Laura Fay

Environmental Impacts of Chemicals for Snow and Ice Control: State of the Knowledge

As chemicals are widely used for snow and ice control of highway and airfield pavements or aircrafts, recent years have seen increased concerns over their potentially detrimental effects on the surrounding environment. The abrasives used for winter operations on pavements are also a cause of environmental concerns. After some background information, this paper presents a review of the environmental impacts of chemicals used for snow and ice control, including those on: surface, ground, and drinking waters; soil; flora; and fauna. The paper provides a state-of-the-art survey of published work (with a focus on those in the last two decades) and examines mainly the impacts of abrasives, chlorides, acetates and formates, urea, glycols, and agro-based deicers. Finally, we conclude with a brief discussion of public perception of such impacts and best management practices (BMPs) to mitigate them.

Corrosion of Deicers to Metals in Transportation Infrastructure: Introduction and Recent Developments

Chemicals used in the snow and ice control operations (also known as deicers) may cause corrosion damage to the transportation infrastructure such as reinforced or pre-stressed concrete structures and steel bridges. This review presents a synthesis of information regarding the impacts of both chloride-based and acetate/formate-based deicers on metals especially steel rebar in concrete, common test methods to quantify such impacts, and countermeasures to manage such impacts. There are many ways to manage the corrosive effects of deicers, such as: selection of high-quality concrete, adequate concrete cover and alternative reinforcement, control of the ingress and accumulation of deleterious species, injection of beneficial species into concrete, and use of non-corrosive deicer alternatives and optimal application rates.

Laboratory Investigation of Performance and Impacts of Snow and Ice Control Chemicals for Winter Road Service

This work evaluated the performance attributes and impacts of several alternative deicers along with traditional chloride-based deicers. Four Strategic Highway Research Program tests were conducted to evaluate the ice melting, ice penetration, and ice undercutting capabilities of the deicers of interest, and also their impact to the freeze-thaw resistance of portland cement concrete. Three additional novel methods were utilized to assess the friction coefficient of deiced concrete surfaces, thermal properties of the deicers, and corrosion effects of deicers to metals. The laboratory data shed light on the complexity and challenges in evaluating various deicers. To facilitate scientifically sound decision-making, the writers propose a systematic approach to integrate the information available regarding various aspects of deicers, and to incorporate agency priorities, which is expected to aid agencies in selecting or formulating their snow and ice control chemicals.

Evaluating Snow and Ice Control Chemicals for Environmentally Sustainable Highway Maintenance Operations

AbstractThe use of chemicals and abrasives for highway winter maintenance operations is an essential strategy for ensuring a reasonably high level of service, yet the performance of such materials has to be balanced with their potential negative impacts on motor vehicles, transportation infrastructure, and the natural environment. In this context, this work presents a comprehensive and quantitative evaluation of snow and ice control chemicals currently used by various Idaho Transportation Department districts for highway maintenance operations, including rock salts (mainly solid sodium chloride), IceSlicer products (solid sodium chloride with trace amounts of other chlorides), and salt brines. The analysis has been enabled by the utilization of existing lab and field test data along with reasonable assumptions, in the effort to identify environmentally sustainable materials for winter highway operations. Despite its caveats, this case study is the first attempt to incorporate the most up-to-date informati...

Strategies to Mitigate the Impacts of Chloride Roadway Deicers on the Natural Environment

This synthesis documents the range of methods, tools, and techniques used by transportation agencies to minimize the environmental impact of chloride-based roadway deicers. The report presents information on preventative measures designed to reduce the amount of chloride deicers entering the natural environment adjacent to roads, as well as strategies for reducing the impacts once the deicers are in the environment. Information used in this study was acquired through a review of the literature and a survey of state departments of transportation and Canadian provincial transportation agencies. Follow-up interviews with selected agencies provided additional information.

Costs and Benefits of Tools to Maintain Winter Roads: A Renewed Perspective Based on Recent Research

Some of the most useful data available to winter road maintenance managers and others charged with decision making are the costs, benefits, and effectiveness associated with winter maintenance of practices, equipment, and operations. However, significant effort may be required to track down this information, and access to published reports and papers is not guaranteed. This paper presents recent research results to assist practitioners in understanding the current state of the practice related to specific items. The information presented here focuses on the top 10 winter maintenance practices, equipment, and procedures as identified by practitioners, including anti-icing, deicing, front and underbody blades, automatic vehicle location and Global Positioning System technologies, pavement temperature sensors, road weather information system (RWIS), maintenance decision support system, carbide blades, air temperature sensors, and zero velocity spreaders. A review of the literature pertaining to these items indicated that, depending on the item of interest, significant data gaps might exist. This was less true for items such as RWIS and more true of items such as temperature sensors and material placement systems. Overall, quantified costs and benefits related to many items are still needed. In addition, further investigation is necessary to quantify the dollar values of costs and benefits associated with many items considered intangible at present. The determination of the values of such costs and benefits would assist in the conduct of cost–benefit studies and decision making.

Cost-Effective and Sustainable Road Slope Stabilization and Erosion Control

In the United States it is estimated that 75% of all roads are low-volume roads maintained by some 35,000 local agencies. Low-volume roads often omit surface slope protection, and this can lead to slope failure, erosion, and maintenance, safety, and ecological issues. This report presents information on cost-effective and sustainable road slope stabilization techniques, with a focus on shallow or near-surface slope stabilization and related erosion control methods used on low-volume roads. To fully address this topic, planning and site investigation are discussed, as well as erosion control techniques, soil bioengineering and biotechnical techniques, mechanical stabilization, and earthwork techniques. Information presented in this report was obtained through an extensive literature review, and from survey and interview responses. From the survey responses, 30 individuals were interviewed based on the information they made available in the survey. A total of 25 interviews were conducted over the phone, and in two cases written responses were received.

A Benefit-Cost Analysis Toolkit for Road Weather Management Technologies

Highway agencies face increasing demands and customer expectations regarding mobility and safety during inclement weather, while confronting unprecedented budget and staffing constraints and a growing awareness of environmental challenges related to the use of chemicals and abrasives. To address these different issues, benefit-cost analysis is typically employed before making investment decisions. In the winter maintenance context, where the costs and benefits of road weather management tools can vary greatly, this presents a significant challenge to managers. This work presents an overview of a new benefit-cost analysis tool developed for winter maintenance practitioners to evaluate different equipment, operations and materials, including road weather management tools, in a streamlined, web-based environment. The toolkit was used to conduct two case studies of the use of Road Weather Information Systems (RWIS) and Maintenance Decision Support Systems (MDSS) for road weather management. The first case study examined the current use of RWIS statewide in Iowa and found that it produced an agency-specific benefit-cost ratio of 3.8 and a total ratio of 45.4. A second case study examined the potential use of MDSS in one subdistrict in Indiana found that a benefit-cost ratio for the agency would be 1.5, while the total ratio would be 3.0.

Laboratory Investigation into Interactions Among Chemicals Used for Snow and Ice Control

Recent years have seen increased use of chemicals for snow and ice control both on roadways and at airports. One relatively new concern has been the potential chemical and physical reactions among different deicer formulations. This issue has significant operational and safety implications and thus was the focus of this laboratory investigation. When allowed to sit without stirring at room temperature, precipitates formed in the blend solutions of reagent-grade magnesium chloride with acetate- or formate-based deicers. When a magnesium-chloride-based deicer was used in place of its reagent-grade counterpart, precipitates did not form in its blend solutions with a sodium acetate deicer or a potassium formate deicer, but the solutions were milky in appearance. In light of the Fourier transform infrared and solubility data, the precipitates consist of magnesium acetate tetrahydrate or magnesium formate dihydrate formed by chemical reaction, along with additives from the parent solutions.

Converting Paved Roads to Unpaved

The practice of converting paved roads to unpaved is relatively widespread; this study identified recent road conversion projects in 27 states. These are primarily rural, low-volume roads that were paved when asphalt and construction prices were low. Those asphalt roads have now aged well beyond their design service life, are rapidly deteriorating, and are both difficult and expensive to maintain. Instead, many local road agencies are converting these deteriorated paved roads to unpaved as a more sustainable solution. Key findings from this study include: Local road agencies have experienced positive outcomes by converting roads. Many local road agencies reported cost savings after converting, compared with the costs of continuing maintenance of the deteriorating paved road, or repaving. One key to successful conversion is early involvement of the public in the planning process. Other techniques that can be used to improve the overall results of a project include treating or stabilizing granular surfaces to control dust, limiting the rate of aggregate loss, and reducing motor grader/blade maintenance frequency. Stabilization procedures can also improve safety, increase public acceptance, and reduce life-cycle costs and environmental impacts after a conversion has taken place.