Compressive Stress-Induced Microcracks and Effective Elastic Properties of Limestone and Concrete. Phase 1.

摘要

Stress-induced microstructure alterations were observed in Indiana limestone and one type of using low wetting concrete, point metal alloy injection technique. Average microcrack length and aperture decreased with an increase in applied confining stress. Microcrack density increased with an increase in confining stress. Most microcracks were oriented at a small angle to the maximum compression direction. Theoretical solutions for effective moduli and Poisson's ratios of an axisymmetrically microstructured material were obtained using energy conservation principles. Results showed that all effective moduli are less than for the original undamaged and decreased with an increase in microcrack density. Ultrasonic velocities measured concurrently during static compression tests conformed the observations. 'Dynamic' stress-strain curves constructed from the measured ultrasonic velocities showed relatively similar behavior as the static stress-strain curves. Both static and dynamic moduli decreased with an increase in axial devatoric stress.