發(fā)布時間：2018-06-13 22:14

  本文選題：混凝土 + 耐久性��； 參考：《蘭州交通大學(xué)》2014年碩士論文

【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區(qū)，由于長期受到低溫、大溫差、風(fēng)蝕、凍融循環(huán)等一系列自然因素的作用和影響，混凝土結(jié)構(gòu)面臨著耐久性不足而導(dǎo)致出現(xiàn)裂縫、破壞等問題，這嚴重影響到混凝土建筑結(jié)構(gòu)的正常使用。因此，應(yīng)該采取有效的措施對混凝土結(jié)構(gòu)進行防護或修補，以提高混凝土結(jié)構(gòu)的耐久性、延長其使用壽命，保證混凝土結(jié)構(gòu)的正常使用。 本文針對混凝土結(jié)構(gòu)耐久性不足的問題，分別開發(fā)用于混凝土結(jié)構(gòu)防護的濕固化型單組份聚氨酯防護涂層和用于混凝土裂縫修補用的聚氨酯改性環(huán)氧樹脂材料，以期通過混凝土結(jié)構(gòu)的表面防護和裂縫的有效修補，從而提高混凝土結(jié)構(gòu)的耐久性。 (1)通過配方設(shè)計和實驗研究，合成了聚氨酯預(yù)聚體，，然后通過在空氣中進行濕氣固化，成功開發(fā)得到具有良好抗凍融性能的單組份濕固化聚氨酯涂層。研究了原料配比及反應(yīng)工藝條件如R值、聚醚質(zhì)量比(N220:N330)、催化劑含量、反應(yīng)溫度和反應(yīng)時間等對單組份聚氨酯涂層的拉伸性能、熱性能、抗凍融性能等的影響規(guī)律。 研究結(jié)果表明：隨著R值的增加，涂層的拉伸強度先增加后降低、斷裂伸長率逐漸降低而硬度逐漸增加。隨著聚醚質(zhì)量比的增加，涂層的拉伸強度和硬度逐漸降低而斷裂伸長率逐漸升高。隨著催化劑含量增加，涂層的表干時間和實干時間逐漸減小。最終確定出制備單組份濕固化聚氨酯涂層的最優(yōu)工藝條件和最佳原料配比分別為：起始反應(yīng)溫度為50℃，聚氨酯合成的最佳溫度為75℃，反應(yīng)時間控制在1.5～2.5h，攪拌速度控制在150～200r/min；聚醚質(zhì)量比為8:1，R值為4，催化劑二月桂酸二丁基錫含量為0.5%～1.0%。在此條件下，制備的單組份濕固化聚氨酯涂層性能最佳，此時拉伸強度可達到6.46MPa、斷裂伸長率為518%、邵(A)硬度為72。而經(jīng)過凍融循環(huán)作用后，涂層的拉伸性能進一步得到明顯提升。 (2)通過聚氨酯對環(huán)氧樹脂進行增韌改性，合成得到聚氨酯改性環(huán)氧樹脂修補材料，以期用于混凝土裂縫的修補。采用FT-IR對所合成的聚氨酯改性環(huán)氧樹脂的化學(xué)結(jié)構(gòu)進行了分析和表征�？疾炝司郯滨ズ繉Ω男原h(huán)氧樹脂的力學(xué)性能、熱性能、耐化學(xué)品性等性能的影響規(guī)律。 研究結(jié)果表明：隨著聚氨酯含量的增加，改性環(huán)氧樹脂的拉伸強度、彎曲強度、沖擊強度均先增大后減小，斷裂伸長率逐漸增加而抗壓強度逐漸減小。改性環(huán)氧樹脂經(jīng)10wt%的硫酸溶液浸泡后質(zhì)量增加，而分別經(jīng)10wt%的氫氧化鈉和氯化鈉溶液浸泡后質(zhì)量減少，并且隨著聚氨酯含量的增加，質(zhì)量增加率和質(zhì)量減少率分別都逐漸增大。最終確定出當環(huán)氧樹脂中聚氨酯的含量為20%時，得到的改性環(huán)氧樹脂的性能最優(yōu)，此時聚氨酯改性環(huán)氧樹脂的拉伸強度、彎曲強度、斷裂伸長率和抗壓強度分別可以達到45.2MPa、78.4MPa、5.8%和36.0MPa，經(jīng)10wt%的硫酸溶液浸泡后重量增加了4.8%，而分別經(jīng)10wt%的氫氧化鈉和氯化鈉溶液浸泡后，其重量分別減少了0.98%和0.89%。另外，隨著凍融循環(huán)次數(shù)的增加，聚氨酯改性環(huán)氧樹脂修補材料的玻璃化轉(zhuǎn)變溫度Tg略有升高，各項力學(xué)性能和耐化學(xué)品性都有明顯地提升。 最后，用聚氨酯改性環(huán)氧樹脂對劈裂后的混凝土裂縫進行了修補，修補后的混凝土試塊的具有良好的力學(xué)性能，并且修補材料對混凝土具有優(yōu)異的粘結(jié)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.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU528;TQ317

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