Chip sealing is a process of covering a gravel road with a layer of liquid asphalt and then a layer of small rocks embedded in the asphalt. The purpose of this maintenance procedure is to extend the useful life of the road by providing a wearing course. For low-volume gravel roads that do not warrant paving, chip sealing is a cost-effective procedure that prevents water from penetrating the road surface, improves skid resistance and suppresses road dust.

Procedure

Level and smooth the gravel road to remove low spots and surface irregularities.

Using a truck-mounted sprayer, apply a thin film of hot liquid emulsified asphalt.

Immediately follow by spreading a layer of small crushed rocks called aggregate.

Roll the rocks into the asphalt layer. Multiple passes of the roller may be needed to set the rock in place.

After the asphalt has had a few days to set, sweep loose rocks from the surface.

Some jurisdictions will follow up several weeks later with an application of diluted emulsified asphalt called a “fog seal” to help keep the rocks in place.