Abstract Manager

Road salt is used during winter weather events in the Province of Ontario, Canada, to prevent frost formation and to assist in plowing accumulated snow off the road. Road salt is effective for pavement temperatures down to approximately -12°C and can adversely affect the roadside environment and infrastructure when used in large quantities. Northern Ontario is subject to extended periods of temperatures in the range -10 to -20°C, increasing the risk of hazardous road conditions or road closures, impacting travel and economic activity.

Ongoing efforts of the Ontario Ministry of Transportation (MTO) are directed to finding alternatives to road salt, including products that augment its performance at lower temperatures and to reduce environmental impacts without significantly increasing the cost of service. Calcium chloride was proposed as an alternative de-icer at low temperatures.

MTO initiated a project in the fall of 2023, to evaluate the effectiveness of flake calcium chloride de-icer at temperatures below the range of effectiveness of road salt. The primary goal is to test its effectiveness between -12°C and -18°C and secondarily, to find optimum application rates over a range of temperature conditions. It is anticipated that cost savings will be realized for temperatures between -15°C and -18°C.

Data collection infrastructure and processes were established in a test area of the Trans-Canada Highway in Northern Ontario. The test includes temperature-dependent protocols for application of calcium chloride and conventional materials on adjacent highway sections, staff and instrumentation dedicated to collection of weather and road conditions data, followed independent, structured analysis of the field data. Data was collected using roadside and mobile RWIS equipment, cameras and road condition sensors, as well as qualitative observations by road maintenance operators. Preliminary assessments appear positive. At the end of the season, analysis will review the challenges of winter road maintenance at cold temperatures, details of the procedures used and conditions experienced, results from the field tests, conclusions, recommendations, and next steps.