LACKAWANNA COUNTY, Pa. — This time of year, you might see signs that say "Fresh Oil and Chips." This is an operation called seal coating. It's different than milling and paving because it is significantly more cost-effective.
"We can't pave every road. We don't have the budget to mill and pave every year. But we could provide this type of seal coating activity every 6 years to the majority of our low-level roads, and that's why we're doing it," explained Jonathan Eboli, P.E., PennDOT, District 4, Assistant District Executive - Maintenance.
Low levels roads are ones like Manning Road in North Abington Township. Roads where less than 12,000 cars per day travel on them. So seal coating would not happen on Interstates like 81. But the end goal is the same: to preserve the life of the road and to keep water out.
"Water is our biggest enemy, especially during our freeze/thaw cycles, so if we can keep all of our cracks sealed and then the surface of our pavement sealed with oil and then stone for traction, that's an excellent opportunity for us to apply a cost-effective method," said Eboli.
Prep work for seal coating can start nearly two years before you see an end result. Road crews sealed all of the cracks here on Manning Road last summer. Now, this season, they are ready to seal coat.
First comes the oil distributor, and then the stone chipper lays stones evenly on top of the hot oil. Finally, rubber tire rollers help adhere the oil and stone to create the chemical reaction needed for it to dry so that we can drive on it.
"A typical seal coat application in District 4, we're applying this at about $16,000 per mile. A typical paving project, start to finish, could be upwards of about $600,000," Eboli said.
It's not a permanent solution like milling and paving, but it is a preventative maintenance.
"To prolong the life of our roadway until we can get to the next paving project. Manning Road, which is being seal coated today, is on its 3rd generation of seal coat, so that has not seen pavement in over 18 years, and it is in very, very good shape because we're able to keep the surface sealed," Eboli said.
About a week after a road gets seal coated, road crews in Lackawanna County will go back and fog seal the road. That will basically lock in the stone and provide just an additional sealing of the roadway. Then about another week after that, the lines will get painted.
This operation is entirely weather-dependent. It cannot be done in the rain. Sunshine, warmer temperatures, and low humidity are the ideal conditions; on a day like that, you can drive on the freshly seal-coated road in about 15 minutes.
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