We’ve seen many pavements over the years, and one thing remains constant: cracks don’t stay small for long. They spread quietly, especially with the weather swings we get in Arkansas. One day it’s a narrow line, and the next it’s deep enough for water to slip in and start breaking down the layers underneath. We’ve repaired driveways, parking lots, and long commercial lanes that could have lasted years longer if the cracks were sealed early.

That’s why knowing which cracks need asphalt crack sealer right away makes such a big difference. Here are the types we always tell people to watch for.

9 Types of Cracks That Must Be Treated with Asphalt Crack Sealer

1. Alligator / Fatigue Cracks

Alligator cracks typically appear in older pavement or in areas that experience heavy traffic loads, such as drive lanes in parking lots. They resemble reptile skin.

Before applying asphalt crack sealer, we look closely at what caused the cracks: a weak base, water damage beneath the pavement, or stress from repeated traffic.

Here’s what we look for in these cracks:

• Web-like patterns that cover one section.

• Soft spots under the cracked area when pressure is applied.

• Cracks connected at several angles instead of running straight.

2. Linear (Longitudinal) Cracks

We often find linear cracks running straight down the pavement, usually parallel to the direction of traffic. They form as the asphalt ages or when two paving lanes start to separate slightly over time. Even though they may look harmless, these cracks allow water to travel a long way through the pavement.

Signs you’re dealing with a linear crack:

• A single long line that seems to keep growing.

• A crack located between two paving passes.

• A narrow but deep opening that widens during winter.

3. Transverse Cracks

These cracks run across the pavement, not along it, and temperature changes usually cause them. Asphalt expands in hot weather and contracts when it cools.

We’ve seen transverse cracks turn into potholes faster than most people expect. Using asphalt crack sealer at these gaps stops that cycle and protects the structure underneath.

You may be looking at a transverse crack if you notice:

• A wide opening running left to right across the asphalt.

• Sharp edges inside the crack.

• Gaps that open more during colder months.

4. Block Cracks

Block cracks appear as big square or rectangular patterns across large sections of pavement. When the asphalt binder dries out, the surface becomes stiff and loses its flexibility. That’s when these big patterns begin to spread.

We seal block cracks to prevent the broken sections from becoming loose pieces.

Block cracks usually have:

• Straight lines forming box-like shapes.

• Wide spacing between cracks.

• Rough edges that start to separate.

5. Edge Cracks

These cracks start at the sides of the pavement and move inward. We often see them in driveways or in parking lots.

Sealing edge cracks with asphalt crack sealer helps stop water from traveling under the edge, which is one of the fastest ways to weaken pavement, because the outer areas already have less support.

Common signs of edge cracking include:

• Cracks that run along the sides of the asphalt

• Grass or weeds pushing through the edges

• Soil erosion or broken edges

6. Slippage Cracks

Slippage cracks are easy to spot because they have a curved or crescent shape. They occur when the top asphalt layer fails to bond well with the layer underneath. When cars turn, brake, or accelerate, the top layer shifts slightly and forms these curved gaps.

They usually look like:

• Half-moon shaped curves.

• Cracks that appear in turning zones.

• Loose surface material around the crack.

7. Reflective Cracks

Reflective cracks are exactly what they sound like: cracks that come up through new pavement from older cracks underneath. You’ll see them commonly in areas that were resurfaced years ago without repairing the original cracks.

Typical signs include:

• Cracks that follow the exact pattern of older cracks.

• Long, straight lines appearing in resurfaced areas.

• Cracks that return shortly after resurfacing.

8. Seam Cracks

Seam cracks form where two asphalt sections meet. These areas are naturally weaker because they cool at different times during the paving process. Over time, traffic pressure and water exposure cause the seam to separate even further, which is why sealing the joint with asphalt crack sealer is so important.

Seam cracks usually appear as:

• Straight lines between paving lanes.

• Cracks forming right at the joint or seam.

• Gaps that open wider during wet weather.

9. Shrinkage Cracks

Shrinkage cracks are thin, shallow lines that appear as the asphalt ages and the binder dries out. These cracks may seem harmless at first, but they’re early signs that the surface is losing flexibility. Over time, the cracks connect and spread across the pavement, at which point asphalt crack sealer becomes necessary to slow the aging process.

They usually look like:

• Thin, short cracks

• Random patterns on older pavement

• Cracks with dry, rough edges

When Crack Sealing Isn’t Enough

Although asphalt crack sealer addresses many issues, there are instances when more extensive repairs are necessary. We always check the strength of the base because cracks sometimes indicate bigger issues under the surface.

Signs a Crack Has Become Structural

A few things tell us the foundation is already compromised:

• Large areas of alligator cracking

• Soft or bouncy spots under the pavement

• Sinking or dips in the surface

• Cracks that open again shortly after sealing

Repairs Needed Beyond Crack Sealer

Patching

If the base is damaged in small areas, we remove the weak section and rebuild it before adding new asphalt. This prevents the same cracks from returning.

Overlay / Resurfacing

When the surface is worn out everywhere except at the base, which remains strong, we place a new asphalt layer on top. This gives the pavement a fresh start without requiring a complete replacement.

Full-Depth Replacement

If both the asphalt and base are failing, replacing the full depth is usually the only way to restore strength. We only recommend this when the damage is too widespread for repairs.

Conclusion

Cracks never stay the same size, and we’ve seen how quickly they turn into bigger problems when they’re left open. Using asphalt crack sealer at the right time protects the surface, keeps water out, and helps your pavement last much longer.

If you’ve spotted any of the cracks we covered here, we’re always ready to take a look. The team at Armor Asphalt can tell you exactly what caused the crack, what it needs, and how to keep the rest of your pavement in good shape. Reach out anytime, and we’ll help you prevent small cracks from becoming costly repairs.