Bowes Construction Regrades, Rubblizes for a Smoother, Safer Ride
BY AsphaltPro Staff
Surrounded by the vast prairies, rolling plains and fertile farmlands that pepper eastern South Dakota is the intersection of highways 14 and 81, just a couple miles south of the community of Arlington.
Joe Gilsdorf, project estimator for Bowes Construction, Brookings, characterized Highway 14 as “your standard rural South Dakota highway,” accommodating both daily commuters to nearby Brookings and recreational visitors drawn to local lakes and hunting areas. “It’s also a heavy agricultural corridor, so there are a lot of trucks running with grain, cattle, etc.”
Highway 14 runs north-south out of Arlington before cutting east-west at Bangor Township, where Highway 81 meets 14 at a 45-degree angle in the middle of that 90-degree turn. “Highway 14 was a four-lane divided highway with a divided median, which didn’t leave the trucks with a whole lot of space,” Gilsdorf said. “If a truck had to sit in the median to make a left handed turn to head north to Arlington, they were kind of sitting in the eastbound lane a bit.”That’s why the South Dakota Department of Transportation decided to replace the divided median with a paved median, readjust the grade for a ¾-mile section of Highway 14 and realign Highway 81 leading into the curve. In addition to the realignment, the DOT decided it was time to rehabilitate roughly one mile of Highway 14 on each side of the realigned curve. “The existing roadway was starting to get rough,” Gilsdorf said. “There were areas where the state had patched the lanes several times over.”
The state opted for rubblization, which fractures the underlying concrete into small pieces (usually 2 to 6 inches) before applying an asphalt overlay. “Breaking up the concrete aims to reduce any reflective cracking that could come up through the asphalt,” Gilsdorf said. “By rubblizing the concrete, you’re basically turning it into gravel that can be rolled to lock together just like any other base material.” The process was selected for its cost-effectiveness as a result of recycling the existing road materials.
“I think the driver of this project was the realignment with 81, but [rubblization and paving an asphalt overlay] also provided a way to improve the condition of the road while we were at it,” Gilsdorf said.
Bowes produced the mix for this project from its batch plant near Brookings. The project required 39,556 tons of Q3R HMA.
From Bid to Built
Bowes Construction bid on the Highway 14 project in October 2022. “What caught our eye was that this was a multi-faceted project that used many of our different divisions from crushing and grading all the way up to asphalt,” Gilsdorf said. “That, and it was a pretty significant asphalt paving project.”
Bowes started work on the project in April 2023. It moved all traffic head-to-head onto Highway 14’s eastbound lanes and began milling the asphalt off the existing westbound lanes. “The plans called for 4 inches of milling, but there were some sections where the asphalt was 6 to 7 inches thick because of the amount of patching that had been done out there,” Gilsdorf said.
The company set up a stockpile site near the project for the asphalt millings for later use as base course on the realignment portion of the project. The remainder of the millings went back to Bowes’ batch plant in Brookings to be used for the asphalt overlay. “South Dakota DOT projects like this specify that the millings coming off the project have to be reused in the material you produce,” Gilsdorf said. “You can’t use RAP out of an existing stockpile that you may have already had; we have to use the RAP that comes off the job.”
After the asphalt had been milled on the westbound lanes, Bowes used a concrete breaker to break up the concrete along the ¾-mile curved section that was to be realigned, then removed the concrete before undercutting, regrading and compacting the curve. “Then, we brought in a crusher to crush the asphalt millings in our stockpiles and then we blended those into a base course on the newly graded section,” Gilsdorf said.
On each side of the newly realigned section, Bowes’ subcontractor, Antigo Construction, Antigo, Wisconsin, came in to rubblize the existing concrete. “Having never done rubblization before, I really leaned on the expertise of Antigo,” Gilsdorf said.
Rubblization #1
“One aspect that made this project unique for us was that it was the first rubblization project our company has ever done,” Gilsdorf said. Although this made the project exciting, it also presented a bit of a learning curve. “We weren’t exactly sure how the paving was going to go.”
“We were concerned that concrete chunks might cut through that lower lift,” Gilsdorf said. The original specs on the project called for 1 ½ inch lower lift and a 2 ½ inch upper lift. “We worked with the state to change the cross section to two 2-inch lifts, because we thought a 2-inch lower lift would create less opportunity to pick up a chunk of that concrete and drag it under the screed.”
The project also specified rolling the rubblized material with a large steel-drum roller before paving. Bowes opted to do this twice, the second time immediately prior to paving to compact any material that might have been loosened up by the belly dump trucks delivering material for the pickup machine.
Even with these changes, “we had to be prepared to pick up the screed in order to meet our efficiencies if we had issues with drag,” Gilsdorf said. “Thankfully, we didn’t have any issues with that so the change proved successful.”
To ensure densities were achieved, Bowes Construction—with the help of Forester Testing—utilized a nuclear density gauge to immediately test density behind the rollers.
“That way, we had real-time insight on where we were at and could change our processes if needed,” Gilsdorf said. “Ultimately, we never had any issues reaching our densities, but we were certainly prepared to adjust rolling patterns as needed.”
Ultimately, Gilsdorf said the company went into its first rubblization project as prepared as possible and ready to make adjustments as needed. “With a lot of preemptive planning, looking at the processes and thinking through potential causes and effects, we had solutions for what we thought our challenges might be before we even got started,” he added.
Another challenge the crew faced was tying together the asphalt overlays for the regraded section and rubblized section. Bowes Construction had to be very strategic with each lane pull, as the regraded portion called for an initial 5-inch lift, and the rubblized needed an initial 2-inch lift. This required different pull sequencing so the final 2-inch lift could be paved in continuity. “It really came down to sequencing each lift with the paver,” Gilsdorf said.
Once all paving was complete on the westbound lanes in August 2023, Bowes had to repeat the entire process on the eastbound lanes—with the additional challenge of allowing traffic from Highway 81 to cross the eastbound lanes to the completed westbound lanes that were now carrying dual direction traffic.
“We couldn’t shut down that 81 intersection because we were working on this project in the middle of harvest season and that’s a very busy intersection for that agricultural traffic,” Gilsdorf said. The solution was to ready the new tie-in then build an efficient diversion to move traffic off of Highway 81 to the westbound lanes of Highway 14—and plenty of flagging.
“Thankfully, because we had already done the westbound, the eastbound ran a bit smoother because we’d just done the same thing on the westbound,” Gilsdorf said. “Even though we had that traffic to deal with, we were able to make it work.”
Get Results
The company was also concerned with achieving rideability on the project, given that it wasn’t able to use the automatics on its Cat 1055 paver for the first lift on the rubblization section. “The rubblized concrete won’t necessarily be uniform in elevation,” Gilsdorf said. “It’s not like the graded sections where you come through with your grading equipment and it’s all uniform. You have variances throughout the entire rubblized section that make it more of a challenge.”
Given the realities of that first lift on rubblized concrete, Gilsdorf said the first lift of asphalt “gets you coverage and density and provides a good base for the second lift.” However, the South Dakota ride spec is based on the number of attempts the contractor has to achieve the ride spec.
“When you have two lifts, the DOT considers that a two-pass opportunity and with three lifts, that’s considered a three-pass opportunity,” Gilsdorf said. “The first lift on this project really only covered the rubblized concrete, which meant we only had one opportunity to meet the ride spec using our automatics on the paver during the second lift, but we were held to a two-pass opportunity on the job spec.”
However, Bowes’ crew was able to achieve an average IRI of 45.0 on the project. “We met all the state ride specs and achieved a ride incentive bonus,” Gilsdorf said. In addition to meeting or exceeding the DOT’s specs, those driving the road seem to be pleased.
Since Bowes completed the project Oct. 27, 2023, “we’ve heard from some local farmers and truck drivers who have said how much better the intersection is now,” Gilsdorf said. “By widening that [curve] with the paved median, it’s easier to make that left handed turn north on 14. Those changes have made it a much safer intersection for the traveling public.”