Guidelines for the Selection of Snow and Ice Control Materials to Mitigate Environmental Impacts (2007) / Chapter Skim
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10 2.1 Products Used and Properties Snow and ice control materials include various chemical product types as well as abrasives. These have been classified as shown in Table 2-1.
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2.1.1.2 Calcium Chloride (CaCl2) Calcium chloride (CaCl2)
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stated as the lowest freeze-point achievable by a given chemical through an optimum ratio of chemical to water. The prices shown in Table 2-2 are from contracts published in 2003 available on the Internet.
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although some can be synthesized from petroleum sources. Alcohols are volatile and flammable and present some storage and handling concerns.
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survey (included as Appendix A, which is available for download from the TRB website) was designed to gather the following information: • Product use and methods of application, • Environmental concerns, • Corrosion concerns, and • Product selection process.
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lar, with 12 of the respondents rating it as either their first, second, or third preference (43 percent)
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pads with some form of runoff control. However, some respondents reported storing solid chemicals outdoors with and without cover.
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Purchase price was the most important criterion for the respondents and probably will remain so. Seven of the respondents cited "tradition" as a current purchase criterion and four respondents indicated they would continue to use tradition as a purchase criterion in the near future.
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• The cost of testing, particularly when extensive laboratory testing is needed (This is particularly true when using the PNS specifications that are far more extensive in scope) ; • The use of AASHTO and ASTM specifications, which have been a standard for solid NaCl for a number of years (these specifications primarily address gradation and moisture content, which are not normally tested in the field)
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of solids applied for 0°C to –10°C. Within this temperature range, most snow and ice control products have similar levels of performance.
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2.5.4 Dry Abrasive/Chemical Mixes Application of abrasive/salt mixes, a popular strategy, typically involves approximately 1:1 mixtures of abrasive and salt. This strategy is not as cost-efficient as using chemicals only and is less effective at reducing accidents.
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21 British Columbia Ministry of Transportation and Highways Oregon Department of TransportationSieve Size Designated 12.5 mm % passing Designated 16 mm % passing Designated 19 mm % passing Designated 6.75 mm (.25 in) % passing 19.000 mm (3/4")
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materials used in winter maintenance is related to the type of product used and the amount applied. Any measure to reduce volumes of materials applied can reduce the magnitude of environmental effects.
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23 Using the above comparison, one could reasonably conclude that a smaller application of KA would yield the same results in terms of ice removal at this temperature. PI is used to estimate relative performance of products, but can be affected by changes in temperatures, so care should be taken in its use.
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24 Original Loading 1 Pre-wetting Solids Loading 2 Anti-Icing Loading 3 Low High Low High Low HighOriginal Strategy Kg (Lb)
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