Calcium magnesium acetate (CMA) is an alternative deicing agent that was developed in the USA around 1980. On commission by the Swedish National Road Administration a review of the literature on CMA has been done. A small selection of the numerous studies that have been conducted since 1980 is presented in this report. In the majority of the field studies it is observed that CMA is slower acting than sodium chloride (NaCl). A longer lasting effect of CMA compared to NaCl has, however, been observed in some studies. CMA is furthermore described as an anti-icing, rather than a de-icing agent. Several studies also show that CMA is less corrosive than NaCl and that CMA causes less freeze/thaw damage to concrete than NaCl. Earlier studies have shown that CMA is less harmful to the environment than NaCl. Oxygen is, however, consumed when acetate is decomposed. The decomposition rate is strongly temperature dependent and at low temperatures the prerequisite increases for nondecomposed CMA to be transported to shallow lakes and groundwaters and there reduce the oxygen level. The results from a Finnish study show that the infiltration of nondecomposed CMA into deeper ground layers is so significant that massive deicing with CMA should not take place close to groundwater areas. (A)
Samenvatting