Techniques for monitoring slump characteristic of concrete in a rotating container or drum

1. A system comprising:

an acoustic sensor configured to mount on an exterior wall of a mixing drum, sense an acoustic characteristic of a mixture of a slurry, including concrete, contained in the mixing drum when rotating, and provide acoustic sensor signaling containing information about the acoustic characteristic sensed;

a signal processor configured to

receive the acoustic sensor signaling, and

determine corresponding signaling containing information about a slump characteristic of the mixture of the slurry, including concrete, contained in the mixing drum, based upon the acoustic sensor signaling received;

the acoustic sensor being configured to

sense a first acoustic characteristic when the concrete is lifted by a vane of the mixing drum and provide first acoustic sensor signaling containing information about when the concrete is lifted by the vane, and

sense a second acoustic characteristic when the concrete flows off the vane and falls back into the mixture and provide second acoustic sensor signaling containing information about when the concrete flows off the vane and falls back into the mixture; and

the signal processor being configured to

receive the first acoustic sensor signaling and the second acoustic sensor signaling, and

determine the corresponding signaling containing information about the slump characteristic of the mixture of concrete contained in the mixing drum, based upon the first acoustic sensor signaling and the second acoustic sensor signaling received.

2. The system according to claim 1 , wherein the acoustic sensor comprises one or more PVDF patches or one or more PZT elements.

3. The system according to claim 2 , wherein the one or more PVDF patches or PZT elements are mounted on the exterior mixing drum wall of the mixing drum.

4. The system according to claim 2 , wherein the PVDF patches or PZT elements are covered by an outer protective housing/cover, including where the outer protective housing/cover provides external noise protection.

5. The system according to claim 1 , wherein the signal processor is configured to determine the slump characteristic based upon noise characteristic at different spatial locations that indicate differences in the slump of the mixture of concrete.

6. The system according to claim 1 , wherein the vane of the mixing drum is mounted on an interior wall of the mixing drum at an interior location, and the acoustic sensor is mounted on the exterior drum wall of the mixing drum at an exterior location corresponding to the interior location.

7. The system according to claim 1 , wherein the signal processor is configured to determine the slump characteristic based upon a post exit angle of the vane at which the release of the concrete occurs.

8. The system according to claim 7 , wherein the signal processor is configured to determine a first slump mix when the concrete in the mixture is lifted, then pours back off the vane into the mixture at a first post exit angle, and the noise is characterized by a broad band flow noise.

9. The system according to claim 7 , wherein the signal processor is configured to determine a second slump mix when the concrete in the mixture is lifted, then pours back off the vane into the mixture at a second post exit angle, and the noise is characterized by discrete noise transients.

10. The system according to claim 7 , wherein the signal processor is configured to determine the post exit angle by comparing the first acoustic sensor signaling containing information about when the concrete is lifted by a scoop sampler of the mixing drum and the second acoustic sensor signaling containing information about when the concrete flows off the scoop sampler and falls back into the mixture.

11. The system according to claim 1 , wherein the acoustic sensor comprises an outside acoustic sensor mounted on the exterior wall of the mixing drum, and an inside acoustic sensor mounted on an inside wall of the mixing drum.