Heat and Weather Affect Asphalt

How Does Heat Affect Asphalt?

However, after installation, hot temperatures and UV rays from the sun can adversely affect the asphalt. Read about how the summer heat and weather affect asphalt.


Asphalt oxidation is a form of deterioration where UV rays from the sun cause a chemical reaction within the asphalt. Light oils mix with heavier oils, reducing the binding oils in the asphalt which weakens the asphalt structural sturdiness and integrity.

Oxidation will result in the asphalt becoming less elastic, the heavier oils will cause the asphalt to be brittle, and more fragility on the asphalt makes it prone to cracks, buckles, and failure. As this happens, the dark black hue of the asphalt fades to a lighter shade, eventually looking black-grey. If this were to occur in parking lots or roads, you would also notice stripping of pavement markings.

The more UV radiation occurs, the more severe oxidation happens, which then progresses to deep cracks or potholes, leading to failure of the asphalt construction.

Asphalt oxidation can result from asphalt aging, say after two or three decades in service, but the sun’s rays can hasten its deterioration.


Cracking, as mentioned before, can be caused by solar radiation and oxidation. However, cracking can also be a result of thermal changes in the asphalt. When there’s extreme heat, say over 90° Fahrenheit (like summer), the asphalt can expand, and as the temperatures drop at night or when it rains, the asphalt contracts again.

The expansion and contraction of the asphalt can cause cracks to appear, and in some cases, the road can even buckle up.
Cracking often occurs with old asphalt but it can also happen in newly installed asphalt if the installation wasn’t proper or there wasn’t regular maintenance. Also, cracking is common in asphalt surfaces with a lot of traffic like roads and parking spaces.

Unfortunately, asphalt cracking can cause additional problems like water infiltration, where water from the rain seeps in through the crack openings causing more damage. Furthermore, if this continues past the summer, the water will remain in the gaps and expand into ice as the seasons shift to winter or fall, damaging the subbase of the asphalt. Therefore, the repair is prudent.


Raveling occurs when water or excess moisture gets into the cracks causing a binder cohesion in the asphalt mixture. The asphalt will ravel in combination with the aggregate and the soil, causing further danger to the surface.

Raveling can occur due to inadequate compaction or separation of the binder and aggregate, but it’s typical from asphalt cracking. Note that the more cracks the asphalt gets, the more the asphalt damages. Plus, you might also notice settling, rutting, or base failure from water penetration through cracks.


The last type of damage on asphalt from heat is tracking. Solar reflectance values range from zero (no reflectance) to one (all sun reflectance), where asphalt has reflectance values ranging from 0.04 to 0.16, whereas concrete has values of between 0.18 to 0.35. However, the darker the asphalt, the higher the value with black concrete at a solar reflectance of 0.69.

The asphalt absorbs the sun’s heat energy causing the surface temperatures to be extremely high. As a result, the asphalt surface can soften, releasing specks of asphalt which can adhere to shoes or tires. While it’s not a severe side effect of the sun, it doesn’t mean it causes asphalt to withhold extreme heat temperatures.

Heat damage is inevitable to your asphalt surface, but you can prevent excess damage and elongate its lifespan significantly with a seal coat and regular asphalt repairs.

Contact JR Paving & Construction Co., Inc., today for all your paving needs.