The Great East Japan Earthquake hit Tohoku Area in Japan on March 11, 2011. A large number of concrete structures were damaged by the 9.0 magnitude earthquake in Richter-scale. Prior to reconstruction and retrofit of these structures, damage evaluation of…
The Great East Japan Earthquake hit Tohoku Area in Japan on March 11, 2011. A large number of concrete structures were damaged by the 9.0 magnitude earthquake in Richter-scale. Prior to reconstruction and retrofit of these structures, damage evaluation of in-situ concrete is now in urgent demand. In this concern, quantitative estimation of damaged concrete is going to be performed, applying acoustic emission (AE) measurement in the compression test of core samples. The procedure is named DeCAT (Damage Estimation of Concrete by Acoustic Emission Technique), which is based on estimating an intact modulus of elasticity in concrete. Distribution of micro-cracks in a concrete-core sample is inspected by helical X-ray computer tomography (CT) scans at one-millimeter intervals. Then, damaged samples are evaluated based on AE generating behaviors due to fracturing under compression. It is demonstrated that the decrease in physical properties could be evaluated by comparing an average CT number with a rate of AE generation, which is analyzed by the AE rate process. A relation between AE rate and damage parameters is correlated. Thus, by calculating initial Young’s modulus from the DeCAT system, the damage of concrete is quantitatively estimated.