NEW TECHNOLOGY OF SURFACE TREATMENT TARGETING TEMPERATURE REDUCTION OF ASPHALT PAVEMENT

Reducing asphalt pavement temperature during summer season contributes to mitigate rut generation of the pavement effectively. New surface treatment materials which reflects both sunshine and infrared rays has been developed and applied on existing asphalt pavement surface. The rate of solar reflectance of the pavement is from 30 to 50 % depending on the color of the materials (black to gray). Measured surface temperature of the pavement applied with this type of surface treatment is by utmost 20 degree K lower than that of conventional asphalt pavement. Its maximum temperature reaches 60℃ and more during summer in Japan. The effect of temperature of the pavement is verified by showing a smaller rut depth generation in accelerated actual wheel load test. Rate of rut depth is approximately one third compared to conventional pavement. This surface treatment applied for pedestrian pavement offers comfortable feeling while walking. This result also brings to alleviate heat-island phenomena in urban growth area, where the rate of pavement area in large as about 20%. This paper presents outline of newly developed pavement technology which reduces surface temperature due to prevent pavement from absorbing solar radiation and its reflection properties. This paper also shows measured pavement temperature of some colored types, durability of the asphalt pavement with and without application of this surface treatment.