混凝土防护及修补用聚氨酯—环氧树脂材料的开发研究

发布时间：2018-06-13 22:14

本文选题：混凝土 + 耐久性　；参考：《兰州交通大学》2014年硕士论文

【摘要】：水泥混凝土是土木工程中最重要的建筑材料之一。然而在一些高寒高原地区，由于长期受到低温、大温差、风蚀、冻融循环等一系列自然因素的作用和影响，混凝土结构面临着耐久性不足而导致出现裂缝、破坏等问题，这严重影响到混凝土建筑结构的正常使用。因此，应该采取有效的措施对混凝土结构进行防护或修补，以提高混凝土结构的耐久性、延长其使用寿命，保证混凝土结构的正常使用。本文针对混凝土结构耐久性不足的问题，分别开发用于混凝土结构防护的湿固化型单组份聚氨酯防护涂层和用于混凝土裂缝修补用的聚氨酯改性环氧树脂材料，以期通过混凝土结构的表面防护和裂缝的有效修补，从而提高混凝土结构的耐久性。 (1)通过配方设计和实验研究，合成了聚氨酯预聚体，，然后通过在空气中进行湿气固化，成功开发得到具有良好抗冻融性能的单组份湿固化聚氨酯涂层。研究了原料配比及反应工艺条件如R值、聚醚质量比(N220:N330)、催化剂含量、反应温度和反应时间等对单组份聚氨酯涂层的拉伸性能、热性能、抗冻融性能等的影响规律。研究结果表明：随着R值的增加，涂层的拉伸强度先增加后降低、断裂伸长率逐渐降低而硬度逐渐增加。随着聚醚质量比的增加，涂层的拉伸强度和硬度逐渐降低而断裂伸长率逐渐升高。随着催化剂含量增加，涂层的表干时间和实干时间逐渐减小。最终确定出制备单组份湿固化聚氨酯涂层的最优工艺条件和最佳原料配比分别为：起始反应温度为50℃，聚氨酯合成的最佳温度为75℃，反应时间控制在1.5～2.5h，搅拌速度控制在150～200r/min；聚醚质量比为8:1，R值为4，催化剂二月桂酸二丁基锡含量为0.5%～1.0%。在此条件下，制备的单组份湿固化聚氨酯涂层性能最佳，此时拉伸强度可达到6.46MPa、断裂伸长率为518%、邵(A)硬度为72。而经过冻融循环作用后，涂层的拉伸性能进一步得到明显提升。 (2)通过聚氨酯对环氧树脂进行增韧改性，合成得到聚氨酯改性环氧树脂修补材料，以期用于混凝土裂缝的修补。采用FT-IR对所合成的聚氨酯改性环氧树脂的化学结构进行了分析和表征。考察了聚氨酯含量对改性环氧树脂的力学性能、热性能、耐化学品性等性能的影响规律。研究结果表明：随着聚氨酯含量的增加，改性环氧树脂的拉伸强度、弯曲强度、冲击强度均先增大后减小，断裂伸长率逐渐增加而抗压强度逐渐减小。改性环氧树脂经10wt%的硫酸溶液浸泡后质量增加，而分别经10wt%的氢氧化钠和氯化钠溶液浸泡后质量减少，并且随着聚氨酯含量的增加，质量增加率和质量减少率分别都逐渐增大。最终确定出当环氧树脂中聚氨酯的含量为20%时，得到的改性环氧树脂的性能最优，此时聚氨酯改性环氧树脂的拉伸强度、弯曲强度、断裂伸长率和抗压强度分别可以达到45.2MPa、78.4MPa、5.8%和36.0MPa，经10wt%的硫酸溶液浸泡后重量增加了4.8%，而分别经10wt%的氢氧化钠和氯化钠溶液浸泡后，其重量分别减少了0.98%和0.89%。另外，随着冻融循环次数的增加，聚氨酯改性环氧树脂修补材料的玻璃化转变温度Tg略有升高，各项力学性能和耐化学品性都有明显地提升。最后，用聚氨酯改性环氧树脂对劈裂后的混凝土裂缝进行了修补，修补后的混凝土试块的具有良好的力学性能，并且修补材料对混凝土具有优异的粘结性能。
[Abstract]:Concrete is one of the most important building materials in civil engineering. However, in some high cold plateau areas, due to a series of natural factors such as low temperature, large temperature difference, wind erosion, freezing thawing cycle and so on, concrete structures are faced with problems such as cracks and damage caused by the lack of durability, which seriously affects the concrete. Therefore, effective measures should be taken to protect or repair the concrete structure to improve the durability of the concrete structure, prolong its service life, and ensure the normal use of the concrete structure.
Aiming at the problem of insufficient durability of concrete structure, this paper develops wet solidified single component polyurethane protective coating for concrete structure protection and polyurethane modified epoxy resin materials used for concrete crack repair, in order to improve concrete structure through surface protection of concrete structure and effective repair of cracks. Durability of the structure.
(1) the polyurethane prepolymer was synthesized by formula design and experimental study. Then the wet curing polyurethane coating with good resistance to freezing and thawing was successfully developed by curing the wet air in the air. The ratio of raw materials and reaction conditions, such as R value, mass ratio of polyether (N220:N330), catalyst content, reaction temperature and reaction temperature were studied. The effect of reaction time on tensile properties, thermal properties, freeze-thaw resistance and other properties of one component polyurethane coating was studied.
The results show that with the increase of R value, the tensile strength of the coating increases first and then decreases, the elongation at break gradually decreases, and the hardness gradually increases. With the increase of the mass ratio of polyether, the tensile strength and hardness of the coating gradually decrease and the elongation at break gradually increases. The optimum process conditions and the optimum raw material ratio are as follows: the initial reaction temperature is 50, the optimum temperature is 75 C, the reaction time is 1.5 ~ 2.5h, the stirring speed is 150 ~ 200r/min, the mass ratio of polyether is 8:1, the R value is 4, the catalyst is 4, the catalyst is 4. Under the conditions of 0.5% ~ 1.0%. of lauric acid two butyl tin, the performance of the prepared single component wet curing polyurethane coating is the best. At this time the tensile strength can reach 6.46MPa, the elongation at break is 518%, and the hardness of the Shaw (A) is 72. and the tensile property of the coating can be further improved after the freezing and thawing cycle.
(2) the polyurethane modified epoxy resin was toughened and modified by polyurethane, and the modified epoxy resin mending material was synthesized to repair the cracks of concrete. The chemical structure of the modified epoxy resin was analyzed and characterized by FT-IR. The mechanical properties of the modified epoxy resin were investigated. The effect of performance, chemical resistance and other properties.
The results showed that with the increase of polyurethane content, the tensile strength, bending strength and impact strength of the modified epoxy resin increased first and then decreased, the elongation at break gradually increased and the compressive strength decreased gradually. The quality of the modified epoxy resin was soaked in 10wt% sulfuric acid solution, and the sodium hydroxide and sodium chloride were dissolved by 10wt% respectively. With the increase of polyurethane content, the mass increase rate and the mass reduction rate are increased respectively. Finally, when the content of the polyurethane in the epoxy resin is 20%, the properties of the modified epoxy resin are the best. At this time, the tensile strength, bending strength and elongation at break of the polyurethane modified ring oxygen resin are obtained. The weight of 45.2MPa, 78.4MPa, 5.8% and 36.0MPa can be increased by 4.8% by soaking in 10wt% sulfuric acid solution, respectively, while the weight of 10wt%'s sodium hydroxide and Sodium Chloride Solution is reduced by 0.98% and 0.89%. respectively. With the increase of the number of freeze-thaw cycles, the polyurethane modified epoxy resin mending material The glass transition temperature Tg increased slightly, and the mechanical properties and chemical resistance of the composites increased significantly.
Finally, the split concrete cracks were repaired with polyurethane modified epoxy resin. The repaired concrete specimen has good mechanical properties, and the repair material has excellent bonding properties to the concrete.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528;TQ317

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