基于水泥基材料微结构参数的高性能抗冲磨混凝土设计与调控

Abrasion and erosion failure of concrete in hydraulic engineering subjected to high velocity flow with sand, concrete cover abrasion with sediment burden flow in marine environment, and concrete abrasion in pavement with vehicles become serious increasingly every day. Traditional design method based on empirical or semi empirical methods about abrasion resistant concrete cannot be satisfactory with the need of application in the environments above mentioned. Thanks to modern materials testing technology and microstructural theory of concrete, the design of abrasion resistant concrete and its goal-directed optimization become possibly. This proposal attempts to reveal the intrinsic mechanism of concrete resistance through connecting the micro- structural and macro- structural properties of abrasion concrete based on microstructural theory of cement based materials. The micromechanical properties of raw materials, including cement and aggregate, main hydrates, and the interface between paste and aggregate, such as hardness and elastic modulus, will be investigated through AFM, nanoindentation, etc. The relationship between micromechanical parameters and abrasive resistance of concrete will be established. Meanwhile, the porosity of paste and concrete will be investigated and analyzed through nitrogen adsorption, mercury intrusion porosimetry and sorption method. The pore diameters and distribution will be analyzed to link with the abrasion resistance of concrete. Eventually, the design method and approaches for property improvement of abrasion concrete based on microstructural parameters of cement based materials combining micromechanical characteristics of solid phase and pore structures of concrete. The results of this proposal can improve the life service of concrete subjected to abrasive environments.

水工结构泄水建筑物冲磨破坏、近海工程挟沙浪涌冲刷、道路路面磨蚀磨损等混凝土冲磨破坏带来的耐久性问题日趋严重，传统经验/半经验抗冲磨混凝土设计方法已无法满足材料设计与工程建设需求；材料测试技术及混凝土微结构理论发展为抗冲磨混凝土科学设计、制备与调控提供了条件。本项目从水泥基材料纳微观力学参数出发，采用现代综合测试分析技术，从原材料(水泥和骨料)、主要水化产物相及浆体与骨料界面分别研究其纳微观力学参数(硬度与弹性模量)，与宏观抗冲磨性能进行对比分析，揭示混凝土抗冲磨性能内在作用机制；同时，采用不同孔结构测试与分析方法从浆体和混凝土两个层次研究孔隙结构参数对混凝土抗冲磨性能的影响规律；最后，结合固相微观力学特性和孔隙结构特征提出基于水泥基材料微结构参数的高性能抗冲磨混凝土设计方法，并尝试采用多种调控途径改善混凝土抗冲磨性能，为提高混凝土抗冲磨耐久性寿命提供理论指导与技术途径。

水工结构泄水建筑物冲磨破坏、近海工程挟沙浪涌冲刷、道路路面磨蚀磨损等混凝土冲磨破坏带来的耐久性问题日趋严重，传统经验/半经验抗冲磨混凝土设计方法已无法满足材料设计与工程建设需求；材料测试技术及混凝土微结构理论发展为抗冲磨混凝土科学设计、制备与调控提供了条件。.本项目基于此背景，从水泥基材料纳微观结构参数出发，围绕抗冲磨混凝土原材料相关微结构参数研究、抗冲磨混凝土骨料与浆体界面性能研究、抗冲磨混凝土孔结构参数研究以及抗冲磨混凝土设计方法与性能优化等四个方面的主要内容展开相关研究，既围绕既有方案执行，又有一定的拓展和延伸。主要结果归纳如下：一、研究了花岗岩、玄武岩、大理岩、灰岩和白云岩5种岩石骨料在微切削模式下的耐磨性能进行了试验研究和微观作用机制分析，探明岩石骨料耐磨性能变化规律的内在因素。二、表征抗冲磨混凝土浆体的耐磨性与浆体微观力学性能及组成结构之间相关关系，将不同组成材料的浆体耐磨强度、显微硬度、Ca(OH)2含量、结合水含量、C-S-H平均链长、孔隙率以及平均孔径进行对比研究，并尝试建立浆体耐磨性与各微观力学参数及结构组成间的潜在规律。三、研究了几种高性能抗冲磨混凝土设计制备过程与性能优化措施，主要包括掺超细矿渣粉水泥基材料抗冲磨性能的微观机制、中热水泥制备高性能抗冲磨混凝土、超高性能混凝土（UHPC）抗冲磨性能、超细钢纤维混凝土抗冲磨性能、掺石粉超高性能混凝土（UHPC）抗冲磨性能等。此外，还对混凝土抗冲磨破坏数值模拟进行了一部分尝试性工作。.该项目从微观机理上揭示混凝土抗冲磨性能的内在影响机制，为从本质上理解混凝土抗冲磨性能与材料设计之间的关系提供了一定的理论依据。同时，基于抗冲磨性能内在作用机制，对不同类型抗冲磨混凝土的设计给出了具体案例，为有效寻求其性能调控的途径与手段提供科学基础。