【作者】 杨长利；

【导师】 郑娟荣；

【作者基本信息】 郑州大学 ， 结构工程， 2012， 硕士

【摘要】 二十世纪末,干混砂浆作为一种新型建筑材料出现在我国建筑业市场。相对于传统现场拌制砂浆而言,干混砂浆有更加精确的配比、更加合适的外加剂,具有优良的工作性能和良好的质量保证。干混砂浆能利用大量的粉煤灰、脱硫石膏、矿渣等工业废料,减轻环境压力,为施工现场节约材料堆放场地,提高施工效率。我国通用硅酸盐水泥的最低强度等级为32.5MPa,而干混砂浆(如抹灰砂浆的强度等级为M5、M10、M15和M20)的强度等级偏低。目前我国市场上没有专用砂浆水泥,建筑施工现场用通用硅酸盐水泥(即纯水泥)直接配制砂浆,这导致水泥的浪费和砂浆质量问题的频频发生；干混砂浆企业采用通用硅酸盐水泥配制砂浆、同时大掺量粉煤灰调节强度等级。如何发挥干混砂浆中粉煤灰的胶凝作用,进一步降低干混砂浆中水泥掺量,从而进一步降低成本和改善砂浆的质量,这是砂浆企业急需解决的问题。本论文以郑州电厂原状粉煤灰、郑州电厂磨细粉煤灰、洛阳低钙粉煤灰和郑州电厂脱硫石膏与水泥为主要原材料,采用固定变量的研究方法,对“低水泥大掺量粉煤灰和烟气脱硫石膏”的胶凝性进行了系统研究。研究结果表明：郑州电厂原状粉煤灰的性能指标达不到Ⅲ级灰指标,但经过磨细处理,达到Ⅱ级灰的指标,磨细灰可以完全代替Ⅱ级洛阳低钙粉煤灰配制干混抹灰砂浆,并且配制的砂浆各项性能指标更好；“低水泥大掺量粉煤灰和烟气脱硫石膏”的胶砂强度随水泥掺量增加而提高,与烟气脱硫石膏的掺量有一个较优比例,例如当水泥掺量20%和30%、烟气脱硫石膏30%时,“低水泥大掺量磨细粉煤灰和烟气脱硫石膏”的胶砂强度分别为19.3MPa和24.6MPa,达到我国砌筑水泥12.5和22.5强度等级；“低水泥大掺量粉煤灰和烟气脱硫石膏”的胶凝材料体积收缩率随水泥掺量增加而加大、随烟气脱硫石膏的掺量增加而减小,掺磨细粉煤灰的干混砂浆专用胶凝材料体积收缩率比原状粉煤灰略小。本文采用扫描电镜(SEM)和X射线衍射(XRD)分析表明：与原状粉煤灰相比,磨细粉煤灰由于表面经过机械活化作用,在水泥和脱硫石膏的双重激发作用下,磨细粉煤灰水化硬化速度更快、微观结构更致密、硬化体强度更高。更多还原

【Abstract】 The end of the twentieth century, dry-mixed mortar was introduced in our country’s construction market as a newly building. This mortar has more accurate proportion, more proper additives, it has excellent workability and better quality assurance after experimental demonstration, it can also use a large number of fly ash, gypsum, slag and other industrial waste and relieve environmental pressure, save material stacking sites for the construction site, improve construction efficiency etc. Minimum strength grade of our common Portland cement is32.5MPa, and dry mixed mortar (such as grade of plastering mortar strength is M5, M10, M15and M20) Strength is relatively low. At present there is no special mortar cement in our market, general Portland cement (i.e. pure cement mortar) formulated mortar directly in the construction, which led to the waste of cement and mortar quality problems occurred frequently, Dry mixed mortar enterprises use common Portland cement mixing of mortar, and mixed with large amount of fly ash by modulating the intensity grade. How to play the cementitious role of fly ash in dry mixed mortar, further reduce the cement content of dry mixed mortar to reduce the cost and improve the quality of mortar, which is in need of the problem of solving by mortar enterprises.The original fly ash and ground fly ash of Zhengzhou power plant, Luoyang low calcium fly ash, desulfurization gypsum in Zhengzhou power plant as main raw materials were taken in this paper. The study method of fixed variables was used, the cementitious material of " low cement content with a large volume of fly ash and flue gas desulfurization gypsum " was studied systematically in this paper. The results showed that:Zhengzhou power plant fly ash performance indicators are not up to class Ⅲ ash index, but after ground treatment, which achieves class Ⅱ ash index. Ground ash can completely replace the grade Ⅱ Luoyang low calcium fly ash in dry mixed plastering mortar, and the performances of producing mortar are better; The compressive strengths of the mortar produced by " low cement content with a large volume of fly ash and flue gas desulfurization gypsum " increase with the cement content increase, and there is an optimal value of compressive strengths with the increase of the gas desulfurization gypsum content. For example, when the cement content is of20%and30%and flue gas desulfurization gypsum is of30%in " low cement mixed with large amount of ground fly ash and flue gas desulfurization gypsum ", the compressive strengths of producing mortars are19.3MPa and24.6MPa, this value reaches our country masonry cement strength grade of12.5and22.5; The volume shrinkage of the mortar produced by " low cement content with a ground of fly ash and flue gas desulfurization gypsum" increase with cement content increase and reduce with flue gas desulfurization gypsum content increase, and the volume shrinkage of the mortar with pulverized fly ash is smaller than that of the mortar with original fly ash.The scanning electron microscope (SEM) and Ⅹ ray diffraction (XRD) analysis were used in this paper, the results showed that compared with original fly ash, the ground fly-ash has faster speed of hydration hardening and more compact microstructure and higher strength of hardened paste because of the surface of mechanical activation and cement and gypsum double excitation.更多还原