All Title Author
Keywords Abstract


Nondestructive Investigation of Stress-Induced Damage in Concrete

DOI: 10.1155/2010/740189

Full-Text   Cite this paper   Add to My Lib

Abstract:

The changes in the sonic surface wave velocity of concrete under stress were investigated in this paper. Surface wave velocities at sonic frequency range were measured on a prismatic concrete specimen undergoing several cycles of uniaxial compression. The loading was applied (or removed) gradually in predefined small steps (stress-controlled). The surface wave velocity was measured at every load step during both loading and unloading phases. Acoustic Emission (AE) test was conducted simultaneously to monitor the microcracking activities at different levels of loading. It was found that the sonic surface wave velocity is highly stress dependent and the velocity-stress relationship follows a particular trend. The observed trend could be explained by a combination of acoustoelasticity and microcracking theories, each valid over a certain range of applied stresses. Having measured the velocities while unloading, when the material suffers no further damage, the effect of stress and damage could be differentiated. The slope of the velocity-stress curves over the elastic region was calculated for different load cycles. This quantity was normalized to yield a dimensionless nonlinear parameter. This parameter generally increases with the level of induced damage in concrete. 1. Introduction To ensure the integrity of an existing structure, one needs to have a reliable estimation of in-situ material properties, the remaining strength and relevant damages in the load-carrying components. Nondestructive testing (NDT) techniques which can provide a reliable assessment of one or more of these parameters, without harming the structure itself, are invaluable to inspectors and engineers. Among the applicable NDT methods, acoustic techniques have long been used for inspection of concrete structures, both in defect detection and material characterization applications. When used for defect detection, acoustic techniques are especially powerful tools for locating the defects, which introduce an impedance discontinuity within the concrete structure (e.g., voids, cracks, and flaws). In applications concerning material characterization, their advantage lies in their ability to give a direct estimation of mechanical material properties through measuring the acoustic wave velocities. The results of acoustic tests are usually analyzed and interpreted based on the theory of elastic wave propagations in linearly elastic homogenous solids. According to this theory, the velocity of acoustic waves propagating in linear elastic materials is a function of elastic material properties

References

[1]  V. Hauk, Structural and Residual Stress Analysis by Nondestructive Methods: Evaluation—Application—Assessment, Elsevier Science B.V., Amsterdam, The Netherlands, 1997.
[2]  F. G. Makhort, O. I. Gushcha, and A. A. Chernoochenko, “On the relations governing rayleigh wave propagation in bodies with initial stresses,” International Applied Mechanics, vol. 29, no. 11, pp. 915–920, 1993.
[3]  R. H. Bergman and R. A. Shahbender, “Effect of statically applied stresses on the velocity of propagation of ultrasonic waves,” Journal of Applied Physics, vol. 29, no. 12, pp. 1736–1738, 1958.
[4]  C. Payan, V. Garnier, J. Moysan, and P. A. Johnson, “Determination of third order elastic constants in a complex solid applying coda wave interferometry,” Applied Physics Letters, vol. 94, no. 1, Article ID 011904, 2009.
[5]  E. Larose and S. Hall, “Monitoring stress related velocity variation in concrete with a relative resolution using diffuse ultrasound,” Journal of the Acoustical Society of America, vol. 125, no. 4, pp. 1853–1856, 2009.
[6]  Chaix J.-F., I. Lillamand, M.-A. Ploix, V. Garnier, and G. Corneloup, “Study of acoustoelasticity bahavior of concrete material under uniaxial compression,” in Proceedings of the Acoustics, pp. 6267–6272, Paris, France, June 2008.
[7]  C. M. Sayers, J. G. Van Munster, and M. S. King, “Stress-induced ultrasonic anisotrophy in Berea sandstone,” International Journal of Rock Mechanics and Mining Sciences, vol. 27, no. 5, pp. 429–436, 1990.
[8]  X. J. Huang, D. R. Burns, and M. N. Toks?z, “The effect of stresses on the sound velocity in rocks: theory of acoustoelasticity and experimental measurements,” 2000, http://eaps.mit.edu/erl/research/report1/pdf/huang.pdf.
[9]  W. Suaris and V. Fernando, “Detection of crack growth in concrete from ultrasonic intensity measurements,” Materials and Structures, vol. 20, no. 3, pp. 214–220, 1987.
[10]  C. L. Nogueira and K. J. Willam, “Ultrasonic testing of damage in concrete under uniaxial compression,” ACI Materials Journal, vol. 98, no. 3, pp. 265–275, 2001.
[11]  S. Takahashi and R. Motegi, “Stress dependency on ultrasonic wave propagation velocity—part 1. Analysis by the Eulerian viewpoint of ultrasonic wave velocity in the uniformly deformed isotropic solid,” Journal of Materials Science, vol. 22, no. 5, pp. 1850–1856, 1987.
[12]  J. A. Hudson, “Wave speeds and attenuation of elastic waves in material containing cracks,” Journal of Royal Astronomical Society, vol. 64, no. 1, pp. 133–150, 1981.
[13]  P. Shokouhi, R. Feldmann, and H. Wiggenhauser, “Stress-dependency of sonic velocity in concrete under uniaxial load,” in Proceedings of the 87th TRB Annual Meeting, Washington, DC, USA, 2008.
[14]  A. Zo?ga and H. Wiggenhauser, “Propagation time measurements of elastic surface waves on concrete specimens while under different loads and dependent to the direction of strain,” in NDE/NDT for Highways and Bridges: Structural Materials Technology (SMT), ASNT, Oakland, Calif, USA, 2008.
[15]  A. Zo?ga, P. Shokouhi, and H. Wiggenhauser, “Propagation time of elastic surface waves on concrete specimens under uniaxial loads,” Journal of Structural Engineering, vol. 36, no. 1, pp. 11–15, 2009.

Full-Text

comments powered by Disqus