基于氧化石墨烯改性水泥基材料微结构及自修复性能的基础研究

Cement-based materials are brittle materials with internal micro defects. When cement products are under stress or in a harsh environment for a long time, microcracks usually occur inside the cement stone, and these microcracks will continue to evolve into large cracks under the influence of loads or other factors, thus the service life of cement based materials is reduced. In this project, for cement-based materials such as high brittleness and easy to crack defects, based on the synergetic influence of graphene oxide (GO) and plasticizer on the performance of cement-based materials, the influence of SiO2-GO microcapsules self-repairing system on the repairing of cement-based materials, the relationship between microcosmic properties and durability of GO modified cement-based materials, the microstructure of cement-based materials and the self-healing process of defects are proposed, and the GO modified cement and concrete microstructure and self-healing system are innovatively designed. The aims of this project are to optimize the microstructure and to improve the self-healing performance of cement-based, and the development of micro cracks and deterioration of reinforced concrete can be prevented and suppressed by GO modified cement-based materials. By revealing the microstructural characteristics of cement-based materials and the self-healing process and mechanism, and finally the purpose of fully improving the mechanical properties, the volume stability and the durability of cement-based materials can be achieved.

水泥基材料是具有内部微观缺陷的脆性材料。当水泥制品在受力或长时间处于恶劣环境中时其内部往往会发展形成微裂缝，这些微裂缝会在载荷或其他因素的影响下继续发展形成大的裂缝，降低了水泥基材料的使用寿命。针对水泥基材料高脆性和易开裂等缺陷，围绕氧化石墨烯（GO）与减水剂对水泥基材料性能协同影响规律，SiO2-GO微胶囊体系对水泥基材料自修复性能的影响以及GO改性水泥基材料微观性能与耐久性关系作用机理三个方面，本项目提出了水泥基材料微结构和缺陷自修复的作用过程，创新性地设计了基于GO改性水泥基材料微结构和自修复系统。本研究以优化水泥基材料微结构和提高自修复性能为设计目标，通过GO改性水泥基材料，实现预防并抑制水泥基材料的微裂缝发展和钢筋混凝土锈蚀劣化。通过揭示水泥基材料微结构特征及自修复过程和机理，最终达到全面提升水泥基材料力学性能、体积稳定性和耐久性的目的。

氧化石墨烯(GO)可以有效改善水泥基材料的微观结构，提高水泥的力学性能、耐久性能以及功能性，但是由于GO很容易在水泥浆体中发生团聚，限制了它们在水泥基材料中的应用效果。为了让它们可以在水泥中实现均匀稳定分散，从而充分发挥它们的优良性能，本项目系统地研究了不同分散剂对GO的物相组成、微观结构和形貌的影响，同时考察了GO、分散剂与硅灰的协同效应以及对水泥基材料微结构的影响。本项目阐明了GO以及碳纳米管(Carbonnanotubes, CNTs)经过改性之后对水泥基材料各项性能的影响，以及GO和CNTs两者杂化掺加之后对混凝土材料各项性能的影响；深入分析了少量PCE改性纳米硅溶胶和氧化石墨烯掺入粉煤灰水泥后，对水泥石水化早期的性能及产物的影响以及硅灰(SF)、硅溶胶(SS)和氧化石墨烯复掺对水泥水化和力学性能的影响；通过研究GO对水泥石力学性能的影响，分析了GO影响水泥水化过程和对水泥石微观结构的改善和其自修复的机制，得出了GO对改性水泥基材料改性较优的方法，为GO改性增韧水泥基材料提供了方法指导；开创了CaCO3和SiO2作为负载和GO结合的新体系，并得出了较优的GO提高水泥石力学性能、改善其微结构并提高其耐久性的方法，为GO和水泥基材料的结合提供了新的参考。