A Survey Method for Measuring Load Transmission Rates in Concrete Pavements Covered Using Asphalt

National Road No.17 starts from Nihonbashi (which means the name of Bridge in Tokyo) and connects the metropolitan area and Northwestern Region of Japan. Among them, Omiya Bypass which runs through the central area of Saitama Prefecture was started as concrete pavement in 1963. However, damage to concrete slabs and joints progressed due to increasing the large car traffics and deteriorations, at present, it has been changed to the overlaid structure with asphalt pavement on a concrete slab (3.25mx10m). In recent year, in Omiya Bypass, cracks on the road surface and vibrations become noticeable and repair work is being carried out from the high urgency area with priority.　From a large-scale research implemented in 2017, the cause of vibration is considered to be the impact of passing large vehicles and cracks occur on the road surface due to damage (break of Dowel bar, gap) near the joints of concrete plates that laid under asphalt. Surface cracks can be used to determine the damage status by road surface survey but joints in asphalt covered concrete slabs cannot be surveyed directly and the efficient investigation is required because the repair wide range extending. In this paper, in order to evaluate the soundness of the joints between asphalt covered concrete slabs we can describe the content of the method of efficiently investigating the load transfer rate which is one of the items to evaluate the joints.