Field measurements of road surface temperature of several asphalt pavements with temperature rise reducing function

In the urban area, the heat island phenomenon and hot nights when the temperature does not fall below 25 °C outdoors are becoming environmental problems. Pavements cover a high percentage of the urban area and largely affect the development of the urban heat island phenomenon. The authors have developed water retaining pavements with several cement-based grouting materials poured into voids of open graded asphalt pavements (porous asphalt pavements) to reduce the surface temperature in the hot summer climate. The cement-based grouting materials consist of cement, ceramic waste powder, and fly ash or natural zeolite. In field measurements conducted in the summer season, all of the water retaining pavements reduced the surface temperature by 10 °C and more, when the porous asphalt pavement reached over 60 °C. Especially, one of the water retaining pavements, which uses ultra-rapid hardening cement, ceramic waste powder, and natural zeolite, reduced the surface temperature by about 20 °C. In this paper, the details of the cement-based grouting materials used in the field tests are described. Also, the field test results on the thermal performance of the water retaining pavements are reported.