Every year, considerable quantities of snow and ice control products are applied to highways, and environmental and regulatory agencies have questioned the environmental impact of these products. Transportation agencies are asked to use “environmentally friendly” or less toxic alternatives wherever possible, but there is no commonly accepted guidance for determining which products are acceptable. The traditional use of roadsalt has been prohibited in some locations, leaving highway agencies uncertain about how traffic safety can be maintained in bad weather. For example, Environment Canada has concluded that inorganic chloride roadsalts are harmful to the environment under the Canadian Environmental Protection Act, thus requiring development and implementation of improved management practices. Studies of the most common chemical alternatives—sodium chloride (salt), magnesium chloride, calcium chloride, calcium magnesium acetate, potassium acetate, and urea—have focused on performance and cost under various weather conditions without evaluating their relative impacts on the environment. Several new chemical preparations, including some that are trademarked, have entered the market as snow and ice control chemicals for use by transportation agencies, but there is limited information about their environmental impacts. There is a need for rational decision-making guidelines to assist DOT maintenance managers in selecting the most appropriate snow and ice control materials for the conditions that exist in their jurisdictions. Under NCHRP Project 06-16, a research team led by Levelton Consultants Ltd. conducted an extensive review of relevant technical information, then conducted a program of analytical laboratory testing on a wide range of products currently available in the North American market. The results were used to develop three products for the end user: a decision tool for the selection of the most appropriate snow and ice control materials to suit the specific needs of any given highway agency, a purchase specification that can be used by an agency once agency staff have selected materials for use, and a quality assurance monitoring program that includes procedures and standard test methods to characterize snow and ice control products before their purchase or use. There are two major components to this report. Chapters 1 through 11 (a) summarize the review of technical information on the performance and environmental impacts of currently available snow and ice control materials, and (b) present the results of an analytical laboratory testing program designed to address gaps in the current literature and to develop a matrix of properties of 42 chemicals. The second component presents guidelines for the user with three products: a decision tool for the selection of materials, a purchase specification, and the quality assurance monitoring program. An electronic version of the decision tool and several appendixes to the final report can be downloaded from the TRB website at http://www.trb.org/TRBNet/ProjectDisplay.asp?ProjectID=883. (Author/publisher) This report may be accessed by Internet users at http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_577.pdf
Samenvatting