Focus On Fundamentals Crucial For Contractor
Credits Cat Paving Operations training for helping them take on bigger jobs
Mainline production-paving contractors receive much of the industry’s attention, yet there is obviously a need for small- and mid-sized contractors too. They improve the local roads and provide niche services the larger contractors don’t.
The smaller contractors, of course, have the same demands regarding quality. This requires adherence to fundamentals and using state-of-the-art equipment that enables delivery of a high-quality product.
Teletractors Inc. is a smaller contractor that has found niches to fill. “We have to be diversified because we are in a small town,” said Lance Biffle, vice president of the company in Pinedale, Wyoming. “We handle all types of projects both large and small – underground utility work, general excavation, road work, sand and gravel sales, and asphalt sales/paving. We are becoming more specialized in aggregate sales and as an asphalt paving contractor.”
Elevation is also a factor in their work since they are located at an elevation of 2,165 metres (7,100 feet), about 145 km from Yellowstone National Park, and are surrounded by three mountain ranges.
Teletractors recently took a step forward with a paving job on Fremont Lake Road in Sublette County, Wyoming. This is one of the larger projects the company has taken on as a general contractor. “It also was the biggest paving job,” Biffle said. Experience gained from other jobs made the step to the larger project manageable.
“We learned from previous work, as 2013 was our sixth year in the paving business,” Biffle said. “We started out paving parking lots and driveways, then moved on to city streets. A sizable county road project was the next goal, and Fremont Lake Road was it.”
The project called for paving 4.2 km (2.6 miles) of the road, which has two 4-metre (13 feet) travel lanes and an accompanying 8-foot-wide bike path. The curvy road has steep grades and a 64 km/h (40 mph) speed limit.
Placement of 12,700 metric tons (14,000 U.S. tons) was required, though poor weather meant only half of the bottom lift could be completed before winter arrived. The mix featured 19-mm (¾-inch) stone and 70-28 oil.
Cold weather heightened segregation concerns
Belly dumps hauled the mix approximately four miles from the plant to the jobsite. The mix was about 163°C (325°F) upon arrival, 149°C (300°F) when placed and 138°C (280°F) when compacted.
Challenging weather led to delivery and temperature adjustments. The cold temperatures required the mix to leave the plant hotter than normal and to be dumped close to the pickup machine. The crew kept a close watch on plant output, paving speed and the trucks’ cycle time to ensure mix was hot when delivered. The cold fall weather heightened segregation concerns, so extra attention was given to proper loading at the plant. On the jobsite, a windrow elevator also helped prevent segregation.
“We like the idea of using a windrow elevator so continuous paving can be achieved,” Biffle said. “Windrow elevator paving also eliminates end-dump truck exchanges and the risks of a truck rolling away when negotiating up and down hills that were encountered on the job.”
The Cat AP555E Asphalt Paver with AS2252C Screed handled the paving work. Plans called for placing two lifts of asphalt over the 4.2 km (2.6 miles). A 51-mm (2-inch) base lift was placed in late fall, with a 51-mm (2-inch) surface lift to be placed in spring when warmer weather returns.
The paver moved at a pace of about 6.1 m (20 feet) per minute based on plant output of 145 to 163 metric tons (160 to 180 U.S. tons) per hour. Joints were tacked and then placed with around 13 mm (1/2 inch) of overlap.
Teletractors adjusted to the cold temperatures by using two Cat CB54 Tandem Vibratory Rollers in breakdown mode. The rollers ran side-by-side, with each completing five vibratory passes. A smaller finish roller made two or three static passes.
“We had to stay really close to the paver because of the cold temperatures,” Biffle said. Breakdown compaction occurred at about 138°C (280°F), while the mat temperature was about 93°C (200°F) during finish compaction.
Longitudinal joints were compacted by making the first vibe pass about 30 cm (1 foot) inside the joint and all other passes on the joint. Transverse joints were compacted using a smaller roller that ran side-to-side on the joint. The work was checked with a straight edge.
Fundamentals and training pay off
The work, started late due to circumstances beyond Teletractors’ control, went well despite the onset of cold weather.
Biffle believes the commitment to fundamentals was crucial given the quickly cooling weather. Enrollment in Cat Paving Operations Training the previous winter paid dividends when it was time to pave the road. The training focuses on segregation prevention techniques such as proper head of material, auger utilization, proper dumping and continuous movement.
“Last winter, three of us went to the training in Florida,” Biffle said. “It really helped us with the fundamentals of paving and gave us the confidence to take on bigger projects. It was also a great way for us to familiarize ourselves with our new Cat paver before taking it out on the job.”
Sticking to fundamentals worked, with a quality mat produced in challenging conditions.