纳米改性混凝土微观结构调控对侵蚀介质多尺度传输行为的影响

The durability of concrete is governed by its microstructure and service environment. As such, it is crucial to characterize and control the microstructure of such concrete to realize the properties optimization. The objective of this project is to tune the microstructure and macroscopic properties of concrete by introducing various nano-materials, and thus illustrate the mechanisms underlying the influence of nano-materials on the hydration process of cement concrete. The microstructure changes induced by the admixed nano-materials of concrete will be observed and quantitatively characterized. This project will not only shed light on the correlations between the microstructure and properties of concrete but also connect them with various service environment factors. The changes resulted from the admixed nano-materials to the rebar corrosion behavior in concretes will be analyzed, and linked to the influence of concrete microstructure to the percolation properties of deleterious and corrosive species. The experimental data obtained will also be utilized to investigate the rebar corrosion processes at multi-scale lengths, thus improving the current models of the percolation behavior of the corrosive media in concrete. In addition, an integrated model will be developed to describe the corrosive environment resistance of concrete which helps illustrating the underlying mechanisms. These studies will not only benefit the application of nanotechnology in civil engineering but also lay the theoretical groundwork for the durability of concrete with exposure to corrosive marine environment, featuring great intellectual merits and broad engineering implications.

混凝土在腐蚀环境下的耐久性很大程度上受其微观结构影响。运用纳米材料实现混凝土微观结构调控是提升混凝土在腐蚀环境下耐久性的有效方法之一。本研究将采用溶胶-凝胶法或水热法获得形貌与尺寸可控的纳米材料。通过对合成的纳米材料进行表面处理，使其获得在混凝土中良好的分散状态，进而优化混凝土的宏观性能。通过对纳米改性混凝土的微观结构在不同尺度下的观测与分析，结合宏观性能变化规律，确定纳米改性混凝土微观结构与宏观性能之间的对应关系，并揭示纳米材料对混凝土的改性机理。通过对侵蚀环境下纳米改性混凝土中钢筋锈蚀行为的分析，以及侵蚀介质在纳米改性混凝土中传输途径的定量表征，确定纳米改性混凝土微观结构调控对侵蚀介质传输行为的影响机理，建立侵蚀介质在纳米改性混凝土中的多尺度传输模型。该研究不仅能拓展纳米技术在混凝土材料科学以及土木工程中的应用，而且为腐蚀环境下混凝土耐久性设计提供理论依据。

本项目运用纳米材料实现混凝土微观结构调控，获得了提升混凝土在腐蚀环境下耐久性的有效方法。项目采用了形貌与尺寸可控的纳米材料，通过表面活性剂的使用，获得在混凝土中良好的分散状态，并优化了混凝土的宏观性能。通过对纳米改性混凝土的微观结构在不同尺度下的观测与分析，结合宏观性能变化规律，确定了纳米改性混凝土微观结构与宏观性能之间的对应关系，并揭示不同纳米材料对混凝土的改性机理。通过对侵蚀环境下纳米改性混凝土失效行为的分析，厘清了侵蚀介质对纳米改性混凝土中腐蚀机理，确定了纳米改性混凝土微观结构调控以及传输行为的影响机理，建立了侵蚀介质在纳米改性混凝土中的多尺度传输模型。该研究不仅能拓展纳米技术在混凝土材料科学以及土木工程中的应用，而且为腐蚀环境下混凝土耐久性设计提供理论依据。