Title: Study on dynamic relaxation time and modulus of cement mortar by ultrasonic technique

Authors: Jian-Kang Chen, Jue Zhu, Yong-Hui Cao, Ding-Yi Yang

Addresses: School of Engineering, Ningbo University, Ningbo 315211, China. ' School of Engineering, Ningbo University, Ningbo 315211, China. ' School of Engineering, Ningbo University, Ningbo 315211, China. ' School of Civil Engineering, Yangzhou University, Yangzhou 225009, China

Abstract: Ultrasonic wave technique is employed to determine relaxation time and modulus of cement mortar. First, the property of attenuation of amplitude at different cross sections of the specimen may be obtained by detecting the ultrasonic signal at the ends of specimens with different lengths. Secondly, the coefficient of attenuation of the ultrasonic wave is obtained by simulating experimental results. Thirdly, one-dimensional propagation of the ultrasonic wave in cement mortar is analysed by considering the transversal inertial effect. Two important parameters of viscoelastic constitutive model of cement mortar, namely, modulus and relaxation time, are obtained. Finally, the transversal inertial effect on the relaxation time and modulus of material is examined numerically. The results obtained show that the transversal inertial effect may lead to increase of relaxation time and modulus. The method proposed in this paper is effective to measure parameters of the constitutive relation of cement mortar by ultrasonic wave technique.

Keywords: cement mortar; ultrasonic waves; viscoelastic constitutive modelling; relaxation time; modulus; transversal inertial effect; concrete materials.

DOI: 10.1504/IJMIC.2008.021165

International Journal of Modelling, Identification and Control, 2008 Vol.4 No.3, pp.278 - 285

Published online: 07 Nov 2008 *

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