Asphalt Overlay Just Won't Do

The Challenge: A heavily trafficked and failing asphalt parking lot needed repair and previous overlays have proven unsuccessful.

The Player:
S&G Asphalt, Slatington, PA

The Process:
The Mack Truck company had a 55,000-sq.-ft. failing parking lot at its Macungie, PA, location. S&G Asphalt was one of three companies asked to submit an estimate, says S&G Owner Tony Sorrentino. Sorrentino says both the original asphalt and the overlay on top of it were cracking and failing. Instead of suggesting another overlay, Sorrentino wanted to tear out the old asphalt down to the stone subbase and replace it with new asphalt. Despite not being the low bid, Mack Truck awarded S&G the job.

S&G only had a two week time frame to complete the parking lot. Sorrentino also had to take into consideration the soil conditions in the area. The Macungie area has soft soil conditions - making it a challenge to achieve and keep a solid base during and after paving. Coupled with the spring thaw and some rainy weather, the S&G crew had to be extra considerate of how often they ran equipment over the soft soil.

S&G started the parking lot in mid-April 2010. In order to save time and use as much manpower as possible, Sorrentino combined his prep and paving crews having them work together at the job. The first step was to remove the old failing asphalt. Removal and stone base preparation took two days, Sorrentino says.

S&G used a track loader to remove the old asphalt and followed behind with a motor grader to level and fine grade the stone base. "We had to methodically plan so we weren't running our equipment repeatedly over the existing base and creating soft spots," Sorrentino says.

Once the stone base was ready, the paving crew got started using a PF150 Blaw-Knox paver. The crew laid a 2.5-in. lift of binder over the entire parking lot. "Because the subgrade was moving, that first lift gave us a better grade to follow," Sorrentino says. The first lift was then compacted to 2 in. using two Ingersoll Rand DD24 roller compactors. S&G then laid down a second 2.5-in. lift which was compacted again to 2 in. resulting in a 4 in. asphalt base. "Two layers of binder allowed for proper compaction with each lift while keeping the number of roller passes down," Sorrentino says.

After the first two lifts, the paving crew followed up with a 1.5-in. overlay. The overlay gave the finished parking lot a smoother look than the two lifts of binder, Sorrentino says. "The binder lifts are porous so we put a final wear coat over them to make it smooth and to help keep water out of the subbase," he says. "It's harder for water to penetrate three layers of asphalt. That helps to keep the already soft subgrade dry resulting is less chance for movement in the subgrade to occur."

S&G subbed out the line striping work to finish off the lot. Despite encountering some rainy weather, S&G was able to complete the parking lot within the two week time frame.

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