Edmonton

Pothole battle goes indoors to engineering lab

The surge of early spring weather in Edmonton has meant city crews have been splurging on filling in potholes.

City hopes right asphalt mix can slow damage from frequent freeze-thaw cycles

A city of Edmonton worker fills a pothole on Wednesday. (CBC)

The city is hoping science can help in the annual pothole crisis. 

The relentless freeze-thaw cycles that eat up Edmonton roads are becoming more frequent, thanks to climate change, so the city is studying how to adapt asphalt to the new conditions.

“Ultimately what it has given us the opportunity to do is to take our mixes and tailor them to our climate conditions so we can hopefully get better performance,” said Hugh Donovan, with the city’s Engineering Services Quality Assurance Laboratory.

Hugh Donovan, with the city’s Engineering Services Quality Assurance Laboratory, shows off asphalt samples. (CBC)
His lab is anything but high-tech. It’s freezers and vats of hot water, reaching temperatures of 60 C.

Donovan's job is to put different asphalt samples put through various freeze-thaw cycles and test their endurance over time, mimicking what’s happening on Edmonton’s roads.

Better asphalt performance translates to better roads and fewer potholes.

"It's our hope that continued research into asphalt mixes in northern climates will lead to the development of materials that will prolong the life cycle of roads in this extreme northern climate,” Donovan said.

The budget for pothole repair in Edmonton is $5.9 million for 2015 while $55 million has been set aside for rehabilitating arterial roads.

This year's early spring has meant city crews have been busy filling potholes — 65,000 since January.

“We’ve just taken advantage of the weather," said Bob Dunford, the city’s director of roadway maintenance. "We’ve been able to get at it, put a lot of crews out.”

Dunford predicted this spring will be a “big year for potholes,” but doesn’t expect it to surpass the record number of 750,000 seen in 2013.

In 2014, the city filled 485,000 potholes, which according to Dunford was an average year.