水泥水化产物抗海水侵蚀机理研究

发布时间：2018-07-02 15:03

本文选题：海工水泥 + 水化产物　；参考：《中北大学》2017年硕士论文

【摘要】：随着国家对海洋资源和海疆安全越来越重视,海洋工程大量兴建,混凝土作为海洋工程的基本结构材料其稳定性非常重要,不同于陆地环境,海水中存在大量的离子,其中有些对混凝土材料具有较强的腐蚀作用,本文针对海水中三种主要侵蚀离子:Cl-、Mg~(2+)和SO_4~(2-),根据其侵蚀机理不同分别进行实验研究。通过C_3A、AFm与AFt之间相互转化的关系,以及转化条件进行研究,首先进行了热力学理论分析,提出物质转化的理论基础;然后进行实验验证,包括通过高温炉煅烧制成纯度较高的C_3A,进行转化实验,并对得到的试样进行XRD和SEM微观分析,结果证明:无论是热力学理论分析还是实际操作实验C_3A与AFm可以在Cl-存在的环境下转化为Fridel's盐,而热力学理论分析AFt并不能与Cl-反应生成Fridel's盐或者三氯铝酸盐,但是实验得到的XRD衍射图谱中却发现了Fridel's盐的存在,推测原因是钙矾石转化过程中不够彻底,还存在一定量的C_3A或者AFm,或AFt与AFm存在一个动态平衡,他们之间可以相互转化。对于Mg~(2+)和SO_4~(2-),本文进行了水泥胶砂试件浸没于侵蚀离子溶液中不同龄期的腐蚀实验,然后对各腐蚀龄期胶砂试块进行了力学性能测试(抗折、抗压),然后对净浆试样进行XRD、SEM、BET等微观测试,结合微观和宏观分析了不同侵蚀离子对于不同水泥混凝土的侵蚀机理。结果证明普硅水泥在面对Mg~(2+)和SO_4~(2-)侵蚀的时候表现很差;矿渣水泥抗Mg~(2+)侵蚀能力表现较差,而抗SO_4~(2-)侵蚀能力相对普硅水泥要好一些;超硫酸盐水泥相较于矿渣水泥拥有更好的抗Mg~(2+)和SO_4~(2-)侵蚀能力;硫铝酸盐基水泥由于其独特的水化特性,在Mg~(2+)和SO_4~(2-)侵蚀的环境下,强度保持好,抗侵蚀能力也相对更好,自配硫铝酸盐A型和自配硫铝酸盐B型水泥从微观以及宏观相比较差别不大。纵向比较几种水泥抗侵蚀能力,自配A型=自配B型超硫酸盐水泥矿渣水泥普硅水泥。
[Abstract]:With the country paying more and more attention to the marine resources and the safety of the maritime boundary, a large number of marine projects have been built. As the basic structural material of marine engineering, the stability of concrete is very important. Different from the terrestrial environment, there are a lot of ions in the sea water. Some of them have a strong corrosion effect on concrete materials. In this paper, the corrosion mechanism of the three main erosion ions: Cl-mg2 and SO42- in seawater is studied experimentally according to their different erosion mechanisms. Based on the study of the relationship between C3Am and AFT and the transformation conditions, the thermodynamic theory analysis was carried out, the theoretical basis of material transformation was put forward, and the experiment was carried out to verify the relationship between C3Am and AFT. Including calcination of C3A with high purity by high temperature furnace, the conversion experiment was carried out, and the samples obtained were analyzed by XRD and SEM. The results show that C3A and AFM can be transformed into Fridels salt in the presence of Cl-, but the thermodynamics theory analysis can not react with Cl- to produce Fridels salt or trichloroaluminate. However, the existence of Fridels salt was found in the XRD diffraction patterns. The reason is that ettringite transformation is not thorough enough, and there is a certain amount of C 3A or AFM, or there is a dynamic equilibrium between AFT and AFM, and they can transform each other. For mg ~ (2) and so _ 4 ~ (2-), the corrosion tests of cement sand specimens immersed in different ages of corrosion ion solution were carried out. Then the microcosmic tests such as XRDX SEMT-BET were carried out, and the erosion mechanism of different corroded ions to different cement concrete was analyzed in combination with microscopic and macroscopic analysis. The results show that the performance of ordinary silicon cement is very poor in the face of Mg2 and SO42- erosion, the slag cement has poor corrosion resistance to Mg2, and the corrosion resistance of slag cement is better than that of ordinary silicon cement. Supersulphate cement has better corrosion resistance to Mg2 and SO42- than slag cement, and sulphoaluminate based cement has better strength and better corrosion resistance under Mg2 and SO42- erosion environment due to its unique hydration characteristics. Self-made sulphoaluminate A cement and self-made sulphoaluminate B cement have little difference in microscopic and macro phase. Longitudinal comparison of several kinds of cement corrosion resistance, self-made type A = self-made type B supersulphate cement slag cement silicon cement.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P755.3

【参考文献】