Since self-healing of cementitious materials can theoretically improve the service-life of concrete structures, it has gathered significant attention from both researchers and industry during the last two decades. Many researchers have proposed different methods to assess and quantify the self-healing capacity (i.e. the ability of cementitious materials to heal cracks) that is generated in concrete autogenously as well as autonomously. Even though many methodologies can be found in the literature, a way to accurately quantify the healing products produced by any self-healing mechanism has not been yet achieved. In this study, a methodology is proposed to observe and to quantify in-time formation of healing products based on active thin sections. Thin sections of Portland cement paste have been prepared with no epoxy impregnation to facilitate reactions between the cement matrix and the surrounding environment. Artificial cracks (260 μm wide) were induced at 28 days of age and the crystal growth was continuously monitored up to 28 days of self-healing. Through image analysis of the micrographs, it was calculated that the autogenous self-healing capacity of paste (triggered by portlandite carbonation in uncontrolled indoor conditions) was around 55% after 28 days of self-healing. Healing products were further characterised through Environmental Scanning Electron Microscope analysis. Based on the results obtained in this study, the proposed methodology seems to be promising to compare the self-healing mechanisms triggered by different healing agents.

中文翻译：

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通过活性薄片评估胶凝材料的自愈能力

由于胶凝材料的自修复理论上可以提高混凝土结构的使用寿命，在过去的二十年里，它引起了研究人员和工业界的极大关注。许多研究人员提出了不同的方法来评估和量化混凝土自生和自主产生的自修复能力（即胶凝材料修复裂缝的能力）。尽管在文献中可以找到许多方法，但尚未实现准确量化任何自愈机制产生的愈合产物的方法。在这项研究中，提出了一种方法来观察和量化基于活性薄片的愈合产物的及时形成。波特兰水泥浆的薄片已制备成没有环氧树脂浸渍，以促进水泥基体与周围环境之间的反应。人工裂纹（260 μm 宽）在 28 天龄时诱发，并连续监测晶体生长直至 28 天的自我修复。通过对显微照片的图像分析，计算出自愈28天后，糊状物的自愈能力（在不受控制的室内条件下由硅酸盐碳酸化引发）约为55%。通过环境扫描电子显微镜分析进一步表征了愈合产品。根据本研究中获得的结果，所提出的方法似乎有望比较不同愈合剂触发的自愈机制。