Pennsylvania has become the testing ground for a new experimental pavement preservation method called RoadArmor. Pennsylvania's' Dept. of Transportation (PennDOT) said that new road pavement process could help low-traffic volume roads handling 20,000 vehicles a day or less last longer than by using conventional preservation methods.
For years, "oil and chip" resurfacing has been the most cost-effective method of preserving low-traffic roads across the state, said PennDOT chief engineer Gary Hoffman. The oil and chip process starts with a water-based liquid asphalt being put on the road surface, followed by applying limestone chips into the asphalt, rolling the chips, and finally brushing off any loose material.
With RoadArmor, however, the materials are applied, rolled and swept almost simultaneously, the road can be opened to traffic much sooner than traditional methods, thereby reducing traffic congestion, said Hoffman. Also, the stone chips used are all the same size and the emulsion material that the stones are pressed into uses a special polymer to enhance its ability to hold the stone chips.
The new procedure costs about $18,000 per mile, compared to about $10,000 per mile for oil and chip resurfacing, said Hoffman. Though the new material is more expensive, it is expected to last five to 10 years as opposed to oil and chip, which lasts three to six years. Another benefit is that RoadArmor can help restore the overall friction to a road surface, to make it safer during rain.
It also dries faster since it does not rely on the sun's heat for drying. Instead, a chemical reaction helps to dry the material. This promises to provide a huge benefit because this material can be applied to shaded roadways where traditional oil and chip does not perform as well because it dries too slowly, said Hoffman.