Gallagher Asphalt: The Wizards of Wide
BY Tom Kuennen
Gallagher Asphalt eliminates long joints on Illinois S.R. 50
The problem of deteriorating longitudinal cold joints between parallel one-lane lifts of asphalt has long perplexed pavement owners. These joints between paved lanes can degrade and permit water to enter the pavement, which leads to debonding, delamination, long joint patches, or potholes.
There have been many fixes offered, including wedge joint designs and paver-mounted devices that are supposed to knit the edges of the lifts together.
Paving in echelon using two pavers close together—placing the lifts of hot-mix asphalt (HMA) next to each other so they are thermally bonded—is one solution. But the best solution is no longitudinal joint at all, as demonstrated August 2017 on Illinois State Route 50 near Monee, just south of the Chicago metro area.
There, Gallagher Asphalt Corp., Thornton, Illinois, placed a Superpave HMA friction course two lanes wide using a new Vögele Super 2000-3i and VF 600 screed with 25.5-foot kit. The result is an attractive mat that will resist moisture infiltration and deterioration for years to come.
Placing two lanes with one paver at the same time also is more productive for a contractor.
“Paving wide eliminates the lane joint and provides a smoother ride,” Gallagher Asphalt’s operations engineer, Don Gallagher, said. “It also allows us to complete the job faster as we make one pass instead of two.”
“To both the contractor and government agency, wide paving enhances pavement durability by eliminating the longitudinal joint,” Laikram “Nars” Narsingh said. He’s the manager, commercial support and development, for Vögele, Antioch, Tennessee. “That joint usually is the first place for failure in a pavement. Every time you can eliminate a joint, you eliminate the first point of failure.”
In addition to providing a more durable pavement, wide paving makes a job site safer. “From a safety standpoint, when you eliminate the longitudinal joint, you avoid the need for safety edges or Michigan wedge joints for motorists,” Narsingh said. “If the joint is not taken care of that same day, and if the lanes are open to traffic, traffic will attempt to climb that open joint, which is unsafe and also can degrade the edge.”
Finally, by paving two lanes at the same time, you reduce construction time, with the opportunity to reduce the impact to the motoring public as well.
Paving wide is not an option for all projects, Narsingh said. “Because of the need to maintain traffic, it has to have somewhere to go. It’s not too often you can close two lanes while diverting all traffic. But when you can, it always makes sense.”
“Wide paving is the kind of thing our company always is looking to do, and that is something out of the ordinary, that takes us to the next level,” Gallagher’s project superintendent, Terry Sullivan, said. “We are putting down the best quality product we can, both in material and laydown. Wide paving is important for longevity, and rideability as well.”
Patch, Then Mill
The entire project was eight miles long by four lanes, and began with extensive patching of the pavement, much of it full-depth into a crumbling underlying concrete pavement which was reflecting through asphalt overlays.
“We had a significant amount of patching that needed to be done,” Gallagher’s vice president of operations, Jim Trost, said. “There was concrete under some sections, asphalt under others. We had to go down full-depth to repair the sections, and patched them with an IL 19.0 mm N70 (70 gyration) Superpave mix.”
These included extensive failed concrete expansion joints which had to be cut with saws. Because of the substantial amount of patching required—at 15 inches deep—approximately 16,000 tons of PG58-28 N70 Superpave mix was required.
Echelon milling followed the patching work, in which Gallagher’s 7-foot, 3-inch wide W 210i and new, 8-foot, 2-inch wide W 220 removed 2.25 inches average from the pavement. The W 220 was purchased with a 7-foot, 3-inch drum, but because it incorporated Wirtgen’s Flexible Cutter System, Gallagher widened the drum to 8 feet, 2 inches for this project.
“Both machines working in echelon took out a full lane and a half with each pass,” Trost said. “We ran our Level Pro systems on both machines to ensure consistency and as smooth a pavement as possible as a base for the new pavement layers. We used long skis for the Level Pro system on the mills, and later, separate long skis for the Niveltronic Plus leveling system for our Super 2000-3i paver. We utilized a material transfer device, and even paved long days to eliminate the number of transverse joints in the pavement. We did all this to deliver a top quality finished product that would be as smooth as possible.”
Following milling, because the drop-off between lanes was too high to be left for drivers to negotiate safely, Gallagher followed with the paver placing the required IL 4.75 mm N50 (50 gyration) PG70-28 polymer-modified leveling course.
“Illinois allows no more than 1.5 inches of drop-off in the pavement for motorist safety,” Trost said. “Because we cut 2.25 inches of pavement, we chose to pave the 0.75-inch leveling course right behind the milling operation.” About 9,500 tons of leveling course was placed on the project.
Following the patching and leveling course, Gallagher set up its Super 2000-3i to pave 21 feet, 6 inches wide, 1.5-inches compacted lift thickness, placing two lanes of surface course with each pass of the paving operation.
Initial set-up advice and support for wide paving was provided by Vögele’s regional product support manager James Boucher and Narsingh.
It’s not unheard of in North America, but paving two or more lanes wide is not common here. One reason is the reluctance of government agencies to try new processes, and with good reason: they are stewards of the public’s resources, and if a new process is tried and fails, the money is wasted. It makes sense to stick with the tried-and-true basics. Therefore, the success of the test strip was vital to the project.
“The test strip was exciting,” Don Gallagher said. “We had a lot of executives who came out, and everybody was impressed by the job and the quality of the test strip. I believe IDOT was very happy with the test strip and because of that they allowed us to continue with wide paving for the entire project.”
The surface material was another Superpave mix, an IL 9.5 mm N70 (70 gyration) PG58-28 design. Approximately 19,000 tons of surface mix was placed, manufactured by Gallagher’s plant.
The project fell under Illinois DOT’s Pay for Performance (PFP) quality management program (QMP), in which bonuses or penalties are imposed according to two plant mix qualities of air voids in the HMA mixture, and voids in the mineral aggregate (VMA).
“We are getting paid based on test results from the mix, and each of these properties accounts for 30 percent of the overall pay factor,” Trost said. “In-place density is the final pay factor and accounts for 40 percent of our overall pay factor. It’s important to us to have good control over the mix, and making it in our own plant helps us achieve this.” Ride quality is evaluated outside the PFP program.
For the first day of wide paving, using a material transfer vehicle, Gallagher Asphalt was able to place some 4,400 tons of HMA, and the second day placed about 4,800 tons, Don Gallagher said in mid-August.
“We paved the four-lane S.R. 50 highway two lanes at a time,” Trost said. “Our schedule was to get all the paving done in four days, so after test strip approval, we did four miles a day for two days southbound. Then, the following week we turned around and did four miles a day for two days northbound.”
Density target for the wide lift was 93 percent, but Gallagher was routinely hitting 94 percent, Sullivan said. The VF 600 screed was providing initial compaction.
Paver operator James Benson said the screed was vibrating at 65 percent of capacity, and he was paving at 32 feet per minute. “It’s slower than we usually would pave, but we want slow and steady,” Benson said. “The object of the material transfer vehicle is to not stop paving, because every time the paver stops, we get a small bump.”
The longevity of the friction course was enhanced by use of a thorough bond or tack coat, placed full width, instead of the minimal spritzes sometimes seen in paving jobs.
“The tack coat is very important,” Gallagher said. “If you don’t get a proper tack coat down, you won’t get the proper bonding between the two layers, which will cause problems in the future.”
The asphalt emulsion tack coat used an SS-1H emulsion, at 70 percent emulsion, and 30 percent dilution, and was placed the complete width of the lanes, per IDOT specifications.
Breakdown rolling for the wide paving was done by four tandem vibratory compactors, behind the screed side-by-side in seven-pass echelon. Included was a Hamm HD+ 120i VV HF.
“We have four vibratory rollers up front, running side-by-side, each making about seven passes,” Gallagher said. “They’re followed by two finish rollers to get out lines in the pavement. Final smoothness is the result of consistent material supply, the paver with wide screed moving at a consistent paving speed, the MTV eliminating mix segregation, truck bumping and stops in paving, and careful and consistent compaction.”
Having that many rollers doing breakdown is important because the Superpave wide lift must be compacted before it loses heat.
Temperatures of mix coming out behind the screed varied from 290 to 310 degrees F. On this job, a thermal sensor system that sits on the paver and measures the mat temperature out of the screed was used. “I think it’s very important going forward to know you are consistently laying down a nice temperature mat that will roll nicely, as temperature plays a big role in how well the pavement will be compacted,” Gallagher said.
“We also were running intelligent compaction on the rollers, logging temperature, roller speed and pass counts,” he added. “Being able to pull the reports, and see that we are consistently rolling the same number of passes, lets us monitor the compaction process, and diagnose problems if something comes up. They can show our consistency in compaction, which will point to something else having gone wrong if there is an issue.”
Because Gallagher was using a variety of roller makes, it was using an aftermarket IC system retrofitted on the four breakdown rollers.
Over the years, Gallagher Asphalt has relied on Wirtgen Group equipment to stay productive and profitable.
In addition to the W 210i and new W 220, Gallagher has a 4-foot W 120 F cold mill. “We use them for leveling, grinding out shoulders and main line milling,” Gallagher said. “Having these three units allows us to handle about any type of milling work we need at our own schedule and not have to rely on subcontractors.”
Gallagher also has a variety of Hamm rollers, ranging from 48-inch to 66-inch drums. It has a number of the Hamm CompactLine small machines. And it uses Hamm HD 110 VT-S and HD 70 VT-S combination smooth drum/rubber-tired rollers in their hot in-place recycling operations as well as conventional HMA paving.
While the Super 2000-3i, acquired in early 2017, has replaced its 10-foot Vision 5200-2i paver, the firm retains its 8-foot Vision 5103-2i wheeled paver. “Our new Super paver is great, and this project is a testament to how well the machine was developed and designed,” Gallagher said. “The rideability of the pavement that it’s provided is outstanding.”