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Satellite System May Help Improve Future Road

Someday when you drive down a perfectly paved road, you may have a satellite to thank. The satellite is part of a Global Positioning System (GPS) researchers are using in a new way: as an aide to more consistent road paving and better economy on paving jobs. The system is being tested by the UW-Madison College of Engineering's Construction Engineering and Management Program with the help of paving contractors like Payne and Dolan Inc. of Waukesha, Wisconsin.

Every driver can appreciate the goal of better road paving, or as they call it in the business, asphalt laydown. Ever driven on a road that felt like you were traversing a washboard? That's the consequence of poor laydown, says Kurt Bechthold, a vice president at Payne and Dolan and a 1985 graduate of the college's Department of Civil and Environmental Engineering.

"For proper laydown, you need a continuous flow of material and equipment," Bechthold says. "If it's not done evenly, you get poor asphalt density and that's linked with lower longevity of product." It's a tricky business--the idea is to apply the right amount of asphalt and compact it to the appropriate density. The whole process has to occur within a set range of variables for rutting not to occur: If you under-compact, the road has a lower life expectancy. Compact too much and you waste energy, effort and resources.

GPS could add a new layer of confidence in optimizing the laydown process, says Civil and Environmental Engineering Associate Professor Jeffrey S. Russell, director of the Construction Engineering and Management Program. GPS links positionally where the paver and rollers (the compactors) are in the laydown process. "The relationship has to be just right--the correct distance between paver and roller," Russell says.

Asphalt paving train

The asphalt paving train during an actual paving test using a GPS system co-developed by the college and Payne and Dolan. The GPS antenna can be seen atop the roller at far left. (large image)

Before the GPS system could be rolled out for testing, Russell's team (which included graduate students Bob Schmitt, Jack Tserng, Bharath Krishnamurthy, Heejune Lee, and Winston Shr; and Civil and Environmental Engineering Professors Awad S. Hanna and Hussain U. Bahia) had to write the necessary software to take positional information from the paver and roller on the computer reference system. They spent months tweaking the software with engineers from Payne and Dolan and Trimble Navigation Ltd. of Elgin, Illinois (which loaned the project both equipment and technical assistance).

The system was then mounted on a paver and roller and given tests which simulated field conditions. A number of refinements resulted, including providing the GPS feedback via audio means, rather than visual, so the roller operator could keep his eyes firmly on the road. Then in October 1996, the system was successfully used on an actual paving project on County Trunk Road V in East Bristol, Wisconsin.

While better asphalt laydown is important, the GPS project is really a piece of a larger effort to get better, more immediate feedback to improve efficiency on construction projects, says Russell. "Very few productivity studies have been done in this industry, because there tends to be the assumption that 'we already are as productive as we can be.' Real-time productivity measurement will enable managers to look at the whole process and tell them how well they are doing."

While the GPS technology--at $100,000 per system--is currently too expensive for wide utilization, Russell is optimistic about its future use. "If the cost of the technology can go down, all trucks, rollers and pavers could be hooked into GPS, which would constantly pull off efficiency data. We can then convert it into a project management system, and I as a manager could get up-to-date information on equipment utilization as well as what level of productivity has been achieved.

"Right now, you don't find out how well you did till the job is done," Russell adds. "In many cases, the feedback loop as to how you are doing today doesn't happen in time to take corrective action. You may have lost the opportunity to make changes."

Involvement with this "blue sky" use of GPS is a logical outgrowth of Payne and Dolan's dedication to advancing new technology--a philosophy that merges well with its UW-Madison partnership. "This project looks at high technology we couldn't attempt to do ourselves," Bechthold says. "We wouldn't have the people to spend the time developing solutions like this. It's invaluable to have the university involved with it from a computer programming and materials standpoint."

The company's commitment to helping develop the asphalt portion of the civil and environmental engineering department benefits people as well as pavement, Bechthold adds, with students working on the research and taking jobs with the company. Payne and Dolan has hired four full-time students over the last five years, and a number of interns. The company has also hired several of the college's minority students as part of a special effort which ties academic performance goals to financial incentives and summer employment. "The value of the UW on its most practical basis is the quality of student that it turns out. Prior to our involvement, students didn't have much knowledge of our product or its production.

"The cooperative relationship and monetary support we provide to the university is in the long term what's best for the industry. We know at a gut level that we're going to help improve the quality of student coming out of the UW. When you think about it, the vast majority of students will probably stay within the state of Wisconsin for their careers--so our partnership affects the quality of our industry and the quality of life here in state."