The crunch of salt underfoot and the stain on your winter boots is all part of a typical Canadian winter. But what if there was a way to make it better for the Earth, the asphalt and the cars or bikes travelling over it?
Western researchers are studying nine varieties of winter road salt and its corrosive effects on six different types of metals. They’ll investigate how the different salts help or harm icy roads, infrastructure and the environment.
The study, jointly led by chemistry professor Yolanda Hedberg and engineering professor Chris Power, is in its second year. It has garnered attention on Western’s campus this winter, thanks to a cordoned-off area near the chemistry building on Perth Drive where samples of steel are sprayed with various salt brines once a week.
“Salt is not sustainable. We are basically turning our Great Lakes into oceans if we continue this way. We are completely changing the ecosystem with the use of salt,” Hedberg said.
The team is examining a range of different salts – from sodium chloride, the kind we use on food, to magnesium chloride to pure sodium acetate – to determine which ones perform best melting snow and ice or providing traction. At the same time, they’re measuring the effects on soil, roads and different metals used in cars, bikes and assets like bridges.
Western researchers are working with Facilities Management and a private company testing an organic road salt in hopes it will be less damaging.
“It’s a big interest-generating problem because it’s so relevant, and so applied,” Hedberg said.
That interest is apparent among university staff and faculty. Western’s campus is carefully maintained in the winter by a team of 17 university staff and additional contractors in the worst of the season.
“Western Facilities are partners. They gave us the salt used on campus, a lot of expertise and signage, and they help us to perform the salt spreading on Perth Drive at night. It’s quite a committed team,” Hedberg said.
Salt is a ‘tool in the toolbox’
Looking for innovative ways to evolve winter maintenance strategies is always top of mind for the Facilities Management team, said landscape services manager Mike Lunau. All but a few of the staff involved have extensive training on the science of snow and ice management, beyond a typical industry level, he said.
“We take our role as stewards of the facilities on campus, including its natural environments, very seriously,” Lunau said. “The connected nature of campus and the impact on the Thames River ecosystem is not lost on myself or any of my team. Any opportunity we have to engage in research to support that, to optimize our use of anti-icing and de-icing products, it’s always great to take those opportunities.”
Western’s team uses a combination of treated and untreated salts to better target various temperature ranges over a winter. The goal is always to use the least amount of salt and employ it alongside other options to keep the campus clear and safe.
“We think about timing. We use salt as a tool in that toolbox, to prevent bonding of snow and ice to surfaces, so we can mechanically clear (the roads and pathways) and use less salt,” Lunau said.
As technologies advance, it’s also becoming more realistic and achievement to use products that have fewer effects on the environment or infrastructure. Lunau’s team is examining new options – such as using liquids, essentially salt brines with a lower chloride content – and strategies that may better protect the environment while still offering a fiscally responsible approach.
The tide is changing for many institutions and players, he said.
“The industry as a whole is aware of and conscious of the environmental impacts. There are many really advocating and pushing the boundaries of technologies and material sciences.”
Sustainability work extends to winter maintenance
The road salt study is now one of the projects under Western’s Campus as a Living Lab initiative, which merges academics and the university’s commitment to sustainability by bringing together faculty, staff and students to do research right on campus.
A new internal grant, the Western Sustainable Impact Fund, also provided funding for the road salt research.
Robert Addai, a PhD candidate in chemistry supervised by Hedberg, said the research is about comparing today’s costs – both financial and environmental – to those over the long –term.
“We know Canada uses a lot of sodium chloride because it is cheap. We don’t take into consideration the side effects, the future costs, we only think about now. This is why we want to analyze sodium chloride compared to other salts, to see which one will benefit us today and tomorrow,” Addai said.
Balancing effectiveness, impact and cost is the goal, both for researchers and those tossing the salt.
For Addai, it’s simply part of the scientific equation.
“Like we say, for every action there is an equal and opposite reaction. For us, we are trying to keep the snow away from the road. But the salt can also corrode metal, it melts into the waterbodies. As scientists, we always do a risk assessment. With every product, we consider, ‘How much is this helping and how much is this harming the society?’” – Robert Addai, PhD candidate in chemistry
“This study is very important because at the end of the day we want to find a type of salt that is beneficial for pedestrians and cars, and also helps melt the snow. We must consider the environmental impact on grasses, plants and animals as we are checking the cost.”
Hedberg, who is also an engineer, lived in Sweden for more than a decade, where she worked part-time as a politician in a suburb of Stockholm. She provided scientific knowledge to the technical committee responsible for winter maintenance and bike lanes, saying it was rewarding to “contribute to democracy and the community.”
There, she saw other ideas for snow clearing, such as the Swedish approach of clearing sidewalks, cycling and bus lanes first, before roads. In her home country of Germany, property owners are prohibited from putting salt on their own stairs, with stiff penalties and fines for those flouting the rules, thanks to the potential for structural damage.
“It’s quite fascinating to see how other countries address this,” Hedberg said.
The current project wraps up this year, but there is interest in partnering next with a municipality, applying the research findings across an entire community.
“We hope our results can convince municipalities this can be done (using alternative salts),” Hedberg said.