December 2011 Newsletter (vol.2)   >>   Ice, Ice Baby

Ice coverb crab apples

The winter season is fast approaching, and you want to be prepared for the unpredictable snow and ice. It is important to choose the right de-icing chemical to fit your needs. There are several de-icers to choose from, but before you make your purchase you should understand the benefits and disadvantages of each chemical and how to use them. Using blends of de-icers, in addition with mechanical strategies, will help you keep ice and snow at a manageable and safe level.

Anti-icing is proactive snow and ice control. It prevents a strong bond between frozen precipitation and pavement surfaces by timely application of a chemical freezing point depressant. Snow is easily removed as ice has not formed or remains slushy. You will use less de-icers and equipment maintenance will be reduced.

De-icing De-icer is applied to the top of an accumulation of snow, ice or frost that is already bonded or formed to the pavement surface. Factors affecting de-icing action include; chemical concentration, pavement temperatures, weather conditions, type of road surface, topography, traffic volume, width of application and timing of application. When de-icing, plan on using more mechanical removal methods (i.e. shoveling). It is suggested to use abrasive materials (i.e. sand) in conjunction with mechanical removal and chemical de-icers.

Pre-wetting salt has become a common practice. This is done by simply mixing salt with liquid. Wetting provides moisture to make brine, which will increase the melting time. This also will reduce salt bounce and prevent it from being blown off by traffic. Liquid calcium chloride is widely used but any liquid de-icing chemical can be used.

Affects of De-icers on new concrete: De-icing chemicals can accelerate deterioration of concrete and steel structures. Avoid use of any de-icers in the first year. Use plain sand. Apply concrete sealer after first winter.

Plant damage: Most soil and plant damage occurs within 60 feet of the road and is greatest close to the pavement. Planting salt-tolerant vegetation (i.e. bermudagrass or zoysia) in areas receiving large amounts of chemical de-icing salts will help keep areas covered with vegetation. The application of gypsum (calcium sulfate) in spring to lawn areas that have been damaged by salt applications can help reduce damage to plants. Apply according to the below recommendations and then irrigate heavily to remove Na (sodium) from the soil.

Moderate contaminated soil gypsum rate: 100 to 200 lbs/1000 sq ft
Heavily contaminated soil gypsum rate: 700 lbs/1000 sq ft or 150 to 200 lbs per year up to 3 years

 

Types of Ice Melts

Sodium chloride (NaCl - rock salt) is the most commonly used and least expensive de-icing chemical. It keeps sidewalks dry, and can be spread on top of ice and snow. Drawbacks are that it corrodes concrete rebar and metal in cars. Applied at excessive rates it can cause plant damage, destroy soil structure and inhibit root growth and expansion.

Form: Granular - solid crystal
Working temperature: +20F
Effectively melts to: +12F
Liquefied solution: 23%
Rate: 200 to 500 lbs/lane mile (LM); Can be mixed with abrasives
Hardscapes: Severe effect
Carpet/Floors: Slight effect
Vegetation: Severe effect

Potassium chloride (KCl) will melt ice at temperatures down to 20° F and at recommended dosages won’t harm vegetation. Potassium chloride works faster than rock salt, and won’t leave a chalky residue.

Form: Solid crystal
Working temperature: +25F
Effectively melts to: +20F
Rate: slightly higher than NaCl; De-icer
Hardscapes: Severe effect
Carpet/Floors: Slight effect
Vegetation: Moderate effect

Magnesium chloride (MgCl2) is considered to be the best total ice melter. Magnesium chloride melts faster than sodium chloride. When compared to rock salt it is less corrosive to metal and concrete, less toxic to plants and more environmentally friendly. Magnesium chloride is a liquid in its natural state. Once solid magnesium chloride touches ice it readily reverts to a liquid and it picks up water to form strong brine, emits heat, creates more water, and forms more brine. Liquid magnesium chloride is routinely sprayed on pavement prior to precipitation or freezing temperatures to prevent snow and ice from adhering and bonding to the roadway.

Form: Granular - hygroscopic
Working temperature: +5F
Effectively melts to: -25F
Liquefied solution: 25 to 35% solution
Rate: 15 to 35 gal/LM; De-ice, anti-ice, pre-wet
Hardscapes: Severe effect
Carpet/Floors: Severe effect
Vegetation: Moderate effect

Calcium chloride (CaCl2) melts ice down to -25° F degrees but it doesn't prevent refreezing. Melts faster than sodium chloride. It can damage vegetation at excessive rates, corrode metal, and irritate eyes and skin.
Form: Pellet, flake, granular - hygroscopic

Working temperature: -25F
Effectively melts to: -25F
Liquefied solution: 25 to 35% solution
Rate of liquid: 15 to 25 gal/LM; De-ice, anti-ice; pre-wet
Hardscapes: Severe effect
Carpet/Floors: Severe effect; hard on leather shoes and gloves
Vegetation: Moderate effect

Calcium Magnesium Acetate (CMA) is a non-corrosive de-icer but it is relatively expensive. It is considered the safest de-icer for new concrete. It is a De-icer, an anti-ice, and a pre-wet which contains no chlorides.

Form: Solid and liquid
Working temperature: +20F
Effectively melts to: +15F
Liquefied solution: 25 to 30 % solution
Solid Rate: 200 to 400 lbs/LM (10 to 25 lbs /1000 sq ft)
Liquid Rate: anti-icing: 15 to 25 gal/LM; de-icing: 25 to 60 gal/LM or 0.5 to 1 gal/1000 sq ft.
Hardscapes: Slight effect
Carpet/Floors: Moderate effect
Vegetation: Slight effect

Potassium Acetate - (CH3COOK - Ice Clear) is environmentally friendly and effective. It can be applied directly to snow and ice and works to –15° F.

Urea (Carbamide (NH2)2CO) does not contain chlorides, so it's less corrosive and safer for use on concrete. Urea-based products work well down to 21° F.

Sand is an abrasive that will improve vehicle and pedestrian traction on snow- and ice-covered roads and sidewalks. Sand is especially valuable when temperatures are too low for chemical de-icers to work. Treating sand with salt (50 to 100 lbs per cu yd) will improve its performance. Clean up may require extra labor.

 
Hummert's Ice Melts Ingredients
Zero Ice Snow Melt 3-Way Magnesium Chloride (MgCl), Potassium Chloride (KCl), Sodium Chloride (NaCl)
Pet Guard Zero Ice Urea (NH2)2CO
MAG Magnesium Chloride (MgCl)
Earth-Wise Potassium Chloride (KCl) & Sodium Chloride (NaCl)
Melt Man Potassium Chloride (KCl)
Ice-Clear Potassium Acetate (CH3COOK)
Calcium Spray Calcium Chloride (CaCl)
Calcium Chloride Pellets Calcium Chloride (CaCl)
 

Sources:

  1. Breaking the Ice: What Facility Managers Need to Know about Ice Melters, J. Brower. www.magcs.org On Course.
  2. Using Salt and Sand for Winter Road Maintenance. Road Management Journal. Dec. 1997.
  3. De-icing Agents: Pros and Cons. Turf Info for the North Central US. Univ. Neb. Lincoln
  4. Treating for Salt Damage to Plants. Mo. Dept. Conservation.