At the outset, it is important to point out that asphalt usually does not burn from wildfires. However, the biggest threats to asphalt pavement from wildfires include landslides, deformation, and cracks. Potholes can also appear later on.
Why Large Pavements Do Not Burn Easily?
Typically, large pavements do not get burned due to some major reasons. One of these reasons is asphalt is made of non-combustible elements. Sand and little stones are made of 90 percent of the volume of the pavement. Another key reason is that bitumen’s ignition temperature is 900 degrees Fahrenheit. It, however, boils at 600 degrees and is more likely to vaporize and melt before burning. Usually, the ground is cooler as compared to the effect of flames on vehicles, bushes, trees, and homes. Therefore, the short time the fire is over the asphalt pavement does not raise the heat to 900 degrees.
As such although wildfires cruelly burn businesses and homes, it is not true for patios, sidewalks, pavements, and roads. However, there are certain situations when an asphalt pavement may burn from excessive hot temperatures. It may happen when oil gets accumulated. For instance, a vehicle frequently parked is constantly leaking fluids. The asphalt pavement may also appear to burn when a car traveling through a tunnel catches fire. The vehicle’s content may be burning or burning vehicle fuel may explode at times. It can further intensify in a tunnel and lead to burning or melted pavement in case it reaches the 900 degrees Fahrenheit point. There could be a lot of severe damage and even death in such a scenario.
Wildfires Can Damage Asphalt Pavement in Different Ways
However, just because a pavement made of asphalt burns on rare occasions does not signify that wildfires do not damage an asphalt pavement. Many roads in rural locations are not suitably built for fire fighting vehicles and heavy fire trucks. Things may further worsen then the fires’ heat is near enough to almost melt the pavement. Such damage is quite similar to that of a regular highway but external elements such as rotting, tear and wear also cause damage to highways over some time.
Another effect of wildfires on asphalt pavement is cracking. Similar to any other temperature swing, it results in the infiltration of water into the road’s sub-layers. It finally leads to big potholes. People who closely work with asphalt may be vulnerable to physical risks while inhaling fuming from asphalt that is very hot.
Some other effects of fires on roads include hot embers and fallen trees making them highly risky for people who are making attempts to escape the wildfire. In hilly areas. if a wildfire is followed by heavy or torrential rainfall, it can lead to landslides blocking, as well as, destroying roads.
To conclude, it can be said that while driveways and roads made of asphalt pavement may not burn due to wildfires, the actual damage could occur in various ways in the weeks and days to come.