Title: Nonlinear Ultrasonic Testing with Resonant and Pulse Velocity Parameters for Early Damage in Concrete

Author(s): Jason D. Stauffer, Clinton B. Woodward, and Kenneth R. White

Publication: Materials Journal

Volume: 102

Issue: 2

Appears on pages(s): 118-121

Keywords: damage; microcracking; testing

DOI: 10.14359/14305

Date: 3/1/2005

Abstract:
The objective of this research was to compare the effectiveness of a nonlinear ultrasonic testing method with established ASTM testing methods in detecting early damage in concrete. In this study, geometrically identical concrete specimens were evaluated with nonlinear ultrasonic techniques. These prismatic specimens were of three distinct water-cement ratios. They were compressed at regular load increments to induce damage and ultrasonically tested for fundamental, second, and third harmonics of the original driving frequencies after each load increment. Other additional ASTM tests were performed for comparison. At each load increment, no cracking was visually observed. However, with increases in damage to the specimens, substantial increases in nonlinear parameters were observed. These increases in harmonic ratios were markedly larger as compared with changes noted with other nondestructive ASTM tests performed. This nonlinear ultrasonic method shows considerable promise as a sound, nondestructive evaluation technique for detecting early damage in concrete.