Integration of imaging and mechanics for advanced material characterization and structural repair

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Materials research is at the heart of advances in a broad range of seemingly disparate applications, spanning structures, pavement, automotive and emerging biomedical technologies. For example, Canada's aging infrastructure is deteriorating at a rate that requires immediate repair or renewal, placing a huge strain on our economy and highlighting a critical need for new methods to evaluate and delay structural materials failure. The proposed research program advances concrete material characterization from the conventional `overall' evaluation to a `components-based' characterization. The role of void contents, cracks propagation, corrosion micromechanics and repair schemes on material performance will be investigated. This innovative approach will provide detailed image-based stress distribution and deformation maps to identify failure initiation and propagation. As the program grows, the scope of potential new research directions can expand to include fracture mechanics, steel welding, asphalt and biomaterials. The main objective of the proposed research is to develop a novel approach for mechanical characterization of concrete that merges imaging, computational mechanics, and experiments. The three dimensional (3D) configuration, spatial distribution and propagation of cracks and inclusions, such as voids and corrosion products, will be monitored by imaging. Stress and strain of aggregate, reinforcement and fiber reinforced polymer (FRP) sheet will be calculated. Such investigations will pave the way for optimized material mix design and repair schemes, and will provide comprehensive understanding of the role of each component's strength, morphology, and surface texture on material behaviour. Experimental testing, 3D imaging and sample-specific finite element (FE) modeling will be implemented. Microscale images will be acquired using a computed tomography imaging system to identify spatial and geometric configurations of aggregate, corrosion product, voids and cracks. The images will be transferred to detailed 3D and components-based FE models to investigate intensity and locations of stress concentration. Each of the components will be modeled using its own mechanical properties, spatial distribution and geometry. In addition, each element's interaction with other components will be modeled using interfacial mechanics to investigate debonding behaviour. The proposed research will provide unique training opportunities in imaging, mechanics, and emerging techniques of image-mechanics integration that prepare graduates to work in a number of fields that strive to find innovative solutions, including non-destructive testing, manufacturing, structural engineering, and biophysics. This innovative research will have a direct impact on extending the service life and increasing the load carrying capacity of existing and renewed infrastructures in Canada and the world, while reducing the cost of repair and renewal by efficient use of materials.