改性纤维增强聚合物水泥砂浆的制备与性能试验研究

发布时间：2018-05-07 13:48

  本文选题：改性PP纤维 + 聚合物胶粉　； 参考：《长沙理工大学》2014年硕士论文

【摘要】：水泥砂浆因具有成本低、经久耐用、性质稳定等优势而作为一种常见的水泥混凝土结构物的粘结和修补材料,在建筑、桥梁、道路和其他方面应用十分广泛。但是在日新月异的当代社会,普通水泥砂浆已经难以满足各类工程对其不同性能的要求。为了改善普通水泥砂浆的缺陷,如脆性大、变形能力差、抗拉和粘结强度较低等,更为了赋予其更丰富实用的性能,众多学者对水泥砂浆性能的提高和改善进行了大量研究,例如掺加不同种类的聚合物和纤维对水泥砂浆进行改性,都对改善和提高水泥砂浆的性能具有重要意义。本文是在此基础上重点研究聚丙烯纤维(PP纤维)表面亲水改性以及与聚合物胶粉混掺对水泥砂浆性能的影响。主要研究内容包括：(1)根据水泥砂浆的应用场所确定所用的原材料；(2)利用轻质碳酸钙包覆PP纤维对其表面进行亲水改性,通过扫描电镜(SEM)观察PP纤维表面包覆的轻质碳酸钙颗粒的分布情况和改性PP纤维在水中的分散情况来表征改性PP纤维；(3)以水泥砂浆的力学性能为指标,通过对比试验确定水灰比、聚合物胶粉和PP纤维的适宜掺量,选出最佳配比；(4)在PP纤维增强水泥砂浆的最佳配比的基础上,用改性PP纤维替换普通PP纤维,并研究改性PP纤维以及改性PP纤维与聚合物胶粉共混对水泥砂浆力学性能的影响；(5)以水泥砂浆的力学性能为指标,本文还研究了不同长度的PP纤维,不同长度的聚乙烯醇纤维(PVA纤维)以及不同长度的两种纤维混合对水泥砂浆力学性能的影响,并选出最佳纤维长度和最佳混合纤维长度,并在此基础上掺加聚合物胶粉,研究不同长度和不同种类纤维与聚合物胶粉共混对水泥砂浆力学性能的影响；(6)利用SEM对水泥砂浆试样进行微观分析,对比不同放大倍数的SEM照片研究水泥砂浆断裂面的形貌、纤维的分布规律以及改性PP纤维和聚合物胶粉水泥基体的粘结形式；以此重点分析改性PP纤维和聚合物胶粉共混对水泥砂浆力学性能的增强机理。本文得到的结论有：(1)较合适的纤维和聚合物改性水泥砂浆的配比为：胶砂比为1：2,水灰比为0.30,纤维的掺量为2kg/m3,聚合物胶粉的掺量为水泥质量的1%,减水剂的掺量为水泥质量的1%,消泡剂的掺量为水泥质量的1%；(2)改性后的PP纤维具有良好的亲水性,能在水中均匀分散,不漂浮,不成团；利用改性后的PP纤维替代普通的PP纤维掺入聚合物水泥砂浆中,能较明显的改善纤维与水泥基体的粘结性能,提高水泥砂浆的抗折强度和韧性；(3)在一定长度范围内,建议采用长为15mm的纤维；不同长度的PVA纤维混合确实会对水泥砂浆的强度产生一定的影响,其中以3mm和18mm这种混合方式获得的强度最高；(4)不同长度的PP纤维和PVA纤维混合对水泥砂浆的强度有一定的影响,长度为6mm的两种纤维混合试样各龄期的强度相对较高。
[Abstract]:Because of its advantages of low cost, durability and stability, cement mortar is widely used in construction, bridge, road and other fields as a common cement concrete structure bond and repair material. However, in the modern society, ordinary cement mortar has been difficult to meet the different performance requirements of various projects. In order to improve the defects of ordinary cement mortar, such as high brittleness, poor deformation ability, low tensile strength and bond strength, and more abundant and practical properties, many scholars have done a lot of research on the improvement and improvement of cement mortar performance. For example, the modification of cement mortar by adding different kinds of polymers and fibers is of great significance to improve the properties of cement mortar. In this paper, the hydrophilic modification on the surface of PP fiber and the effect of blending with polymer powder on the properties of cement mortar were studied. The main research contents include: (1) according to the application place of cement mortar, the raw material used is determined.) the surface of the cement mortar is modified with light calcium carbonate coated PP fiber. The distribution of light calcium carbonate particles coated on the surface of PP fiber and the dispersion of modified PP fiber in water were observed by scanning electron microscope (SEM). The water / cement ratio, the proper content of polymer rubber powder and PP fiber were determined by the contrast test. The optimum proportion was selected. On the basis of the optimum ratio of PP fiber reinforced cement mortar, the modified PP fiber was used to replace the common PP fiber. The effect of modified PP fiber and the blending of modified PP fiber with polymer powder on the mechanical properties of cement mortar was studied. The effects of PVA fiber of different length and two fibers of different length on the mechanical properties of cement mortar were studied. The optimum fiber length and the optimum fiber length were selected, and the polymer rubber powder was added on the basis. The effects of different lengths and kinds of fibers on the mechanical properties of cement mortar were studied. The microcosmic analysis of cement mortar samples was carried out by SEM. The morphology of fracture surface of cement mortar was studied by comparing SEM photographs with different magnification ratio. The distribution of the fibers and the bond form of the modified PP fiber and the cement based body of polymer powder were analyzed, and the mechanism of strengthening the mechanical properties of the cement mortar by blending the modified PP fiber with the polymer powder was analyzed. The results of this paper show that the ratio of fiber to polymer modified cement mortar is 1: 2, the ratio of water to cement is 0.30, the amount of fiber is 2 kg / m ~ 3, the content of polymer rubber powder is 1 / 1 of cement mass, the amount of water reducer is water, the ratio of polymer to polymer is 1: 2, the ratio of water to cement is 0.30, the content of fiber is 2 kg / m ~ (3). The modified PP fiber has good hydrophilicity, and the content of defoamer is 1 / 2 of the cement mass. The modified PP fiber can be used instead of the ordinary PP fiber in the polymer cement mortar, which can obviously improve the adhesion between the fiber and the cement base. To improve the flexural strength and toughness of cement mortar within a certain length range, it is suggested that the fiber with length of 15mm should be used, and the mixing of PVA fibers of different lengths will have a certain effect on the strength of cement mortar. The strength obtained by mixing 3mm and 18mm is the highest. (4) the mixing of PP fiber and PVA fiber of different length has certain influence on the strength of cement mortar, and the strength of the two kinds of fiber mixed with 6mm is relatively high at each age.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TQ177.62
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本文编号：1857163