• A Bio-Wicking System to Prevent Frost Heave in Alaskan Pavements: Phase II Implementation

      Galinmoghadan, Javad; Zhang, Xiong; Lin, Chang (2019-11)
      Water within pavement layers is the major cause of pavement deterioration. High water content results in significant reduction in soil’s resilient behavior and an increase in permanent deformation. Especially in cold regions, frost heave and thaw weakening cause extensive damage to roads and airfields. Conventional drainage systems can only drain gravity water not capillary water. Both preliminary lab and field tests have proven the drainage efficiency of a newly developed H2Ri geotextile with wicking fabrics. In this report, continuous research was conducted to verify the effectiveness of the wicking fabric in mitigating frost boil issues in Alaskan pavemnets. Two test sections were selected at two low volume roads on the campus of the University of Alaska Fairbanks. Soil moisture and temperature sensors were installed within the road embankments. The monitored data was used to analyze the soil migrations and evaluate the drainage performance of the wicking fabric. Preliminary monitoring results showed that the wicking fabric was effective in mitigating the frost boil problem.
    • 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.
    • Stormwater-Pavement Interface in Cold Climates

      Haselbach, Liv; Nassiri, Somayeh (Center for Environmentally Sustainable Transportation in Cold Climates, 2017-05-27)
      This project relates to “managing stormwater runoff in cold climates” and addresses the feasibility of low-impact development at a regional demonstration site in eastern Washington. The studies relate to seven large permeable pavement systems. The findings for similar climates and soils are as follows:  The draindown times for retention in Palouse or similar clay soils may handle many typical storms.  On average, every square foot of a permeable pavement system installed also receives run-on from another square foot of impermeable pavement, doubling its impact on both stormwater quantity reduction and stormwater quality improvement.  Most of the clogged sections on various applications were downslope of other areas.  Permeable pavements installed in areas targeted for additional stormwater quantity control and quality improvement may be feasible.  On average, the cleaning for installations is less frequent than annually. Power washing plus vacuuming appears to be an effective method for pervious concrete.  Surface distress was usually where vehicles turned, or from placement activities.  Preliminary studies on various surface treatments on pervious concrete show promise for added safety benefits under wintry conditions.  Both detention-type and retention-type permeable pavement systems appear to have little negative impact on neighboring soils in the winter under the study conditions. However, further research is needed for different designs of retention-type systems to ensure that water volumes in the aggregate storage bed do not allow for sufficient water flow into neighboring soils that might result in ice lens formation or other negative impacts.