Even though the cost of maintaining concrete structures is becoming prohibitively expensive mainly due to the effects of deicing salts, the benefits provided by adding these salts on icy roads are too great for their use to see any decrease in the future. The use of road deicing salts, which are extremely corrosive due to the disruptive effects of chloride ions on protective films on metals has dramatically increased in cold regions since it was introduced in the first part of the twentieth century.
The impact of deicing salts on green spaces adjacent to roads where such salts are used is quite obvious if you happen to travel on these roads in the Summer. However, there is concern that the massive use of these salts has an impact on human health. Although an alternative effective and less corrosive deicing agent, calcium magnesium acetate (CMA), is available, its price is apparently not yet reasonable enough for winter maintenance engineers to use widely. Therefore, it can be expected that the road environment would likely remain corrosive, if not more, well into the future.
One simple method of assessing the local corrosivity of an environment is with the use of CLIMAT coupons, Some of these coupons were deployed in the Kingston (Ontario) area in 1997, 1998 and 1999. The most striking results were obtained closed to two well traveled highways during the winter months, when deicing slats are profusely spread on the roads to prevent ice formation. 'Click' on the dates on the following map to access some of these results.