Colored asphalt is currently being tested around the world. Blue asphalt reflects sunlight better, lowers temperatures by up to 10 degrees and improves traffic safety.
Blue asphalt can cool roads by up to 10 degrees. The new technology is being tested in several places around the world to counteract the negative effects of heat. The goal is to lower the temperature on roadways and improve traffic safety during heat waves.
Plain black asphalt absorbs a large amount of sunlight. It is the dark color that is the reason. This causes the temperature of the road surface to rise sharply on sunny days.
The energy from the sun's rays heats the asphalt. The dark color reflects sunlight poorly compared to lighter colors.
By coloring the asphalt blue, the reflection of sunlight is increased, meaning that less heat is absorbed by the road material.
The color blue has a higher albedo value than black. This means that a larger portion of the sun's radiation is reflected instead of being absorbed as heat.
Hot asphalt causes traffic problems
The difference in surface temperature can be significant. Measurements show that the colored asphalt can cause the temperature to drop by as much as 10 degrees.
When asphalt gets very hot, it becomes more slippery. This can create challenges for traffic, especially on hot summer days.
Heavy vehicles, especially trucks and buses, can leave deep ruts. This causes unnecessary wear and tear on the roads and can require more frequent repairs.
Another problem related to heat is road safety, as the binder in the asphalt can be released at high temperatures.
The released binder forms a thin film on the surface, making the road surface slippery, especially if there is a light shower right after the heat.
Global testing of blue asphalt and future prospects
Hot asphalt also contributes to a phenomenon known as the 'Urban Heat Island' (UHI), which negatively affects the overall temperature in urban areas.
The effect means that the air in densely built-up areas is further heated by the hot surfaces. The asphalt releases the stored heat to the surroundings, especially in the evening and at night.
This can make staying in cities more uncomfortable during heat waves. It can also increase the need for cooling in buildings, which requires more energy.
The technology of colored asphalt is not entirely new. In several countries in the Middle East, blue asphalt is already used on the road network.
Here it is primarily used to reduce the high surface temperatures on roads and streets in an attempt to make the environment more bearable.
Experiments with colored asphalt are also taking place in other places around the world. In Los Angeles, where high temperatures are often encountered, colored asphalt is being actively tested in several places.
The results from the various test projects are being closely monitored. Experience will show how effective and sustainable the solution is under different conditions.
This could mean that technologies like blue asphalt will become more relevant for road maintenance. Perhaps we will see the colored asphalt in Denmark or other Nordic countries in the future.
Technological solutions are constantly being developed to improve our infrastructure and vehicles, especially when it comes to the cars themselves.
Porsche, Toyota and BMW, for example, believe that the internal combustion engine has a future that cannot simply be written off with a stroke of a pen.
The Japanese, for example, are developing an engine that burns hydrogen. Ferrari is actually working on the same thing. Although it's upside down. Read more about it here .
