non corrosive de-icing chemicals

[ajk1]

1. Has anyone any experience with non-corrosive deicing chemicals such as calcium magnesium acetate or urea? I know these will not melt ice at lower than about minus 5 degres C, but what I am interested in is whether anyone knows anyone (other than an airport on their runways) that is actually using these chemocals?

2. Does anyone have expreince with or know where a less corrosive de-icing chemical than clacium chloride or sodium chloride is being used in Canada or parts of the U.S. with similar climates?

 

[ztengguy]

Im pretty sure that they use these in the Bahamas. Whats the structural issue or question?

 

[CarlB]

According to this article (1999), MgCl is a deicer of choice in southcentral Alaska.

http://www.dot.state.ak.us/stwddes/research/assets/pdf/99v24n4.pdf

 

[CarlB]

And a report that compares varios chemicals-

http://www.dot.state.ak.us/stwddes/research/assets/pdf/ine_autc_07_06.pdf

 

[TXStructural]

When you say non-corrosive, I assume you mean for steel. Acetates cause deterioration of concrete, so there is a trade-off.

Plain old salt (NaCl) is a good choice, as long as there is good quality concrete protecting any steel. Properly placed epoxy-coated reinforcement will last indefinitely (all steel must be coated, and coated tie wire and bar supports must be used.) Mag chloride provides twice as much chloride ion (the damaging part for steel) so it is a poor choice, unless you can apply half as much and get the same control.

For steel structures, where concrete durability is not an issue, the acetates may work well.

 

[jie5]

i have recommended Calcium Magnesium Acetate (CMA) for use on 5ksi concrete less then 1 year old in the northeast and have had good results. no corrosion or spalling.

 

[ajk1]

Thanks for the replies. Plain old salt is the absolutely worst thing for corrosion. That is precisely what causes all the corrosion in Ontario, Quebec, the northeast U.S. etc. area. Epoxy coated bars are not the answer although they can help to extend the life if they can be placed without damaging the epoxy (which for practical reasons is impossible); other things can help, like lower w/cm concrete, greater cover, etc. - see CSA Standard S413 "Parking Structures". The best answer is a waterproofing membrane (mandatory in Canada) but if there is a less corrosive material than NaCl or CaCl that will not harm concrete and will be effective down to minus 12 degrees Celsius, I would like to know of it. Calcium magnesium acetete works only to about minus 6 degrees C which may be ok in some geographic areas , but not around southern Ontario or northern U.S. In adition to the rebar in the concrete there are also steel columns, steel beams etc. to be protected, so a non-corosive deicer is really required to address the issue most broadly.

 

[Captain37]

You may research aqueous Potassium Acetate (KAc) for use. This is marketed for use because of its reduced concrete degradation, low temp effectiveness (-9 C documented research/-15 C observed), as well as having exceptional environmental/biological performance (very low BOD). This chemical is currently being employed across the northern U.S. as well as in Ontario and Alberta, Canada. It is the preferred chemical for use by many agencies. C/B studies have been performed on the KAc. Cost has been a concern, however it appears to have specific benefits across many agencies (DOT effectiveness, EPA/DEP quality/risk).

 

[ajk1]

Thanks for the responses to-date. Much appreciated.