When asphalt cracks are too large or extensive for crack repair treatments, you may need to consider crack filling. By simply measuring and analyzing cracks you can identify the best option: crack sealing or crack filling?
Do Cracks Need To Be Sealed Or Filled?
In order to determine the best crack repair treatment you must determine how wide cracks are. Sealant is typically used for cracks that measure less than 3/4–inch wide and are spaced evenly throughout pavement with limited edge deterioration. In order for cracks to benefit from sealant, the router must simultaneously touch both sides of the crack. Filling better suits pavement surface cracks that measure greater than ¾-inch wide.
Sealing Asphalt Cracks
Crack sealing is a localized treatment that prevents water and other debris from getting inside of asphalt abrasions and causing further damage to roadways. In order to properly seal a crack, all debris must be blown out and cleaned away. A saw or router may also be used to dig out a reservoir, which is then filled with sealant.
Crack sealant is generally used when cracks measure no more than ¾-inch wide. There are three different approaches that fall under the crack sealant category,: clean and seal, saw and seal and rout and seal.
What Is Clean and Seal?
The clean and seal method benefits numerous types of cracks. This method involves using a hot air lance or compressed air to blow away any debris trapped in the crack. The clean crack is then filled with sealant.
The purpose of this treatment is to prevent water and other elements from getting inside of the pavement and weakening the base material.
Pavement surfaces must be relatively new or in good condition with a sound base, cross section and lateral support. This method is best applied during moderate temperatures, such as during the spring or fall.
You can expect this treatment form to last around three years before sealant begins pealing off and away from the sides of the crack. At this stage, the sealant is no longer keeping water and other materials out of pavement, although it is likely still reducing infiltration and extending pavement life to some degree.
What Is Saw and Seal?
Saw and seal is used to create evenly spaced transverse joints on newly placed pavement prior to filling it with sealant. This is performed on new asphalt at least 48-hours post-paving.
The purpose of saw and seal is to reduce shrinkage cracks that result from thermal changes. Prior to application, pavement surfaces should be free of cracks.
Saw and seal applied to new asphalt surfaces can last 7 to 10-years when proper maintenance techniques are applied. During this time the number of cracks in asphalt pavement is greatly reduced. Too much sealant is never a good thing, leading to reduced pavement friction and safety concerns.
What Is Rout & Seal?
Rout and seal is used for transverse and longitudinal cracks with little to no secondary cracking or raveling at the crack face. A pavement saw or router is used to dig out a reservoir that is centered over the crack; this reservoir is then filled with sealant. This procedure prevents water penetration. It is most effective when applied to newish pavement.
Cracks should never measure too wide or be too badly deteriorated for this method to be successful. Pavement needs to have a sound base with a good cross section and lateral support.
This method is best applied during moderate weather conditions, such as spring and fall. Too much moisture prevents sealant from adhering to the walls of the crack. Rout and seal methods have been shown to add anywhere from 2 to 5+ years of life to pavement surfaces.
Filling Asphalt Cracks
Crack filling is different than sealant for two main reasons: the preparation process of the crack before treatment as well as the type of sealant used. Crack filling is not going to completely seal water out of cracks, but it does reduce the amount of water and other materials that are able to penetrate pavement surfaces. Filler material is quick to harden. For best results, most crack-filling processes are repeated once a year.
Crack filling is generally applied when cracks measure wider than 3/4 of an inch, or on worn pavements with wider and more random crack patterns.
What is full-and partial-depth crack repair?
Full-depth crack repair is a form of localized treatment used to repair cracks too severe for sealant to fix alone. The process starts by milling a trench directly over the existing crack. Hot-mix asphalt is then poured into the reservoir and compacted to the appropriate density. Density has a lot to do with the anticipated performance and lifeline of pavement surfaces. If it is not dense enough it will quickly be destroyed by traffic. Other factors that limit results include wet pavement and poor mix design.