Title: Investigation of Alternate Concrete Deicers

Author(s): P. P. Hudec, C. Macinnis, and S. P. Mccann

Publication: Symposium Paper

Volume: 145

Issue:

Appears on pages(s): 65 -84

Keywords: calcium acetate; calcium phosphates; concretes; corrosion; deicers; durability; freeze-thaw durability; melting; potassium; salts; scaling; sodium; Materials Research

DOI: 10.14359/4541

Date: 5/1/1994

Abstract:
The commonly used deicing salts (sodium and calcium chloride) are well known for their ability to melt ice, but unfortunately are also well known for their detrimental effect on freeze-thaw resistance and surface scaling of concrete. For the past several years, the authors have been conducting a search for a noncorrosive deicer to replace or modify sodium and calcium chloride. The investigation focused on phosphate-chloride mixtures, but also included potassium acetate, calcium magnesium acetate, and phosphate pretreatments of specimens. Testing was done on mortars containing a known, frost-susceptible aggregate (shale sand); the mortar was exposed to various destructive deicer concentrations under freezing and thawing conditions. Scaling loss and ice-melting ability of the various concentrations are compared. Simple experiments to evaluate corrosion of steel were also performed. Although phosphate salts have long been suggested as alternate deicers, they are not effective by themselves. Most promising in the current study are the monophosphates of sodium, potassium, and calcium mixed in specific proportions with chlorides. The phosphate-chloride mixtures also provide some corrosion protection. A deicer mixture of sodium chloride with a relatively small proportion of phosphate may prove to be an effective, benign, and economic deicer.