ASPHALT PAVEMENT MAINTENANCE METHODS AND APPLICATIONS

Properly maintaining an asphalt pavement surface is essential to the durability and the life of any asphalt pavement. Performing routine maintenance such as seal coating and crack filling will extend the life of the pavement and decrease the need for pavement repairs. Once the asphalt pavement surface is showing signs of distress or deterioration, it is critical to perform maintenance or make repairs to minimize future costly repairs or replacement.

The most common asphalt maintenance procedures include asphalt patching, crack sealing, seal coating and resurfacing with an asphalt overlay.

Asphalt patching is appropriate for potholes, depressions, ?alligator? cracking, slippage cracks & rutting. Once the asphalt begins to crack in a concentrated area it will become ?alligatored? and eventually become a pothole. When longitudinal and transverse cracks in the asphalt pavement become more concentrated in a particular area, it is time to make repairs to minimize the impacts and salvage the pavement surface as much as possible. The correct and more permanent way to repair the concentrated cracking is with a full depth asphalt patch. Beyond the limits of the damaged asphalt, the existing asphalt should be completely removed to the base rock. The base rock should be properly compacted prior to asphalt replacement and the vertical sides of the patch should be coated with a liquid tack coat to assure proper adhesion with the new asphalt. The new asphalt should be placed within the patch in lifts no greater than 3? thickness at a time and properly compacted flush with the existing surrounding asphalt surface.

Crack sealing is critical to extending the life of an asphalt pavement surface. Crack sealing prevents water from infiltrating through the asphalt surface and into the base rock and sub grade. Once water is allowed through the asphalt surface it will weaken the underlying pavement structure and thus compromising the asphalt surface leading to further cracking and pavement failures. Prior to installing the crack sealer, the existing cracks must be cleaned and dried to allow for proper adhesion between the sealer and the asphalt pavement.

Seal coating is also essential to extending the life of an asphalt pavement surface. Direct sun exposure and ultraviolet rays from the sun will create oxidation of the asphalt allowing essential liquid chemicals in the asphalt to escape and leave the pavement vulnerable to raveling and cracking. Seal coating is appropriate for weathered and worn surfaces, small and minor cracking in the asphalt, and segregated or raveling surfaces. By sealing the existing asphalt pavement through seal coating, the essential elements are locked into the existing pavement while keeping water and other elements from infiltrating the surface of the asphalt pavement surface thus extending its life.

Resurfacing with an asphalt overlay is a way to salvage and strengthen an existing asphalt pavement surface. If the pavement defects in the existing surface are not a result of base or sub grade failure, the existing pavement surface can be resurfaced with an asphalt overlay. This will repair and correct minor deficiencies in the existing asphalt pavement as well as prolonging the life of the pavement structure without major replacement costs.