Two ways to think of it

Crews initially laid a course of all-gravel 19 mm as the base course, followed by a predominantly gravel 12.5 mm for the intermediate course.

Conflict and confusion

Lehman-Roberts Co., a nearly 80-year-old asphalt production and paving contractor, signed on as a subcontractor for the job. The prime contractor, Ferrell Paving, has 60 years of experience in performing street, drainage, highway and sitework projects. The issues the two firms were dealt started immediately with the job’s design and construction plans.

The construction plans for the project were designed by one engineer, but a second construction engineer was hired as a consultant. The two firms often had conflicting opinions on the design, which led to additional confusion for both the prime and paving contractors.

The curb-and-gutter elevations were different on each side of the road, making it impossible to get a consistent 2% crown and cross slope. The structural thickness of the existing asphalt that was to be preserved for the new roadway was less than what showed on the plans for the original section, and that ultimately exposed an unexpected number of soft areas that would require repair. Issues with the original curb-and-gutter were to be left in place and tied into, contributing to rideability problems. Rideablilty also was negatively impacted by utilities in the road, as well as multiple intersections.

Ultimately, it was up to the paving contractor to meet the rideability requirement.

Caterpillar pavers used 50-ft Blaw-Knox ski poles and worked side by side with adjacent pavers slightly offset.

An old trick

When concerns about the job were shared with Lehman-Roberts Co. Project Superintendent Terry Ketchum, he devised a plan around two options.

The first option was to lay a leveling course of asphalt, 6 ft from the curb and stretching to 19 ft, making the total coverage area 25 ft wide and also making the slope more consistent.

For the second option, Ketchum went back to a lesson he learned nearly 30 years prior from a mentor who taught him to use an extended contact ski pole to make a bad ride smoother. The longer ski pole would stretch over the knots further and lay more asphalt in the low spots. When presented to the prime contractor, the idea was met with optimism and relief.

Because most of the current employees would know nothing of this method, Ketchum mentioned it to a peer, Preston Bryson, who also had more than 30 years of paving experience. When the two men began paving in the late 1980s and early 1990s, Blaw-Knox contact ski poles were commonly used. A trip to the boneyard to search through various pieces of equipment and discarded parts yielded enough sections to make a 50-ft Blaw-Knox ski pole.

With the aid of some brackets and the Lehman-Roberts Co. fabrication shop team, the ski pole was added to a Caterpillar 1055E paver and integrated with modern paving electronics in their shop.

Over the course of the $6.9 million project, from June 2015 to April 2017, four different crews worked on the job. Initially, a course of all-gravel 19 mm as the base course was followed by a predominantly gravel 12.5 mm for the intermediate course.

When the patching was completed, the profile ride on the roadway received an average IRI reading of 187 in./mile. The average profile reading dropped significantly to 88 in./mile after the leveling was complete, but clearly the biggest challenge was still ahead for the crews who would prepare the road for final surface and lay the final lift of asphalt.

Two crews laid the final lift, using an all-gravel 9.5-mm surface course, paving multiple lanes in echelon. Two Caterpillar 1055E pavers used the 50-ft Blaw-Knox ski poles and worked side by side with adjacent pavers slightly offset.

Targeted paving speed was 25 ft per minute with each paver pulling a 15-ft-wide mat. To obtain maximum density over the 30-ft-wide mat, four Caterpillar CB66 rollers were used in the breakdown.

These rollers behind the echelon passed directly over the longitudinal joint while both sides were hot, which resulted in better joint compaction. The wider sections all but eliminated one visible joint. Finally, two Caterpillar CB66s also were used as finish rollers.

When the final profile ride was done, the profile reading had dropped to 59 in./mile.

While not the numbers the team originally hoped to achieve, they were such a marked improvement that it far exceeded the expectations of everyone else involved, including Ferrell Paving, MDOT, the consulting engineers and the Southaven Board of Aldermen.

Ketchum and the paving foremen who worked on the job received letters from the prime contractor, stating in part, “We at Ferrell Paving Inc. want to acknowledge your above and beyond efforts to solve a multitude of concerns and issues on this very difficult project. Through your efforts, the project is one of which everyone is proud.”

The project was completed in April 2017, just ahead of schedule. With the new lanes in place, Southaven is enjoying reduced congestion and the area is well-positioned for future economic growth.

“This job is a personal win for me,” said Ketchum. “It showed that when you rely on past experiences, create a plan, and get everyone to pull in the same direction, this company can take a bad situation and turn it into a great-looking job we can all be proud of. I thank every person on these crews and the others I worked with on this job for the effort you gave and the quality of work.”

About The Author: Foster is director of communications & community engagement for Lehman-Roberts Co., Memphis, Tenn.