Use of the Impact-Echo Method to Evaluate Damage due to Distributed Cracking in Concrete Plate Members: Theory and Field Trials

Abstract

The research evaluated the feasibility of using transient stress waves to detect and quantify cracking caused by distributed damage mechanisms, specifically alkali-silica reactivity and delayed ettringite formation. It was found that distributed damage produced significant and quantifiable changes in the waveforms and spectra obtained from impact-echo results. Numerical (finite element) studies were used to determine how distributed damage in concrete plates affected propagation of impact generated stress waves. To quantify the damage, the rate of stress wave attenuation can be assessed and compared with values predicted by theory. To verify the results obtained in the numerical simulations and to develop correlation between changes in impact-echo signals and the actual amount of damage, impact-echo tests were performed on a specially prepared plate specimen made from concrete modified to produce distributed cracking over time. The actual amount of damage in the plate was determined periodically by using neutron radiography. A correlation between the amount of damage in the samples and changes in impact-echo signals was established. The correlation was verified in field and laboratory studies on concrete sections with distributed damage. The amount of cracking predicted from the analysis of impact-echo tests agreed with the actual amount of cracking obtained from neutron radiography of the core samples. This research demonstrates that the impact-echo method can be used to detect and quantify the amount of distributed damage in concrete plates. However, the mechanism responsible for the damage cannot be ascertained from either impact-echo test results or neutron radiographs.

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References

Sansalone

, and Streett

. Impact-Echo Nondestructive Evaluation of Concrete and Masonry. Bullbrier Press, Jersey Shore, Pa., 1997.

Sansalone

Impact-Echo: The Complete Story. ACI Structures Journal, Vol. 94, No. 6, Nov.-Dec. 1997, pp. 777–787.

Day

The Effect of Secondary Ettringite Formation on the Durability of Concrete: A Literature Analysis. Research and Development Bulletin RD108T. Portland Cement Association, Skokie, Ill., 1992.

Mielenz

, Marusin

, Hime

, and Jugovic

. Investigation of Prestressed Concrete Railway Tie Distress. Concrete International, Vol. 17, No. 12, Dec. 1995, pp. 62–68.

Kesner

K. E.

Detection and Quantification of Distributed Damage Mechanisms in Concrete Using Transient Stress Waves. Departmental Report 97-6. School of Civil and Environmental Engineering, Cornell University, Ithaca, N.Y., 1997.

Krautkramer

, and Krautkramer

. Ultrasonic Testing of Materials. 4th ed. Springer-Verlag, Berlin, 1990.

Sansalone

, and Carino

. Impact-Echo: A Method for Flaw Detection in Concrete Using Transient Stress Waves. NSBIR 86-3452. National Bureau of Standards, Gaithersburg, Md., Sept. 1987.

Cheng

, and Sansalone

. Determining the Minimum Crack Width That Can Be Detected Using the Impact-Echo Method, Part I: Experimental Study. RILEM Journal of Materials and Structures, Vol. 276, pp. 274–285.

Halloquist

, and Whirley

. DYNA3D A Nonlinear, Explicit, Three-Dimensional, Finite Element Code for Solid and Structural Mechanics: User's Manual. Report UCRL-MA-107254. Lawrence Livermore National Laboratories, Livermore, Calif, May 1991.

10.

Matlab High-Signal Processing Toolbox. Mathworks, Inc., Natick, Mass., 1992.

11.

Najjar

, Aderhold

, and Hover

. The Application of Neutron Radiography to the Study of Microcracking in Concrete. Cement, Concrete and Aggregates, Winter 1986, pp. 103–109.

12.

Skalny

, and Mindless

(eds.). Material Science of Concrete II. American Ceramic Society, Westerville, Ohio, 1989.

13.

Kim

Y.-M.

Structural Evaluation of In-Service Prestressed Bridge Girders with Premature Concrete Deterioration. M.S. dissertation. University of Texas at Austin, Dec. 2003.