Volume 36, Issue 2 (March 2008)
Ultrasonic Testing of Concrete Structures Using Indirect Transmission
Laboratory studies and computer simulation were used to develop a procedure for the interpretation of the results of nondestructive testing of concrete structures using the indirect transmission method. The results of the laboratory studies indicate a 10-cm spacing is best for making ultrasonic pulse measurements. A new method of calculating the velocity of the pulse is presented. The method enables concrete quality to be evaluated over short distances rather than the existing method which gives a mean velocity over an extended distance. The method can thus determine the extent of delamination of concrete at a specific location. The laboratory analyses verified using computer simulations show the effect of concrete heterogeneity on the detection of variation in concrete quality. Ultrasonic pulse velocities have a coefficient of variation of about 2 %.