Characterization of Cement-Based Materials Using Diffuse Ultrasound

The objective of this research is to develop a quantitative understanding of the propagation of ultrasonic waves in cement-based materials by examining specimens made of a portland cement-paste matrix and glass bead "aggregate." The incident ultrasonic waves are broadband and contain wavelengths on the order of the glass bead scatterers. Experimentally measured ultrasonic waves are interpreted using diffusion theory to quantitatively measure dissipation and diffusion coefficients as functions of frequency and microstructure. These results provide a basic understanding of the effect of some features of the microstructure on the propagation of ultrasonic waves, as well as supplying a first step in the characterization of distributed damage using ultrasonic methodologies.