A chemical engineer is asking the City of Edmonton to stop using calcium chloride on roads in the wintertime.
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On Wednesday, council’s Community Services committee was reviewing a report that says using the solution last winter saved taxpayers $4.3 million.
However, Arthur Potts says the cost of potential future damage to vehicles and corroded concrete caused by calcium chloride would be 10 times that.
“It stays warm longer, so it’s liquid longer and so therefore since it isn’t as prone to freezing as say sodium chloride would be, that means that liquid is then available to go into all areas of your vehicle beyond just the splashing that might occur on the outside of it.”
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Potts has been working in this field for 30 years. He says he didn’t have time to exhaustively research the subject but what he’s seen already is cause for concern.
He’s adamant the solution used last winter isn’t just damaging vehicles, but garages too.
“There’s sort of a – if you will, for a lack of better way of saying it – a binder within the concrete and calcium chloride attacks that binder. It ends up affecting what holds the concrete together. So the evidence of the problem could be something as simple as spalling, although spalling could also come from other reasons as well.
“Basically, the concrete starts to become much more susceptible to breaking apart.”
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“The fact that today they talked about the program being a success and there was absolutely no mention made of any measurement related to corrosion or how they were going to assess that suggests to me quite strongly that there isn’t enough consideration being made of all the factors that affect the decision.”
Potts says washing vehicles more often won’t help because calcium chloride, as opposed to sodium chloride, stays liquid longer and can seep into places washing won’t remove, like inside the door frame.
The information is giving at least one city councillor pause.
“We had a chemist come before us today raising more red flags,” Scott McKeen said.
“I’m not a chemist but it raised enough concern with me to wonder about what we might be looking at as far as delayed costs to our bridges and sidewalks and roads as well as to personal vehicles.
McKeen said he received a number of emails this past winter concerned about the impact of the solution on their vehicles.
“I worry about this being an expedient answer and we’ll get what looks, short-term, like a gain — increased traction, fewer accidents, that sort of thing — but we need to look at this really globally too.
“What are the costs to individual cars, to the city fleet, to the city’s infrastructure — bridge decks, sidewalks, everything — and are there other answers?”
McKeen also suggested administration look at other municipalities that have implemented mandatory winter tires.
While speaking at city hall, Potts suggested the city look at options that reduce ice and snow on roads but don’t damage property, like beet juice.
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The city has tested the effects that different solutions have on iron in a lab, according to Janet Tecklenborg, but staff would like to do more situational testing specific to Edmonton.
She said the city is looking at potentially expanding the calcium chloride program next winter, but not before more research is done.
“We want to bring back the environmental data and changes to the snow and ice policy before we make any amendments.”
Tecklenborg also said a priority this winter will be simply optimizing material usage.
“Optimzing the sand, the salt and the calcium chloride. The new equipment that we’re looking at purchasing would allow us to more effectively meter and apply the calcium chloride.”
— With files from CHED’s Scott Johnston