Crack Sealing: The Squiggly Lines on the Road

Have you ever wondered about the squiggly black lines on asphalt roads, especially in rural areas? Contrary to what you might think, the squiggly lines don’t indicate a problem with the road surface. Neither are the lines proof of haphazard work by those responsible for maintaining the roadway. Instead, they are crack sealing patches, an efficient yet cost-effective solution to an unavoidable issue with asphalt roads.

What Are the Squiggly Lines on the Asphalt Road?

The squiggly lines on asphalt road surfaces are fractures sealed by crack sealant. They can withstand the same stresses as the undamaged asphalt pavement, so it’s safe to drive your car over them.

What Is Crack Sealing?

Crack sealing refers to the process of putting an adhesive sealant in the asphalt cracks in the pavement surface. Workers remove debris and water from the crack before injecting hot sealant into or above the fracture.

Modern crack sealants look like tar, but they actually don’t have tar. They contain polymer-modified asphalts and asphalt rubber. They create a flexible bond that prevents the road surface from cracking even more.

Crack sealing does several jobs. It prevents water and incompressible debris from entering asphalt cracks, where they can cause problems with the base, subgrade, and joints. Second, it prepares the road surface for additional maintenance or overlays. Finally, it extends the lifespan of the asphalt pavement by several years.

Applying a de-tacking agent or sealant finisher removes the surface tack that forms on freshly poured crack sealant. It speeds up the crack sealing process, allowing drivers to use sealed roads much earlier.

Crack sealing is ideal for block, longitudinal, and transverse cracking that measure between 0.12 and 1 inch at their widest point. The edges must be smooth, not jagged.

Why Do Asphalt Roads Need Crack Sealing?

The surface layer of asphalt roads accumulates stress over time. Stress comes from various sources, such as road traffic and the surface layer contracting and expanding as the temperature changes alongside the seasons. When the built-up stress exceeds asphalt’s tensile strength, the surface layer develops cracks.

Heavy traffic is arguably the most common reason for asphalt cracks. Whether it’s a constant flow of vehicles or the regular passage of commercial trucks, traffic puts a lot of stress on the road surface.

Another common cause of asphalt cracks is seasonal temperature changes. Asphalt expands when heated and contracts when cooled. The material can deform and fracture if the temperature abruptly changes, such as during seasonal shifts.

The road might also have flaws in its design and construction. One example is road drainage, the ability of the road to remove water from its surface and below it. If the designers didn’t consider environmental factors like precipitation, they might not have given the road enough drainage to handle heavy rainfall and snowfall.

Whatever caused the asphalt to crack, it’s up to crack sealing to fix the issues. It restores the integrity of the road surface, protecting the more vulnerable parts of the road under the pavement.

Advantages of Crack Sealing Over Road Rebuilds

So, why are road crews sealing asphalt cracks instead of doing more extensive repairs that will surely last longer? Crack sealing is a cost-efficient, long-lasting option to repair most cracked roads.

Tearing up the damaged pavement and resurfacing the road uses up almost as much asphalt and related materials as laying down an equivalent length of brand-new road. There are also equipment and labor costs to consider.

In contrast, crack sealing uses less asphalt-based materials and requires fewer workers. While the process calls for expensive specialized equipment, such as melter ovens and melter applicators, it doesn’t need heavy machinery like earthmovers.

Crack sealing also lasts for several years. Using hot-applied rubber and fiber-modified asphalt in flush or overbanded configuration gives between six to eight years of protection.

Drawbacks and Limitations of Crack Sealing

Crack sealing isn’t perfect. Understanding its limitations can give an idea of how to compensate for its failings.

The biggest issue with crack sealing is that it doesn’t smoothen the road surface. Crack sealing patches generally look rougher than the rest of the pavement. The suspension on most cars can smooth out the vibrations created when you drive over the repaired patches. But if you ride a motorcycle, you’ll definitely feel the difference in the texture of the repaired road.

Crack Sealing vs. Crack Filling

Before crack sealing, there was crack filling. The latter process continues to see use in situations where crack sealant might not cut it. Knowing the difference between the two asphalt crack repair methods is helpful.

Crack filling uses cold-patch or hot-patch asphalt to fill non-working cracks and holes that are too deep for crack sealant. Non-working cracks have closely spaced edges that prevent them from moving and expanding or contracting in size. Unlike the crack sealing process, there’s no need to clean the fracture before filling it with the patch mix.

The crack filling process needs simpler equipment. If you have a shovel, an asphalt tamper, and a supply of pressurized air, you’re ready to fill deep cracks in the asphalt road.

However, crack sealing patches last longer (6-8 years) than crack filling, which only lasts a couple of seasons. Crack sealing can also compensate for working cracks that move more often and might get bigger.

The next time you see squiggly lines on the road, rest assured that they can handle your vehicle’s weight when you drive over them. Crack sealing is an effective way to repair and extend the lifespan of asphalt roads.