New Version of Cold Weather Paving Tool
Roads must often be paved under adverse conditions in Minnesota. This can mean poor compaction and early deterioration of an asphalt pavement.
A new paving tool may make paving in a variety of conditions more viable. The software, PaveCool Version 2.0, offers users insights into how adverse climate conditions will affect their ability to produce a durable, quality road surface. Users input the type of existing surface, type of asphalt mix, and weather conditions. The output shows a cooling curve with recommended compaction starting and stopping times. Field tests have confirmed the value of this program as an aid to cold weather paving.
The software was developed by researchers at the University of Minnesota led by Professors David Newcomb and Vaughan Voller of the Department of Civil Engineering, with support from Mn/DOT and the Minnesota Asphalt Pavement Association. Members of the Mn/DOT technical advisory panel were David Janisch, George Cochran, Jay Koski, Keith Englesby, and Roger Olson.
PaveCool 2.0 replaces earlier versions 1.6, 1.7, and 1.8. Improvements in 2.0 include corrections to the aggregate thermal properties, a plot that users can view from the input window, and the recommended start compaction time-temperature.
Versions 1.6, 1.7, and 1.8 were released in limited distribution with aggregate thermal properties that later proved invalid. Researchers corrected the thermal properties in Version 1.6 because they discovered the water content used to calculate the wet condition was unreasonably high.
New thermal conductivity values tested in Versions 1.7 and 1.8 were found to produce longer cooling times for pavements placed on wet or dry aggregates than those cooling times observed in the field. A reevaluation of typical moisture contents, densities, and equations for thermal conductivity and specific heat resulted in the release of Version 2.0. Researchers encourage replacement of previous versions with Version 2.0
PaveCool 2.0 is a Windows program that runs on laptops (Windows 95, 98, or NT required). To download your copy, visit the following Web site: mnroad.dot.state.mn.us/restools/cooltool.html.
For a TRAK fact sheet about the tool, call Mn/DOT's Office of Research Services, (http://www.dot.state.mn.us/inra.shtml) 612-282-2272.