Abstract：
The visualisation and quantification of pore networks and main phases have been critical research topics in cementitious materials as many critical mechanical and chemical properties and infrastructure reliability rely on these 3D characteristics. In this study, we realised the mesoscale serial sectioning and analysis up to ∼80 μm by ∼90 μm by ∼60 μm on portland cement mortar using plasma focused ion beam (PFIB) for the first time. The workflow of working with mortar and PFIB was established applying a prepositioned hard silicon mask to reduce curtaining. Segmentation with minimal human interference was performed using a trained neural network, in which multiple types of segmentation models were compared. Combining PFIB analysis at microscale with X-ray micro-computed tomography, the analysis of capillary pores and air voids ranging from hundreds of nanometres (nm) to millimetres (mm) can be conducted. The volume fraction of large capillary pores and air voids are 11.5% and 12.7%, respectively. Moreover, the skeletonisation of connected capillary pores clearly shows fluid transport pathways, which is a key factor determining durability performance of concrete in aggressive environments. Another interesting aspect of the FIB tomography is the reconstruction of anhydrous phases, which could enable direct study of hydration kinetics of individual cement phases.
摘要：
孔隙网络和主要阶段的可视化和量化一直是胶凝材料的关键研究课题，因为许多关键的机械和化学性质以及基础设施的可靠性都依赖于这些3D特性。在这项研究中,我们首次使用等离子聚焦离子束（PFIB）对波特兰水泥砂浆进行了中尺度连续切片和分析，分析达到80μm×90μm×60μm。使用砂浆和PFIB的工作流程是建立的，应用预先放置的硬硅掩模以减少幕布。使用经过训练的神经网络进行最小人为干扰的分割，其中比较了多种类型的分割模型。将微尺度PFIB分析与X射线显微计算机断层扫描相结合，可以进行从数百纳米（nm）到毫米（mm）的毛细管孔和空气空隙的分析。大毛细管孔和气孔的体积分数分别为11.5%和12.7%，分别。此外，相连的毛细管孔的骨架化清楚地显示了流体运输途径，是决定混凝土在侵蚀性环境中耐久性能的关键因素。FIB层析成像的另一个有趣的方面是无水相的重建，这可以直接研究各个水泥相的水化动力学。
