Two Caterpillar rollers were used for asphalt compaction on the Mooney Road project, allowing the project team to achieve 92% smoothness for an incentive bonus.
Twists and turns
Pavement Recycling Systems (PRS) out of Jurupa Valley in southern California was subcontracted to execute the CIR. The twisting mountain road provided a challenging course, with the width, cross slopes and shoulder conditions varying from one portion to the next. In general, though, PRS and Hat Creek were able to mill and pave at a width of 16 ft. The 102-ft-long recycling train was led by a 4-ft miller handling the outer edge when needed, followed closely by a 12.5-ft Caterpillar PR-1000 milling machine. Both pieces of equipment milled off 3 in. of the existing failing pavement.
Thanks to the forest around them, it was impossible to turn the train around at the end of a pass, which meant unhooking it at the end of each day and starting over. “We would go down one side and do 2 miles, then we’d back up and do 2 miles on the other side,” Hutchings said. “You had to plan your work, know your targets and know what you were going for because you’ve got to go park a 120-ft train everyday on a rural two-lane road without much of a shoulder.”
Following behind the milling machines was a Cedarapids CR551 rubber-tire paver, which picked up and replaced the recycled asphalt. Even with the added inconvenience of stopping and starting, Hutchings said the milling and paving was completely finished in just eight or nine days.
The mix design for the recycled pavement was 3% mixing water and 1.4% HFMS-2p emulsion content, which Hecox said was one of the key elements the design team discussed. The hot-mix asphalt (HMA) overlay consisted of Superpave with 20% recycled asphalt pavement (RAP), PG 64-28 binder and nominal size aggregate of ¾ in. Two layers of overlay were placed on top of the recycled asphalt.
Recycling and revitalizing the existing pavement also saved the project team from having to haul materials in and out of the jobsite—a perk considering the site’s remote, mountainous location. As it was, Hutchings said, “The oil was coming from 31⁄2 to 4 hours away,” meaning they tried to stockpile as much onsite as they could, and they were using as many as four loads a day. “You had to get your loads of oil timed so you didn’t run out of oil but you didn’t order too much either,” Hutchings explained.
Mother Nature kept everyone on their toes as well, with frequent thundershowers in the area that would force production to shut down until they passed. “That can really screw up your production for the next day and when you’re trying to unhook everything,” Hutchings admitted.
While fairly remote, Mooney Road generates enough traffic that the project team had to keep the connector open throughout the duration of construction. According to Hecox, they could have a maximum delay of just 15 minutes per day.