Asphalt Pavement Magazine - July/August 2012 - (Page 32)

C hicago’s Magnificent Mile, North Michigan Avenue from the Chicago River to Oak Street, is home to high-end shopping and historic buildings like the landmark Chicago Water Tower. Unfortunately, while impressive garden beds had been placed along the street in an earlier beautification effort, the condition of the roadway itself was less than magnificent. In 2011, the Chicago Department of Transportation (CDOT) began work on rectifying the situation. From late September to midNovember, workers patched curbs and sidewalks, removed old asphalt, and adjusted manholes and other utility structures. But the most magnificent part of the $1  million job was the new asphalt pavement that was placed. Traditionally, CDOT would use a densegraded Superpave mix with traditional binder for resurfacing projects, but budget and time limitations, as well as inconsistencies in the subbase, meant something different needed to be done. Working with engineering and materials testing firm S.T.A.T.E. Testing LLC, CDOT developed an alternative that suited the road and budget conditions. It also allowed CDOT to create a showcase environmentally friendly pavement that broke new ground by n e e r G combining recycled asphalt shingles (RAS), reclaimed asphalt pavement (RAP), and ground tire rubber (GTR) in a stone-matrix asphalt (SMA). SMA pavements are designed to stand up to heavy truck traffic and to resist rutting thanks to the hard aggregate and stiff binder. With about a dozen Chicago Transit Authority bus routes travelling through the 12-block project area, North Michigan Avenue looked like a good candidate for testing an innovative SMA. Work was conducted on an accelerated schedule. In fact, the project was originally not planned for the 2011 paving season and approvals were not granted until late August. Construction began on Sept. 28; milling was completed on Oct. 19; paving was finished on Oct. 22; and the project was substantially completed on Nov. 14 in time for the Magnificent Mile Lights Festival parade. The paving was handled by Arrow Road Construction, which placed the SMA in a single 2-inch lift. A trackless prime coat was used to help bind the new pavement to the sub-base. Much of the project work was done overnight, and there were significant work-hour and noise restrictions on the project. Although lanes were closed one or two at a time through the project, at no time was traffic completely halted on the street. AP See details of the mix design on page 34 32 • View past issues online at

Table of Contents for the Digital Edition of Asphalt Pavement Magazine - July/August 2012

President’s Perspective
Industry News
Warm Mix Fixes I-55
The Magnificent Green Mile
Caltrans Improves Preservation With Warm Mix
Power Washing Restores Porous Pavement
Tools of the Trade
Industry Events
Index of Advertisers/

Asphalt Pavement Magazine - July/August 2012