Abstract
It is possible to predict detectable defects diameter in the inner parts of mortar and concrete, from relations between echo-height from defect and scattered echoes from both fine and coarse aggregates ; the relations can be evident by making use of a longitudinal probe with a central frequency of 1 MHz and a double crystal probe with a 1 MHz. An A-scope has been generally used for ultrasonic testing (UT), whose users need the technical knowledge and experience for interpretation or analysis of the echoes received. If the imaging of defects is realized by the B-scope, users of the UT do not need the technical knowledge and experience. The joint reseachers have succeeded in imaging defects and embedded bars by the use of the B-scope.
