微生物多糖对水泥浆体性能影响的研究

发布时间：2018-03-11 06:04

本文选题：水泥浆体　切入点：微生物多糖　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：粘度改性剂是水下浇筑混凝土、自密实混凝土的重要组成成分之一,它可以减少水泥基材料泌水,提高其粘聚性能。一些微生物多糖作为粘度改性剂在水泥基材料中已经得到广泛的运用。微生物多糖是一些微生物在代谢生长过程中产生的生物高聚物,具有优良的理化性质。近年来,随着研究者们对微生物多糖研究的逐步深入,开始不断有新型微生物多糖以及各种微生物多糖的新用途被研究和开发出来,因此充分发掘新型微生物多糖的新用途以及利用其优良特性来改善水泥基材料性能的研究是十分有必要的。本文以普鲁兰多糖、威兰胶、定优胶三种微生物多糖为研究对象,研究了微生物多糖对水泥浆体的标准稠度用水量、凝结时间、流动度、Zeta电位、力学性能等性质的影响,以及对砂浆流动性、力学性能和抗碳化性能的影响,此外探究了新型微生物多糖—普鲁兰多糖的成膜性在水泥基材料中的运用。研究结果表明,微生物多糖的掺入增大了水泥标准稠度用水量,而减水剂存在时,标准稠度用水量对微生物多糖掺量更为敏感;微生物多糖均具有缓凝效应,其中普鲁兰多糖的缓凝效果最明显;微生物多糖的掺入均会降低水泥浆体的流动度,阻止水泥浆体泌水,随着时间的延长,掺普鲁兰多糖水泥浆体的流动度不降反升;微生物多糖和聚羧酸减水剂的掺入均会降低水泥浆体Zeta电位值;当微生物多糖的掺量在0.08%以下时,其掺入对硬化水泥浆体和水泥砂浆抗压强度并没有明显的不利影响,且对砂浆后期强度有明显的改善作用;含普鲁兰多糖水泥浆体的水分蒸发损失率低于空白浆体;微生物多糖的掺入均会不同程度地减小砂浆的碳化深度,提高砂浆的抗碳化性能,但随着微生物多糖掺量的增加,砂浆碳化深度亦会加深,其中掺0.02%普鲁兰多糖砂浆的抗碳化性能最好。
[Abstract]:Viscosity modifier is an important component of underwater pouring concrete, self-compacting concrete, it can reduce bleeding of cement based materials, Some microbial polysaccharides have been widely used in cement-based materials as viscosity modifiers. Microbial polysaccharides are biological polymers produced by some microorganisms during metabolic growth. In recent years, with the development of researchers' research on microbial polysaccharides, new types of microbial polysaccharides and new uses of microbial polysaccharides have been studied and developed. Therefore, it is necessary to fully explore the new uses of new microbial polysaccharides and to improve the properties of cement-based materials by using their excellent properties. In this paper, three kinds of microbial polysaccharides, such as pullulan polysaccharide, Weilan gum and Dingyou gum, are taken as the research objects. The effects of microbial polysaccharides on the standard consistency water consumption, setting time, fluidity and Zeta potential of cement paste, mechanical properties, and the effects of microbial polysaccharides on mortar fluidity, mechanical properties and carbonation resistance were studied. In addition, the film-forming properties of a new type of microbial polysaccharide, Prulan polysaccharide, were investigated. The results showed that the incorporation of microbial polysaccharides increased the water consumption of cement standard consistency, and when the water reducer existed, The water consumption of standard consistency is more sensitive to the amount of microbial polysaccharides, the microbial polysaccharides have retarding effect, the effect of pullulan is the most obvious, and the incorporation of microbial polysaccharides can decrease the fluidity of cement slurry. With the prolongation of time, the fluidity of the cement paste with pullulan was not decreased but increased, and the Zeta potential of cement paste was decreased with the addition of microbial polysaccharides and polycarboxylic acid superplasticizer. When the amount of microbial polysaccharides is below 0.08%, the addition of microbial polysaccharides has no obvious adverse effect on the compressive strength of hardened cement paste and cement mortar, and it can obviously improve the later strength of mortar. The evaporation loss rate of the cement paste containing pullulan polysaccharides was lower than that of the blank slurry, and the incorporation of microbial polysaccharides decreased the carbonation depth of mortar to some extent, and improved the carbonation resistance of mortar, but with the increase of the amount of microbial polysaccharides, The carbonation depth of mortar will also be deepened, and the carbonation resistance of 0.02% Pluran polysaccharide mortar is the best.
【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】：TU528

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