Apparatus and method for non-destructive testing of concrete

1. A system for determining characteristics of a concrete sample, comprising:

a concrete sample;

a frame;

a plurality of transducers secured by the frame at predetermined positions with respect to each other and so that coupling surfaces of the transducers are generally coplanar with each other; and

a processor in communication with the transducers and configured to execute computer program instructions to

actuate a first plurality of the transducers secured by the frame so that the first plurality of transducers impart respective mechanical waves in the concrete sample, and

receive output signals from a second plurality of the transducers secured by the frame in response to reception of the mechanical waves by the second plurality of transducers,

wherein the first plurality of transducers are arranged in the frame so that an area

that is within a plane parallel to the coupling surfaces and in the concrete sample and

that is bounded within the plane by a collective extent of the respective mechanical waves that pass through the plane and that are receivable by the second plurality of transducers

has a dimension at least as long as a distance between adjacent reinforcing bars in the concrete sample.

2. The system as in claim 1 , wherein the first plurality of transducers and the second plurality of transducers comprise the same transducers.

3. The system as in claim 2 , wherein the processor is configured to receive a respective said output signal from each transducer of the second plurality of transducers in response to reception of a said mechanical wave from a different transducer of the first plurality of transducers.

4. The system as in claim 3 , wherein the processor is configured to actuate the first plurality of transducers sequentially.

5. The system as in claim 1 , wherein the coupling surface of each transducer of the plurality of transducers secured by the frame is circular and has a diameter of about one inch or less.

6. The system as in claim 1 , wherein the transducers of the first plurality of transducers are aligned linearly with respect to each other.

7. The system as in claim 6 , wherein the coupling surface of each transducer of the plurality of transducers secured by the frame has a center.

8. The system as in claim 7 , wherein the centers of each pair of adjacent first transducers are separated by at most about 1.5 inches.

9. The system as in claim 8 , wherein the centers of each pair of adjacent first transducers are separated by at most about one inch.

10. The system as in claim 7 , wherein the centers of two transducers of the first transducers having the greatest separation between them among the first transducers are separated by at most about 19.5 inches.

11. The system as in claim 8 , wherein the centers of two transducers of the first transducers having the greatest separation between them among the first transducers are separated by at most about 19.5 inches.

12. A method for determining characteristics of a concrete sample, comprising:

providing

a frame, and

a plurality of transducers secured by the frame at predetermined positions with respect to each other and having respective coupling surfaces;

placing the coupling surfaces on a surface of the concrete sample;

actuating a first plurality of the transducers secured by the frame so that the first plurality of transducers impart respective mechanical waves in the concrete sample; and

receiving output signals from a second plurality of the transducers secured by the frame in response to reception of the mechanical waves by the second plurality of transducers,

wherein the first plurality of transducers are arranged in the frame so that an area

that is within a plane offset from the coupling surfaces and in the concrete sample and

that is bounded within the plane by a collective extent of the respective mechanical waves that pass through the plane and that are receivable by the second plurality of transducers

has a dimension at least as long as a distance between adjacent reinforcing bars in the concrete sample.

13. The method as in claim 12 , wherein the first plurality of transducers and the second plurality of transducers comprise the same transducers.

14. The method as in claim 13 , wherein the receiving step comprises receiving a respective said output signal from each transducer of the second plurality of transducers in response to reception of a said mechanical wave from a different transducer of the first plurality of transducers.

15. The method as in claim 14 , wherein the actuating step comprises actuating the first plurality of transducers sequentially.

16. The method as in claim 12 , wherein the transducers of the first plurality of transducers are aligned linearly with respect to each other.

17. The method as in claim 16 , wherein the coupling surface of each transducer of the plurality of transducers secured by the frame has a center.

18. The method as in claim 17 , wherein the centers of each pair of adjacent first transducers are separated by at most a distance equal to about one-half of a minimum separation between adjacent reinforcing bars in the concrete sample.

19. The method as in claim 18 , wherein the centers of each pair of adjacent first transducers are separated by at most about 1.5 inches.

20. The method as in claim 17 , wherein the centers of two transducers of the first transducers having the greatest separation between them among the first transducers are separated by at most about 19.5 inches.

21. The method as in claim 19 , wherein the centers of two transducers of the first transducers having the greatest separation between them among the first transducers are separated by at most about 19.5 inches.

22. The method as in claim 12 , wherein the distance corresponds to a maximum separation between adjacent reinforcing bars in the concrete sample.