Evaluation of the compressional damage evolution of ancient fired clay bricks using coda wave analysis

Coda waves have been proven to be sensitive to small changes in the medium. In this paper, moving reference coda wave interferometry and decorrelation were adopted to monitor the compressional damage process of ancient fired clay bricks. Two sets of brick cores obtained from an ancient tomb were loaded to failure, and the ultrasonic signals during the loading process were analyzed. Experimental results showed that moving reference-based analysis is more suitable for damage monitoring and coda wave analysis could provide some precursory indications of brick yielding, the yield strength is highly associated with relative velocity change at yielding.