A new study presented at the International Winter Road congress draws attention on the effective economic and environmental contribution of using calcium chloride for de-icing. The congress, which is held once in four years, unites professionals working on winter road safety from all over the world which enables knowledge sharing for best practices. As salt spraying is one of the most important tasks to keep roads safe during cold winters, too much salt can be harmful for the near environment. New research shows how adding calcium chloride to de-icing salt contributes to keeping environmental impact at a minimum.
The effectiveness is explained by the sticky layer formed on the road surface when calcium chloride is added to de-icing salt. Due to the hygroscopic property, the de-icing salt mix sticks directly to the road surface, thereby preventing it to end up in the environment through wind and traffic.
Another beneficial property is the long-lasting effect of the de-icing solution. Calcium chloride stays wet until 30% air humidity, while sodium chloride dries below 85% air humidity. Especially during winter months when air is colder and dry, these effects have a significant impact on enduring road safety. Furthermore, less salt is needed compared to traditional salt, which minimizes environmental concerns.
As an increase in efficiency of the de-icing mix results in lower maintenance costs, this study shows how a noteworthy addition can enhance efficiency as well as maintaining safety and the environment.
Source: Effectiveness of combinations of de-icing salts with NaCl or CaCl2 brines for friction control on roads. Kalman, B. Pavement Technology, VTI, Sweden.