• Bio-Based Renewable Additives for Anti-Icing Applications (Phase II)

      Nazari, Mehdi Honarvar; Oh, Taekil; Ewing, Alexander Charlemagne; Okon, Deborah Ave; Avalos, Brandon; Alnuaimi, Eisa; Havens, Eden Adele; Shi, Xianming (Center for Environmentally Sustainable Transportation in Cold Climates, 2019-01-24)
      The performance and impacts of several agro-based anti-icers along with a traditional chloride-based anti-icer (salt brine) were evaluated. A statistical design of experiments (central composite design) was employed for developing anti-icing liquids consisting of cost-competitive chemicals such as agro-based compounds (e.g., Concord grape extract and glycerin), sodium chloride, sodium metasilicate, and sodium formate. The following experimentally obtained parameters were examined as a function of the formulation design: ice-melting capacity at 25°F (−3.9°C), splitting strength of Portland cement mortar samples after 10 freeze-thaw/deicer cycles, corrosion rate of C1010 carbon steel after 24-hour immersion, and impact on asphalt binder stiffness and m-value. One viable formula (“best performer”) was tested for thermal properties by measuring its differential scanning calorimetry (DSC) thermograms, the friction coefficient of asphalt pavement treated by this anti-icing formulation (vs. 23 wt.% NaCl and beet juice blend) at 25°F after being applied at 30 gallons per lane mile (1 hour after simulated trafficking and plowing), and other properties (pH, oxygen demand in COD). Laboratory data shed light on the selection and formulation of innovative agro-based snow- and ice-control chemicals that can significantly reduce the costs of winter maintenance operations.
    • An Empirical Model for Optimal Highway Durability in Cold Regions

      Yan, Jia (Center for Environmentally Sustainable Transportation in Cold Climates, 2016-03-10)
      We develop an empirical tool to estimate optimal highway durability in cold regions. To test the model, we assemble a data set containing all highway construction and maintenance projects in Arizona and Washington State from 1990 to 2014. The data set includes information on location, time, type (resurfacing, construction, or lane widening), pavement material and thickness, and total expenditure for these projects. Using the data, we first estimate how highway maintenance costs and highway duration depend on pavement thickness and traffic loading. We then calibrate the effects of different deicers on highway durability and thus on highway maintenance costs. Finally, we demonstrate how the estimated and calibrated model can be used by planners to make optimal decisions for highway pavement and winter operations in cold regions.
    • Estimating the Application Rate of Liquid Chloride Products Based on Residual Salt Concentration on Pavement

      Fay, Laura; Akin, Michelle; Muthumani, Anburaj (Center for Environmentally Sustainable Transportation in Cold Climates, 2018-03-21)
      This technical report summarizes the results of laboratory testing on asphalt and concrete pavement. A known quantity of salt brine was applied as an anti-icer, followed by snow application, traffic simulation, and mechanical snow removal via simulated plowing. Using a sample from this plowed snow, researchers measured the chloride concentration to determine the amount of salt brine (as chloride) that remained on the pavement surface. Under the investigated scenarios, the asphalt samples showed higher concentrations of chloride in the plowed-off snow, and therefore lower concentrations of chlorides remaining on the pavement surface. In comparison, the concrete samples had much lower chloride concentrations in the plowed-off snow, and much higher chloride concentrations remaining on the pavement surface. An interesting pattern revealed by the testing was the variation in the percentage of residual chloride on the pavement surface with changes in temperature. When pavement type was not considered, more residual chloride was present at warmer temperatures and less residual chloride was present at colder temperatures. This observation warrants additional testing to determine if the pattern is in fact a statistically valid trend. The findings from the study will help winter maintenance agencies reduce salt usage while meeting the defined Level of Service. In addition, findings will contribute to environmentally sustainable policies and reduce the level of salt usage (from snow- and ice-control products) introduced into the environment.
    • Evaluating the Potential Effects of Deicing Salts on Roadside Carbon Sequestration

      Fay, Laura; Ament, Rob; Hartshorn, Tony; Powell, Scott (2019-01)
      This project sought to document patterns of road deicing salts and the effects of these salts on the amount of carbon being sequestered passively along Montana Department of Transportation roads; it was designed collaboratively with a related roadside project that tested three different highway right-of-way management techniques (mowing height, shrub planting, disturbance) to determine whether they have the capacity to increase soil organic carbon. Our sampling did not reveal elevated salt levels at any of the nine locations sampled at each of the three I-90 sites. The greatest saline concentrations were found at the sample locations farthest from the road. This pattern was consistent across all three sites. The range of soil organic matter (SOM) was broad, from ~1% to >10%. Generally, SOM values were lowest adjacent to the road and highest farthest from the road. We found no or weak evidence of a relationship between our indices of soil salinity and SOM levels, with electrical conductivity, exchangeable calcium, and cation exchange capacity. Results imply that if road deicing salts are altering patterns of roadside SOM and potential carbon sequestration, this effect was not captured by our experimental design, nor did deicing salts appear to have affected roadside vegetation during our most recent sampling effort. Our findings highlight the value of experimentally separating the multiple potentially confounding effects of winter maintenance operations on roadside soils: roads could focus the flow of water, salts, and sands to roadside soils. How these types of mass inputs to roadside soils might influence medium- or long-term carbon dynamics remains an open question, but their fuller characterization and possible flow paths will be essential to clarifying the role of roadside soils in terrestrial soil organic carbon sequestration strategies.
    • Evaluation of Deicer Impacts on Pervious Concrete Specimens (Phase II)

      Haselbach, Liv; Temizel-Sekeryan, Sila; Ross, Molly; Almeida, Nara (Center for Environmentally Sustainable Transportation in Cold Climates, 2018-05-31)
      This research examined the chemical degradation of pervious concrete due to calcium chloride or magnesium chloride deicers. The project consisted of Phase I, Phase IIa, and Phase IIb. Phase I was previous work where a testing protocol was developed to mimic deicer applications. Phases IIa and IIb are parts of this project. Phase IIa used split tensile testing on Phase I specimens and further evaluated the chemical data from Phase I magnesium chloride applications. Phase IIb repeated the Phase I protocol for a larger number of new ordinary Portland cement specimens and evaluated the impact on strength using the unconfined compressive strength test. The hypotheses were based on complexation and precipitation chemistry. Specimens subjected to calcium chloride showed visible degradation. Specimens exposed to magnesium chloride deicer showed a large increase in loss of calcium ions in Phase I. Both deicers showed a loss in strength compared with a water control in Phase IIb. Results from the split tensile testing were inconclusive. The protocol from Phase I with the unconfined compression test may be an effective testing procedure to determine if different designs might be more resistant to chemical degradation by these two deicing chemicals.
    • Investigation of Alternative Deicers for Snow and Ice Control

      Fay, Laura; Akin, Michelle (Center for Environmentally Sustainable Transportation in Cold Climates, 2018-03-15)
      This technical report presents the findings of the laboratory analysis of potassium succinate (KSu) as a roadway deicer. Laboratory analysis included modified SHRP ice-melting testing, a differential scanning calorimetry (DSC) thermogram, and friction measurements to quantify performance. The overall results indicate that the performance of KSu is similar to that of NaCl at improving friction on roadways during snow and ice conditions. The results of DSC suggest that KSu can be applied as a roadway deicer at -5°C (23°F) and above. However, KSu does not function as a deicer at colder temperatures where salt brine will work (the generally agreed upon lowest working temperature for salt brine is 15°F [-9.5°C]). The results of the laboratory testing show that KSu functions as a roadway deicer with slightly lower ice-melting rates than salt brine. The ice-melting rates, DSC, and friction performance testing of KSu show that the product performs as a deicer at warmer temperatures than salt brine, with slightly less ice-melting capacity and similar friction performance. Based on these and previous results showing lack of corrosion in metals, equipment, and pavements from use of KSu and similar BOD of KSu to potassium acetates, KSu appears to be a viable option as a roadway deicer at temperatures at or above -5°C (23°F). Use of KSu as a roadway deicer may be focused in areas where there are concerns about impacts to infrastructure, equipment, or pavements, such as on bridges, elevated roadways, in parking garages, or on newer concrete pavements. Potential concerns with the use of KSu as a roadway deicer are its price, lack of full-scale manufacturing of KSu at this time, and the BOD exerted by the product. Additional testing to fully quantify the environmental impacts of KSu on soil, water, flora, and fauna is recommended. If water quality and BOD are of concern, application of this product is not recommended in large quantities and during times of low water flow.
    • Prediction of Thermal Behavior of Pervious Concrete Pavements in Winter

      Chen, Zhao; Nantasai, Benjamin; Nassiri, Somayeh; Haselbach, Liv (Center for Environmentally Sustainable Transportation in Cold Climates, 2017-05-15)
      Because application of pervious concrete pavement (PCPs) has extended to cold-climate regions of the United States, the safety and mobility of PCP installations during the winter season need to be maintained. Timely application of salt, anti-icing, and deicing agents for ice/snow control is most effective in providing sufficient surface friction when done at a suitable pavement surface temperature. The aim of this project was to determine the thermal properties of PCP during the winter season, and to develop a theoretical model to predict PCP surface temperature. The project included a laboratory and a field component. In the laboratory, thermal conductivity of pervious concrete was determined. A linear relationship was established between thermal conductivity and porosity for pervious concrete specimens. In the field, the pavement temperature in a PCP sidewalk installation at Washington State University was monitored via in-pavement instrumentation. Based on the field data, the Enhanced Integrated Climatic Model (EICM) was developed and validated for the site, using PCP thermal properties and local climatic data. The EICM-predicted PCP surface temperature during the winter season agreed well with the field temperature. Overall, the predicted number of days that the pavement surface fell below 32°F agreed well with the number based on field data for 85% of the days. Therefore, the developed model is useful in identifying those days to apply deicer agents. Finally, a regression model using climatic indices was developed for PCP surface temperature prediction in the absence of a more advanced temperature model.
    • Recent Advances in Sustainable Winter Road Operations – A Book Proposal

      Shi, Xianming (Center for Environmentally Sustainable Transportation in Cold Climates, 2017-08)
      Investing in winter transportation operations is essential and beneficial to the public and the economy. The U.S. economy cannot afford the cost of shutting down highways, airports, etc., during winter weather. In the northern U.S. and other cold-climate areas, winter maintenance operations are essential to ensure the safety, mobility, and productivity of transportation systems. Agencies are continually challenged to provide a high level of service and improve safety and mobility in a fiscally and environmentally responsible manner. To this end, it is desirable to use the most recent advances in the application of materials, practices, equipment, and other technologies. Such best practices are expected to improve the effectiveness and efficiency of winter operations, to optimize material usage, and to reduce associated annual spending, corrosion, and environmental impacts. Currently, no professional societies, scientific journals, or textbooks are dedicated solely to sustainable winter road operations, and key information is scattered across a variety of disciplines. The objective of the proposed book is to summarize the best practices and recent advances in sustainable winter road operations for the purposes of education and workforce development. This book is now in press and can be cited as follows: Shi, X., Fu, L. (2017). Sustainable Winter Road Operations (Eds.). ISBN: 978-1-119-18506-2. Wiley-Blackwell.