This paper presents a methodology for numerically simulating the chloride diffusivity in mortar subjected to corrosion-induced cracking with the aid of X-ray microcomputed tomography (X-ray µCT). In the research, the mortar sample with embedded steel rod was subjected to accelerated corrosion and then scanned by X-ray µCT at consecutive corrosion periods of 0, 1,000, and 2,000 minutes. Upon the scanned CT images, a meso-scale model consisting of multiple material phases with their intrinsic structures was built up and implemented into a finite element method for diffusion simulation. In the numerical simulation, the effects of multiple phases (void, crack, aggregate, rust, and interfacial transition zone between cement and aggregate) on the chloride diffusion of mortar are studied. Since the X-ray µCT facilitates accurate local material information in time-dependent and in situ manner, the diffusivity of mortar under different corrosion time and its spatial distribution characteristics (e.g., at different locations from the mortar surface) can be evaluated.

中文翻译：

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腐蚀诱导开裂的砂浆中氯离子扩散率的中尺度模拟

本文介绍了一种借助X射线微计算机断层扫描（X射线µCT）数值模拟砂浆中腐蚀引起的开裂后氯离子扩散率的方法。在研究中，对带有嵌入式钢棒的砂浆样品进行加速腐蚀，然后在连续的0、1,000和2,000分钟的腐蚀时间段内通过X射线µCT进行扫描。在扫描的CT图像上，建立了包含多种材料相及其固有结构的介观模型，并将其实现为用于扩散模拟的有限元方法。在数值模拟中，研究了多个相（空隙，裂纹，骨料，铁锈，水泥与骨料之间的界面过渡区）对砂浆中氯离子扩散的影响。