### Abstract

The propagation and scattering of high-frequency ultrasound in concrete is discussed. Frequencies above 100 kHz have wavelengths short enough for sensitivity to microcracking. However, the heterogeneous composition of concrete causes the ultrasound at such frequencies to scatter considerably. Theoretical descriptions of the scattering attenuations based on a stochastic wave equation are discussed. These expression require information about the two-point spatial correlation function. The form for this function is proposed and confirmed experimentally. Finally, ultrasound diffusion experiments are discussed. In the limit of many scattering events, the ultrasonic energy density in circular cylinders of concrete is shown to evolve in accordance with a one-dimensional diffusion equation. The ultrasonic diffusivity was measured experimentally over the frequency range of 100-900 kHz. Theoretical descriptions of the diffusivity are in accord with the experimental values. Such frequencies are well above typical frequencies used for concrete inspection. Thus, it is anticipated that the use of these higher frequencies will result in new techniques for characterizing material properties and damage in concrete structures.

Original language | English (US) |
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Pages (from-to) | 95-104 |

Number of pages | 10 |

Journal | Proceedings of SPIE - The International Society for Optical Engineering |

Volume | 4337 |

DOIs | |

State | Published - Jan 1 2001 |

Event | Health Monitoring and Management of Civil Infrastructure Systems - Newport Beach,CA, United States Duration: Mar 6 2001 → Mar 8 2001 |

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### ASJC Scopus subject areas

- Electrical and Electronic Engineering
- Condensed Matter Physics

### Cite this

**Diffuse ultrasonics for inspection of concrete.** / Turner, Joseph A.

Research output: Contribution to journal › Conference article

}

TY - JOUR

T1 - Diffuse ultrasonics for inspection of concrete

AU - Turner, Joseph A

PY - 2001/1/1

Y1 - 2001/1/1

N2 - The propagation and scattering of high-frequency ultrasound in concrete is discussed. Frequencies above 100 kHz have wavelengths short enough for sensitivity to microcracking. However, the heterogeneous composition of concrete causes the ultrasound at such frequencies to scatter considerably. Theoretical descriptions of the scattering attenuations based on a stochastic wave equation are discussed. These expression require information about the two-point spatial correlation function. The form for this function is proposed and confirmed experimentally. Finally, ultrasound diffusion experiments are discussed. In the limit of many scattering events, the ultrasonic energy density in circular cylinders of concrete is shown to evolve in accordance with a one-dimensional diffusion equation. The ultrasonic diffusivity was measured experimentally over the frequency range of 100-900 kHz. Theoretical descriptions of the diffusivity are in accord with the experimental values. Such frequencies are well above typical frequencies used for concrete inspection. Thus, it is anticipated that the use of these higher frequencies will result in new techniques for characterizing material properties and damage in concrete structures.

AB - The propagation and scattering of high-frequency ultrasound in concrete is discussed. Frequencies above 100 kHz have wavelengths short enough for sensitivity to microcracking. However, the heterogeneous composition of concrete causes the ultrasound at such frequencies to scatter considerably. Theoretical descriptions of the scattering attenuations based on a stochastic wave equation are discussed. These expression require information about the two-point spatial correlation function. The form for this function is proposed and confirmed experimentally. Finally, ultrasound diffusion experiments are discussed. In the limit of many scattering events, the ultrasonic energy density in circular cylinders of concrete is shown to evolve in accordance with a one-dimensional diffusion equation. The ultrasonic diffusivity was measured experimentally over the frequency range of 100-900 kHz. Theoretical descriptions of the diffusivity are in accord with the experimental values. Such frequencies are well above typical frequencies used for concrete inspection. Thus, it is anticipated that the use of these higher frequencies will result in new techniques for characterizing material properties and damage in concrete structures.

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UR - http://www.scopus.com/inward/citedby.url?scp=0034774922&partnerID=8YFLogxK

U2 - 10.1117/12.435580

DO - 10.1117/12.435580

M3 - Conference article

VL - 4337

SP - 95

EP - 104

JO - Proceedings of SPIE - The International Society for Optical Engineering

JF - Proceedings of SPIE - The International Society for Optical Engineering

SN - 0277-786X

ER -