COMPARATIVE STUDY OF UNDERCUTTING AND DISBONDMENT CHARACTERISTICS OF CHEMICAL DEICERS

A laboratory study was conducted to determine the undercutting and disbondment characteristic of 10 chemical deicers. The materials included six discrete deicing chemicals and four blends: calcium chloride pellets, calcium chloride flakes, two sodium chloride products, potassium chloride, pelletized urea, sodium chloride with a small amount of carboxymethocellulose, a blend of sodium chloride and potassium chloride sprayed with urea, a blend of sodium chloride and urea, and calcium magnesium acetate. In the undercutting tests, deicer particles were distributed on 6- x 9- x 2-in. concrete slabs covered with a 1/8-in. layer of ice. Tests were conducted at temperatures ranging from 0 deg F to 25 deg F in 5 deg F increments. Results were photographed and subsequently measured with a computerized stylus. The disbondment test apparatus measured and recorded the horizontal and vertical forces required to remove ice from a concrete specimen as it was drawn beneath a stationary blade. Each deicer was applied to the 1/8-in. ice samples and allowed to undercut for 30 min before disbondment forces were recorded. The tests showed that at least a 95% complete undercutting is necessary for ice removal by mechanical disbondment forces of 2.8 lb per inch of blade width.