自组装纳米碳材料复合混凝土及其基本构件的高性能、多功能特性

The self-assembled methods can integrate nanocarbon materials with raw materials or reinforcing fibers of concrete into a whole, which can overcome the issue of heterogeneous dispersion of nanocarbon materials when they are directly added into concrete. This has the potential to fully realize composite efficiency of nanocarbon materials and multiscale reinforcement or modification, thus providing a new approach for developing high-performance and multifunctional nanocarbon materials filled concrete composites. This project will firstly in-situ grow or graft nanocarbon materials on raw materials and reinforcing fibers of concrete to fabricate effective self-assembled multiscale nanocarbon material reinforcing fillers and obtain their fabrication theory, method and technology. Secondly, this project will investigate the relationships between the component, fabrication technology, properties, space field and time domain of the concrete composites with self-assembled multiscale nanocarbon material reinforcing fillers, and then obtain the design and fabrication methods of these composites, and the physical and chemical mechanisms of reinforcement or modification, and the constitutive models of properties of these composites. Finally, this project will further study the mechanical properties, durability and in-situ sensing ability of basic compressive and bending components fabricated with the self-assembled nanocarbon materials filled concrete composites, obtain reinforcement or modification mechanisms of the self-assembled multiscale nanocarbon material reinforcing fillers to properties of the basic compressive and bending components, and build up the mechanical or sensing constitutive models and the in-situ monitoring methods and the prediction models of durability degeneration of these basic components.

采用自组装方法将纳米碳材料与混凝土原材料或增强纤维结合成一体可解决纳米碳材料直接掺入混凝土时的分散不均问题，有望充分发挥纳米碳材料的复合效率并实现多尺度增强与改性，为发展高性能、多功能纳米碳材料复合混凝土提供新途径。本项目将首先采用自组装方法在混凝土原材料及增强纤维上原位生长或接枝纳米碳材料，研制出有效的自组装纳米碳材料多尺度增强体并获得其制备原理、方法和工艺；其次，研究复合自组装纳米碳材料多尺度增强体混凝土的组成-工艺-结构-性能-空间场-时间域之间的内在关联，获得自组装纳米碳材料复合混凝土的设计和制备方法、性能增强或改性的物理和化学机制以及本构模型；最后，研究自组装纳米碳材料复合混凝土基本压弯构件的力学性能、耐久性和原位感知性能，探明自组装纳米碳材料多尺度增强体对混凝土基本压弯构件性能的增强或改性机制，建立其力学和感知本构模型以及耐久性退化原位监测方法和预测模型。

纳米技术作为新工业革命的主导技术，其向土木工程领域的渗透为混凝土的高性能、多功能化提供了新的发展动力。本项目提出了纳米增强改性混凝土的纳米中心效应，并基于该效应研究自组装纳米碳材料对混凝土力学性能、电学性能、感知性能、电磁波屏蔽和吸收等性能的影响规律与机理，特别是复合材料的等效电路模型和压敏性模型；同时结合数值模拟和试验分析研究了基于自组装纳米碳材料复合混凝土的智能结构的性能。研究表明，自组装纳米碳材料对混凝土具有良好的力学增强效果，复合材料抗折强度可达到10MPa，比空白材料提高了18%。复合材料的渗流区间为0.14vol.%-0.45vol.%，直流电导率和交流电导率都具有显著的渗流特征。复合材料电阻变化率和应变灵敏度最大值分别可达84%和704。复合材料具有良好的电磁波吸收性能，电磁波反射率最小可达−32dB，小于−10dB的带宽和小于−15dB的带宽分别为2.16GHz和0.72GHz。上述结果的机理可归结为自组装纳米碳材料在混凝土基体中分散均匀且具有长程和短程的协同作用从而在混凝土中更容易形成广泛的增强和导电网络。基于自组装纳米碳材料复合混凝土的智能结构可以实现其自身的应力、应变以及损伤监测。本项目的开展可促进纳米混凝土制备、性能与机理研究，并为其应用奠定理论基础。