石灰石粉复合胶凝粉体材料的颗粒级配设计研究

发布时间：2018-02-03 07:44

本文关键词： 石灰石粉复合胶凝粉体材料颗粒级配设计最佳堆积密度粒度分布活性指数流动度　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：石灰石粉作为一种普遍而廉价的材料,其在复合胶凝材料中的合理应用,不仅能够很好地缓解当前粉煤灰等传统掺合料日益紧缺的现状,甚至能够成为功能性组分,解决一些地方性掺合料单掺时在流动性能等方面存在的缺陷与问题。因此,从当下愈发受到重视的颗粒级配角度出发,研究石灰石粉在不同水泥基粉体胶凝体系中的复合应用特点,从而具有一定普适性且较大程度地实现石灰石粉的有效利用,意义重大。本文将粉体颗粒级配作为主要侧重点,尝试将石灰石粉作为功能性组分进行复合利用,通过引入级配参数,研究石灰石粉在几种复合胶凝体系中的应用特点及作用机理。结合实际项目,分别选取分布较为广泛的天然火山灰与自燃煤矸石作为复合组分,尝试从颗粒级配角度最大化发挥石灰石粉的性能特点,以解决这些地方性掺合料单掺时存在的问题,并取得了良好的效果。另一方面,将石灰石粉与超细粉煤灰和硅灰复合使用,依托Fuller曲线模型设计体系颗粒级配,通过达到最佳堆积密度来最大化发挥石灰石粉在颗粒填充方面的优势,最终成功配制出强度及流动性能良好且较为经济的高性能复合掺合料。通过本文的研究得出:(1)在石灰石粉-天然火山灰复合体系中,保证充足的石灰石粉细颗粒含量以增大颗粒堆积密度十分重要。颗粒级配设计结果表明,复合粒度分布与水泥基本相同的天然火山灰以及细颗粒含量较高的石灰石粉最为适宜,能够在保证粉磨能耗成本经济性的同时,使体系性能得到较大程度的提高。(2)复合一部分粒度分布适宜的石灰石粉能够很好地解决自燃煤矸石单掺时流动性能较差的问题。其中,复掺细颗粒含量较高的石灰石粉以愈发接近Fuller曲线的级配要求,流动性能越好。颗粒级配设计结果显示,复合中粒径D50为水泥0.75倍的自燃煤矸石以及D50为基准水泥0.348倍的石灰石粉,能够较好地发挥物理颗粒填充效应,使复合体系胶砂性能得到较大程度的优化。(3)在石灰石粉-超细粉煤灰-硅灰复合体系中,对水吸附性较小的石灰石粉在体系颗粒级配方面所发挥的填充作用相比材性更为重要,因此在定量硅灰等一些材性影响较大的组分后,根据石灰石粉的粒度分布,依托Fuller曲线最终确定出最接近体系最佳堆积密度的粉体复合比例,这种设计手段对于石灰石粉在该复合体系中的应用是十分可行的。(4)从颗粒级配角度出发,将石灰石粉作为功能性组分进行复合利用,用来解决一些地方性掺合料单掺时存在的缺陷或替代一部分价格较高的活性组分是十分可行的。在复合利用石灰石粉时,更应该以整个粉体体系尽可能达到最佳堆积密度为目的,将其粒度分布的选择设计作为实际应用的关键。
[Abstract]:As a universal and cheap material, the reasonable application of limestone powder in composite cementitious materials can not only alleviate the current situation of increasing shortage of traditional admixtures such as fly ash. It can even become a functional component to solve some local admixtures in the flow performance of the defects and problems. Therefore, from the point of view of more and more attention to particle gradation. The composite application characteristics of limestone powder in different cement-based powder cementing systems are studied, so that the limestone powder can be widely used to a certain extent. In this paper, the gradation of powder particles as the main focus, try to use limestone powder as a functional component for composite use, through the introduction of gradation parameters. The application characteristics and mechanism of limestone powder in several kinds of composite cementing systems were studied. Combined with practical projects, natural volcanic ash and spontaneous combustion coal gangue, which were widely distributed, were selected as composite components respectively. This paper tries to maximize the performance characteristics of limestone powder from the angle of particle gradation, in order to solve the problems existing in the single blending of these local admixtures, and obtain good results on the other hand. Limestone powder was combined with ultrafine fly ash and silica fume to design particle gradation based on Fuller curve model. In order to maximize the advantages of limestone powder in particle filling, the best packing density can be achieved. Finally, the high performance compound admixture with good strength and flow performance was prepared successfully. Through the research of this paper, it was concluded that the composition of limestone powder and natural pozzolanic ash was in the composite system of limestone powder and natural pozzolanic ash. It is very important to ensure sufficient fine particle content of limestone powder in order to increase the density of particles. The results of particle gradation design show that. The composite particle size distribution is basically the same as cement natural pozzolanic ash and limestone powder with high content of fine particles is the most suitable, which can ensure the cost and economy of grinding energy consumption at the same time. The composite limestone powder with proper particle size distribution can solve the problem of poor flow performance of spontaneous combustion gangue when it is mixed with coal gangue. The fluidity of limestone powder mixed with high content of fine particles is closer to the requirement of Fuller curve. The results of particle gradation design show that the fluidity of limestone powder is better than that of Fuller curve. The self-ignition coal gangue with the particle size D50 of 0.75 times of cement and the limestone powder with D50 of 0.348 times of the benchmark cement can play a better role in the filling effect of physical particles. The cemented sand properties of the composite system can be optimized to a greater extent in the limestone powder-ultrafine fly ash-silica fume composite system. Limestone powder with less water absorbability plays a more important role in filling the particle gradation of the system than the wood property, so after the quantitative silica fume and other material properties of some more important components. According to the particle size distribution of limestone powder, the composite ratio of powder closest to the best packing density of the system was finally determined by Fuller curve. This design method is very feasible for the application of limestone powder in the composite system. It is very feasible to solve the defects of some local admixtures or to replace some expensive active components. The best packing density of the whole powder system should be taken as the goal, and the selection and design of the particle size distribution should be regarded as the key point of practical application.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU526

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