Concrete and mortar deterioration and fracture: a forensic approach

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Concrete and mortar deterioration and fracture: a forensic approach This research aims to improve understanding of the complex combinations of factors that lead to deterioration from a microscopic perspective, and to devise solutions for more durable concrete and mortar based infrastructure. An important focus of this effort will be to unite factors that involve artisanship, choice of materials, and environmental exposure with load-induced stresses, to better understand the development of fracture networks, through a combination of microstructural analysis, experiment, and fracture modeling. This approach requires detailed characterization of not only the mineralogy, chemistry, and distribution of the constituents within the concrete or mortar, but also detailed characterization of the fractures themselves. The research program relies on 3D and 2D imaging techniques well-suited to fracture characterization: x-ray computed tomography followed by thin sectioning and examination by optical microscopy. This combination allows for detailed crack mapping that spans both the macro and micro-level. The same samples are further interrogated under a scanning electron microscope and by indentation, allowing for micro to nano level chemical and micro mechanical exploration of cementitious and aggregate components. Together these techniques provide a thorough assessment that allows for interpretation of manifestations of concrete and mortar deterioration. This forensic approach builds on research efforts currently underway, including investigations of (1) the influence of coarse aggregate on concrete strength, (2) crack development in protective concrete coatings for pipelines, and (3) the restoration, rehabilitation, and preservation of historic masonry. The research will advance understanding of the roles binder and aggregate play under load-induced concrete fracture, the interaction of concrete fracture networks with aggressive solutions in subsurface environments, and bond strength development in restoration mortars. These outcomes will inform and improve practices around concrete and mortar mix design, and support the construction industry's efforts to meet the many challenges of maintaining and creating tomorrow's concrete and masonry based infrastructure.