| In order to enhance safety on rainy days and reduce traffic noise for nearby residents, porous asphalt pavements have been constructed since 1987 in Japan. Such pavement accounts for approximately thirty percent of national highways and seventy percent of toll motorways nationwide. Although recycling technology for pavements made of straight bitumen is widespread in Japan, it has yet to be established for porous asphalt, which is significantly defferent from conventional types in its aggregate gradation and higher ratio of polymer modifiers. There have been several technical issues to develop or elucidate, such as mix design methods for how to rejuvenate existing materials in the roadway. In order to deal with these themes, field experiments were conducted on five sections of national highway. The two sections with dense recycled mixes focused on the appropriate ratio of existing porou materials and the degree of rejuvenating the highly viscous modified bitumen. The other three porous sections with target air porous gradations, the manner of rejuvenating the highly viscous modified bitumen, and the appropriate ratio for existing porous materials. This paper describes the technicak findings from the follow-up field surveys for two years. |
