Abstract: In the Report a summary is given of the method of structural design of flexible pavements laid on very weak subgrade with CBR as low as 2 or less, which is a condition frequently encountered in Japan. Also included is a description of the so - called sandwaich method which has steel plates in the intermediate layer and has been specially designed to solve the soft subgrade problem. Full-scale test pavements and performance surfeys of existing pavements have been made in various places to study the applicability of the new design. Some typical expamples are described in this report. Also, the method of performance survey and the general conditions of the survey and research for determining the timing of pavement repair and the method of repair based upon the serviceability which is derived from the performance survey are reported. As for bitumionus binders, their present status in our country, including special buituminous materials, is briefly explained. Bitumen stabilized roadbases have been widely used in our country and the economic benefits of this type of stabilizatin has been probed especially in large projects such as Tokyo-Nagoya Expressway construction. The design standards of bitumen stabilized base course in Tokyo-Nagoya Expressway and those specified in the Asphalt Pavement Manual are described in this report. Full-scale test pavements for various purposes have been carried out in order to study bituminous mixtures. Also refered to are the test pavements which have been designed to study the characteristics of bituminous mixtures such as stability, adhesion, and resistance against abrasion by tyre chains. A few interesting results are now evident although test pavements have not been subjected to traffic long enough to obtain comprehensive results. Precautions for laying bituminous mixture during cold weather in our country are mentioned. Thin wearing course overlays are used for road maintenance. The results of full-scale test pavements to compare the different types of thin wearing courses are also given in the report. /Author/
Publication Year: 1971
Publication Date: 1971-01-01
Language: en
Type: article
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot