While many people think of crack sealing as a way to repair badly deteriorated asphalt, more property owners are beginning to look at it as a preventive measure to prolong the life of their pavement and delay the need for expensive asphalt repair. It makes sense. Sealing small asphalt pavement cracks is easier and more cost effective than filling larger cracks later on.
Cracksealing is more complicated than it might seem at first glance. Aside from choosing the correct fill material, the single most crucial determinant of success in a crackseal operation is proper preparation of the cracked surface to be repaired. The successful outcome of a seal is based on the thorough cleaning of the crack and surrounding pavement.
Many contractors begin with a general sweeping of the area with a sweeper or hand broom. But most don’t stop there. It is necessary to blow debris out of individual cracks with an air compressor, or even hot air blasting. Each speck or crumb of dust, gravel or similar debris in the crack weakens the ability of the fill material to make the best bond with the surface. Further, the slightest droplets of moisture seriously degrade the quality of the repair.
Contractors generally use high-pressure air compressors with hoses and wands to acieve sufficient pressure to blow fragments and particles from the crack. The compressor must be constantly checked to make sure it is completely dry as some compressors may introduce water or oil into the air supply. The compressor must be equipped with moisture and oil filters to assure thorough dryness of the crack.
Also key to success is to clean and dry the crack immediately before introducing the fill material. Even overnight, a cleaned crack can attract dust and moisture, so it’s important to clean then seal immediately.
The compressor operator should hold the nozzle about 2 inches from the surface and make slow, repeated passes, blowing the debris forward of the nozzle. The final pass should move across the general surface area to remove debris from the vicinity that might re-contaminate the joints.