水泥基材料用微胶囊自修复技术与原理的研究

发布时间：2019-05-30 11:29

【摘要】：混凝土开裂损伤部位的智能化感知和即实时自修复是水泥混凝土微裂纹修复的新技术和新方法,对于改善混凝土材料耐久性,提高混凝土构筑物服役寿命具有重要意义。本文运用混凝土材料科学、有机高分子化学和物理化学等相关理论与知识,创立了适用于水泥基材料的微胶囊自修复体系,分析了相关技术原理,提出了自修复效果的评价方法。采用原位聚合法合成了一种适用于水泥基材料裂缝修复的UF/E型微胶囊,它是以脲醛树脂为囊壁包裹以环氧树脂胶液组成的囊芯构成的直径为微米级的球形颗粒。通过正交试验,并基于微观分析和合成反应动力学,分析了表征UF/E微胶囊的粒径、囊壁厚度、表面形貌和包封率等技术参数的主要影响因素,得出了微胶囊最优合成工艺路线与参数,将尿素和甲醛摩尔比为1.5：1.0的溶液在70℃下反应1h合成脲醛树脂预聚体,环氧树脂胶液芯材/脲醛树脂预聚体壁材的质量比为(1.0～1.2)：1.0,酸化阶段适宜温度为50℃,囊壁形成的pH值为2-3,囊壁固化增强阶段的适宜温度为60℃。研发了一种可在水泥基材料中发生固化反应并具有良好胶粘性的环氧树脂基裂缝修复剂,它由E-51环氧树脂、正丁基缩水甘油醚(BGE)稀释剂、咪唑类固化剂(MC120D)等组分构成。基于Kissinger和Arrhenius方程,分析了E-51/BGE/MC120D修复剂的固化反应动力学,当BGE为E-51质量的17.5%、MC120D为E-51质量的20%时,修复剂的固化反应活化能最低,有利于在水泥基材料中常温固化；借助差热和红外技术探讨了固化反应机理,MC120D掺量为10～30%时,修复体系固化分两步进行,而其掺量超过30%时,固化反应一步完成；运用毛细动力和虹吸原理,分析了水泥基材料中微胶囊破裂、环氧树脂胶液流出并渗入到裂缝处与固化剂发生固化反应修复裂缝的界面性能要求。由此得到了环氧树脂基修复剂的最优组成。设计并制备了一种基于微胶囊技术的自修复水泥基材料,试件由合成纤维、硅酸盐水泥、砂子、微胶囊和固化剂等组分构成。分析了含有微胶囊的水泥基材料的自修复机理,当水泥基材料开裂时,裂缝处的微胶囊破裂,环氧树脂胶液渗入裂缝内并与裂缝壁渗出的固化剂发生固化反应,形成具有强胶黏性的固化物,填塞缝隙,降低了孔隙率,阻断了连续孔缝,从而,修复了水泥基材料的强度和抗渗性,实现水泥基材料的自修复功能。建立了水泥基材料自修复性能评价方法,利用电化学阻抗谱法(EIS)、压汞法(MIP)和氮吸附法(BET),以渗流结构参数、孔结构参数和吸附-脱附曲线特征等指标,评价水泥基材料在不同荷载作用下损伤程度,并得出外加荷载达40～50%σmax时,水泥基材料开始出现明显裂缝—损伤；以损伤水泥基材料的强度、氯离子渗透性作为水泥基材料自修复率的评价指标,探讨了掺有微胶囊的水泥基材料自修复率的主要影响因素,其影响程度顺序为：微胶囊掺量微胶囊直径损伤程度修复龄期。得出获得最大修复率的条件组合是6.0%微胶囊掺量、微胶囊直径为230μm、预压力为60%σmax时的损伤程度、修复龄期7d。通过上述研究,创立了一种水泥基材料自修复的UF/E型微胶囊技术,并试验验证了该技术可使水泥基材料具有一定的自修复功能,分析了微胶囊修复率的主要影响因素及其规律。但仍有一些问题需进一步研究,以实现该技术的工程化应用。
[Abstract]:The intelligent sensing and real-time self-repairing of the concrete crack damage part is a new technology and a new method for repairing the micro-crack of the cement concrete, which is of great significance in improving the durability of the concrete material and improving the service life of the concrete structure. In this paper, the self-repairing system of micro-capsule, which is suitable for cement-based materials, is established by using the related theories and knowledge of material science, organic polymer chemistry and physical chemistry. A UF/ E-type microcapsule suitable for crack repair of cement-based material is synthesized by in-situ polymerization method, The main influencing factors of the parameters such as the size of the UF/ E microcapsule, the thickness of the capsule wall, the surface morphology and the encapsulation rate were analyzed based on the micro-analysis and the synthesis reaction kinetics. The optimum synthetic route of the microcapsule was obtained. The method comprises the following steps of: reacting a solution with a molar ratio of urea and formaldehyde at a molar ratio of 1.5: 1.0 at 70 DEG C for 1 hour to synthesize a fluorocarbon prepolymer, wherein the mass ratio of the core material of the epoxy resin glue solution to the prepolymerized body wall material is (1.0-1.2): 1.0, the appropriate temperature of the acidification stage is 50 DEG C, and the pH value formed by the capsule wall is 2-3. The appropriate temperature for the solidification and enhancement phase of the capsule wall is 60. degree. C., an epoxy-based crack repair agent that can be cured in a cement-based material and has a good adhesive tack, which is formed from an E-51 epoxy resin, a n-butyl glycidyl ether (BGE) diluent, a detomidine curing agent (MC120D), The curing reaction kinetics of E-51/ BGE/ MC120D repairing agent is analyzed based on Kissinger and Arrhenius equation. When BGE is 17.5% of E-51, MC120D is 20% of E-51 mass, the activation energy of curing reaction of the repairing agent is the lowest, which is beneficial to the cement-based material. The curing reaction mechanism is discussed by means of differential thermal and infrared technology. The cure system is cured in two steps by means of differential thermal and infrared technology, and the curing reaction is completed in two steps when the content of MC120D is more than 30%. The capillary force and the siphon principle are used to analyze the cement-based material. the boundary of the crack is repaired by the solidification reaction of the epoxy resin glue solution and the curing agent when the microcapsule is broken and the epoxy resin glue solution flows out and penetrates into the crack and the surface property requirement is obtained, thereby the epoxy resin-based repairing agent is obtained, The self-repairing cement based material based on the microcapsule technology is designed and prepared, and the test piece is made of synthetic fiber, silicate cement, sand, microcapsule and solid. the self-repairing mechanism of the cement-based material containing the microcapsule is analyzed, And the strength and the impermeability of the cement-based material are fixed, and the cement base material is realized. The self-repairing function of cement-based material was established. The self-repairing performance evaluation method of cement-based material was established, using electrochemical impedance spectroscopy (EIS), mercury-mercury method (MIP) and nitrogen adsorption (BET) method to measure the flow structure parameters, pore structure parameters and adsorption- The characteristics of the desorption curve and other indexes are used to evaluate the degree of damage of the cement-based material under different loads, and when the applied load is 40-50%/ max, the cement-based material will start to have obvious cracks and damage; in order to damage the strength of the cement-based material, the chloride ion permeability is used as the cement-based material. The main influencing factors of the self-repair rate of the cement-based material with micro-capsule are discussed in this paper. The condition combination of the maximum repair rate was 6.0%, the diameter of the microcapsule was 230. m u.m, and the pre-pressure was 60%. The technology of self-repairing of cement-based material was established by the above-mentioned research, and the self-repairing function of the cement-based material was tested. The repair rate of the microcapsules was analyzed. However, there are still some problems that need to be further studied.
【学位授予单位】：中南大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU528

【参考文献】