PVA纤维增强水泥基复合材料的耐久性能研究

发布时间：2018-04-28 01:11

本文选题：耐久性 + PVA纤维　；参考：《河北工业大学》2014年硕士论文

【摘要】：近年来，随着人们对高性能混凝土越来越重视，纤维混凝土的研究也进入了快速发展的阶段。本文配制的聚乙烯醇（polyvinyl alcohol，简称PVA）纤维水泥基复合材料是一种性能卓越的复合材料，具有应变硬化和多缝开裂的特征。近二十年来，国内外对纤维增强水泥基复合材料的性能做了大量研究工作，并尝试在道路工程中应用，相关研究集中在理论分析、力学性能和收缩开裂上，而对耐久性的研究相对较少。本文主要研究水胶比、粉煤灰掺量、硅粉掺量和PVA纤维掺量对复合材料抗冻性和抗扩散性的影响。采用单面盐冻试验法，测定单位面积质量损失和超声波相对动弹性模量损失率分析PVA增强水泥基复合材料的抗冻性能；采用快速氯离子迁移试验方法，测定扩散系数分析PVA增强水泥基复合材料的抗氯离子扩散性能。主要研究结论如下： 1.水胶比影响PVA增强水泥基复合材料内部孔隙率、孔直径、和孔隙间距，改变了内部的孔结构特征，水胶比为0.27~0.4之间时制备的PVA增强水泥基复合材料,随着水胶比的增加抗冻性能和抗扩散性能下降； 2.粉煤灰填充了PVA增强水泥基复合材料内部缺陷，使结构更密实、孔径细化。试验测试了FA掺量40%~50%PVA增强水泥基复合材料抗冻融剥落性能，结果显示当粉煤灰掺量在45%~50%之间时，具有较强的抗冻性和抗扩散性； 3.PVA纤维具有较强和水泥基体结合能力、较高的弹性模量，均匀分散的PVA纤维有效地阻止了水泥基复合材料的裂缝的扩展，，PVA纤维掺量在1.5%~2%之间时，PVA纤维增强水泥基复合材料的抗冻性能和抗扩散性能优于不加入纤维的水泥基复合材料； 4.硅粉的填充效应和火山灰效应，使PVA增强水泥基复合材料结构更为致密，孔隙尺寸得以减小，阻止了毛细孔的连通。硅粉的掺入量为5%~20%，水泥基复合材料的抗扩散性提高。本文研究对于正确评价道路混凝土在有除冰盐环境下的抗冻性和抗扩散性，解决寒冷地区路面混凝土盐冻破坏的实际问题具有重要的现实意义和广阔的工程应用前景。
[Abstract]:In recent years, as people pay more and more attention to high performance concrete, the research of fiber reinforced concrete has entered a stage of rapid development. The polyvinyl alcohol (PVA) fiber cement matrix composite prepared in this paper is a kind of composite with excellent properties, which has the characteristics of strain hardening and multi-joint cracking. In the past two decades, a great deal of research work has been done on the properties of fiber reinforced cement matrix composites, and they have tried to be applied in road engineering. The related research focuses on theoretical analysis, mechanical properties and shrinkage cracking. However, the research on durability is relatively few. In this paper, the effects of water / binder ratio, fly ash content, silica content and PVA fiber content on the frost resistance and diffusion resistance of composites were studied. The freezing resistance of PVA reinforced cement matrix composites was analyzed by single side salt freezing test, the mass loss per unit area and the loss rate of ultrasonic relative dynamic modulus of elasticity, and the fast chlorine ion migration test method was used. The diffusion resistance of PVA reinforced cement matrix composites was analyzed by measuring diffusion coefficient. The main findings are as follows: 1. The water / binder ratio affects the internal porosity, pore diameter and pore spacing of PVA reinforced cement matrix composites, and changes the internal pore structure characteristics. When the water / binder ratio is between 0. 27 and 0. 4, the PVA reinforced cement matrix composites are prepared. With the increase of water-binder ratio, the frost resistance and diffusion resistance decreased. 2. Fly ash filled PVA reinforced cement matrix composites with internal defects, making the structure more compact and the pore size refined. The freezing and thawing resistance of cement matrix composites reinforced with FA 40%~50%PVA was tested. The results showed that when the content of fly ash was between 45% and 50%, it had strong frost resistance and diffusion resistance. 3.PVA fiber has strong bonding ability with cement matrix and high elastic modulus. The uniformly dispersed PVA fiber can effectively prevent the crack propagation of cement matrix composites. When the content of PVA fiber is between 1.5% and 2%, the freezing resistance and diffusion resistance of PVA fiber reinforced cement matrix composites are better than that of cement matrix composites without fiber addition. 4. The filling effect of silica powder and the pozzolanic effect make the structure of PVA reinforced cement matrix composites more compact and the pore size decrease, thus preventing the capillary from connecting. The diffusion resistance of cement-based composites is improved by the addition of silica fume to 5% and 20% respectively. The research in this paper has important practical significance and broad engineering application prospect for correctly evaluating the frost resistance and diffusion resistance of road concrete in the environment of deicing salt and solving the actual problem of salt freezing damage of pavement concrete in cold area.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528.572

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