Pavement Maintenance
The 7.4-mile project would divide the two-lane road into two sections. The north half of the project used CIR, while the southern half was pulverized and overlaid.
Wisconsin Job Compares Cold In-Place and Pulverize/Relay When the asphalt pavement along State Trunk Highway 49 in Wisconsin’s Green Lake County needed to be replaced, the job presented an ideal opportunity for a side-by-side, long-term performance comparison of two asphalt pavement recycling processes: cold inplace recycling (CIR) and pulverize and relay (PR). “WisDOT wanted to find out which pavement recycling treatment would give them the best pavement life for their investment,” Bryan Schaller said. He was the project construction leader on the STH-49 job for Alfred Benesch & Company, Chicago, Illinois, which acted as WisDOT’s onsite engineering personnel on the project. The 7.4-mile project would divide the two-lane road into two sections. The north half of the project used CIR, while the southern half was pulverized and overlaid.
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22 // November 2020
The average annual daily traffic on this section of STH-49 is 3,800, with roughly 17 percent truck traffic. “This was a good project to try this on, because traffic is largely consistent between the north and south halves of the project,” Schaller said. Another feature of the project that made it an ideal candidate for this research was that this segment of STH-49 had both higher hill areas and lower swamp areas on both of the test areas, which was important to account for the potential of capillary action in the CIR in the low-lying areas to be able to apply results to a wider variety of projects. Not least of all, the pavement had also reached the end of its service life and was in need of reconstruction, whether in the form of CIR or PR.
The research project on STH-49 would span 10 years, and began before any work on the pavement had started. WisDOT brought out its falling weight deflectometer (FWD) to measure the modulus of resiliency of the existing pavement along the length of the project. After the pavement had been rehabilitated, they took another measurement over the length of the project, and will continue to take these measurements once a year for the next 10 years to compare the results of the CIR and PR areas. The prime contractor, Northeast Asphalt, Greenville, Wisconsin, began its work in May 2019. However, the project manager for Northeast Asphalt on this job, Heather Sayler, met with the DOT and engineering staff ahead of time to recommend some changes to the plan. For example, the DOT originally wanted to do a varying width of CIR, specifically in turn lane and intersection areas.
