What is bitumen spray seal?

Spray sealing is the fast and economical way to surface a roadway. Hundreds of thousands of kilometres of vital Australian roads have been constructed and maintained using bitumen spray seal, 

Spray sealing is achieved by spraying a  film of bituminous binder (tar)on to a road surface, and then covering it with a layer

of aggregate. The bituminous binder acts as a waterproofing layer and prevents water entering the underlying road structure. The aggregate protects this layer from damage by vehicle tyres, and together they form a durable, skid resistant and dustfree surface.