Throughout the U.S., contactors and inspectors must contend with less-than-favorable weather conditions for road construction and rehabilitation. If an asphalt mix cools too rapidly, the mix will become stiff, making it difficult to compact to proper density. A pavement that is not properly compacted will not hold up well to traffic loads.
Successful cold-weather asphalt paving thus hinges on knowing when to start and end pavement compaction.
A new customized software program, PaveCool, can help contractors, inspectors and engineers make quick, informed field decisions about when to startand when to finishcompacting the pavement. The user enters the time and date of paving, as well as information on the type of mix, the paving location and environmental conditions. The program then calculates the rate of cooling, which lets the user know how much time is available to properly compact the mix.
Armed with that information, the paving crew knows when to start and finish paving. If that paving window isnt big enough, the crew can take steps, such as increasing lift thickness or adding additional rollers, to mitigate the effects of the daily environment on pavement compaction.
The software features include a menu of performance-graded binders used in Superpave mixes.
According to Steve Scheuring of Glacier Paving, Cloquet, Minn., PaveCool is "great as a reference. It does the homework for you, while you continue to progress in the paving process."
PaveCool was developed at the University of Minnesota with assistance from the Minnesota Asphalt Paving Association and the Minnesota DOT. PaveCool is available in an updated 2.0 version.
The Federal Highway Administration assisted in the review process for PaveCool 2.0 and is helping to distribute the software to state highway agencies and paving contractors.
Jim Sorenson of the FHWA said, "PaveCool provides engineers with another tool to use when building high quality, durable pavements."
PaveCool 2.0, which runs on Windows 95/98/NT, is now available free from the Minnesota DOT website (www. mnroad.dot.state.mn.us/MNROAD_PROJECT/restools/restools.html), or can be purchased from the National Technical Information Services website (www.ntis.gov./fcpc/cpn8573.htm).
Seattle-based Pizer announced an update for its HYDRA 6 sewer modeling software. The new update provides additional analysis settings, including variable "n", storm delay and storm analysis for worst-case scenarios. It also provides a new hydraulic calculation engine with several significant improvements.
Additional reporting options in the new update include preformatted reports for analysis results data. The update also offers improved help file documentation, including a WinHelp 2000 Explorer View window that displays contents, index and search tabs alongside topics.
Keyword indexing also has been expanded. It includes an improved graphical user interface seamlessly integrated with a new 32-bit hydraulic analysis engine.
Asphalt recycling website
The company that pioneered single-machine, hot in-place asphalt recycling has introduced a website which illustrates how the asphalt recycling process works, and provides examples of recent asphalt recycling projects completed.
This information can be found at the new Cutler Repaving site (cutlerrepaving.com).
A sequence of photos and brief explanatory text illustrates each step in the Lawrence, Kan.-based companys hot in-place recycling process, from preheating, scarification and application of a recycling agent through the asphalt recycling process and laydown of the final wearing surface.
The website provides documented economic benefits of the single-machine asphalt recycling process and supplies concise answers to the questions most frequently asked about the companys hot in-place asphalt recycling process.