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Proceedings Paper

Effects of exciting frequencies, grain sizes, and damage upon P-wave velocity for ultrasonic NDT of concrete
Author(s): Jiann Wen Ju; Lisheng Weng
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Paper Abstract

This paper focuses on the experimental study of the effects of exciting frequencies, grain (aggregate) sizes, and damage upon the ultrasonic P-wave velocity when performing the ultrasonic nondestructive testing (NDT) for concrete specimens. Two batches of concrete and mortar specimens were prepared in the laboratory for the investigation of the effects from the stated factors upon the P-wave velocity. Damage here mostly refers to microcracks and microvoids in concrete. Five different aggregate sizes, 0' (mortar), 3/8', 1/2', 3/4', and 1', were selected to demonstrate the grain (aggregate) size effect. Exciting frequencies of the ultrasonic wave were set to range from 100 kHz to 1,000 kHz, with increment of 50 kHz, to demonstrate the frequency effect. Styrofoam particles were mixed into the comparison concrete and mortar specimens to simulate the distributed microvoids (damage). Different volume fractions of styrofoam particles were mixed into the mortar specimens in order to study the effect of different porosities (damage) upon the P-wave velocity. The experimental observations show that, for mortar and concrete specimens with aggregate sizes from 0 to 1 inch, the P-wave velocity would not be affected significantly within the tested frequency range (100 - 1000 kHz). The normalized P-wave velocity exhibits almost identical pattern upon the exciting frequencies for all specimens.

Paper Details

Date Published: 5 May 2000
PDF: 8 pages
Proc. SPIE 3994, Nondestructive Evaluation of Aging Aircraft, Airports, and Aerospace Hardware IV, (5 May 2000);
Show Author Affiliations
Jiann Wen Ju, Univ. of California/Los Angeles (United States)
Lisheng Weng, Univ. of California/Los Angeles (United States)


Published in SPIE Proceedings Vol. 3994:
Nondestructive Evaluation of Aging Aircraft, Airports, and Aerospace Hardware IV
Ajit K. Mal, Editor(s)

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