How cold weather takes a toll on asphalt pavement.

As winter's icy grip tightens in the Northern Hemisphere, our roads undergo a transformation beneath layers of snow and ice. By exploring this relationship between asphalt and plummeting temperatures, we can also identify solutions to the challenges that cold weather poses for asphalt roads and surfaces.

The chilling impact on asphalt.

“Asphalt is a viscoelastic material, meaning it exhibits both solid-like and liquid-like properties,” said Brayden Lester, asphalt territory manager at Colorbiotics. “When temperatures drop to 32 degrees Fahrenheit or below, asphalt undergoes a process known as embrittlement. The material becomes stiffer and more rigid, losing its flexibility. This change in mechanical properties sets the stage for a plethora of challenges that affect the overall integrity of road surfaces.”

Flexibility in an asphalt road is essential for its ability to withstand various traffic loads, temperature changes and ground movement, and to prevent cracks and other structural failures. Without flexibility, the likelihood that cracks and potholes will pop up on your daily commute is more probable.

Breaking down asphalt challenges.

One of the most significant issues arising from cold weather's impact on asphalt is the increased susceptibility to cracking. As the material loses its ability to flex, it becomes more prone to the formation of cracks. These cracks can take various forms, including transverse cracks that run perpendicular to the road, longitudinal cracks parallel to the direction of travel, and alligator cracks resembling a pattern like reptilian scales. These openings serve as entry points for moisture, which can intensify the damage and compromise the road's aesthetics.

Cold weather doesn't just affect the surface — it extends its icy fingers beneath the pavement, too. Frost heaving, a phenomenon where soil freezes and expands, exerts upward pressure on the pavement. This swelling of the ground beneath the road can lead to the formation of uneven surfaces and in some instances, the upheaval of asphalt, causing bumps and potholes.

To combat the hazards of ice buildup on road surfaces, winter maintenance crews often employ de-icing agents such as rock salt or calcium chloride. While these reliable asphalt products are effective in enhancing traction, they can also contribute to the deterioration of asphalt. “The repeated freeze-then-thaw cycle caused by de-icing products actually accelerates the wear and tear on the surface,” Lester said. “The cycle can lead to premature aging and breakup of the asphalt’s structural integrity.”

Reliable asphalt products and asphalt solutions for cold weather.

Despite cold weather challenges, proactive measures can be taken to mitigate its impact on asphalt pavement:

1. Routine maintenance, including crack sealing and pothole repairs, can prevent small issues from escalating into major problems.
2. Preventive asphalt solutions such as Invigorate sealcoat or Invigorate Plus sealcoat, can penetrate four times deeper than typical topical solutions to address potential cracking, enhancing the lifespan and resiliency of surfaces. Invigorate Plus sealcoat forms a water-resistant protective barrier, preventing water infiltration between the asphalt binder and aggregates.
3. Apart from employing an asphalt solution like a sealcoat, using a hot and warm mix product while laying asphalt in cooler temperatures, can help reduce asphalt stiffness and improve compaction and paving.
4. Using magnesium chloride instead of the conventional sodium chloride for de-icing proves to be more efficient, as magnesium chloride works to melt ice faster compared to many other de-icing agents. Additionally, research done by the Colorado Department of Transportation indicates that magnesium chloride is less likely to result in adverse environmental effects compared to other de-icing products.

“Understanding the balance between temperature and road surfaces is crucial for implementing effective strategies to preserve the infrastructure of our roads,” Lester said. “That way, we’re not seeing the need for as many corrective projects after every winter season. By acknowledging the challenges posed by dropping temperatures and adopting preventative measures, we can ensure that our roads withstand the freezing temperatures that creep in every winter.”