Since piloting a road micro-surfacing program in 2017 for St. Albert’s infrastructure network, the city has expanded its use of the program as one tool in an pavement strategy toolbox.
Last summer, the city did a total of 60,000 square metres micro-surfacing, and this year has upped it to 100,000 square metres. Micro-surfacing uses a mixture of asphalt emulsion that has water and aggregate and is used in addition to traditional paving methods to maximize the lifespan of a roadway.
Transportation and infrastructure engineer Brett Newstead said St. Albert has found a lot of success in the program, and found it is most successful when applied to roads that are still in good condition.
“Think of it like painting a fence. If you paint a fence and it’s still in good shape, the paint will last longer. Versus if you’ve got a few rotten boards and you paint it won’t last very long,” Newstead said.
During the 2018 road construction season Newstead said the city chose to micro-surface roads that were earlier in their life cycle – within approximately seven years of paving – and had good results. He pointed to Poirier Avenue, Campbell Road and Carnegie Drive as examples of some roads the city applied treatment to last summer.
This year, the city also started adding specification to work contracts to also add a tack coat, which is a primer that allows the material to bond better and therefore get a longer life out of it. Some roads that was applied to this year include Bellerose Drive and Liberton Drive.
Newstead said micro-surfacing is a component of a broad pavement management strategy that works to minimize the capital investment required for roads.
“If we use micro-surfacing at the right time in the asset's life, after it's had crack filling and everything else, we’re really extending the road's life with a minimal amount of cost inputted into the road's entire life,” he said. “It doesn’t make something pothole-proof but it does slow down potholes from showing up later on ... things people really notice when they’re driving.”
