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256 IBRACON Structures and Materials Journal • 2013 • vol. 6 • nº 2
Ultrasonic tomography in concrete
wall effect. It only occurs because it is considered that ultrasonic
pulses travel in linear path between the transducers.
The tomogram of CP4 specimen (Figure 17) shows a similar be-
havior to the one for CP3 specimen (Figure 16), with wall effect
also present in CP4, but overlapped in the vertical and horizontal
directions. As noted, this provides more circular shape for the vio-
let area in the tomogram.
5. Conclusions
As a result of this research, it can be concluded that the tomo-
graphic software TUCon is able to assemble and to solve the to-
mographic problem, having been validated from experimental data.
The two-dimensional tomograms produced by ultrasound readings
with 200 kHz transducers were able to well represent the analyzed
sections of the specimens. The tomograms for CP3 and CP4 spec-
imens exhibited some irregularities, suggesting an oval or circular
shape for a rectangular internal flaw. This effect was called wall
effect. It happened due to the consideration of linear ray-paths be-
tween transducers.
The wall effect can be minimized by introducing an algorithm inside
the tomographic processing that would calculate the real ray-path,
avoiding objects or regions of low velocity. Jackson et al. [19] pro-
posed a method to make this consideration. The implementation
of this routine is already being developed and should be included
in future versions of the software TUCon.
This work also demonstrated the great potential for the utilization
of ultrasonic tomography in the nondestructive evaluation of con-
crete structures. It is expected that this line of research will help to
diffuse this knowledge in the academic and technical fields.
6. Acknowledgment
The authors would like to express their gratitute to CNPq, to the
Research Group on Nondestructive Testing – GPEND of the Fed-
eral University of Santa Catarina, and to Professor Ivo Padaratz by
providing resources, equipment and physical space for this work.
Figure 18 – Possible ray-paths of ultrasound pulses within the specimen – (a) CP1 – (b) CP2
A B
7. References
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