Asphalt damage is caused by both moisture and temperature. This is just half of the story. Our roads can also be damaged by very cold air and excessive summer sun.

It is well-known that asphalt pavement freeze-thaw cycles can cause cracks to open and then freeze. The expansion of liquid water when it freezes causes cracks to be pried apart. It is a gradual process that eventually leads to pavement failure and canker holes if temperatures fluctuate above and below 32°F several times.

There are more factors that contribute to asphalt-paved roads' deterioration than simply cycles of warm/cold. It is also caused by moisture from rain and snow. However, cold can have an additional effect as well as the changing nature of weather that is largely a result of climate change. These conditions and cycles keep concrete contractors and asphalt pavement companies busy.

The bitumen is the petrochemical "goop," which holds together small stones and sand to make asphalt. The bitumen contracts and pulls apart the pavement. After a certain time, cracks will form on the asphalt's surface. These kind of cracks allow moisture to enter the pavement, which in turn makes it more susceptible to the freeze-thaw phenomenon.

However, it is alarming for state and local transportation departments that the weather patterns are changing. Some cities experienced near-record or record low temperatures during the 2021 polar vortex. These include Oklahoma City (-14ºF), Dallas (-2ºF), Houston (13ºF), San Antonio (12ºF), Little Rock (-1ºF), Fayetteville, Arkansas (-20ºF), and Hastings, Nebraska (-30ºF), among others.

This is especially true for asphalt pavements that haven't been exposed to such low temperatures in the past. Global warming is also causing higher levels of precipitation: Warmer temperatures worldwide mean more water evaporation and thus more moisture in the atmosphere. This moisture is what gets into pavement cracks.

It's not as if asphalt roads are easy to maintain in warm, temperate climates. Oxidation is the most damaging effect on asphalt caused by sunlight. The asphalt becomes more brittle from prolonged exposure to ultraviolet radiation. This causes cracking, or as it is sometimes known, spalling and raveling.

Smart preventative maintenance should be performed in all climates. Crack sealing, overlays, and filling potholes are some options. In colder and wintry conditions, the biggest problem is finding permanent solutions that can be applied before temperatures rise.