shore of the Saint Lawrence, at the mouth of the Saint-Maurice River, on a thick deposit of Champlain Sea clays and deltaic sands. Frost penetration here exceeds 1.5 metres in an average winter. That freeze-thaw cycle is the number one pavement killer. We design asphalt sections that work with the subgrade, not against it. Layer coefficients, drainage, and the right granular base thickness matter more here than in warmer regions. For sites with marginal subgrade, we correlate pavement design with a CBR road study to validate the bearing capacity of the compacted formation before placing the first lift.
Frost depth in Trois-Rivières exceeds 1.5 m. If the granular base doesn't cut capillary rise, the pavement fails before the first truck rolls.
Methodology applied in Trois-Rivieres
Demonstration video
Critical ground factors in Trois-Rivieres
Trois-Rivières has two pavement enemies: frost heave in winter and softening in spring. The silty clays of the Champlain Sea deposit are moderately to highly frost-susceptible. Without proper granular thickness, ice lenses form at the subgrade interface. Come April, those lenses melt and the road base turns to soup. We've measured CBR drops from 12% to 3% within two weeks of thaw in untreated sections. Another risk is the water table—often within 2 metres of the surface near the Saint-Maurice floodplain. Capillary rise feeds moisture into the base course year-round. We mitigate this with free-draining granular layers and edge drains, designed to lower the phreatic surface below the frost zone. A pavement that ignores drainage in this city is a liability.
Our services
Our flexible pavement design in Trois-Rivières covers the full chain from subgrade investigation to thickness design and construction specifications.
Subgrade evaluation
In-situ CBR tests, dynamic cone penetration, and sampling to classify frost susceptibility of the formation soil.
Pavement thickness design
AASHTO 93 layer analysis calibrated with local traffic data (ESALs) and frost penetration depth for the Trois-Rivières area.
Drainage and frost protection
Design of subdrain networks, geotextile separation, and granular frost blankets to prevent heave and spring softening.
Frequently asked questions
What's the typical pavement structure in Trois-Rivières for a commercial parking lot?
For a parking lot with light truck traffic, we usually specify 100–125 mm of asphalt over 300 mm of MG-20 base course, on a geotextile separator. If the subgrade is the Champlain clay, we add 350 mm of MG-112 subbase. The exact build-up depends on the CBR test results and the frost susceptibility classification.
What is the estimated cost range for flexible pavement design in Trois-Rivières?
A flexible pavement design package for a standard commercial or industrial site in Trois-Rivières ranges from CA$2,280 to CA$6,300, depending on the number of boreholes, traffic data analysis, and whether frost-depth monitoring is included.
How do you account for the freeze-thaw cycles in this region?
We use the MTQ frost index for the Mauricie region and design the total granular thickness to cover at least 85% of the historical frost penetration depth. This prevents ice lens formation at the subgrade interface. We also specify open-graded base materials and edge drains to intercept meltwater before the subgrade saturates in spring.