中子散射谱分析研究水泥中水动态

发布时间：2018-10-23 18:54

【摘要】：水泥是全球广泛使用的建筑材料。存在于不同受限体系中的水的动态密切影响着受限物体的各种宏观性能。研究受限体系中的水动态有助于深层次理解体系中微观水动态对体系宏观性质的作用及影响,从而根据人们的需求改善修饰各种宏观受限体系的功能。准弹性中子散射实验是一种极其优良的研究受限体系水动态的新型科学技术。它具有较高的能量分辨率,可以探测皮秒到纳秒量级的水分子动态。通过采用适宜的理论模型对准弹性中子散射谱进行拟合分析,我们就可以得到表征水动态信息的相关物理参数,进而探知所研究受限体系中的水动态。本项工作中研究的受限体系是普通波特兰水泥浆和新型氧化镁基环保水泥浆。水泥灰加水凝固变硬,产生微观多孔结构。这些空隙中存在着受限水。受限水的含量及动态会随着时间变化,从而不断对受限体系即水泥的微观孔隙结构产生直接影响,最终影响着作为受限体系的成品水泥的宏观机械性能如强度、耐久性。本项工作主要分为两大部分:第一,用跳跃扩散和旋转扩散模型分析不同老化时间含添加剂及不含添加剂的普通波特兰水泥的准弹性中子谱数据,得到表征水动态相关信息的物理参数,如不动水指数、平均位移平方、平移弛豫时间、旋转弛豫时间及自扩散系数等。第二,用弛豫盒子模型分析不同温度下含添加剂及不含添加剂的新型氧化镁基环保水泥的准弹性中子散射谱数据,得到其中受限水动态的相关物理参数,如结构水指数、平均弛豫时间及旋转弛豫时间。这些物理参数可以定量描述不同条件下受限体系中水动态,如水泥老化时间、添加剂、温度及不同种类样品对受限体系水泥水化过程的影响,从而为设计研究更优更环保的水泥提供参考。
[Abstract]:Cement is a widely used building material all over the world. The dynamics of water in different confined systems have a close effect on the macroscopic properties of confined bodies. The study of water dynamics in confined systems is helpful to understand the effect and influence of micro-water dynamics on the macroscopic properties of the system, and to improve the function of modifying various macro-confined systems according to the needs of people. The quasi-elastic neutron scattering experiment is an excellent new science and technology for studying the water dynamics of confined systems. It has high energy resolution and can detect the dynamics of water molecules from picosecond to nanosecond. By fitting and analyzing the elastic neutron scattering spectrum with a suitable theoretical model, we can obtain the relevant physical parameters to characterize the water dynamic information, and then we can find out the water dynamics in the confined system studied in this paper. The limited systems studied in this work are ordinary Portland cement slurry and new MgO-based environmental cement slurry. Cement ash is solidified by adding water, resulting in microporous structure. There is confined water in these voids. The content and dynamics of confined water will change with time, which will have a direct impact on the micropore structure of the confined system, I. e., the micropore structure of the cement, and ultimately affect the macroscopic mechanical properties such as strength and durability of the finished cement as a confined system. This work is mainly divided into two parts: first, the quasi-elastic neutron spectra of Portland cement with and without additives at different aging times are analyzed by using jump diffusion and rotation diffusion models. The physical parameters, such as immovable water index, mean displacement square, translation relaxation time, rotation relaxation time and self diffusion coefficient, are obtained. Secondly, the quasi-elastic neutron scattering spectra of a new type of MgO-based environmental cement with and without additives at different temperatures are analyzed by using the relaxation box model, and the physical parameters of the confined water dynamics, such as structural water index, are obtained. Mean relaxation time and rotation relaxation time. These physical parameters can be used to quantitatively describe the water dynamics in confined systems under different conditions, such as the aging time of cement, additives, temperature and the effects of different kinds of samples on the hydration process of confined cement. So as to design better and more environmentally friendly cement to provide a reference.
【学位授予单位】：暨南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ172.1

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