A load of asphalt being placed into a shuttle buggy, which acts as a buffer between the asphalt paver and the truck to reduce the time it takes the spreader to lay the asphalt. As the shuttle buggy conveyor dumps into the holding bin on the paver, the sp
The Mississippi Department of Transportation (MDOT) is currently supervising the resurfacing of 5.3 mi. (8.5 km) of U.S. 49 in Hattiesburg. The contract for the $8.3 million project was handled by Dunn Roadbuilders LLC of Laurel under the direction of Pepper Beckman.
Work began in July, and the expected completion date was set at Nov. 30.
The project was made possible through federal funds as part of the American Recovery and Reinvestment Act (ARRA), also known as the stimulus package. Through this package, an estimated $27.5 billion will go toward roadway and bridge improvements.
According to Dan Ashley, project manager of Dunn Roadbuilders, the project begins just north of the Edwards Street intersection and runs north to the intersection of 31st Avenue. It is the second of four projects that has been awarded to Dunn Roadbuilders by MDOT since the ARRA projects began at the beginning of 2009.
“The main focus of this project is to remove five and one-half inches of existing asphalt pavement in the two main travel lanes of U.S. 49 and replace it with two lifts of a polymer modified asphalt mix,” Ashley explained. “Once completed, this project will provide a smoother ride for the traveling public as well as providing a maintenance-free roadway for the department of transportation for as long as 20 years in the future.”
Ashley noted that liquid polymers are added to the asphalt mix design to provide a better bonding strength among the asphalt components of stone and liquid asphalt cement. The strength of the mix reduces rutting, which in turn prevents water from standing on the roadway.
In addition, adjacent frontage roads, crossovers and connector roads are receiving a new overlay to produce a desirable product from start to finish.
“After the Mississippi gulf coast area, Hattiesburg has a high number of passenger cars and freight trucking vehicles,” Ashley explained. “This high traffic count, along with numerous businesses, a hospital and the University of Southern Mississippi location forces MDOT to declare this work is done during night time hours. Normal roadway work hours are 6 p.m. to 6:30 a.m. Sunday through Thursday. Adjacent service roads are allowed to be paved during daylight hours.”
In order to complete the project by Nov. 30, Dunn Roadbuilders was running four paving and milling/cleanup crews at the same time. Another crew was responsible for maintaining a safe work zone.
Ashley explained that the original concrete roadway was poured many years ago in joints ranging from 12 to 20 ft. (3.6 to 6 m) in length.
“As the concrete roadway expands and contracts during the heat and cold of summer and winter months, joint lines become evident and produce an uneven roadway at most of the joint lines,” he said. “Repair choices to a roadway like U.S. 49 are to remove the concrete completely or place asphalt pavement on top of the asphalt in order to smooth the joint lines. At its completion, the U.S. 49 project will have five and one-half inches of asphalt on top of the existing concrete roadway.”
According to Ashley, in order to open the U.S. 49 roadway at 6:30 a.m. without penalty, all removal and placement of asphalt must be completed by an exact time every morning.
“Coordination among milling, clean up and asphalt pavement crews to determine exactly how many feet of roadway to repair during the allowed work time is challenging,” he said. “Roadway repair lengths vary from night to night according to varying factors such as intersections, crossovers and turn lanes.”
He noted that weather is another crucial factor. Nighttime thunderstorms at times caused delays and even termination of work. In addition, lights must be used that allow workers to see, but at the same time must not blind the traveling public.
Milling and cleanup crews are made up of eight to 10 employees, and paving crews require 12 to 15 people to place asphalt pavement. An additional eight to 10 more employees are needed as truck drivers to deliver milling from the job to the stockpile location and to deliver asphalt from the plant to the job. Maintaining traffic requires another four employees to protect workers from traffic and traffic from working equipment. Excluding contractors, a total of 46 employees were on the project in the average 48-hour period.
The 5.3-mi. project involved 209,000 sq. yd. (174,750 sq m) of cold milling, 87,000 tons (78,925 t) of hot mix asphalt, 34,000 linear ft. (10,363 m) of sawing and sealing transverse joints in asphalt pavement.
Ashley noted that up to 25 percent of the materials required to make a ton of asphalt come from the recycled pavement received from the same project. The milled asphalt pavement is injected into the new asphalt mix that is being laid back on the project. This particular project is expected to yield approximately 50,000 tons (45,359 t) of recycled asphalt pavement (RAP).
Major subcontractors include A-1 Sealing, Richton, Miss., for asphalt joint sealing; J.L. McCool Contractors, Inc., Pascagoula, Miss., to place temporary and permanent traffic stripe; Atwood Fence Company, Inc., Kosciusko, Miss., to remove and install new guard rail; and Lewis Electric Company, Flowood, Miss., to install traffic signalization poles and traffic lights.
All equipment used by the crews was company owned. The asphalt paving crews used a Cat AP1055 paver, a TREX Cedar Rapids asphalt transfer machine, a Broce Broom RC350, two steel wheel roller Sakai SW900, and a cat rubber tired roller PS360. Milling crews used two Roadtec RX50B milling machines, a Cat 420D rubber tired backhoe, a John Deere 310SG rubber tired backhoe, two Broce RC350 brooms, and a Ford service truck F650.
Dunn Roadbuilders was established in 1997. It is one of five companies under the management direction of Dunn Investment Company based in Birmingham, Ala.