Hi-Way Paving Inc., based in Hilliard, OH, put its first new generation Commander III with high-drive tracks to work on two projects in PA last summer. Its projects included the rehabilitation of Route 30 near Lancaster and work on the 181 and 83 Interchange in Harrisburg.
The Route 30 project involves the reconstruction of approximately 5 mi. (8 km) of four-lane interstate. Hi-Way Paving is responsible for all of the concrete work on the project. It’s all phase work and includes the construction of new interchanges and ramps.
Hi-Way Paving is utilizing both the Commander III and its new generation Commander III to complete the work on both projects.
“Our longest pour on this job was only 2,000 ft.,” Kevin Stephen, Hi-Way Paving’s superintendent, said. “We’d move the paver and pour two, three, four different places every day during the summer hours.”
The project cannot be completed in the typical fashion because of the project’s sequencing. Most of the time, the ramps are completed before the mainline.
“It’s just like a big puzzle,” Stephen said. “We complete a phase, it’s opened back up to traffic and then the next section is torn out.”
The interchange in Harrisburg has its challenges, also. It’s a four-year project to rebuild approximately 9 mi. (14.48 km) of six-lane highway. Tight clearances created an extra challenge that had to be dealt with.
The projects are further complicated because the paving requires three different widths. The paving passes range from 12 ft. (3.66 m) wide for a single lane or shoulder, 16 ft. (4.88 m) to include a 12 ft. (3.66 m) lane with a 4-ft. (1.22) shoulder, or a 10-ft. (3.05 m) wide shoulder.
The different widths are simplified with the presence of two pavers. Each is set to a different width with the occasional change.
“We try to keep each paver set up for a different width, but we’ve had times when we’ve needed them both so we’ll take a 2-ft. section out or put a 4-ft. section in,” Stephen said. “It’s no big deal for our mechanic to switch from 10 to 12 ft., or vice versa.”
The thickness of the concrete also differs. In Harrisburg, both the mainline paving and ramps are 15 in. (38.1 cm). The mainline is 13 in. (33 cm) with the ramps varying between 9 and 10 in. (22.8 and 25.4 cm) thick in Lancaster.
Both the Commander IIIs are equipped with sidemounted bar inserters to shoot bars into the side of the new slab. The new generation Commander III also is equipped with a front-mounted bar inserter when Hi-Way Paving is slipping the 12-ft. (3.66 m) with 4-ft. (1.22 m) shoulder.
“It’s kind of weird looking because the inserter is offset on the 4-ft. shoulder side, but it works real good.” Stephen said. “It puts the bar right where we need it to be and it saves us a lot of time.”
It saves time, too, being able to slipform the shoulder with the lane.
“We run our machine off the stringline and control the 4-ft. shoulder with the inverted crowning device,” Stephen said. “We can change the outer edge slope from four to two percent or bring it up to pave at grade.”
Workers then go back and saw a 4-ft. joint in later.
A female keyway is slipformed into the side of the slab. The Pennsylvania Department of Transportation requires keyway when another lane will be added.
Sidemounted bar inserters shoot L-bars into the side of the slab every 30 in. (76.2 cm).
“I like the keyway because it gives a place for the L-bars to lay,” Stephen said. “I’d rather use straight bars instead of the bent ones, but there isn’t enough room for them.”
Hi-Way Paving had to deal with some very tight clearances on these projects.
“The tightest offset we’re capable of with regular tracks is 32 in.,” Stephen said. “That’s about 4 in. too tight. We prefer
48 in. minimum, because it gives the guy putting the bars in some room to move.”
Clearances were as tight as 24 to 19 in. (60.9 to 48.2 cm) at one point on the project, too tight for standard tracks. Special high-drive tracks are being used on the left side of the new generation Commander III. The high-drive tracks are approximately 18 in. (45.7 cm) wide and allow Hi-Way Paving to clear the portable barrier wall with just 1 in. (2.5 cm) to spare.
Stringline also had to be set carefully to deal with the tight clearances. The stringline wands were cut down to a shorter size and mounted to the portable wall.
A 50188 concrete mix design with 501 cement and 88 fly ash content is used to pave the projects. The fly ash adds strength to the mix design but also requires a longer cure time. Slump averages 1.25 in. (3.1 cm).
Joints are cut in at a 20-ft. (6.1 m) maximum with a 10-ft. (3.05 m) minimum spacing. Stephen prefers to let the pavers do the finishing work, but it’s a theory he has trouble selling the state inspectors on.
“We have a hard time convincing the inspectors, because they think we really need to work that edge. It just makes it worse,” Stephen said. “You can’t rub the edge from end to end and then try to come back and match it with the next lane. We’re finally convincing them to leave that edge alone and we’re coming back in again, tying on the next lane, and we’re getting a neater job.
“We just check the slab with a straight edge, run a mop over it to seal off any holes and check the edges for edge slump.”
Production is dependent on the amount of concrete Hi-Way must place for the day. A typical average is approximately 600 cu. yd. (458.7 cu m) on the Lancaster project. Harrisburg is slightly higher because of the concrete depths. Production there reaches approximately 1,000 cu. yd. (764.6 cu m).
All of the tie-in work and the challenging project sequencing demands some organizational skills.
“Ed Wessel, the project engineer, and I sit down daily and talk with our foremen and map out a two-week schedule and we try to stay with it,” Stephen said. “We may not follow it to a ’T’, but at the end of two weeks, the work is complete. There’s a lot of coordination on these rehab jobs and you have to make sure you don’t catch yourself with cure times and things like that.”
The new generation Commander III is working out well on both of the projects. Hi-Way Paving is enjoying its versatility, easy setup with the smart cylinders, increased travel speed and its transportability.
“It’s a fast machine,” Stephen said. “We’re doing a lot of moving here and there are very few places where we have the opportunity to pave all day in one area. We’re constantly moving the paver. The name of the game is putting concrete on the ground. You can’t be putting it down when you’re moving the machine.”
(This article appears courtesy of “Gomaco World”).
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