Dixie Contractor, Volume 84, Number 10, October 2010
A new type of asphalt binder that was developed to improve pavement durability and resistance to rutting and shoving is being tested by the Georgia Department of Transportation (GDOT) at the junction of two busy state highways in Henry County.
GDOT approved the substitution of Kraton highly modified asphalt binder (HiMA) for the binder originally specified for a Superpave hot mix overlay that was recently installed by C.W. Matthews Contracting Co., Inc. at the intersection of Routes 138 and 155 in Stockbridge.
The agency is concerned about pavement rutting and shoving at the intersection, which is located at the foot of a hill and experiences repeated hard braking by motorists. Vehicle travel has risen dramatically in recent years in Henry County, which is part of the fast growing Atlanta Metropolitan Area, while Stockbridge is the county’s largest city.
“The population has been growing in the Stockbridge area, and those two state highways serve as corridors to several Interstates,” said Peter Wu, P.E., who is responsible for technical assistance in GDOT’s Office of Materials and Research. “This means there’s a lot of traffic going through that intersection – about 25,000 vehicles a day – and about 1,400 of those are trucks,” he said. Wu explained that paving was part of a larger contract awarded to C.W. Matthews to reconstruct the intersection, including widening and adding turning lanes in each direction. He added that specifications originally called for a Superpave overlay using a performance graded PG 76-22 asphalt binder but GDOT area office personnel agreed to allow the use of HiMA at the request of C.W. Matthews on behalf of Kraton Polymers LLC, which developed and manufactures its newest SBS polymer modifier and wished to demonstrate its effectiveness.