Crack & Joint Sealing
Hot Pour Rubberized
Cracks in pavement are the early phase of asphalt failure. Although asphalt is a flexible pavement, cracking is a normal occurrence. Cracks allow water to penetrate into the sub base which will eventually lead to pavement failure. Hot pour crack sealant is ideal for asphalt because it has superior elasticity, bonds well, and is black in color. Hot pour sealant expands and contracts through seasonal temperature changes and can keep cracks sealed for many years.
- Crack sealing to be completed on cracks 1/8″ and larger. If there is vegetation in the cracks, a water-based weed killer should be applied at least one week prior to crack sealing.
- Clean cracks with a combination of power braided wire wheel, forced air and hand tools.
- Cracks must be dry before being filled. The temperature should be above 32ºF degrees.
- Fill cracks with rubberized crack sealant, such as Crafco 532 or equivalent. The sealant should be a hot-applied modified asphalt product heated in an oil-jacketed double boiler to 400ºF degrees and agitated. AC-20, roofing material, or any type of asphalt cut back is not acceptable.
- The material should be applied to the cracks with a walk-behind bander so it is flush with the pavement. The material should be banded a uniform width of approximately. 4 inches.
- Traffic should stay off of the fresh sealant for at least 15 minutes. If the area needs to be opened or is a high traffic area, the material should be dusted with black sand.
- If sealcoating is part of the project, the crack sealing should be completed prior to the sealcoating.
Saw & Seal
In areas where temperature fluctuations are very severe (upper tier of United States), the saw and seal method is ideal for increasing the longevity of asphalt pavement. By installing control joints in the new pavement and sealing the joints, the expansion and contraction process tends to cause many less random cracks in the pavement. (This is similar to installing control joints in concrete.)
Studies by State Departments of Transportation in northern states, have shown the saw and seal method to be effective in significantly reducing pavement maintenance costs in the long run.
- Transverse saw cut joints will extend the full width of the pavement. They should extend 1 foot beyond the edge of the mainline pavement into the asphalt shoulder. The traverse saw cut joints should be spaced at 40 foot intervals.
- Clean dry sawed joints with an air compressor until the joint is dry and debris is removed from joint and surrounding pavement.
- Wet sawed joints should be cleaned with a water blast to remove debris. Then dry the joints with an air compressor.
- Place backer tape on the bottom of the joint reservoir.
- Seal the joint with sealant material.
- Make sure the sealant is tack free before opening to traffic.