Oki, cement firm work on strain sensing with RFID

Oki ElectricIndustry Co. Ltd and Taiheiyo Cement Corp. have developed the "Strain Sensing System" to maintain and manage structures using a passive-type sensor-integrated RFID. The RFIDconnects to various sensors with no need of a batterysince it does not emit radio waveon its own.

There has been a rising need to examine structures easily and appropriately, as efficient maintenance and management of roads, bridges and public housing are required. Concrete and steel structures are constantly under various loads including everyday traffic, wind and earth pressure and earthquakes. Thus, the load bearing ability declines through damage from deterioration until the structure can no longer perform its function. Conventionally, the maintenance and management of structures involved estimating the degree of deformation from outward appearance. For this reason, it has been very difficult to directly measure deformation caused by loading.

Oki and Taiheiyo embarked on the joint development of the system because their views to reduce maintenance costs and to provide new services, such as information management for maintenance and management, conformed. The companies have been able to directly measuring structure load and deformation levels using the Strain Sensing System, which includes a sensing function, and plan to expand applications in the construction industry.

The Strain Sensing System, based on a passive-type sensor-integrated RFID, measures the changes and deformation caused by various types of deterioration and loading on the structure, without using a battery. By embedding a sensor-integrated steel within the concrete, the system can perform measurements at a strain resolution level of approximately 10X10-6. In addition, with a thermistor, the system simultaneously measures temperature and can account for deformation caused by temperature.

With this system, Taiheiyo Cement will execute the verification tests on-site and will use the system in its "Concrete Solution," a Taiheiyo Cement's initiative for proposing the most suitable concrete material and technologies. In addition, with a target date of April 2008, Taiheiyo Consultant Co. Ltd will initiate trial sales of the system in the Japanese market to expand its consultation business by performing services such as examining structures after the system has been installed.