Chip sealing is the most common resurfacing method on Jefferson County roads, as is the case for surrounding counties. Chip sealing is usually used to pave long stretches of rural roads, but it has also been used successfully on urban roads. This process helps seal the road and provides a new riding surface.
The process of chip sealing a road causes minor traffic disruptions to the road and intersecting roads during the summer months.
What is Chip Seal?
Chip seal is the application of a protective wearing surface to an existing pavement. Emulsified oil is applied to the road surface, with chip rock added on top and rolled into the oil.
An overview of the chip-seal process
The process begins with preparing the road to fix discrepancies, to fill cracks and to address drainage issues. The surrounding right of way is prepared by removing excess shoulder buildup, mowing brush, trimming trees and restoring ditches. Our intent is to leave each chip-sealed road in great shape so we do not have to return for regular maintenance for several years.
On the day of chip sealing, the road is swept to remove any remaining debris. An asphalt distributor truck applies emulsion to the road; as the liquid asphalt emulsion meets the warm road surface, the water in the emulsion starts to evaporate.
Immediately after spraying asphalt, a layer of chips is applied by a chip spreader. The chips are small, uniformly sized, crushed pieces of durable rock. The maximum size of each chip is usually 1/2", but we use 1/4" chips on some low-volume roads.
The chips are embedded into the asphalt by several passes of rubber-tired rollers. Some chips do not get embedded in the asphalt and remain loose on the surface to be removed by follow-up sweeping. The road is opened to traffic.
Hot, dry weather helps to speed the process of curing the new surface. All of the remaining water in the emulsion evaporates, and the asphalt hardens. Traffic helps to further seat the chips into the curing asphalt. A pass of the sweeper removes the remaining loose gravel.
Following the completion of chip sealing, most roads are also treated with fog sealing. The fog seal procedure involves using the asphalt distributor to apply a very thin coat of diluted asphalt over the top of the chip seal. This turns the surface black, makes it easier to see road stripes and helps to retain chips that were not completely seated in the chip-seal oil.
Following the curing of fog sealing, the road is striped and returned to normal operation.
Benefits of chip sealing roads
- To keep water from penetrating the road structure beneath a paved surface
- To fill and seal cracks and raveled surfaces of old pavement
- To seal the pavement surface, minimizing the effects of aging
- To provide a highly skid-resistant surface, particularly helpful when pavement is wet.
As with any road construction project, motorists must exercise caution. Reduced speeds ensure your safety and minimize the chance of damaging your vehicle.
From the time the chips are placed on the road to when the excess is swept away, the speed limit is 25 mph. At that speed, vehicles should not be damaged by flying rocks.
Traffic moving at higher speeds can create dust, limit visibility, and cause an inconvenience to local residents. Increased speeds can also cause gravel to break loose from a fresh chip seal creating the risk of flying rock. Rocks thrown from your tires may crack or break a windshield. Flying rocks might also injure pedestrians, bicycle riders, or motorcyclists.
Chip Seal Lists