Anti-icing agent damages Edmonton roads, study shows

The City of Edmonton's anti-icing pilot project is getting more scrutiny after a memorandum showing the negative effects of calcium chloride was made public this week.

Engineers with the city's Integrated Infrastructure Services studied the impact of the city's anti-icing program on infrastructure in February last year. 

They found that the brine containing calcium chloride is more damaging to concrete and asphalt than sodium chloride, or plain salt.

"Application of calcium chloride over the life of a pavement may negatively impact its long-term performance," the memo states.

The findings are outlined in a memo dated June 11, 2018 and addressed to city's director of Infrastructure Operations, Janet Tecklenborg, who requested the evaluation. 

Senior research engineer, Faizal Kanji, and Aleem Nawla, a research and development student are listed as sending the memo to Tecklenborg. 

The study concluded that the brine with calcium chloride is about 20 per cent more detrimental to concrete than salt and that "applying calcium chloride and sodium chloride on the roads may produce impacts to infrastructure in Edmonton."

'That's distressing'

Coun. Tim Cartmell said he doesn't recall city administration sharing the findings last October when council debated extending the pilot project. 

"Certainly, that's distressing," Cartmell told CBC News Tuesday. "To think they did have some feedback at those two meetings, by virtue of this memo, and that that feedback had not been shared."

Cartmell said he would expect city administration to communicate the findings to city councillors, but that didn't happen.

"It's left me in a place where I'm not quite sure what we knew and what we didn't know, which really means then we have to reexamine this whole thing."

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The memo was obtained through a Freedom of Information and Protection of Privacy request by Global News, which reported the findings this week. 

Mayor Don Iveson said council is often given "high level" information and that it's not uncommon for council to not see every report the city generates.

"Administration felt that the trade-offs with respect to infrastructure — pavement and asphalt conditions —  were reasonable."

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But he acknowledged the findings show calcium chloride has an impact on infrastructure.

"Obviously, that's something to keep an eye on in the pilot."

Cartmell was one of six councillors who voted against continuing the pilot project, but it went ahead with the support of seven other councillors.

"I have a concern that it was not adequately addressed, in my view, back in October when he talked about continuing the pilot." 

At the time, Cartmell raised red flags that the city has been using far more salt than it did a few years ago, and that people were reporting more corroded vehicles and infrastructure.

Edmonton's concrete may not contain protective elements against salt, the way other cities have, he said.

"My concern is that we're particularly vulnerable," he said. "And because that was not really answered, to my view, that's why I didn't support the pilot."

Cartmell expects council will discuss the engineer's findings — and the memo — at a meeting Jan. 22.

@natashariebe