Common asphalt roads are dark gray, but in urban areas such as Tokyo, you may find roads painted in other colors.
Did you know that some of the roads are painted in a light gray color?
this is,It is called “functional pavement” and has a role to suppress the “heat island phenomenon” that is seen in urban areas where the temperature rises higher than in the suburbs.It is said that.
10 ℃ cooler than ordinary roads! ?? Why?
In urban areas, the heat island phenomenon keeps temperatures high all day long.It was developed to suppress such a phenomenon as much as possible.“Water-retaining pavement” and “heat-shielding pavement”It is a functional pavement called.
Water-retaining pavement has the characteristic that the water that has permeated the road surface can be stored as it is when it rains or when water is sprinkled.When the water on the asphalt pavement evaporates, the heat of vaporization can be used to lower the temperature of the road surface.
This is because the surface of the road surface is paved with cement containing a water-retaining agent and has many gaps so that water can be stored.
According to a survey by the Pavement Study Group for Suppressing Road Temperature Rise,It can suppress the temperature rise of about 14 ° C compared to the unpaved road surface.It is said.
On the other hand, heat-shielding pavementIt can be expected to have the effect of reflecting the infrared rays of the sun and suppressing the temperature rise of the road surface.It’s a road. Applying a paint that reflects infrared rays to the surface of the asphalt has the effect of preventing heat from accumulating on the asphalt.
According to the above-mentioned study group’s research, even if you compare a paved road that does nothing in the summer with a paved road that has been painted to reflect infrared rays,We were able to suppress the rise in temperature by a maximum of 10 ° C or more.It’s called.
In any case, the key to suppressing the heat island phenomenon is whether or not heat is accumulated in the asphalt, or even if heat is accumulated, heat can be released efficiently.
Roads painted in light gray are “functional pavements” that can be expected to play such a role.