Magnesium chloride often said to be “safe on concrete”. However, there is plenty of research evidence showing magnesium chloride (MgCl2) is harmful to concrete as referenced below:
Expansive Mineral Growth and Concrete DeteriorationProject Development Division of the Iowa Department of Transportation
The Iowa Highway Research Board
Department of Geological and Atmospheric Sciences, Iowa State University
The Role of Magnesium in Concrete DeteriorationProject Development Division of the Iowa Department of Transportation
The Iowa Highway Research Board
Department of Geological and Atmospheric Sciences, Iowa State University
Magnesium Chloride as a Road Deicer: A Critical ReviewPeter G. Snow, FACI
Burns Concrete, Inc.
Idaho Falls, Idaho
American Concrete Institute Tech Paper 105-M70Effects of Deicers on Concrete Deterioration
ACI Materials Journal, V. 105, No. 6, November-December 2008
The Role of Magnesium in Concrete DeteriorationIowa DOT HR-355, Final Report
The Iowa Highway Research Board
Department of Geological and Atmospheric Sciences, Iowa State University
Effects of Various Deicing Chemicals on Pavement Concrete DeteriorationMid-Continent Transportation Symposium
Hyomin Lee, Robert D. Cody, Anita M. Cody, and Paul G. Spry
Department of Geological and Atmospheric Sciences, Iowa State University
Supply Warehouse, Inc. has concluded from the above evidence not to recommend deicers with magnesium chloride. We have also concluded that deicers should be applied per manufacturer’s instructions and NOT be over applied. Over application leaves excess chemical on the pavement when the ice is cleared. The excess deicer puts the concrete through additional, unnecessary freeze/thaw cycles which can cause concrete of questionable quality to scale. We recommend using deicers with a coverage Indicator (coloring) which significantly helps control the product application rate.