超早强水泥基材料的制备与性能研究

发布时间：2018-06-29 14:58

本文选题：路面修补 + 硅酸盐水泥　；参考：《东南大学》2015年硕士论文

【摘要】：随着我国经济的不断发展,当前我国公路总里程和高速公路里程均达到世界首位,公路交通承担78.2%的货运量和93.5%的客运量,可见公路对支撑我国经济的发展发挥着巨大作用。而交通压力的增大使水泥混凝土路面出现大量损坏,仅车辆超载造成的公路损失每年超过300亿元,路面一旦损坏必须进行快速修补从而尽快开放交通,减少经济损失。本文针对目前对路面修补材料的要求,结合超早强修补材料的制备现状,通过使用产量大、易获取的硅酸盐水泥,结合自主研制的无碱、无氯的新型复合超早强剂,制备了具有超早强性能、施工性能良好的修补混凝土。得出的结论如下：1)复合超早强剂的设计与制备：通过组分单独作用时抗压强度、凝结时间的试验结果,结合早强、速凝的机理,对超早强剂中速凝组分和早强组分进行优化选择,提出了超早强剂组分配制方法,选择硫酸盐、甲酸盐和硝酸盐作为超早强剂的配制组分。继而进行组分间的正交试验,研制出适用于硅酸盐水泥混凝土的无碱、无氯超早强剂,其组分间的掺量为：硫酸盐1.6%,甲酸盐2.0%,硝酸盐1.0%,进一步的研究选择聚羧酸高性能减水剂作为复配的减水组分。2)超早强混凝土配制及基本性能：为研究制备出的超早强剂作用效果,将超早强剂应用到混凝土中,系统研究了超早强剂掺量为1%、2%和3%时混凝土的物理力学性能,包括混凝土不同龄期抗压强度、凝结时间、坍落度及其经时损失,根据试验结果分析后确定超早强剂的最佳掺量为2%,同时复配的减水组分掺量为1.2%，，在对混凝土的配合比进行调整后,系统研究了掺复合超早强剂混凝土的物理力学性能,结果发现混凝土在初始坍落度为80mm的情况下,60min的坍损小于35%,满足1小时施工要求；混凝土16h抗压强度达到20MPa,完全满足道路快速修补后开放交通的要求。3)超早强剂作用机理及结构形成过程：基于扫描电子显微镜(SEM)、X射线衍射仪(XRD)和水化热试验,系统研究了超早强剂各组分单独作用及超早强剂作用下的微观形貌、物相组成及水化过程,分析各组分及超早强剂的作用机理,并与宏观试验结果相验证,为超早强剂的应用奠定科学的理论基础。结果发现超早强剂的作用机理表现为各组分间的协同互补作用,即在早期形成钙矾石的骨架结构同时,产生大量的C-S-H凝胶,相互胶结在一起促进体系的凝结硬化：超早强剂作用下的后期水化热较低,有利于实际应用过程中混凝土耐久性的发展。
[Abstract]:With the development of our country's economy, the total mileage of highway and the mileage of highway reach the first place in the world at present. The highway traffic undertakes 78.2% of the freight and 93.5% of the passenger traffic. It can be seen that the highway plays a great role in supporting the development of our country's economy. However, the increase of traffic pressure causes a lot of damage to cement concrete pavement, only the highway loss caused by vehicle overload exceeds 30 billion yuan per year. Once the road is damaged, it must be repaired quickly so as to open up traffic as soon as possible and reduce the economic loss. In this paper, according to the requirement of pavement repair material at present, combined with the present situation of preparation of super early strength repair material, through the use of Portland cement, which is high yield and easy to obtain, combined with a new type of compound super early strength agent without alkali and chlorine developed by ourselves, Repair concrete with super early strength and good construction performance was prepared. The conclusions are as follows: (1) the design and preparation of the composite superearly strength agent: through the experimental results of compressive strength and setting time of components acting alone, combined with the mechanism of early strength and rapid setting, The formulation method of super early strength agent component was put forward. Sulfate, formate and nitrate were selected as the composition of super early strength agent. Then the orthogonal test between the components was carried out, and a super early strength agent without alkali and chlorine was developed for Portland cement concrete. The contents of its components are as follows: sulphate 1.6, formate 2.0, nitrate 1.0. Further study and selection of polycarboxylic acid high performance water reducing agent as water reducing component .2) preparation and basic properties of super early strength concrete: for the study of the super strength concrete prepared The effect of early strength agent, The physical and mechanical properties of concrete with 1% and 3% super early strength agent were systematically studied, including compressive strength, setting time, slump and its time loss at different ages. According to the analysis of the test results, it is determined that the optimum dosage of super early strength agent is 2 and the addition of water reducing component is 1.2. After adjusting the mix ratio of concrete, the physical and mechanical properties of concrete with composite super early strength agent are systematically studied. The results show that when the initial slump is 80mm, the concrete collapse is less than 35 minutes, which meets the requirement of 1 hour construction. The compressive strength of concrete reaches 20MPa in 16h, which fully meets the requirements of open traffic after rapid road repair. 3) the mechanism and structure formation process of super early strength agent: based on scanning electron microscope (SEM) X-ray diffraction (XRD) and hydration heat test, The micromorphology, phase composition and hydration process of each component of super early strength agent were systematically studied, and the mechanism of each component and super early strength agent was analyzed, and the results were verified by macroscopic test. It lays a scientific theoretical foundation for the application of super early strength agent. The results showed that the mechanism of ultra early strength agent was the synergistic and complementary action of each component, that is to say, a large number of C-S-H gels were produced at the same time when the framework structure of ettringite was formed in the early stage. Mutual cementation promotes the condensation and hardening of the system: the later hydration heat under the action of super early strength agent is lower, which is beneficial to the development of concrete durability in practical application.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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