What types of concrete overlays are available?
Concrete overlays can be applied to asphalt, concrete and composite pavements. Two main types of concrete overlays are available: bonded and unbonded. Bonded overlays should be considered on existing pavements when a structural upgrade is needed and/or surface distresses are in need of repair. The existing pavement system should be in good structural condition. Ultra-thin whitetopping was used in the past to describe a bonded concrete overlay on an asphalt pavement. Bonded concrete overlays can vary from 2 to 5 inches and when bonded correctly create a monolithic pavement. Unbonded overlays should be considered when structural deterioration is present in existing asphalt, concrete or composite pavements. Whitetopping was previously used to describe an unbonded concrete overlay on an asphalt pavement. The restoration of structural capacity to a pavement system is accomplished by concrete overlay thicknesses of 4 to 11 inches. Though no bond is designed, a bond may develop with existing
