Doctor of Philosophy (PhD)
Engineering Science (Interdepartmental Program)
Self-healing concrete through microencapsulated calcium nitrate is a novel approach to enhance durability and decrease the costs associated with maintenance and repairs. However, to fully assess the potential of this technology, there are many questions to be answered, ranging from identifying the microcapsule properties that are successfully carry the healing agent, to the effect of the microcapsule size, concentration (by weight of cement), and morphology have on the intrinsic concrete material properties and self-healing potential. Hence, the objectives of this study were to: (a) Develop a microencapsulation procedure for calcium nitrate as the healing agent; (b) Measure the short-term healing efficiency of the developed microcapsules in concrete; (c) Measure the long-term healing efficiency of such microcapsules in concrete. To achieve objective A, the effect of the production parameters was quantified with respect to the microcapsule size and morphology. The results indicated that the agitation rate, emulsifier type, and emulsifier concentration affected the mean microcapsule diameter. The morphology of the microcapsule did not vary significantly between the tested production parameters. Objectives B and C measured the healing performance of concrete with embedded microcapsules. For the short-term healing period, the microcapsules proved to be significantly detrimental to the intrinsic concrete properties as the air content in the cement paste was substantially increased. Hence, factors contributing to the concrete strength deficiencies were addressed and corrected with modifications to the mix design and encapsulation procedures to evaluate the long-term healing period with respect to the mechanical properties and crack-sealing of concrete with embedded microcapsules.
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Milla, Jose Eduardo, "Performance Evaluation and Characterization of Encapsulated Calcium Nitrate for Self-Healing Concrete Applications" (2017). LSU Doctoral Dissertations. 4398.