26 Feb 2022

KEEPING CLEAN AND SAFE: deicing in different countries

At the XVI World Winter Service and Road Resilience Congress participants from 53 countries of the world shared their approaches and best case studies. 

World Road Association (PIARC) arranged the event in Calgary. Since 1969, the professional association has been holding the Congress each four years. This season the Congress was arranged online and that allowed bringing together 785 participants at a time. WTG experts were among them. 

Representatives of different countries of the word presented their reports to the participants. Key issues included traffic management, road surface condition, deicing materials, equipment, user information, and many others. 

Speakers from Scotland, for instance, shared their experience in winter road maintenance. Transport Scotland, the national transport agency of Scotland, plays the main role in the process. The agency signs contracts with operating companies and arranges service of main-line highways in severe weather conditions during the longest part of the year: from 1 October through 15 May. A specialist in severe weather conditions controls winter road operation: he/she is responsible for all aspects of service planning and provision. 

As soon as winter weather in Scotland can be rather unpredictable, special winter road patrolling has been introduced. Operating companies are engaged in such work from 1 November through 30 April. Patrols operate on the busiest roads, as well as on highways experiencing the most severe winter conditions. Such monitoring begins immediately once the risk of icing appears. 

In Scotland salt is widely used on the roads (rock salt replacement with more environment-friendly sea salt is in process). The national consumption of the agent is strictly controlled. In order to avoid salt supply problems and salt shortage, the management strategy specifies the minimum stock levels of the agent for each region. Before each winter, independent auditors check such stock levels. 

The colleagues from Scotland were followed by experts from Austria who raised one more important issue: high corrosive activity of some deicing agents. Annually in Austria there are 20 to 30 snow days and there 40 to 70 days of frost and ice rain. Sodium chloride (NaCl) is used in road maintenance, but the use of sodium chloride reduces the life of infrastructure facilities. The reports of the Austrian researchers were dedicated to searching possible alternatives to sodium chloride in the framework of the WINTER LIFE Project. 

Conventional deicing agents, such as CaCl2 and MgCl2, reduce corrosion at least by 60–75%, as compared to NaCl. Potassium carbonate (KCO) demonstrates even better characteristics: it can reduce corrosive effect by more than 90%. In addition to that, the use of inhibitive substances allows significant reduction of corrosion-induced mass loss up to 40% and more. 

The researchers analyzed asset life cycle cost. They found that steel mass lost caused by corrosion could be reduced by up to 90 % through the use of alternative deicing agents and at least by up to 40 % through the use of corrosion inhibitors, as compared to sodium chloride. The tests demonstrated that the rate of corrosion significantly increased as the environment temperature rose; that showed the importance of cleaning critical areas of residues of salt after winter. 

During the Congress, the results of testing of self-deicing asphalt on the road network of England were presented. The site monitoring demonstrated that Winterpave additive was efficient during the first year. It was noticed, that Winterpave additive produced some melting effect when a thin snow layer appeared on the road surface, for instance, during snowfalls, and it was easier to remove snow from the surface. That was confirmed by a laboratory test which showed that Winterpave additive produced required effect at a temperature up to as low as -8 °C and less effort was needed to remove snow from laboratory samples. A decision was taken to continue further tests to study the material more thoroughly. 

Experts from Germany addressed the environmental impact of agents. They tested materials based on different parameters and came to a conclusion that a more updated preliminary standard should be developed for future unified interpretation of testing results. That will allow having unified statements concerning environmental impact, as well as concerning efficiency of materials, and material handling issues. 

The Canadians spoke about snow removal quality standards and winter road maintenance. The purpose of the researchers was to revise and update the WQMS for pavements, pathways, winter cycling networks, and light traffic roads in Ottawa. That should contribute to bringing the infrastructure in compliance with the idea of a fair, healthy, stable, safe, and integrated world-class capital city. The results and recommendations concerning the WMQS were presented to Ottawa city council. 

Speakers from Sweden emphasized the amount of salt needed on the roads in order to ensure safe road use for all road users. So, it is important to know whether any salt has remained on the road surface after the previous use of agents. If some agent has remained after the previous use, you need not apply a full dosage, i.e. you may save material and still ensure proper quality of the road infrastructure maintenance. 

The Swedish researchers studied the issue and measured the residual amount of salt throughout 3 years. Based on the obtained data they generated an algorithm which represents a residual salt content prediction model. This is needed for the calculation of theoretical residual content of agent on the road. The model is successfully in use in Sweden to predict weather conditions on the road. 

Based on the Congress results the best articles and reports were published in Routes/Roads Magazine.



World Road Association (PIARC) has been in operation since 1909 and today it brings together 124 government members worldwide. The Association retains consultative status to the Economic and Social Council of the United Nations. PIARC is a world leader in the international exchange of advanced experience in solving numerous road and road transport issues.