Chip seal is a term used in the paving industry for a process of applying a sealing layer of liquid asphalt to an existing asphalt surface and topping it with a layer of aggregate, thus sealing the old asphalt surface from further damage from the elements and providing a new ‘wearing’ surface.
The process is labor intensive and requires specialized machinery. First, a “distributor” applies liquid asphalt from a heated storage tank that keeps the asphalt hot enough to flow evenly. Then, a pump and spray bar applies the hot asphalt onto a roadway surface. A “chip spreader” goes to work, spreading a layer of stone aggregate. Lastly, the layers are set by rolling and compaction.