As it sounds, crack sealing is where we seal the cracks in asphalt and bituminous spray seals.
Why do we seal cracks?
Crack Sealing is done to prevent the ingress of water below the pavement wearing course, into the sub structure of the pavement.
Water infiltration is “the beginning of the end” for a pavement. Water that penetrates to the sub base of the pavement will allow it to soften and become unstable.
Unsealed cracks may either; slowly widen and accelerate the propagation of crocodile cracks.
Unsealed cracks eventually led to various pavement deformations, potholes and complete pavement failure.
The use of crack sealing on a pavement prior to asphalt re-sheeting or bituminous resealing slows and greatly reduces the possibility of reflective cracking on the new pavement layer.
This again extends the life of the pavement.
If utilized early enough crack sealing defers all of the more expensive maintenance and the eventual pavement reconstruction.
What type of cracks are suitable for sealing?
- Longitudinal cracks/joints.
- Transverse cracks/joints.
- Meandering cracks.
- Diagonal cracks.
- Crescent shaped cracks.
- Block cracking when the pavement structure is still firm.
- Minor Crocodile Cracking, where there is no base deformation and the wearing surface is not loose.
Cracks must always be dry.
Depending on; the type of crack, desired service life, serviceability, and budget, crack preparation may involve any combination of the following; weed poisoning and/or raking/ripping, power routing, blowing out with compressed air. Excessively deep cracks may also be packed with backing rod prior to sealing.
Generally cracks need to be blown with compressed air to clean the crack of loose material, which may prevent bonding of the sealant.
What type, of materials are suitable for crack sealing?
For the best performance and cost effectiveness, a hot applied rubber modified bitumen sealant will always yield the best results.
All Pavement Management Systems should include a suitable crack sealing program. This allows greater utilization of your pavement maintenance budget. Crack Sealing works effectively as both preventative and routine maintenance.
With an effective crack sealing regime you will be able to prevent water from deteriorating your pavement sub-bases and prevent the need for expensive unnecessary patching and reconstruction.
Crack Sealing of residential streets usually first require cleaning cracks with compressed air.