Winter performance assessment of permeable pavements: A comparative study of porous asphalt, pervious concrete, and conventional asphalt in a northern climate

This study presents the findings from two active parking lots constructed of permeable pavements: porous asphalt and pervious concrete. Focus is given to the performance of these pavements in a cold-climate setting. Winter places great demands on pavements so it is of particular interest to evaluate how they compare to conventional designs. Analyses include measurements of frost penetration, surface infiltration rates, snow and ice cover, skid resistance, chloride retention, and effective salt loads. Infiltration rates were retained in winter conditions and with frost depths as high as 27-inches. A 75% average reduction in annual salt use was observed for porous asphalt based on low amounts of snow and ice cover and high skid resistance. \u27Black-ice\u27 did not form on pervious concrete, eliminating the need for salt during thawing-refreezing conditions. Pavement color and shading were found to be major factors influencing the amount and duration of snow/ice cover. A comparison of project costs is discussed

Water Quality and Hydrologic Performance of a Porous Asphalt Pavement as a Stormwater Treatment Strategy in a Cold Climate

This study examined the functionality of a porous pavement storm-water management system in coastal New Hampshire where 6 months of subfreezing temperatures typically occur. The usage of porous pavements for storm-water management in northern climates has many challenges, most of which relate to the extreme cold and significant frost penetration into the porous media. The porous pavement system was monitored for hydraulic and water-quality performance from 2004 to 2008. The use of porous pavements for parking lots for new and redevelopment projects are one watershed-based strategy that can both mitigate impacts for new development and reverse impacts in areas with redevelopment. Surface infiltration capacity and frost penetration were measured monthly to assess winter performance. Because of the well-drained nature of the porous pavement and reservoir base, issues related to frozen media were minimized. Significant frost penetration was observed up to depths of 71 cm without declines in hydrologic performance or observable frost heave. No consistent statistical difference was observed for seasonal hydrologic performance with mean infiltration capacity ranging from 1,490 to 2,690  cm/h. Adverse freeze-thaw effects, such as heaving, were not observed, and for that reason, the life span is expected to exceed that of typical pavement applications in northern climates. Observed hydrologic response resembled shallow depth groundwater drainage, as is the goal for low-impact development designs. Peak flows were reduced by 90% to 0.58  m3/s/km2±0.74 in comparison with standard impervious cover=5.5  m3/s/km2±7.7. There was exceptional water-quality treatment performance for petroleum hydrocarbons, zinc, and total suspended solids with nearly every value below detection limits. Only moderate removal was observed for phosphorous, and treatment for nitrate (NO3) was negative

Bicycle theft prevention in Denmark.

This project, completed in Copenhagen, Denmark, for the Danish Cyclists Federation, describes the current situation of bicycle theft and security in Denmark and suggests possible solutions to alleviate this problem. Using extensive background research, interviews, focus groups and field observations, the team determined that a system using radio frequency identification tags and scanning technology would greatly improve on the current frame number system and more easily identify bicycles. Guidelines and important contacts crucial to implementing such a system are included