Mountain States Constructors Inc. is used to working in the mountains, making roads out of nothing. In the summer of 2015, looking up at concrete and steel, the New Mexico-based contractor was right in its element.
Work on a section of I-40, which consisted of 35 lane-miles and 10 ramps (some high off the ground), at the Coors Interchange was indeed covered in a different backdrop, but it was still a comfort zone for Mountain States Constructors. Maintaining a hard push while producing a quality product would put any road builder in the right frame of mind.
The Coors Interchange at I-40 in Albuquerque, N.M., is one of the most active in the region, and handles a heavy load of truck traffic (over 40%). Cracks and potholes also were fighting for space on the pavement, and emergency maintenance was no longer putting it back in working order. The section needed a new life, fast.
“It’s one of the busiest sections,” Henry Smith, operations manager for Mountain States Constructors Inc., told Roads & Bridges, “so the only way to do it was to conduct maintenance on it at night and just patch and patch and patch. They were having a lot of trouble with it.”
One of the busiest sections needed one of the tightest schedules, so the New Mexico Department of Transportation (NMDOT) bid the project—a complete rebuild—to be complete in 150 days. Mountain States Constructors banged it out in 85, beating an internal goal by 15 days while collecting $1 million in incentives for finishing the $8.3 million job in less then 100. The National Asphalt Pavement Association awarded Mountain State Constructors Inc. with a 2015 Larry H. Lemon paving award.
“This is just the way we do it,” said Smith. “It’s our M.O. We build to get finished, so we figured we could beat the 100 days from the very beginning.”
Then the rains came
Subgrade failure was prominent on this section of I-40, which carries six lanes of traffic, signaling the need for a complete reconstruction. Work started on the westbound side and all traffic was moved to the eastbound portion.
The skies also opened up, and opened up often, during the initial weeks of construction in May 2015, darkening an already intimidating schedule. Mountain States Constructors worked around the clock to stay on target in the early going.
“We had some major weather trouble there for a while where it was raining so much we were getting standing water on the project,” said Smith. “It was saturating the subgrade even more than what it already was, and motor graders were used. Everything was pulled up and windrowed to the side to get it dry. It was very stressful for a while. The rain just would not quit.”
Mountain States Constructors had to mill off all 12 in. of existing pavement, and when that work was complete discovered some sections were in need of new subgrade material. A Wirtgen 2200 chewed up pavement on the mainline sections, tearing up 12 in. in two passes. A Caterpillar PM201 milling machine was used on the ramps and wherever more precision was needed.
Once the existing pavement was removed, and 406 linear ft of new storm-water pipes were installed, Mountain States Constructors was ready to pave. A total of four lifts were necessary—three at 3.5 in. thick and a 5⁄8-in.-thick open-graded friction course that served as a surface layer. A Superpave SP3 warm-mix asphalt blend was used, which contained 15% RAP and a PG 70-22 asphalt binder, for the first three lifts. The open-graded friction course came with a PG 70-28+ binder. The project averaged 3.7% air voids. Mountain States Constructors has been using as much as 35% RAP in its mixes, but the New Mexico DOT District 3 office was seeing some inconsistencies in pavement which contained a higher percentage of RAP and thus made the decision to pull back.
The I-40 mix contained 7⁄8- and 3⁄8-in. aggregate along with sands and versa fines, which served as a mineral filler.
Producing the asphalt was a CMI 400 counterflow plant located at 9 Mile Hill about 6 miles from the jobsite. Smith said on average the plant was producing 330 tons of asphalt per hour. Mountain States Constructors was pulling three samples a day at the plant and testing for volumetrics and gradation. The mix was about 280°F when it was dropped into belly dump trucks, and Smith said that temperature was maintained when the mix was placed on the road and picked up by a Roadtec 2500 Shuttle Buggy.
A Caterpillar 1055D asphalt paver equipped with Topcon non-contact sonic sensors on skis created all four 12-ft-wide mats (as well as a 10-ft-wide outside shoulder and a 4- to 8-ft-wide inside shoulder) and the machine was followed by three Caterpillar CB64 steel double-drum rollers. Mountain States Constructors has a standard rolling pattern for all jobs. The breakdown roller and intermediate rollers make two complete passes in the vibratory mode, and the finish roller, operating in static mode, makes one complete pass. Longitudinal joints were tapered to prevent any separation. The target density for the job was 94.5% and Mountain States Constructors was hitting 94%. An operator was on-site full time to track the density with a Troxler nuclear gauge. According to Smith, he was constantly gathering readings behind the rollers. The contractor also pulled one core every 1,000 tons, while the New Mexico DOT cored every 2,000 tons. The job required just over 42,700 tons of asphalt. Mountain States Constructors used a California profilograph to check for smoothness and averaged 37 in. per mile.
Once work was complete on the westbound portion, traffic was shifted off the eastbound section and the same process was repeated. Highway Supply handled the traffic shifts, and perhaps the biggest challenge was moving the trucks carrying asphalt in and out of the work zone. Special truck exit and entrance ramps were created using traffic barrels.
“It was a lot of traffic to move over,” said Smith. “Trucks had to figure out where they were coming in and out way before they got to the project.
“Traffic for the most part ran smoother under the detour than it did when traffic was open. People were setting themselves up to deal with the ramps earlier than they normally did. Normally people try to beat traffic to get to the ramps, but because they were moving over earlier before they hit the work zone, there really were not any delays.
“This was one of the most intense schedules that we have dealt with, but we had great people on it,” Smith added. R&B
Norris Asphalt claims top asphalt paving award
The National Asphalt Pavement Association (NAPA) announced that Norris Asphalt Paving Co. of Ottumwa, Iowa, was the winner of the 2015 Sheldon G. Hayes Award for excellence in construction of an asphalt pavement. The award, bestowed annually since 1971, recognizes the country’s highest quality highway pavements. Norris Asphalt Paving Co. and the Iowa Department of Transportation received their award at a ceremony during the association’s 61st Annual Meeting in La Quinta, Calif., in February.
The award was earned for Norris Asphalt’s work on U.S. 34 in Montgomery and Adams counties in Iowa. The 15-mile project dealt with variable widths, numerous turning and climbing lanes, and long material hauls. The project also called for the road to be widened and included an almost 2-mile section of roadway that went from two lanes to four lanes and then back down to two lanes. In addition, another Iowa highway, U.S. 71, intersected the middle of the four-lane portion of the project.
“I don’t think there was a flat spot on this project,” said Brady Meldrem, president of Norris Asphalt. “I think there were passing lanes going up every hill.”
The U.S. 34 project used more than 79,000 tons of asphalt. To start, ½ in. to 1 in. of the road surface was milled off the east side of the roadway, said Bob Mobley, Norris Asphalt’s Paving Superintendent.
“It was widened 4 ft on each side, even in the four-lane section,” Mobley said. “What was difficult in the four-lane section was going from two lanes to four lanes in such a short area.”
The four-lane section was 1.8 miles long, and sitting in the middle of this section was U.S. 71 and it’s accompanying interchange and ramps. “When you talk about the varying widths, that’s extremely difficult to do,” said Meldrem. “It’s not just put the paver down and measure. The lanes go from side to side, and Bob Mobley and the whole team did a great job of getting it all laid down.”
The road’s owner, the Iowa Department of Transportation, said the company’s experienced personnel were a valuable asset to this project and its ability to juggle the many variables.
“The U.S. 34 project was fairly complex in the fact that it contained nine climbing lanes, five bridges to transition into, two major intersections with turn lanes and variable widths, as well as transitions into and out of a 2-mile-long, four-lane section with a major interchange,” said Scott Nixon, Iowa DOT’s resident construction engineer.
Dan Roberts, Norris Asphalt’s project manager, said that reclaimed asphalt pavement (RAP) was used in all three of the project’s mixes. “The RAP came from the project as we milled a little over 13 miles,” said Roberts. “The base mix used 21% RAP, the intermediate mix used 20% RAP, and the surfaced mix used 17% RAP.” Putting asphalt pavement material removed from old pavements back into new pavement mixes is a common practice, but the U.S. 34 project was notable for the amount of recycled content in each layer of the pavement structure.
Ray Brown, National Center for Asphalt Technology (NCAT) emeritus director and the independent consultant who inspected each project site, said the pavement performed well in every single category to win the top award.
Norris Asphalt also was named a 2015 Hayes Finalist for work done on S.R. 92 in Adair County, Iowa. The other two finalists were Kelly Paving Inc. for work on I-70 in Wheeling and Tridelphia, W.Va., and Manatt’s Inc. for S.R. 1 in Johnson, Linn and Jones counties, Iowa.