Studies of Fracture Processes in Cement-Based Materials under Compression withMicrotomography and Computer Vision

摘要

Damage and failure mechanisms in cement-based materials such as concrete aredifficult to comprehend due to the heterogeneous microstructure. Experimental analysis of damage localization and failure has traditionally been a compromise between low resolution three-dimensional techniques, and high resolution surface techniques. In this research program, two emerging experimental techniques, x-ray microtomography and computer vision, were combined toward problems of damage and failure of concrete. X-ray microtomography produces a high resolution three-dimensional picture of internal damage evolution, while speed computer vision allows us to quantitatively evaluate surface cracking characteristics at variable loading rates under multiple stress states. The primary focus of the work under this grant was to explore the feasibility of these two techniques for applications to shock physics. Preliminary results showed that high resolution (micron scale) scans of internal structure can be made at multiple levels of damage using the experimental setup developed for microtomography.