【作者】 徐洪涛；

【导师】 高丹盈；

【作者基本信息】 郑州大学 ， 结构工程， 2009， 硕士

【摘要】 许多在役建（构）筑物常因设计不合理、施工不当、运营养护不得法等人为因素,以及冰冻灾害、老化等自然因素,产生了不少隐患,急待进行修复加固。普通水泥基修复材料具有粘结性较差、脆性大等缺点,而传统聚合物水泥基改性材料粘性大、施工性能较差、成本高且污染环境。聚合物乳液改性水泥基复合材料以其和易性好、力学性能高、抗渗性好、具有很强的耐酸、碱、盐腐蚀性能,而被广泛应用于大坝、公路桥涵、码头、停车场、防水、防腐等工程中,已成为重要的非结构性补强材料。因此,本文对聚合物改性水泥砂浆进行了大量的试验研究,旨在为其工程应用提供参考。鉴于修补加固的效果主要取决于新旧两种材料的粘结性能,故本文对聚合物改性水泥砂浆与混凝土的粘结性能进行了系统的试验研究。考虑到聚丙烯纤维具有许多优点,在工程中应用日渐增多,也有许多成功应用的工程实例,本文对聚丙烯纤维聚合物改性水泥砂浆的相关性能也作了试验研究;另外,本文还通过试验,研究了对外加剂及矿物填料对聚合物改性水泥砂浆性能的影响。本文的研究思路及内容包括:第一、选择合适的聚合物改性剂:针对目前工程中应用较多的两类聚合物改性乳液:丙乳（丙烯酸酯共聚乳液）和水性环氧改性乳液,共五个产品,在各自推荐的配合比范围内进行了试验研究。通过不同产品的改性水泥砂浆力学性能的比较分析,同时兼顾方便施工、环保及安全,选择了上海江天高分子材料有限公司生产的水性环氧树脂改性乳液作为进一步试验研究的对象。第二、通过正交试验研究了聚合物改性水泥砂浆性能,同时确定重点考察的因素:将水胶比（A）、聚胶比（B）、砂胶比（C）和矿物填料的取代率（D）作为考察的因素,每个因素四个水平,采用L₁₆（4⁵）正交表进行因素水平的安排。结果表明B、C、D三个因素对聚合物改性水泥砂浆性能的影响显著。以综合力学性能指标为基础,同时考虑到工作性能和工程成本等因素,得到较合适的因素水平组合定为:A（3）B（2）C（2）D（3）。在该水平组合下、并且只考虑十分显著的因素时聚合物改性水泥砂浆的抗折强度、抗压强度、综合力学性能指标及粘结强度（刷毛）的工程平均值分别为:11.23MPa,62.67MPa,2.03MPa,1.714MPa。第三、分别对偶联剂、消泡剂及减缩剂与聚合物改性水泥砂浆凝结时间的相关性进行了试验研究。结果表明:这三种外加剂的掺量及聚灰比与聚合物改性水泥砂浆凝结时间之间存在很强的正相关性。第四、考察了偶联剂、消泡剂及矿物混合填料对聚合物改性水泥砂浆力学性能的影响。结果表明:偶联剂的掺量及添加方式对聚合物改性水泥砂浆的力学性能影响显著;消泡剂与聚合物乳液之间存在相容性问题;硅烷偶联剂作为界面剂可显著改善聚合物改性水泥砂浆与混凝土板的粘结性能,且混凝土板面的细观粗糙度的大小直接影响到聚合物改性水泥砂浆与混凝土板面的粘结强度,应当建立一种能较准确地反映混凝土表面细观粗糙程度的评估机制,用于科学指导聚合物改性水泥砂浆修补时水泥基材料表面的处理;矿物混合填料外掺时作用效果普遍优于内掺,硅灰的加入使聚合物改性水泥砂浆脆性增大。第五、研究了聚丙烯纤维对聚合物改性水泥砂浆性能的影响规律。试验结果表明,聚丙烯纤维的加入不仅可以改善聚合物改性水泥的抗折及抗压性能,同时也提高了材料的综合力学性能指标,使得材料韧性增加,脆性降低,但会使聚合物改性水泥砂浆的表观密度降低;对不同长度的聚丙烯纤维聚合物改性水泥砂浆性能的试验研究表明:长纤维（19mm）更有利于改善聚合物改性水泥砂浆的整体性能;对聚丙烯纤维聚合物改性水泥砂浆加入矿物填料后性能的试验研究表明:随着硅灰取代率的增加,纤维聚合物改性水泥砂浆的表观密度呈现出单调递减的变化规律,而矿渣的加入会使纤维聚合物改性水泥砂浆的表观密度增大,在各个取代率下,硅灰对应的聚丙烯纤维增强聚合物改性水泥砂浆的力学指标值均高于矿渣的相应值,也高于不掺矿物填料的相应值。更多还原

【Abstract】 Lots of buildings and structures in service urgently need repairing and strengthing for the much existing hidden disease trouble, which are caused by human factors such as unreasonable design, incorrect construction and improper curing etc., and natural factors including aging, freeze-thaw damage and so on.Common cement-based repair materials have many disadvantages, such as low bond strength and high brittleness etc. Traditional cement-based modified polymers have poor construction performance, high cost and causing environment pollution etc. Polymer modified cement-based composites were widely used in dams, highway bridges and culverts, ports, parking lots, waterproof and anticorrosion projects and so on, for their excellent workability, high mechanical properties, good impermeability and super corrosion resistance etc, and they have already become an important sort of non-structural reinforcing materials. In this paper, in order to provide some help for the application, many properties of polymer modified cement mortar were experimentally studied.For the close relationship between the effect of repairing and strengthing and the bond strength of the rapair material to the structure need rapairing, a systemic research on the bond strength of the polymer modified cement mortar to the old concrete was studied. Considering the more widespread application of PP fiber in engineering for its many advantages, the influence of PP fiber on polymer modified cement mortar is investigated in this paper. The influence of admixtures and active mineral mixture on the properties of polymer modified cement mortar is investigated too.The reseach thinking and the main contents of this paper are as follows:1. Selection experiment on the polymer modifider. Five kinds of products from the two main sorts of cement-based modified polymer emulsions at present are experimentally studied with recommended mix proportion respectively. By comparing the mechanical properties of the five modified cement mortar each other, simultaneously considering convenient construction, environment propection and safety etc, the waterborne epoxy resin emulsion producted by Shanghai Jiangtian Polymer Materials Co., Ltd. is selected as the further studied object.2. The properties of polymer modified cement mortar and the main investigation factors are studied through orthogonal experiment. Water-binder ratio（A）, polymer-binder ratio（B）, sand-binder ratio（C） and active mineral mixture replacement rate（D） with four levels respectively, are arranged in the orthogonal table L₁₆（4⁵）. The results indicated that there is a significant effect of B, C and D on the properties of polymer modified cement mortar. CMPI is regarded as a focus of investigation, considering convenient construction and cost etc, the optium levels of the factors are A（3）B（2）C（2）D（3）, and the engineering averages of the corresponding compression strength, bending strength, bonding strength and CMPI of the polymer modified cement mortar are 11.23MPa, 62.67MPa, 1.714MPa and 2.03MPa respectively.3. An experimental study on the relativity between polymer-cement ratio, silence coupling agent, defoamer, shrinkage-reducing admixture and the setting time of polymer modified cement mortar was carried out, the results show that there is a significant positive correlation between them. 4. The influence of silence coupling agent, defoamer and active mineral mixture on the mechanical properties of polymer modified cement mortar is investigated. The compatibility problem of defoamer and polymer modified cement mortar is revealed. The bond strength between polymer modified cement mortar and old concrete is enhanced when silence coupling agent is used as the interfacial agent. The surface submicro-roughness of old concrete has an important effect on the bond strength. A reasonable evaluation mechanism for estimating the submicro-roughness of the old surface should be proposed, which could give a scientific effective guidance for the bond between concrete and polymer modified cement mortar. The addition method determines the effect of mixed mineral filler. The results show that external addition is better than internal addition. The results show that the addition of silica fume can increase the brittleness of polymer modified cement mortar.5. The influence of PP fiber on polymer modified cement mortar is investigated. The results indicate that the addition of PP fiber enhances the bending strength, the compressive strength ,the CMPI and the touhness of polymer modified cement mortar, but reduces the apparent density. The results of the influence of different length of PP fiber on the polymer modified cement mortar show that the longer PP fiber is, the better the whole performance of polymer modified cement mortar is. It was found that the apparent density of PP fiber reinforced polymer modified cement mortar increases along with the blast furnace slag replacement rate increasing, but it reduces with the silica fume replacement rate increasing. Comparing with the blast furnace slag incorporation, the addition of silica fume has a more significant enhancement on the bending strength, the compressive strength and the CMPI of the PP fiber reinforced polymer modified cement mortar.更多还原