Simulation of ultrasonic propagation in porous cellular concrete materials

Abstract

While nondestructive ultrasound-based methods are suitable for evaluating the physical and mechanical properties of lightweight cellular concrete (LCC) materials, the quantitative relation between porosity characteristics and acoustic parameters is not well understood. In this study, the micromechanics-based finite-element models are rebuilt using the real porous microstructure of LCC. Various roles of porosity characteristics are analyzed, including equivalent pore radius, pore sphericity value and fractal dimension of pore distribution with different mixture ratios. Effects of porosity characteristics are quantitatively demonstrated on the ultrasonic pulse velocity. It is shown that the ultrasonic pulse velocity is positively correlated with equivalent pore radius and fractal dimension of pore distribution, and negatively correlated with pore sphericity value and porosity. As the orientation of pores increases, the ultrasonic pulse velocity initially drops, followed by the increase. The quantitative understanding of porosity characteristics on ultrasonic responses helps improve the accuracy of ultrasonic detection on LCC properties. Comparisons between simulation results and experimental data of ultrasonic pulse velocities demonstrate good agreement. This study represents an effective quantitative method to explore the ultrasound propagation in LCC.