基于孔结构特征的透水混凝土性能双目标协同优化方法

Strength and permeability are two core problems of pervious concrete in engineering application, The research results show that the strength and permeability of pervious concrete is contradictory.This research is based on the pore structure features which is the common factor of strength and permeability. Firstly, the pore structure features of pervious concrete will be well studied.Secondly, the strength and permeability coefficient of pervious concrete will be studied. The theoretical models of pore structure features related to strength and also the relationship between the pore structure features and permeability coefficient will be established, and the mechanism of which will be revealed. Then, as the bridge of the pore structure features, the theoretical research of the equilibrium relationship between strength and permeability coefficient of pervious concrete will be carried out. The theoretical model of strength and permeability coefficient will be established. A double objective control method will be applied to the performance of pervious concrete with different strength and permeability. Based on the strength and permeability coefficient, the double objective control model and mechanism of pervious concrete are proposed. The research of this project is of great value to the development of pervious concrete materials to meet the needs of different strength and permeability. It can also provide technical basis and reliable design parameters for the establishment of relevant standards. It plays an important role in the engineering practice.

强度与透水性是透水混凝土在工程应用过程中最受关注的两个核心问题，研究表明上述两者性能是相互矛盾的对立关系。本项目以强度和透水性的共同决定因素孔结构特征为切入点，首先，研究透水混凝土孔结构特征的要素及其表征方法。其次，试验研究透水混凝土的强度与透水系数，并分别建立孔结构特征与强度和透水系数的理论模型并揭示其作用机理。然后，以孔结构特征为桥梁，理论研究透水混凝土强度和透水系数之间不断变动的此消彼长的均衡关系，建立强度与透水系数的理论模型，探求适用于不同强度和透水性要求的透水混凝土性能的双目标优化方法，提出基于强度和透水系数的透水混凝土性能双目标优化模型及机理。本项目的研究对开发适应不同强度和透水性需求的透水混凝土材料具有重要价值，而且也可为相关标准的制定提供技术基础和可靠的设计参数，对其工程实践具有重要的指导作用。

随着城市雨洪管理与雨水资源利用的理念的引入，海绵城市建设实践的不断发展，海绵城市被赋予了更多内涵，成为生态文明建设最有效的实现途径之一。透水混凝土作为海绵城市建设重要的透水铺装材料，其性能直接关系到雨水的渗透能力和路面结构的承载能力。本研究基于透水混凝土中微观和宏观孔结构、透水系数和抗压强度的试验研究，以及透水混凝土结构的三维仿真建模，对透水混凝土的结构、透水性能和抗压强度及其形成机理进行了研究，主要研究成果如下：.1.开发了一套用于透水混凝土制备的振动击实仪，能够用以制备较好透水性能的透水混凝土；研发了一种测量透水混凝土透水系数的装置，利用该装置测定对不同配合比透水混凝土的透水系数。.2.应用低场核磁共振技术测试水泥浆体的微观结构，采用CEMHYD3D仿真模拟软件模拟水泥浆体三维微观结构早期变化。得出了不同水灰比、集灰比以及硅灰、纳米SiO2和SAP的掺入下平均孔半径的变化规律。水灰比的增大，导致水泥浆体结构疏松，孔径增大；骨料含量的增加对水泥浆体内微观孔结构的影响不大；硅灰的掺入使得微小孔的含量减少，孔径均匀化；纳米SiO2粒径微小，能很好的填充水泥浆体，使得水泥净浆的孔隙率有效减少。.3.基于称重试验研究透水混凝土的总孔隙率和有效孔隙率，利用CT断层扫描和Avizo仿真软件建立了透水混凝土的三维结构模型，分析孔结构的分布及连通路径。水泥浆体对骨料的有效均匀包裹，骨料骨架间的搭接状态是影响孔结构与透水系数的关键。骨料间的有效粘结与骨料形成框架的状态是影响孔结构与抗压强度的关键。.4.建立了多相多尺度的混凝土抗压强度的理论计算模型。初步定量分析了孔结构特征、强度、透水性能三者关系。

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