Non-Contact NDT of Concrete Structures Using Air -Coupled Sensors

Elastic wave-based non-destructive test (NDT) methods are effective for detecting flaws in concrete structures. With the recent developments in computing hardware and software, imaging techniques have become very popular in NDT applications. However the application of elastic wave-based imaging methods for concrete structures is severely limited by the physical coupling between sensors and concrete surface, which reduces testing efficiency. In this report, the air-coupled sensing technique is proposed as a solution to improve the efficiency of elastic wave-based test methods for concrete structures. Theoretical analyses are first conducted to study the propagation of leaky Rayleigh waves in fluid-solid half spaces. Closed-form solutions of the Green’s function are derived for pressure and displacement in both the fluid and solid. This analysis provides theoretical background necessary for practical air-coupled sensing of leaky Rayleigh waves in concrete. The theory is also extended to underwater NDT applications. Two applications of air-coupled sensing are considered. One is air-coupled leaky surface wave sensing in concrete. A laboratory study and field tests demonstrate that air-coupled sensors are very effective for sensing leaky surface waves in concrete. The sensitivity and accuracy of air-coupled sensors are comparable to contact sensors. Aircoupled sensors are suitable replacement for contact sensors in SASW and MASW tests and moreover help improve test efficiency. In addition, the contact-less nature of aircoupled sensing enables the study of the effect of defects on wave attenuation. The experimental results show leaky Rayleigh waves are sensitive to the existence of cracks in concrete when waves propagate across cracks; the crack positions are clearly located in a 2-D scanning test image. The second application is air-coupled impact-echo. Two reinforced concrete slabs containing different types of defects were inspected using an air-coupled impact test testing scheme. 2-D scanning impact-echo tests were conducted over the slab containing voids and delaminations. The 2-D scanning image clearly shows the location of embedded defects, and their depths are also determined. Air-coupled impact-echo is also applied to examine the grouting condition of embedded ducts. The poorly-grouted and ungrouted sections are identified within the metal duct.

[1]  Larry D. Olson,et al.  Impact Echo Scanning Technology for Internal Grout Condition Evaluation in Post-Tensioned Bridge Ducts , 2004 .

[2]  C. Pekeris,et al.  THE SEISMIC SURFACE PULSE. , 1955, Proceedings of the National Academy of Sciences of the United States of America.

[3]  D. Thompson,et al.  Review of Progress in Quantitative Nondestructive Evaluation , 1982 .

[4]  W Lauriks,et al.  On the character of acoustic waves at the interface between hard and soft solids and liquids. , 2001, The Journal of the Acoustical Society of America.

[5]  Richard D. Miller,et al.  Multichannel analysis of surface waves , 1999 .

[6]  J. Szilard,et al.  Ultrasonic testing: Non-conventional testing techniques , 1982 .

[7]  Surendra P. Shah,et al.  Measurement of surface wave transmission coefficient across surface-breaking cracks and notches in concrete. , 2003, The Journal of the Acoustical Society of America.

[8]  William M Moore,et al.  AN INSTRUMENT FOR DETECTING DELAMINATION IN CONCRETE BRIDGE DECKS , 1970 .

[9]  Martin Krause,et al.  Ultrasonic Imaging of Concrete Elements Using Reconstruction by Synthetic Aperture Focusing Technique , 2003 .

[10]  A G Davis,et al.  FROM THEORY TO FIELD EXPERIENCE WITH THE NON-DESTRUCTIVE VIBRATION TESTING OF PILES. , 1974 .

[11]  M. Weihnacht,et al.  Subsonic leaky Rayleigh waves at liquid-solid interfaces. , 2002, Ultrasonics.

[12]  W. Grandia,et al.  NDE applications of air-coupled ultrasonic transducers , 1995, 1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium.

[13]  Oral Büyüköztürk.  Imaging of concrete structures , 1998 .

[14]  I. A. Viktorov.  Rayleigh and Lamb Waves , 1967 .

[15]  F. Schubert,et al.  Leaky Rayleigh and Scholte waves at the fluid-solid interface subjected to transient point loading , 2004 .

[16]  Nicholas J. Carino,et al.  Detecting Delaminations in Concrete Slabs With and Without Overlays Using the Impact-Echo Method , 1989 .

[17]  René Marklein,et al.  Numerical modeling of elastic wave propagation and scattering with EFIT — elastodynamic finite integration technique , 1995 .

[18]  Mary Sansalone,et al.  Impact-echo : nondestructive evaluation of concrete and masonry , 1997 .

[19]  John S. Popovics,et al.  Non-contact imaging for surface-opening cracks in concrete with air-coupled sensors , 2005 .

[20]  Thomas Bohlen,et al.  1.5D inversion of lateral variation of Scholte-wave dispersion , 2004 .

[21]  J. Achenbach.  Wave propagation in elastic solids , 1962 .

[22]  Juan Carrion,et al.  Model-Based Strategies for Real-Time Hybrid Testing , 2007 .

[23]  Gerardo Clemeña.  Short-Pulse Radar Methods , 2003 .

[24]  Mary Sansalone,et al.  DETECTING VOIDS IN GROUTED TENDON DUCTS OF POST-TENSIONED CONCRETE STRUCTURES USING THE IMPACT-ECHO METHOD , 1996 .

[25]  L. Rayleigh.  On Waves Propagated along the Plane Surface of an Elastic Solid , 1885 .

[26]  Stephen Pessiki,et al.  SettingTime and Strength of Concrete Using the Impact-Echo Method , 1988 .

[27]  Malcolm K. Lim,et al.  RAPID AND ECONOMICAL EVALUATION OF CONCRETE TUNNEL LININGS WITH IMPULSE RESPONSE AND IMPULSE RADAR NONDESTRUCTIVE METHODS , 2005 .

[28]  D. Schindel,et al.  The use of broadband acoustic transducers and pulse-compression techniques for air-coupled ultrasonic imaging. , 2001, Ultrasonics.

[29]  F. E. Richart,et al.  Vibrations of soils and foundations , 1970 .

[30]  Kevin L. Rens,et al.  RECENT TRENDS IN NONDESTRUCTIVE INSPECTIONS IN STATE HIGHWAY AGENCIES. TECHNICAL NOTE , 1998 .

[31]  Nicholas J. Carino,et al.  A Point Source-Point Receiver, Pulse-Echo Technique for FlawDetection in Concrete , 1986 .

[32]  Hitoshi Takeuchi,et al.  Propagation of Tremors over the Surface of an Elastic Solid. , 1954 .

[33]  J. H. Bungey,et al.  SUB-SURFACE RADAR TESTING OF CONCRETE: A REVIEW , 2004 .

[34]  Michael J. S. Lowe,et al.  Guided wave propagation in three-layer pavement structures , 2004 .

[35]  Qing Huo Liu,et al.  Perfectly matched layers for elastic waves in cylindrical and spherical coordinates , 1999 .

[36]  Masoud Ghandehari,et al.  APPLICATION OF SURFACE WAVE TRANSMISSION MEASUREMENTS FOR CRACK DEPTH DETERMINATION IN CONCRETE , 2000 .

[37]  Nils Ryden,et al.  Multimodal approach to seismic pavement testing , 2004 .

[38]  William M Moore.  DETECTION OF BRIDGE DECK DETERIORATION , 1973 .

[39]  Kenneth H. Stokoe,et al.  Application of SASW Method Underwater , 1998 .

[40]  M. Castaings,et al.  Lamb and SH waves generated and detected by air-coupled ultrasonic transducers in composite material plates , 2001 .

[41]  Steve Millard,et al.  RADAR INSPECTION OF STRUCTURES , 1993 .

[42]  C. Yew,et al.  An experimental study of interaction between surface waves and a surface breaking crack , 1984 .

[43]  Chul Park,et al.  Surface waves in inversely dispersive media , 2004 .

[44]  Sebastiano Foti,et al.  Multistation Methods for Geotechnical Characterization using Surface Waves , 2000 .

[45]  Michael Forde,et al.  Ultrasonic tomography of grouted duct post-tensioned reinforced concrete bridge beams , 2001 .

[46]  A. T. Hoop,et al.  Generation of acoustic waves by an impulsive point source in a fluid/porous‐medium configuration with a plane boundary , 1983 .

[47]  Q. Qi.  Attenuated leaky Rayleigh waves , 1993 .

[48]  Bernd Köhler,et al.  The elastodynamic finite integration technique for waves in cylindrical geometries , 1998 .

[49]  Richard D. Miller,et al.  Underwater MASW to evaluate stiffness of water-bottom sediments , 2005 .

[50]  N. Al-Shayea,et al.  NONDESTRUCTIVE TESTING OF CONCRETE STRUCTURES USING THE RAYLEIGH WAVE DISPERSION METHOD , 1996 .

[51]  P. Nagy,et al.  Generalized Lamb Modes in Friction Welded Steel Layer on Aluminum , 1989 .

[52]  John S. Popovics,et al.  NDE techniques for concrete and masonry structures , 2003 .

[53]  C. Glorieux,et al.  Theory of Scholte, leaky Rayleigh, and lateral wave excitation via the laser‐induced thermoelastic effect , 1996 .

[54]  Stephen Pessiki,et al.  Setting time and strength of concrete using the impact-echo method , 1997 .

[55]  Peter Cawley,et al.  ULTRASONIC GUIDED WAVES FOR INSPECTION OF GROUTED TENDONS AND BOLTS , 2003 .

[56]  Yiching Lin,et al.  USE OF STRESS WAVES FOR DETERMINING THE DEPTH OF SURFACE-OPENING CRACKS IN CONCRETE STRUCTURES , 1996 .

[57]  Anatoli L. Levshin,et al.  Estimating shallow shear velocities with marine multicomponent seismic data , 2002 .

[58]  J. Sackman,et al.  Surface Waves in an Elastic Half Space , 1961 .

[59]  Allen G. Davis.  The nondestructive impulse response test in North america : 1985-2001 , 2003 .

[60]  Soheil Nazarian,et al.  ASSESSING QUALITY OF CONCRETE WITH WAVE PROPAGATION TECHNIQUES , 1997 .

[61]  David A. Hutchins,et al.  Air-coupled ultrasonic testing of metals using broadband pulses in through-transmission , 1999 .

[62]  John S. Popovics,et al.  Non-contact detection of surface waves in concrete using an air-coupled sensor , 2002 .

[63]  Erwin Rafael Kohler.  Experimental Mechanics of Crack Width in Full-Scale Sections of Continuously Reinforced Concrete Pavements , 2005 .

[64]  M M Sprinkel,et al.  CONCRETE BRIDGE PROTECTION, REPAIR, AND REHABILITATION RELATIVE TO REINFORCEMENT CORROSION: A METHODS APPLICATION MANUAL , 1993 .

[65]  John S. Popovics,et al.  Lamb wave basis for impact-echo method analysis , 2005 .

[66]  J. Carcione,et al.  The physics and simulation of wave propagation at the ocean bottom , 2004 .

[67]  null null,et al.  2001 Report Card for America's Infrastructure , 2001 .

[68]  Michael Leon Scott.  Automated Characterization of Bridge Deck Distress Using Pattern Recognition Analysis of Ground Penetrating Radar Data , 1999 .