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

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.