Deicing composition

Abstract

A deicing composition is provided. The composition includes a potassium or sodium salt of a carboxylic acid and a lithium salt of a carboxylic acid or lithium nitrate, wherein the molar ratio of lithium to potassium or lithium to sodium is from 10 percent to 80 percent.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority to U.S. Provisional Application Ser. No. 60 / 719,624, filed Sep. 22, 2005, the disclosure of which is incorporated by reference in its entirety.FIELD OF THE INVENTION [0002] The present invention relates to deicing compositions suitable for use on any outdoor exposed concrete surfaces such as airport runways, taxiways and aprons, highways, sidewalks, parking lots, etc. BACKGROUND OF THE INVENTION [0003] Snow and ice on concrete pavements such as airport runways, roads, sidewalks, bridges and the like can lead to significant traffic and safety issues. Thus, various compositions have been proposed to deice such concrete pavements. Historically, alkali and alkaline earth chlorides like sodium chloride, potassium chloride and calcium chloride have been used. These compounds while effective and relatively inexpensive are; however, very corrosive with respect to metals like iron, copper, aluminum, and the like. ...

AI Technical Summary

Benefits of technology

[0010] In another embodiment, in applications where corrosion concerns do not restrict their use, the incorporation of significant ratios of lithium compounds along with metal (e.g., sodium, potassium, calcium, and / or magnesium) halide salts can moderate ASR-aggravating effects that would otherwise ensue with the use of non-lithium-bearing compositions. The molar ratio of lithium to the metal of the salt is from 10 to 80 percent.

Problems solved by technology

Snow and ice on concrete pavements such as airport runways, roads, sidewalks, bridges and the like can lead to significant traffic and safety issues.

These compounds while effective and relatively inexpensive are; however, very corrosive with respect to metals like iron, copper, aluminum, and the like.

In addition, such chlorides can be harmful to the environment.

Thus, while these materials may be acceptable in some applications, chloride-bearing deicers are not suitable for concrete surfaces, particularly those used by aircraft.

These formulations, however, can be toxic, corrosive, and some are highly flammable.

These compositions; however, tend to cause cracking and deterioration on the surface of the concrete structure and within the concrete matrix.

A major cause of this concrete deterioration is due to the alkali-silica reaction (ASR).

ASR, in addition to cracking, can cause deleterious expansion and surface spalling.

ASR can weaken the ability of concrete to withstand other forms of attack.

For example, concrete that is cracked due to this process can permit a greater degree of saturation and is therefore much more susceptible to damage as a result of “freeze-thaw” cycles.

Similarly, cracks in the surfaces of steel reinforced concrete can compromise the ability of the concrete to keep out salts when subjected to deicers, thus allowing corrosion of the steel it was designed to protect.

ASR can also cause the failure of concrete structures.

However, this requires introducing the lithium-based compounds in the concrete or mortar mixture and does not address the problem of controlling or remediating ASR in existing hardened structures or the deicing issues.

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