氧化石墨烯对水泥基材料耐腐蚀性能的影响

发布时间：2018-05-25 08:10

本文选题：氧化石墨烯 + 水泥基材料　；参考：《重庆交通大学》2016年硕士论文

【摘要】：氧化石墨烯(GO)是一种具有超大比表面积和超强力学性能及柔韧性能的二维片层纳米结构。在其结构上含有大量的活性基团:羟基(-OH)、羧基(-COOH)及环氧基(-O-)。这些活性基团的存在使得氧化石墨烯具有良好的亲水性,其很容易在水中被分散制备成纳米分散液,且易于与其他化合物复合形成插层复合物。针对水泥混凝土的自身缺陷,在其内部存在大量的微裂缝和孔隙,直接导致了混凝土的高脆性、低抗拉、低耐久性能的本质特性。因此,本文旨在对氧化石墨烯对水泥基材料的工作性能、力学性能及耐盐碱腐蚀性能的影响进行试验研究。通过Hummers法和超声波分散法制备了氧化石墨烯,并通过SEM、TEM、FT-IR、XPS对其结构进行了表征。研究了不同掺量GO对水泥净浆物理性能及水泥水化产物的影响。XRD研究结果表明,GO的引入可以参与水泥水化反应,并有效的调控CH晶体的生长速率,细化晶体结构,使结构更加密实。通过力学测试分析,在聚羧酸减水剂(PC)和GO复掺的同时,当氧化石墨烯的掺量为0.06%时与基准水泥胶砂相比,3天的抗折强度和抗压强度分别提高了45.8%和59.4%,28天的抗折强度和抗压强度分别提高了33.1%和29.1%。通过SEM分析水泥胶砂断面形貌可知,掺有GO后水泥胶砂断面形貌中水化产物排列整齐,相互交错抱团生长成簇状,从而使整体结构更加致密。因此,GO的引入可以有效改善水泥基材料的抗折强度和抗压强度。研究了不同掺量GO在不同盐溶液中分别经长期浸泡和干湿循环作用后对水泥基材料耐腐蚀性能的影响。研究结果表明:GO的引入对水泥基材料经长期浸泡和干湿循环作用后的耐盐碱腐蚀性能均有着不同程度的提高作用。通过分析试件质量损失率、抗折强度耐蚀系数及抗压强度耐蚀系数可知,当GO掺量为0.03%和0.06%时,可以明显改善水泥基材料的耐盐碱腐蚀性能。通过SEM分析可知,基准试件的内部结构酥松、有明显被腐蚀作用后的痕迹;而0.03%掺量GO的试件内部结构致密,无明显被腐蚀的痕迹。且通过能谱分析可知,在基准试件内部有大量的腐蚀离子存在,而在0.03%掺量GO的试件内部有极少数的腐蚀离子存在,研究结果表明,当GO掺量为0.03%时,可以有效的阻碍腐蚀离子渗透到水泥结构中,从而有效提高水泥基材料的耐腐蚀性能。
[Abstract]:Graphene oxide (GOO) is a two-dimensional lamellar nanostructure with super specific surface area, super mechanical properties and flexibility. There are a lot of active groups in its structure: hydroxyl group-OHH, carboxyl group-COOH) and epoxy group. The existence of these active groups makes graphene oxide have good hydrophilicity, it is easy to be dispersed in water to prepare nano-dispersion, and easy to compound with other compounds to form intercalation complex. Aiming at the defects of cement concrete, there are a large number of micro-cracks and pores in its interior, which directly lead to the essential characteristics of high brittleness, low tensile resistance and low durability of concrete. Therefore, the effects of graphene oxide on the performance, mechanical properties and corrosion resistance of cement-based materials were investigated. Graphene oxide was prepared by Hummers and ultrasonic dispersion. The effects of go on the physical properties of cement paste and cement hydration products were studied. XRD results showed that the introduction of go could participate in the hydration reaction of cement, effectively regulate the growth rate of Ch crystal, and refine the crystal structure. Make the structure more compact. Through mechanical test and analysis, when polycarboxylic acid superplasticizer (PC) and go were mixed, When the content of graphene oxide is 0.06, the flexural strength and compressive strength of three days are increased by 45.8% and 59.4% respectively, and the flexural strength and compressive strength of 28 days are increased by 33.1% and 29.1%, respectively, compared with the reference cement sand. SEM analysis shows that the hydration products of cement sand with go are arranged neatly and interlaced with each other to form clusters, which makes the whole structure more compact. Therefore, the introduction of go can effectively improve the flexural strength and compressive strength of cement based materials. The effects of go content on corrosion resistance of cement based materials were studied after prolonged immersion and dry and wet cycling respectively in different salt solutions. The results show that the introduction of WGO can improve the corrosion resistance of cement-based materials after long-term immersion and dry and wet cycling to varying degrees. By analyzing the mass loss rate of specimens, the corrosion resistance coefficient of flexural strength and compressive strength, it can be seen that when the content of go is 0.03% and 0.06%, the corrosion resistance of cement based materials can be improved obviously. The SEM analysis shows that the internal structure of the benchmark specimen is crisp and has a marked corrosion trace, while the 0.03% go content sample has a dense internal structure and no obvious corrosion trace. The energy spectrum analysis shows that there are a large number of corrosion ions in the base sample, and a few corrosion ions in the 0.03% go sample. The results show that when go content is 0.03%, the corrosion ion exists in the sample with 0.03% go content. It can effectively prevent corrosion ions from infiltrating into cement structure, thus effectively improving the corrosion resistance of cement based materials.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ127.11;TQ172.1

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