Damage Evaluation of Core Concrete by AE

Abstract

For a detailed inspection of a concrete structure, core samples are usually drilled out and then their physical properties are measured.  In this study, damage evaluationmethod for concrete materials is studied,applying acoustic emission (AE) method and computerized tomography (CT) scanning procedure.   We have proposed a quantitative damage evaluation of concrete, based on AE measurement anddamage mechanics in the compression test.  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.  Concrete-core samples were taken from reinforced concrete walls in a canal.  These samples are strongly damaged by a freezing and thawing process.  Crack distributions in the samples were inspected with helical CT scans, which were undertaken at one-millimetre interval.  After the helical CT scan, damage of freeze-thawed samples was evaluated by applying the DeCAT analysis. These results demonstrate that the decrease in physical properties could be evaluated by comparing the averaged CT number with the durability index by AE.The both values clearly reflect amount of internal cracks in core samples.