Preserve, protect pavement performance

By Jeff Winke

Cracks happen. In time, exposed to the world, asphalt paving gets them. And fixing asphalt pavement cracks is critical to maintaining a strong, useable surface. As the National Center for Asphalt Technology (NCAT) at Auburn University states: “Crack sealing and filling can be cost-effective treatments when applied while the pavement is still in a state of good repair. These treatments consist of applying a highly elastic material into pavement cracks to prevent or reduce the intrusion of water and incompressible materials.”

Crack sealing is a significant part of pavement maintenance.

“The first steps to crack sealing is to do a visual inspection of the pavement to identify the cracks that need to be repaired,” stated Jenn Brasher, equipment sales and marketing manager with Marathon Equipment, Burlington, Ontario, Canada. “Measure the width, depth and length of the cracks to determine the appropriate materials and techniques for the repair. If you can determine the underlying causes of the cracks, such as water infiltration or structural issues, this can help in selecting the proper material and method of repair.”

Ben Thielbar, director of sales, Cimline Pavement Maintenance Group, Plymouth, Minnesota asked when a contractor considers crack sealing: “Are you routing or not? If you are routing, the first step should be to identify working cracks, which are cracks that have movement and expansion, versus non-working cracks, which are cracks that generally run longitudinal down the road and are not classified as working cracks.

Thielbar continued: “Only working cracks need to be routed, however all cracks will still be sealed. After identifying these areas then I am looking for an average crack width and depth. I will use this calculation to estimate how much sealant we will need for the job. Sealant product manufacturers typically have nice calculators that will allow for a simple crack fill job or crack seal job and provide the proper coverage rates and material poundage amounts for the job.”

Cracks are inevitable, and neglect leads to more cracking and potholes, which further reduces pavement serviceability.

“According to the Federal Highway Administration, ‘Crack Sealing is the single most effective preventative maintenance tool available.’” stated Tom Pfuelb, eastern regional sales manager with Crafco, Inc., Chandler, Arizona. “The primary objective of crack sealing is to extend the life of the pavement by preventing water and matter from entering the pavement and subbase. The infiltration will not only accelerate cracking but also result in potholes and other discontinuities which decrease the pavement’s life.”

To ensure successful seal coating there is prep work to be completed.

“To prepare the cracks for crack sealing, clean the cracks out by thoroughly removing any loose debris, vegetation, dirt, or loose particles,” Brasher said. “Routing to widen the cracks, is necessary to create a proper reservoir for the sealant. Ensure the cracks are dry before applying any sealant, to ensure proper adhesion.”

Brasher continued: “Choose the appropriate type of sealant based on factors identified during the evaluation process. Apply the sealant using the suitable equipment, such as a hot pour melter, or specialized crack sealant machine. Make sure to allow the sealant sufficient time to cure and achieve its full strength before allowing traffic to resume. You can find the appropriate curing time from your material manufacturer.”

There are advantages to using crack sealing.

The benefits of crack sealing according to NCAT, include decreasing further crack deterioration, protecting the pavement structure from moisture damage, and ultimately extending the pavement life. Although the expected life extension is typically reported to be between two to five years, the benefit obtained depends on several variables such as traffic, climate, and the condition of the pavement at the time of treatment.
After crack sealing is applied there is time that is needed for it to cure and cool down.

“Quality crack sealant from a quality manufacturer is ‘prereacted’ and doesn’t actually ‘cure’ after applied to the pavement, but rather it simply needs to cool and solidify,” said Bryan Darling, western regional sales manager, with Crafco. “After crack sealant has been applied to the pavement, the sealant must be protected from traffic until it has cooled sufficiently to be opened to traffic without tracking or picking by vehicle tires.

Under normal conditions, a properly selected sealant will generally be cooled within 30 minutes to allow traffic to access the payment. This time can be decreased by the application of an approved detackifying agent to the surface of the sealant. Factors taken into condition, when selecting a sealant for a region, include pavement type, climate, traffic type, and desired performance.”

When is the best time to perform crack sealing? The best time to perform crack sealing depends on various factors, including weather conditions, pavement condition, and traffic volume.

“Crack sealing is typically performed during warmer weather when temperatures are consistently above freezing,” Brasher said. “This ensures proper adhesion and curing of the sealant. Avoid performing crack sealing during rainy or humid conditions. The cracks should be dry before applying the sealant to ensure adhesion and prevent moisture entrapment. It is also best to perform crack sealing when the cracks are still relatively small and haven’t developed into larger issues requiring more extensive repairs. Schedule crack sealing during times of lower traffic volume to minimize disruption to road users.”

Brasher added: “In regions with distinct seasons, the best time for crack sealing may vary. For example, in colder climates, crack sealing is often performed in the spring or summer after the winter freeze-thaw cycles have caused cracks to expand. Overall, the best time to perform crack sealing is during dry, warm weather conditions when temperatures are conducive to proper adhesion and curing of the sealant.”

To conclude, crack sealing is an essential practice for preserving the integrity and safety of asphalt pavement. It prevents water from infiltrating the pavement structure, which can cause erosion and further damage. By sealing cracks early, it can extend the life of the pavement, delaying the need for more costly repairs in the future. Crack sealing is a relatively quick process that minimizes disruption to traffic, and creates a smoother, better traction, and safer driving surface.