Why Does Asphalt Turn Gray? The Science Behind Asphalt Discoloration 

Asphalt driveways start off with a rich, dark appearance but over time, they tend to turn gray and lose their luster. This change is more than just an aesthetic issue; it can indicate underlying problems with the asphalt. In this article, we will explore why asphalt turns gray, the dangers associated with it, and how to prevent this process. 

Why Does Asphalt Turn Gray Over Time? 

The primary reason asphalt becomes gray is due to a process called oxidation. When asphalt is exposed to sunlight, the ultraviolet (UV) rays cause the bitumen, or tar, in the asphalt to break down. Bitumen is what gives asphalt its dark color and flexibility. As it degrades, the asphalt loses its dark color and becomes brittle, leading to a gray, flaky appearance. 

Reasons Why Does Asphalt Turn Gray 

  1. Sun Exposure: Prolonged exposure to UV rays accelerates the oxidation process. 
  1. Weather Conditions: Rain, snow, and wind can erode the bitumen, further hastening the degradation. 
  1. Traffic Wear: Heavy vehicles and frequent use can wear down the asphalt surface, exposing the underlying layers. 
  1. Lack of Maintenance: Without regular maintenance, the protective layer of the asphalt wears away faster, making it more susceptible to quicker oxidation. 

Dangers of Asphalt Turning Gray 

A gray asphalt driveway is not just an eyesore; it indicates that there is asphalt deterioration and is becoming brittle and more prone to damage. Here are some potential dangers: 

  1. Cracks and Potholes: As the asphalt oxidizes its flexibility, it becomes more susceptible to cracking and developing potholes. 
  1. Weed Growth: Cracks can allow weeds to grow, further damaging the asphalt and making the surface uneven. 
  1. Water Damage: Gray, brittle asphalt is more likely to allow water to seep through, causing damage to the base layer and leading to further deterioration. 
  1. Reduced Safety: An uneven or cracked driveway can pose a safety hazard for both vehicles and pedestrians. 

How Long Does It Take for Asphalt to Turn Gray? 

The timeframe for asphalt to shift gray can vary depending on several factors, including climate, traffic, and maintenance. Generally, asphalt can start to show signs of graying within a few years if not properly maintained. In harsher climates or high-traffic areas, this process can occur even faster. 

How to Prevent Asphalt from Turning Gray 

Preventing asphalt from turning gray involves regular maintenance and protective measures. Here are some effective strategies: 

  1. Sealcoating: Applying a high-quality sealcoat every 2-3 years can protect the asphalt from UV rays, water, and chemicals. Sealcoating restores the asphalt’s dark color and provides a protective barrier. 
  1. Regular Cleaning: Remove dirt, debris, and chemical spills from the surface to prevent them from penetrating and damaging the asphalt. 
  1. Prompt Repairs: Address cracks and potholes as soon as they appear to prevent them from expanding and causing more significant damage. 
  1. Proper Drainage: Ensure that water drains away from the asphalt surface to prevent water damage. 

How to Maintain a Healthy Asphalt Driveway 

Fill Cracks and Potholes 

Cracks and potholes are early signs of asphalt degradation. Address them promptly to prevent further damage. Use cold-pour liquid crack filler or hot-pour crack filler for smaller cracks and a cold asphalt patch for potholes. 

Clean and Remove Stains 

Oil and chemical stains can weaken the asphalt if not cleaned promptly. Use mild dish soap and warm water for fresh stains, and for more stubborn stains, use an eco-friendly biodegradable degreaser

Remove Vegetation 

Weeds growing through cracks can exacerbate the damage to the asphalt. Remove vegetation regularly and use a leaf blower or crack cleaning machine for thorough cleaning. 


Sealcoating is crucial for maintaining the health and appearance of your asphalt driveway. It provides a protective layer that prevents oxidation and restores the asphalt’s dark color. 

Understanding why asphalt turns gray and taking steps to prevent it can significantly extend the life of your driveway. Regular maintenance, including cleaning, crack filling, and sealcoating, can keep your asphalt looking new and prevent the common issues associated with gray, degraded asphalt. 

For professional asphalt services, including maintenance and sealcoating, contact C. B. Paving Inc. at (830) 222-6317. Keep your asphalt driveway looking fresh and durable for years to come with our expert services. 

Don’t wait until your asphalt driveway turns gray and starts deteriorating. Contact C. B. Paving Inc. today for a free estimate and professional maintenance services. Call us at (830) 222-6317 to schedule your appointment and ensure the longevity and beauty of your asphalt driveway. 

Layfield Crew
Layfield Crew
August 2, 2023
It has been five years since C.B. Paving installed our quarter mile driveway. The work was outstanding, and it is holding up very well. They are very professional and friendly, and with reasonable pricing, too. Highly recommended!