Asphalt Pavement Roads and the Impact of Snow and Cold

It is not the only way asphalt can be damaged by extreme temperatures or moisture. Both very cold and hot summer sunshine can cause damage to our roads.

Understanding how freeze-thaw cycles affect asphalt pavement is a common topic. When liquid water enters cracks and then freezes, the expansion caused by the freezing of the water pries those cracks apart. If temperatures fluctuate more than once, it can lead to pavement failure or potholes.

However, asphalt-paved roads are not only affected by cycles of warmer/colder. There's much more to it. This is caused by rain and snow moisture. Cold has an additional effect. This is due to the climate change-related nature of weather changes. These situations and cycles keep local concrete contractors and asphalt companies busy.

First, a drop in temperature, regardless of whether there is moisture, causes a contraction effect on bitumen. This is the petrochemical "goop" that holds together tiny stones and other sand that makes up the bulk asphalt. Bitumen contracts, pulling the pavement apart. If the temperature drops, cracks can develop in the pavement. These cracks become the entry points for moisture later, which then causes it to freeze.

What's most concerning for state and local transport departments is the changing weather patterns. Some cities saw near-record low temperatures in the polar vortex 2021. They include Oklahoma City (-14ºF), Dallas (-2ºF), Houston (13ºF), San Antonio (12ºF), Little Rock (-1ºF), Fayetteville, Arkansas (-20ºF), and Hastings, Nebraska (-30ºF), and many other cities.

This is especially bad for asphalt pavements that haven't been subject to extreme cold temperatures in the past. Global warming also causes higher levels of precipitation. With warmer temperatures, more water evaporates, and so there is more moisture in the air. This moisture is what causes cracks in pavement.

The summer sun is not always kind to the pavement. The sun's ultraviolet radiation has a negative effect on asphalt. This is called oxidation. This happens when asphalt is exposed to UV radiation, especially in combination with the presence of automotive oils, which makes it more brittle. Cracking can result, also known as spalling or raveling.

Smart preventative maintenance is essential in both warmer and colder climates. This should address small cracks or fissures before they get larger. This can be done by crack sealing, overlays, or filling potholes. It is difficult to find permanent solutions in wintery conditions.