大掺量混合材高强混凝土制备技术研究

发布时间：2018-06-19 08:37

本文选题：超细水泥 + 大掺量　；参考：《中国矿业大学》2017年硕士论文

【摘要】：工业废料如低等粉煤灰、矿渣、赤泥等带来的高产量、高污染和低利用率及水泥的资源短缺是当今世界面临的难题,为解决这两方面的问题,在配制混凝土时大掺量使用工业废料成为研究的热点,但是在大掺量混合材条件下配制的混凝土强度很低,制约了其在工程上的应用。本文采用微观分析和试验研究相结合的方法,综合使用水泥熟料超细粉磨、混合材活性激发、配合比优化和蒸压养护手段配制出大混合材掺量(等量取代水泥70%)、高强度(120MPa以上)混凝土。通过X射线衍射、扫描电镜等微观测试方法,对粉煤灰等混合材性能进行了分析研究,为工业废料用作超细水泥混合材奠定了理论依据。通过对水泥熟料进行不同程度粉磨,并对比掺入不同坚固性混合材后胶砂试件抗压强度,研究水泥熟料颗粒细度和混合材的坚固性对混凝土抗压强度的影响。研究结果表明:粉磨至超细的水泥可以反填充在混合材颗粒中,使得颗粒之间的粘结力增加,提高试件强度;而混合材对试件抗压强度的贡献为其活性与坚固性共同作用的结果。通过物理和化学手段激发混合材的活性,实现了大掺量混合材超细水泥强度提高。研究结果表明:粉煤灰的粉磨细度对水泥胶砂试件的抗压强度影响很大,随着粉煤灰比表面积的增大胶砂试件抗压强度增大;在大掺量混合材的条件下,与使用常规的盐类和碱类激发剂所不同,使用酸也可以用来激发混合材的活性。通过蒸养手段进一步提高大掺量混合材混凝土的强度,研究了蒸养制度对试件抗压强度的影响。研究结果表明:选择合适的试件初始强度及蒸压养护恒温温度和时间可以使得试件的抗压强度大于标养28天的抗压强度,解决了蒸养带来的强度损失缺陷;蒸压石灰水浴养护能解决试件失水问题,可以提高试件强度。通过使用中间集料和镍铁砂,实现了配制高强的胶砂试件,在此基础上研究了混凝土的抗压强度影响因素。研究表明:添加胶凝材料和镍铁砂之间的级配断层的中间集料可以大幅提高试件的强度;在综合使用超细水泥手段、物化激发混合材活性手段、蒸压石灰水浴手段和集料优化手段配制出的70%混合材掺量的混凝土,强度能够达到120MPa以上。
[Abstract]:Industrial waste, such as low grade fly ash, slag, red mud and so on, brings high production, high pollution and low utilization ratio, and the shortage of cement resources is a difficult problem facing the world today. In order to solve these two problems, The use of industrial waste material in the preparation of concrete has become a hot research topic, but the strength of concrete prepared under the condition of large amount of mixed materials is very low, which restricts its application in engineering. In this paper, the microcosmic analysis and experimental study are used to combine the ultra-fine grinding of cement clinker with the activation of the mixture. The mix ratio optimization and autoclaved curing method are used to prepare the concrete with large mixing amount (equal quantity replacing 70% cement and high strength above 120 MPA). By means of X-ray diffraction, scanning electron microscope and other micro-test methods, the properties of fly ash and other mixtures were analyzed and studied, which laid a theoretical foundation for industrial waste as ultra-fine cement mixture. By grinding cement clinker to different degree and comparing the compressive strength of cement sand specimen with different solid mixture, the effect of particle fineness of cement clinker and the firmness of cement clinker on the compressive strength of concrete was studied. The results show that the cement can be filled in the mixture particles, which can increase the adhesion between the particles and improve the strength of the specimens. The contribution of the mixture to the compressive strength of the specimen is the result of the joint action of its activity and firmness. Through the physical and chemical means to stimulate the activity of the mixture, the strength of the superfine cement with large amount of mixed material was improved. The results show that the grinding fineness of fly ash has a great influence on the compressive strength of cement mortar specimens, and the compressive strength of cement sand specimens increases with the increase of specific surface area of fly ash. Unlike conventional salt and alkali activators, acids can also be used to stimulate the activity of mixtures. The influence of steaming system on the compressive strength of the specimens was studied by means of steaming method to further improve the strength of the concrete with large amount of mixed material. The results show that the compressive strength of the specimen can be higher than that of the standard for 28 days by selecting the appropriate initial strength and the temperature and time of autoclaved curing, which solves the defect of strength loss caused by steaming. Autoclaved lime-water bath curing can solve the water loss problem and improve the strength of the specimen. Through the use of intermediate aggregate and nickel-iron sand, the high-strength mortar specimens were prepared. On this basis, the factors affecting the compressive strength of concrete were studied. The results show that the strength of the specimen can be greatly improved by adding the intermediate aggregate of the graded fault between the cementing material and the Ni-Fe sand. The strength of 70% concrete mixed with autoclaved lime-water bath and aggregate optimization can reach 120 MPA.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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