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Sidewalk Seren-aid
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Concrete! The word is synonymous with ruggedness and durability. You wouldn't think that such a tough material could be utterly destroyed by something as innocuous as simple salt; but every winter, countless square feet of defenseless concrete is lost to careless snow and ice removal.
The sad truth is that the humble sidewalk doesn't exactly represent the pinnacle of the concrete placer's art. More often than not, the material is soupy (high water-to-cement ratio), poorly consolidated, not reinforced or air entrained and improperly cured. These shortcomings usually result in inferior concrete, prone to cracking, internal voids and elevated porosity, among other defects. Poor quality concrete is particularly vulnerable to attack by chemical deicers and their accomplice in destruction, water.
Numerous compounds, both mundane and exotic are marketed as deicing agents, but most tend to emulate either salt (which dissolves in water to form a brine, thereby lowering the f4eezing point) or calcium chloride (which releases heat as it absorbs water to form a brine) in their mechanics and performance properties. Some products may be less harmful to concrete, steel, and plant life than others, but may also cost considerably more and be less effective. Others (such as urea and ammonium compounds) are more harmful. Claims made by some manufacturers may also be misleading. As an example, advertised effective melting temperatures may be for concentrations for in excess of what would be practical or prudent in actual use.
There is no perfect deicer (except warm weather, which is free and harmless, but unreliable).
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