基于纳观分析的水泥石徐变机理及调控模型研究

Creep is the hot research problem of the volume stability of cementitious materials, and the intrinsic relationship between nano-structure performance and macro-creep of hardened cement paste is a key scientific problem to reveal the creep mechanism of concrete. The formation inducement mechanism and control pathway of nano-structure of hardened cement paste will be investigated and analyzed. The effect of cementitious materials such as cement, traditional mineral admixture, inert mineral admixture and new mineral admixture on nano-structure evolution and mechanical properties of hardened cement paste will be investigated by many modern testing technologies including nanoindentation. Considering the effect of nano-structure performance of interfacial transition zone of hardened cement paste, the coupling mechanism of nano-creep phase and nano-constraint phase will be investigated by the deformation principle of physics and the quantum mechanics theory in order to reveal the creep mechanism of hardened cement paste. The effect of nano-structure performance of hardened cement paste on macro-creep will be explored by the continuum micromechanics theory. The quantitative indicators of hardened cement paste under the coupling mechanism of nano-creep phase and nano-constraint phase will be proposed to establish the creep control model of hardened cement paste with the characteristic of nano-creep. Based on the coupling mechanism of nano-creep phase and nano-constraint phase, the creep mechanism of hardened cement paste will be investigated, and the multiple compound control method of cementitious materials will be proposed to develop the new technology of concrete creep control, which will have the great scientific research value and broad prospect in engineering applications.

徐变是水泥基材料体积稳定性研究的热点问题，水泥石纳观结构性能与宏观徐变的内在关系是揭示混凝土徐变机理的关键科学问题。通过水泥石纳观结构形成的诱导与控制途径分析，运用纳米压痕等多种现代测试技术，研究水泥、传统矿物掺合料、惰性矿物掺合料和新型矿物掺合料等胶凝材料对水泥石纳观结构演变及力学性能的影响；考虑水泥石中界面过渡区的纳观结构性能的影响，运用变形物理学原理和量子力学理论，研究纳观徐变相和约束相耦合作用机制，揭示水泥石徐变机理；运用连续介质微观力学理论，探寻水泥石纳观结构性能对宏观徐变的影响，提出纳观徐变相和约束相耦合作用下的水泥石定量表征指标，构建具有纳观徐变特征的水泥石徐变调控模型。基于纳观徐变相和约束相耦合作用机制，研究水泥石徐变机理，提出胶凝材料多元复合调控方案，开发混凝土徐变调控新技术，具有重大的科学研究价值和广阔的工程应用前景。

混凝土徐变主要来源于水泥石，其纳观结构对徐变有着重要的影响。通过研究玻璃粉、石灰石粉、稻壳灰和锂渣等矿物掺合料对水泥石纳观结构演变及力学性能的影响，得到了水泥石纳观结构的形成和调控机制；基于纳观试验和分析，得到了影响水泥石徐变的三个主要因素分别为水化硅酸钙与未水化胶凝材料颗粒体积比、不同类型水化硅酸钙的比例和未水化胶凝材料颗粒徐变抵抗因子，据此提出了具有纳观徐变特征的水泥石徐变调控模型；研究了粉煤灰、矿粉、偏高岭土、石灰石粉、石英砂粉、金刚砂粉、稻壳灰、锂渣和玻璃粉等矿物掺合料对混凝土徐变的影响，结合纳米压痕、压汞法和扫描电镜等多种现代测试技术分析了其影响机理。基于胶凝材料优化设计，获取了混凝土徐变调控技术，具有较好的工程应用前景。