基于渗透性的高性能混凝土耐久性评价方法研究

发布时间：2018-03-18 02:14

本文选题：混凝土耐久性　切入点：气体渗透性　出处：《安徽建筑大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着经济的发展以及科技力量的突飞猛进,各种在特种严酷环境下服役的混凝土结构层出不穷,如海底隧道、跨海大桥、核反应堆等。这些混凝土结构不仅要有满足按结构荷载设计的强度要求,更重要的是要有满足在特定环境下能够达到预定工作时间的能力,这就是要求混凝土结构有足够的耐久性。而高性能混凝土正是以耐久性作为其设计的主要指标,不仅对耐久性、工作性有保证,还有必须满足适用性和经济性,是一种新型的高技术混凝土,是未来混凝土技术发展的方向。然而寻求一套科学的、可靠的、实用的方法来检验和评定混凝土的耐久性能,一直是工程界渴望得到解决的问题。长久以来,国内外许多专家学者都对混凝土的渗透性做了广泛而深入的研究,并取得了大量的研究成果。本文基于TORRENT方法,研究了气体在混凝土中的渗透性及其与碳化性之间的关系,结果表明气体渗透性随水灰比的降低而减小,粉煤灰的掺入降低了混凝土碳化性能,气体渗透性与碳化无相关性。同时研究了混凝土的水分渗透与氯离子渗透,结果表明,粉煤灰对混凝土的抗水渗透产生不利影响,使混凝土的渗水系数大幅度提高,而混凝土氯离子迁移系数也随着粉煤灰掺量的增加而增加。通过对比分析水分渗透性及氯离子渗透性与抗冻性的关系,发现水分渗透与抗冻性相关性较小,而混凝土氯离子迁移系数与抗冻性相关性较好。最后对不同配合比、掺合料混凝土的微观结构进行了分析,以探究孔结构对混凝土渗透性的影响,发现混凝土气孔含量随着粉煤灰的增加而增加,粉煤灰可以改善混凝土中的孔结构,使混凝土中的孔隙孔径越多的向无害孔转移。而混凝土孔隙率与氯离子迁移系数DRCM相关性很好,混凝土氯离子迁移系数DRCM随着孔隙率的增加而增加。
[Abstract]:With the development of economy and the rapid development of science and technology, various kinds of concrete structures, such as subsea tunnels and bridges across the sea, have emerged in special and harsh environments. Nuclear reactors and so on. These concrete structures must not only meet the strength requirements of the structural load design, but also, more importantly, have the ability to meet the scheduled working hours in a given environment. This is to require concrete structures to have sufficient durability. And high performance concrete is designed with durability as its main index, not only to ensure durability and workability, but also to satisfy applicability and economy. Is a new type of high-tech concrete, is the direction of the future development of concrete technology. However, to seek a scientific, reliable, practical method to test and evaluate the durability of concrete, For a long time, many experts and scholars at home and abroad have done extensive and in-depth research on the permeability of concrete, and obtained a lot of research results. The relationship between the permeability of gas in concrete and its carbonation is studied. The results show that the gas permeability decreases with the decrease of water-cement ratio, and the carbonation property of concrete decreases with the addition of fly ash. There is no correlation between gas permeability and carbonation. At the same time, the moisture permeation and chloride ion permeation of concrete are studied. The results show that fly ash has a negative effect on the water permeability of concrete, and the permeability coefficient of concrete is greatly increased. The chloride ion transport coefficient of concrete also increases with the increase of fly ash content. By comparing and analyzing the relationship between water permeability and chlorine ion permeability and frost resistance, it is found that the correlation between water permeability and frost resistance is relatively small. However, the chlorine ion transfer coefficient of concrete has a good correlation with the frost resistance. Finally, the microstructure of concrete with different mix ratio and admixture is analyzed to explore the influence of pore structure on the permeability of concrete. It is found that the pore content of concrete increases with the increase of fly ash, and the pore structure in concrete can be improved by fly ash. The more pore pore size in concrete is transferred to the harmless pore, the better the correlation between concrete porosity and chloride migration coefficient (DRCM) is. The chloride ion migration coefficient (DRCM) of concrete increases with the increase of porosity.
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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