Konica Minolta’s SenrigaN, a Nondestructive Inspection Solution, Receives Award for Excellence at the Japan Road Conference
For Its Effectiveness in Detecting Ruptures of Dowel Bars Embedded in Concrete Pavement

December 11, 2023

December 11, 2023 - Konica Minolta, Inc. (Konica Minolta) is pleased to announce that a paper reporting the results of research using SenrigaN, the Company’s nondestructive inspection solution, received the Award for Excellence at the 35th Japan Road Conference hosted by the Japan Road Association.

The Japan Road Conference is the largest conference in Japan’s road industry, bringing together people involved in road administration, construction, maintenance, urban planning and traffic in various parts of the country to present research results on a wide variety of road-related topics and exchange opinions. Winning this award is proof that SenrigaN is recognized as an effective, valuable technology for inspecting the state of each and every dowel bar embedded in concrete pavement, which had been thought impossible to do.

Award-Winning Paper and Its Authors

Title: Nondestructive inspection of ruptures of dowel bars by magnetic measurement Authors:
Masashi Niiyama: Technology Development Headquarters, Konica Minolta, Inc.
Noriko Ohara: Technology Development Headquarters, Konica Minolta, Inc.
Motonori Takakura: Konica Minolta Business Associates Co., Ltd.
Takayuki Ayabe: National Institute for Educational Policy Research; Road Technology Research Group (Pavement Research Team), Public Works Research Institute

Research Background and Results

In Japan, most roads are paved with asphalt; concrete, which is commonly used overseas, is used only for certain structures, such as the interior surfaces of tunnels. Recently, however, concrete pavement has been attracting growing attention for its life-cycle cost effectiveness compared with asphalt.

In concrete pavement, joints are provided at regular intervals to allow for the shrinkage and expansion of concrete, and steel rods called dowel bars are placed at the joints to connect the concrete slabs. These dowel bars, if ruptured, must be replaced with new ones, but it has been difficult to inspect the state of dowel bars embedded in concrete pavements.

SenrigaN generates magnetic forces in the objects to be inspected by using a special magnet. The state of these magnetic forces is detected by a sensor, and this data is then analyzed by a proprietary algorithm to locate ruptures of the objects inside structures. With its ability to promptly detect ruptures of steel materials inside concrete bridges, SenrigaN is assisting the efficient maintenance of bridges to prevent them from collapsing.

The award-winning paper describes an experiment conducted with concrete pavement installed at a test site, containing 13 embedded dowel bars, two of which had been ruptured (one with the ruptured surfaces separated and the other with the ruptured surfaces connected). When the states of the 13 dowel bars were inspected using SenrigaN, only the two ruptured bars showed a significant magnetic attenuation in signals in the depth direction. Consequently, the paper concluded that SenrigaN is an effective way of locating ruptures of dowel bars.