Time to prepare for cold weather construction
Extreme cold weather has the potential to wreak havoc on any construction project, but this is especially true for roads. In a perfect world, excavation, soil stabilization and pavement placement for access roads, highways and other motorways would be scheduled only in the warmer, drier spring and summer months, when there’s no need to account for snow, ice, and sub-zero temperatures.
Unfortunately, construction schedules stop for no one, including Mother Nature. With cold weather already upon us, and more on the way – especially in our frigid northern states – now is the time to make sure your road project starts out with a strong, stable and appropriate sub-base. Doing so will ensure a functional and problem-free road – not only during the cold winter months, but all year round.
A project team in West Seneca, N.Y., was working quickly to wrap up construction of an industrial access road before winter’s freezing temperatures arrived when it ran into trouble. The road was to remain unpaved until the warmer spring months. Just three days after heavy trucks began using the roadway, the stoned surface showed signs of deformation and rutting. Moreover, the area in the middle of the road had heaved, and large bubbles of clay were coming to the surface.
It quickly became clear that the roadway – called Commerce Parkway – would not be usable without a complete overhaul. The construction window was quickly closing as winter set in, and the owner was anxious to finish the project. This job required an immediate fix – and a whole new approach to construction.
When crews inspected the road, they quickly realized the problem: both stabilization products placed over the road’s subgrade had ruptured and split, causing the road to shift and heave. To replace the ruined access road with one that would hold up to heavy equipment and repeated freezing winters, the road project team turned to Tensar’s TriAx Geogrid product to stabilize the pavement foundation.
The system starts with a polypropylene sheet that is rolled over a prepared road base to serve as a stabilizer for the roadbuilding materials that are placed on top. The product replaces other stabilization methods such as cement additives, which often fail in extreme cold. The Triax Geogrid is formed from a solid piece of polypropylene that is punched and stretched to form triangular shapes. Aggregate is placed on top of the geogrid form the road base. The geometry of the triangular apertures holds the road material in place by locking the aggregate together, distributing the load evenly over a large area and maintaining the structure of the pavement over time.
“This road faces some of the worst conditions you can put a road under,” Jason Havens, a civil engineer with Buffalo, New York-based engineering form Clark Patterson Lee said. “Few roads get as much wear and tear as this one.”
The construction team removed the buckled roadway and installed the system over the subbase before rebuilding the roadway and applying asphalt. Once in place, in place, road builders were able to reduce the amount of added stone needed to maintain the road, significantly lowing maintenance costs. Several years after the rebuild, Commerce Parkway is still holding strong.
“The savings were in the project schedule,” says Havens. “When you’re up against snow, you can’t pave. We would have never finished that road in season had (the repairs) not gone as planned.”
David Lipomi has more than 12 years of experience in civil design engineering and currently serves as the North Area Director for Tensar International Corp. He received his civil engineering degree and MBA from Penn State University.