Asphalt cracks are fairly common on driveways, roads, and parking lots. Some are wide and deep; others are minor and hardly noticeable. Unfortunately, cracking is often an inevitable consequence of various factors like temperature fluctuations, heavy traffic, and improper installation.

Understanding the potential ways your surfaces might crack can help you implement a more proactive maintenance routine that addresses specific vulnerabilities. Whether it's base instability, poor bonding, or the wrong mix for a certain application, prevention and repair strategies can vary.

In this blog, R. Stanley Paving LLC's asphalt contractors explore the most common types of cracking, what causes them, and how to prevent and fix them.

Thermal Cracking: Temperature-Induced Asphalt Stress

Thermal cracking can occur when your asphalt surface is subjected to extreme temperature changes, causing it to expand and contract. This type of cracking is common in regions with harsh winters and where temperature swings are more frequent and intense.

Thermal cracking often appears perpendicular to the pavement centerline, creating what looks like a network of interconnected cracks. One prevention technique involves using asphalt binders with improved low-temperature properties for installation. These binders stay flexible in cold weather, reducing the likelihood of cracking.

Proper pavement thickness also provides insulation against temperature swings. If possible, avoid installing your asphalt surface during colder weather to minimize the risk of early cracking.

Fatigue Cracking: Repeated Loads on Asphalt Driveways

Fatigue cracking, often referred to as "alligator cracking" due to its distinctive ribbed pattern, is caused by the repeated application of heavy loads on your asphalt driveway. Over time, the constant pressure, especially in high-traffic areas, can weaken the asphalt's structure without proper preparation.

If your asphalt composition doesn't match load-bearing capacity, these fractures will start to crop up. During installation, reinforcing the base layer and using high-quality asphalt mixtures can enhance durability and resistance to any heavy loads you anticipate.

Techniques like stress-relieving layers can also help mitigate stress concentration. This involves incorporating materials like specialized asphalt mixes that can absorb and redistribute stresses under certain loads.

Block Cracking: How It Affects Aging Asphalt Pavements

Block cracking is characterized by large, rectangular patterns that typically appear on old asphalt surfaces. This type of cracking is usually caused by the asphalt binder losing its elasticity over time, often due to oxidation.

As the binder weakens, it can no longer accommodate the natural expansion and contraction of your pavement, leading to the formation of those block-like cracks. This "blocking" typically has two different causes related to installation: inadequate moisture levels and insufficient compaction.

Moisture levels are typically tested and maintained prior to installation; this allows for optimal compaction and prevents issues like voids and instability, both of which contribute to surface durability.

Reflection Cracking: How Underlying Layers Influence Surface Cracks

Reflection cracking is unique because it's directly caused by cracks in the underlying pavement layer. Essentially, the cracks in the base layer are "reflected" onto the asphalt surface. This means the problem originates below the asphalt rather than within it.

This type of cracking can be common in overlays since the new asphalt is directly applied over the existing concrete base. If your base has any minor weaknesses, they can also transfer to the overlay over time and cause cracking.

Address the underlying base before installation. This includes ensuring the concrete itself is in good condition, free of significant cracks, and properly cured before overlaying with asphalt. A strong, high-quality mix is just as important here as the binding will help mitigate the transfer of stress.

Edge Cracking On an Asphalt Surface: What Causes It?

Edge cracking is a type of longitudinal crack that you might observe along the edges of your asphalt pavement. It appears as a series of small, interconnected cracks that can extend from the pavement edge toward the center.

There are a few common causes:

Poor drainage: Water filtration weakens the pavement edge.
Lack of lateral support: Insufficient support at the pavement edge leads to instability.
Heavy traffic loads: Constant stress on the edge accelerates cracking.
Soil erosion: Loss of soil support weakens the pavement edge.

Adequate drainage will prevent water infiltration that weakens your asphalt's edges. Sufficient support, such as edge restraints or thicker pavement sections, will also help counteract lateral forces.

Longitudinal and Transverse Cracks: Differentiating Directional Stress Fractures

Longitudinal cracks run parallel to the centerline of a road, while transverse cracks run perpendicular to it. There are a few key differences in terms of causes.

Longitudinal Cracks

Repeated heavy loads: Constant pressure from heavy vehicles can cause your pavement to weaken and crack along its length.
Weak pavement structure: Insufficient base support or poor asphalt quality can contribute to longitudinal cracking.
Differential settlement: Uneven sinking of the ground beneath the pavement can cause your surface to crack longitudinally.

Transverse Cracks

Repeated tire flexing: The constant flexing of tires creates stress on the pavement, leading to cracks perpendicular to the road or driveway.
Thermal stresses: Expansion and contraction due to temperature changes can cause transverse cracking.
Weak pavement structure: Similar to longitudinal cracks, a poor pavement foundation can contribute to transverse cracking.

To prevent longitudinal cracking, focus on ensuring proper uniform compaction across the entire area, paying attention to the joints between paving lines. For transverse cracks, mitigate thermal stresses by selecting an appropriate asphalt mix that can withstand temperature variations.

Asphalt Repair Strategies To Address Cracking

The type of cracking you have can help diagnose and determine the right asphalt repair technique. For example, alligator cracking often points to an issue with the base layer and may require base layer reconstruction, while smaller cracks can be dealt with using sealants.

Here are some common asphalt repair strategies:

Crack sealing: Apply a flexible sealant to small, isolated cracks to prevent water infiltration and further damage.
Patching: Larger cracks or potholes may require patching with asphalt repair material. This involves removing the damaged asphalt, filling the area with new material, and compacting it.
Overlay: For extensive cracking or deterioration, an asphalt overlay involves applying a new layer of asphalt over the existing surface.

Keep Your Surfaces Smooth With Our Expert Asphalt Contractors

R. Stanley Paving LLC's asphalt contractors provide expert installation, repair, and maintenance to prevent and resolve any cracking.

Common Causes of Asphalt Cracks and How To Prevent Them