• 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.
    • 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.