The Development of Structural Design Method of Composite Pavement in Japan

Abstract

Zero-maintenance pavements must be a big goal for road administrators around the world. As part of the challenges, a new design of composite pavement that is able to sustain heavy traffic loadings with minimum maintenance for long years was developed in Japan. The new design comprises a porous asphalt surface and continuously reinforced concrete base, which was adopted in the country's alternative beltway project, Shin (New) - Tomei Expressway, connecting Tokyo and Nagoya. The new route was opened to service in April 2012. The design concept of the new pavement is to combine both advantages of asphalt surface and continuously reinforced concrete base; the former assures better riding quality and easier repair job, while the latter provides higher durability for a longer service life. However, it took more than 15 years to finally develop a reliable design method for the pavement. In the process, several full scale test composite pavements were constructed and comprehensively investigated in terms of design, materials, construction and performance. This paper describes the investigation results of the test pavements and the structural design method of the composite pavement that takes into consideration the thermal stress reduction due to asphalt surface and fatigue impact on CRC base.