【作者】 武博；

【导师】 何芳； 许小海；

【作者基本信息】 天津大学 ， 材料工程， 2019， 硕士

【摘要】 碳纤维网格以其优异的力学性能及独特的物理属性,逐渐受到相关研究者的广泛关注。由于具有超高的抗拉强度和弹性模量,优异的耐腐蚀性能及双向受力等突出优势,使其成为复合材料理想的增强相而广泛应用于水泥基复合材料工程修复和加固领域。但是,碳纤维网格增强水泥基复合材料(CMCCs)仍然存在碳纤维网格与水泥基界面粘结强度低等突出问题。因此,探索新的界面改性的方式以突破现有技术对于获得具备优良综合力学性能的水泥基复合材料具有重要意义。本文采用表面改性工艺,成功制备高性能碳纤维网格增强水泥基复合材料。首先利用环氧树脂和硅烷偶联剂(SCA)对碳纤维网格进行表面改性,涂层改性会增强碳纤维网格表面的化学活性。然后在聚合物砂浆中添加羟甲基纤维素(HMC)用于增强砂浆与改性碳纤维织物之间的浸润性,HMC有效促进砂浆基体内部载荷的均匀传递。研究了涂层处理前后对碳纤维网格表面形貌和化学活性的影响;探究了HMC对水泥基体及界面粘结强度的影响;考察了碳纤维网格对混凝土梁抗折性能的影响;探讨了界面处载荷传递机理。本研究的目的是确保实现最终的界面优化及加固系统内部优化。结果表明,相比于利用环氧树脂表面处理的碳纤维网格制备的复合材料,界面处添加SCA和HMC所制备的复合材料纵向剪切强度分别提高28.2%和53.9%,讨论了复合材料界面粘结性能的失效模型和协同增强机理。通过复合材料抗折实验表明,研究获得了碳纤维网格增强混凝土梁抗折性能的最佳加固参数:碳纤维网格的最佳加固位置为混凝土梁底部;最佳加固层数为1层;端部锚固能有效抑制端部裂纹的产生,进而增强混凝土梁抗折性能。与未添加碳纤维网格加固的混凝土抗折试样相比,单层碳纤维网格底部加固后砂浆试样的抗折强度提高174.6%。与碳纤维网格底部&中部加固的抗折试样相比,端部锚固后试样的抗折性能提高28.3%。本研究提出的碳纤维网格增强水泥基复合材料的界面优化方法已顺利通过产品中期试生产验证并被应用于实际加固工程中,为企业带来了可观的经济效益。在天津市科委科技成果转化中心组织的成果鉴定中获评“国际先进”。本研究提供的方案对碳纤维复合加固材料的工业化及实际应用具有指导意义。更多还原

【Abstract】 Carbon fiber mesh has been widely concerned by researchers due to its excellent mechanical properties and unique physical properties.The outstanding advantages of high tensile strength and elastic modulus,excellent corrosion resistance and two-way force make it an ideal reinforcement phase for composite materials in the field of cement-based reinforced composite engineering repair and reinforcement especially.However,carbon fiber mesh reinforced cement matrix composite materials(CMCCs)still have the unavoidable problems such as low interface bond strength between carbon fiber mesh and cement matrix at present.Therefore,exploring new ways of interface modification to break through the prior technology is of great significance for obtaining cement matrix composites with excellent comprehensive mechanical properties.In this paper,the high-performance CMCCs were successfully prepared by surface modification process.Firstly,the surface of the carbon fiber mesh was modified by epoxy resin and silane coupling agent(SCA),which enhanced the chemical activity of the surface of the composite.Then,hydroxymethyl cellulose(HMC)was added to the polymer mortar to enhance the wettability between the cement and the modified carbon fiber fabric.It made that the uniform transfer of the internal load of the mortar matrix was effectively promoted.The effects of coating on the surface morphology and chemical activity of carbon fiber mesh before and after treatment were studied.The effects of HMC on cement matrix and interface bond strength were investigated.The flexural behavior of carbon fiber mesh on concrete beams and the impact of the load transfer mechanism at the interface were discussed.The purpose of this study was to ensure that the final interface optimization.Meanwhile,internal optimization of the reinforcement system was achieved.The results showed that the longitudinal shear strength of the composite with SCA and HMC increased by 28.2% and 53.9%,respectively,compared with the composite prepared by the carbon fiber mesh treated with epoxy resin.The failure model and synergistic enhancement mechanism of the interfacial bonding properties of composites were discussed.The experimental results of composite material flexure showed that the best reinforcement parameters for the flexural behavior of carbon fiber mesh reinforced concrete beam were obtained: the optimal reinforcement position of the carbon fiber mesh was the bottom of the concrete beam;the optimal reinforcement layer was one layer;the end anchoring could effectively suppress the generation of the end crack,which strengthened the flexural behavior of the concrete beam.Compared with the sample of composite without carbon fiber mesh reinforcement,the bending resistance of the sample strengthened by the single carbon fiber mesh layer on the bottom of concrete beam was improved by 174.6%.Compared with the sample strengthened by the double carbon fiber mesh layers on the bottom and middle of concrete beam,the bending resistance of the sample with end anchoring was increased by 28.3%.The interface optimization method of carbon fiber mesh reinforced cement-based composites proposed in this study has passed the mid-term trial production verification.It also has been successfully applied in actual reinforcement projects,which had brought considerable economic benefits to enterprises.It was awarded “International Advanced” in the appraisal of the results organized by the Science and Technology Achievement Transformation Center of Tianjin Science and Technology Commission.The scheme provided in this study had guiding significance for the industrialization and practical application of carbon fiber composite reinforcement materials.更多还原