Investigations on aggregate reactions and the development of damage in concrete

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The growing use of a performance approach in concrete construction has increased the pressure to develop better tools for quickly and reliably evaluating the quality of concrete-making materials. Recent research has shown that many aggregates respond differently in "performance" tests compared to natural exposure conditions, sometimes resulting in poor quality aggregate materials being used at risk in concrete construction, or in good-quality aggregates being rejected. The objective of the research program is to improve our understanding of the influence of the compositional/physical properties of natural and recycled aggregates on their behaviour as concrete-making materials, either under "accelerated" laboratory conditions or when subjected to natural environment. Furthermore, the research program proposes to study how the reaction and expansion processes in different types of reactive coarse and fine aggregates, as well as through other deleterious processes, impact on the development of distress/damage in concrete. This will not only contribute to a better understanding of the mechanisms responsible for the degradation of concrete, but it should in turn contribute to a more reliable prediction and modeling of the performance of concrete infrastructure. Finally, as sources of good quality materials in the vicinity of large urban areas are depleting rapidly, which will likely increase the pressure for using marginal natural aggregates or recycled materials in concrete construction, a better understanding of how the properties of concrete-making materials influence the performance of the final product (concrete) and how it could reliably be evaluated through performance testing, is critical in a proper management scheme of our natural resources.