U.S. Route 24 was a two-lane highway through northwest Ohio. It’s a major shipping route, with trucks representing one third of the total volume of traffic. Safety of residential travelers was becoming a concern with such high truck volumes, so the Ohio Department of Transportation (ODOT) developed a plan to expand U.S. 24 into a four-lane divided highway.
Work was placed underway on a 16-mile stretch between Napoleon and Toledo. Shelly & Sands Inc., based out of Zanesville, OH, was the contractor responsible for the concrete paving. A total of 245,000 cu. yds. of concrete was slated to be slipformed on the project.
Shelly & Sands used a variety of GOMACO equipment, including a PS-30 placer/spreader, a four-track GHP-2800 paver with IDBI and a T/C-600 texture/cure machine for the mainline paving. A four-track Commander III with an IDBI attachment was used to slipform the eight entrance/exit ramps.
“Basically, we have 16 miles of new four-lane divided highway,” says Paul Singleton, project superintendent for Shelly & Sands. “We slipped the roadway 24 ft. wide with the GHP-2800 with IDBI and placed a 12-ft. and a 4-ft. shoulder with our other GOMACOs.” The project was started in September 2010 and completed by January 1, 2012.
Staying Ahead of Spec Requirements
Although Shelly & Sands’ contract didn’t require completion until the end of 2012, mainline paving was finished a full year early, without any sacrifice to quality.
ODOT has rigid specifications for both bar placement accuracy and project smoothness. It uses the International Roughness Index (IRI) to measure pavement smoothness, requiring numbers between 60 to 70 for 100% pay. Anything under a 60 earns an incentive.
“This has been our first major project utilizing the IRI and it created some challenges and also had us reevaluate some of our methods,” notes Brian Little, concrete superintendent for Shelly & Sands.
Two of the changes implemented were the use of a placer/spreader in front of the paver and modification of the Auto-Float on the back. “We used to dump two trucks at a time in front of the paver, and we would go from a big head of concrete to sometimes hardly any at all,” Little explains.
The placer/spreader offered other advantages. “We also don’t start and stop the paver as much with the placer/spreader out front,” Little says. “It all helps achieve smoothness when you’re paving under the IRI specification.”
The project averaged numbers in the upper 50s and low 60s. “We even had numbers in some good-sized sections in the high 40s and mid-50s,” Little notes. “We’re pretty happy with that.”
A 2002 four-track GHP-2800 with IDBI was used to pave 24 ft. wide and 11.5 in. thick. The IDBI inserted 24 bars, on-the-go, every 15 ft. to form the new highway’s transverse joints. The 1.5-in.-diameter bars were 18 in. long and were placed on 12-in. centers across the width of the slab.
“ODOT was on site every day checking and verifying the placement and accuracy of our bars,” Little says. “Everything was right where it should be, and we [didn’t have] any problems at all with the placement of the dowel bars.”
A new T/C-600 texture/cure machine followed the paver, applying a longitudinal tine and white spray cure to the concrete. Paving production on the project averaged 2,800 cu. yds. during a 12-hour shift.
Ramping Up Production
The eight entrance/exit ramps on the project were slipformed 16 ft. wide and 11.5 in. thick using a 2010 four-track Commander III with independent IDBI attachment.
In the past, dowel baskets had to be placed on grade by hand during paving. “We do a lot of ramp work. Very rarely is there any room for a haul road, so we were always putting baskets down by hand as we paved,” Little comments. “This IDBI attachment just makes everything better. You don’t have to worry about getting your baskets placed right and the IDBI attachment is a lot quicker. It takes less people, material costs go way down with a straight dowel bar vs. a basket and we achieve higher production.