海工水泥的制备及其应用的实验研究

发布时间：2018-07-17 04:09

【摘要】：自水泥混凝土材料问世以来,越来越多的学者对其应用技术开展研究。21世纪是海洋的世纪,海洋资源日益被人们发掘利用,海工混凝土构筑物也随之发展起来。与陆地环境不同的是,海洋环境介质中含有大量有害物质,它们会通过混凝土保护层到达钢筋周围,毁坏钢筋表面的钝化膜,降低钢筋与混凝土之间的粘结强度,不利于海工构筑物的长期耐久性应用,而且海工构筑物一旦被破坏,极难甚至不能修复。鉴于资源、经济和安全等因素,提高混凝土构筑物的长期耐久性能已成为土木工程界研究的重点,对海工水泥混凝土耐久性能的研究也显得尤为重要。本论文以粉煤灰、矿粉和硅灰为混合材,通过对水泥砂浆物理性能、抗渗性能、抗硫酸盐侵蚀性能和氯离子扩散系数等项目的检测分析和实验研究,研发出一种具有高耐久性能的海工水泥。以偏高岭土、磨细石英砂、废硅粉和漂珠为矿物外加剂,与化学外加剂(减水剂)复合使用,通过对混凝土工作性能、抗压强度和氯离子扩散系数等项目的检测分析和实验研究,确定矿物外加剂-化学外加剂(减水剂)的最佳配比以及复合外加剂的适宜掺量。论文主要研究工作及成果如下:氯离子是造成钢筋锈蚀的主要原因,因此,要严格控制混凝土原材料组成中的氯离子含量。分别对粉煤灰、矿粉、硅灰以及偏高岭土、废硅粉、磨细石英砂和漂珠等组分进行化学分析,选用无氯离子的原料或氯离子含量小于0.06%的原料。对于所制备的海工硅酸盐水泥,石膏具有很好的缓凝、增强作用。在CH存在的条件下,通过水化反应消耗CH生成AFt产生微膨胀,不但可以提高水泥的强度,而且可以减小孔隙率,提高水泥体系的致密度,有效阻止外界环境中的有害物质进入水泥混凝土内部。研究表明,石膏的最佳掺量为7%,当石膏掺量过高时,会因生成AFt过多而导致膨胀率过大,使水泥体系内部产生微裂纹,对其强度和耐久性产生不利影响;硅灰为高活性超细粉,一方面可以参与水化反应生成胶凝物质,提高水泥体系的强度,另一方面,可以充分发挥其物理填充作用,减小水泥体系的孔隙率,提高致密度。研究表明,硅灰的最佳掺量为4%,当硅灰掺量过高时,反应所需的CH的含量不足,过量硅灰主要起物理填充作用,对强度和耐久性能改善的效果不明显;粉煤灰和矿粉具有火山灰活性,此外,粉煤灰的微观形态为玻璃微珠,能通过滚珠效应而起到润滑作用,提高水泥混凝土的工作性能。研究表明,粉煤灰的掺量不得超过16%,此时,相应的矿粉的掺量为40%,由此制备的水泥的物理性能和耐久性能良好,满足海工水泥的国家标准。对海工混凝土复合外加剂的研究表明,以偏高岭土-磨细石英砂-漂珠-废硅粉为原料按照1:1:2:2的质量比复合制成混凝土矿物外加剂,并以此矿物外加剂配制的海工混凝土具有良好的工作性能、较高的抗压强度和较低的氯离子扩散系数,耐久性能良好;以聚羧酸减水剂为化学外加剂,与矿物外加剂复合使用,所配制的海工混凝土具有良好的粘聚性能、保水性能和工作性能,抗压强度高,氯离子扩散系数低,耐久性能好。
[Abstract]:Since the advent of cement concrete materials, more and more scholars have studied its application technology in the.21 century, the century of ocean, marine resources are increasingly exploited by people, and the marine concrete structures also develop. Unlike the terrestrial environment, the marine environment contains a large number of harmful substances, which will be coagulated by coagulation. The soil protection layer reaches the steel bar, destroys the passivation film on the surface of the steel bar, reduces the bond strength between the reinforcement and the concrete, is not conducive to the long-term durability application of the marine structures, and it is very difficult or impossible to repair the marine structures once they are destroyed. The long-term durability of concrete structures is improved in view of the factors such as resources, economy and safety. The research on the durability of marine cement concrete is also very important. This paper uses fly ash, mineral powder and silica fume as a mixture, and research and Research on the physical properties, impermeability, sulfate corrosion resistance and chloride diffusion coefficient of cement mortar. A kind of marine cement with high durability is issued. Using metakaolin, fine quartz sand, waste silica powder and floating beads as mineral admixtures, and chemical admixtures (water reducing agent), the chemical additives - chemical additives - chemical additives - chemical addition - chemical additives - chemical additives (water reducing agents) are used to determine the mineral admixtures - chemical additives. The best proportion of additive (water reducing agent) and the suitable admixture of compound admixture. The main research work and results are as follows: chlorine ion is the main cause of corrosion of steel bar. Therefore, the content of chloride ion in the composition of concrete is strictly controlled. The fly ash, mineral powder, silica fume, and metakaolin, waste silica powder and fine quartz sand The chemical analysis of the components, such as the floating bead and other components, is made of raw materials with no chloride ions or less than 0.06% of the chlorine ion content. For the prepared marine Portland cement, gypsum has a good retarding and enhancement effect. Under the condition of CH, the micro expansion of AFt is generated by the hydration reaction consumption of CH, not only the strength of the cement can be increased, but also the strength of the cement can be improved. It can reduce the porosity, increase the density of the cement system and effectively prevent the harmful substances from the external environment into the cement concrete. The study shows that the best dosage of gypsum is 7%. When the amount of gypsum is too high, the expansion rate will be too large because of the excessive amount of AFt, which causes the micro cracks in the cement system, and the strength and durability of the cement system. On the one hand, silica fume is highly active superfine powder. On the one hand, it can participate in hydration reaction to produce cementitious material and improve the strength of cement system. On the other hand, it can give full play to its physical filling effect, reduce the porosity of cement system and increase the density. The best dosage of silica fume is 4%, and the reaction is when the amount of silica fume is too high. The required content of CH is insufficient, excessive silica fume mainly plays the role of physical filling, and the effect on strength and durability is not obvious; fly ash and mineral powder have volcanic ash activity. In addition, the micro morphology of fly ash is glass microsphere, which can be lubricated by ball effect and improve the working performance of cement concrete. Research shows powder coal. The amount of ash can not exceed 16%. At this time, the content of the corresponding mineral powder is 40%. The physical and durable properties of the cement are good and meet the national standard of the marine cement. The study on the composite admixtures of the sea workers and concrete shows that the mixture of metakaolin ground quartz sand drift beads and waste silica powder is made in accordance with the mass ratio of 1:1:2:2. As a concrete mineral admixture, the marine concrete prepared with this mineral admixture has good working performance, high compressive strength and low chloride diffusion coefficient and good durability, with Polycarboxylic Water reducing agent as chemical admixture and mineral admixture for use, the prepared Sea industrial concrete has good cohesiveness. Performance, water retention and working performance, high compressive strength, low chloride diffusivity and good durability.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV431;TV41

【参考文献】