Together with plowing and sanding, chemical de-icing and de-icing agents are important tools for highway snow and ice control. The most commonly used de-icing agent is sodium chloride (NaCI), and as such it is effective, easy to handle and inexpensive. Many negative and often costly side effects have, however, been recognised over the years. Extensive research has therefore been conducted to find alternatives. Calcium magnesium acetate (CMA) is an alternative de-icing agent which has given very promising results in laboratory and field tests. The most significant impediment to its use is its high price, which is more than 20 times that of NaCi. To reduce the cost but still benefit from the positive effects with CMA tests have been conducted with CMA/NaCl mixtures. In 1993 the Swedish National Road and Transport Research Institute initiated a research project of testing and evaluating a 20/80 weight% CMA/NaCl mixture. The field evaluation was conducted on highway E4 and included both friction measurements and corrosion tests. The laboratory testing, mainly done at the Swedish National Testing and Research Institute, included corrosion tests and freeze/thaw testing on cement concrete. The laboratory tests showed that the addition of CMA to NaCl does reduce the corrosion of steel and the scaling of concrete. The corrosion of steel is reduced also according to the results from the field tests, but not to the same extent as in the laboratory tests. Furthermore, the same de-icing could be obtained with the CMA/NaCl mixture as with NaC1. (A)
Samenvatting