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Keywords
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Montmorillonite, Mechanical properties, Thermal stability, Self-healing, Cementitious materials
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Abstract
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Propagating micro-cracks in a structure decrease its load bearing capacity and would lead to collapse the entire structure. By the aim of enhancing the microencapsulated self-healing cementitious materials performance, montmorillonite (MMT) is used as a component of ternary healing agent. Microcapsules were synthesized by in-situ polymerization of urea-formaldehyde as shell around the core materials inclusive epoxy resin, calcium nitrate and montmorillonite. Physicochemical characterization of microcapsules was conducted by Fourier transformation infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), particles size analyzer (PSA), atomic force microscopy (AFM), and thermal gravimetric analysis (TGA). The mechanical assessment of cementitious specimens with different dosages of microcapsules (0%, 1%, 3%, and 6%) was performed by three-point bending, and compressive tests. The addition of MMT (0.5 wt.% by epoxy mass) in healing agent led to enhance thermal stability in cementitious materials up to 472 °C, and also showed a significant performance at increasing the flexural and compressive recovery rates up to 170.21%, and 152.02%, respectively.
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