矿物掺合料对硬化水泥浆体抗钙溶蚀性能的影响

发布时间：2018-04-02 10:24

本文选题：硬化水泥浆体　切入点：钙溶蚀　出处：《东南大学》2015年硕士论文

【摘要】：长期处于软水或酸性水等侵蚀性环境中的水泥基材料很容易发生钙溶蚀现象,使材料的物理、力学性能产生严重的劣化行为。水泥基材料的钙溶蚀是由扩散控制的过程,受材料的组成、微观结构及外部环境等的影响很大。考虑到矿物掺合料能够明显改善水泥基材料的钙溶蚀性能,本研究对掺加不同品种和掺量矿物掺合料、不同养护龄期的硬化水泥浆体的溶蚀性能展开了系统的研究,并借助于无损的X射线断层扫描技术(X-CT)对溶蚀进行了深入的分析。具体内容与结论如下：1.分别研究不同掺量的粉煤灰(FA)及不同养护龄期(10个月和3年)对硬化水泥浆体在6 mol/L (6M)硝酸铵溶液加速溶蚀下抗溶蚀性能的影响。以称重法、X-CT法及超声波无损检测法分别测量溶蚀前后浆体的质量损失、溶蚀深度及相对动弹模量,得到：随着FA掺量的增加,相同溶蚀时间浆体的溶蚀量逐渐减少；FA掺量为30%时,硬化水泥浆体的溶蚀深度最小,为最佳掺量；X-CT灰度图像法在表征样品钙溶蚀量的变化程度时与称重法具有一致性；过量的FA会使材料的弹性模量下降。养护龄期越长,FA-硬化水泥浆体的溶蚀量和溶蚀深度均较小2.分别研究不同掺量的硅灰(SF)或粒化矿渣(SL)对硬化水泥浆体的抗溶蚀能力的影响。结果表明：SF掺量为30%时,浆体的溶蚀深度最小：SL的掺量越高,浆体的溶蚀深度越小。SF或SL的掺量越高,浆体的溶蚀量越低,溶蚀后的相对动弹模量较高,抗溶蚀能力提高。水胶比越大的浆体溶蚀深度也越大,溶蚀量越小。3.基于X-CT的成像原理,在特定的X-CT扫描条件下,利用空气、去离子水、单晶硅、高纯铝和单晶石膏五种均质物质对水泥基材料中可能存在的物相的灰度值(GSV)进行标定,并定义了CT数的概念。为进一步定量分析水泥基材料中的各物相打下了基础。
[Abstract]:Cement based materials in corrosive environment such as soft water or acid water for a long time are prone to calcium dissolution, resulting in serious deterioration of physical and mechanical properties of the materials. Calcium dissolution of cement based materials is a process controlled by diffusion. Considering that mineral admixtures can obviously improve the calcium dissolution performance of cement-based materials, the mineral admixtures of different varieties and amounts of mineral admixtures have been studied. The corrosion performance of hardened cement paste with different curing age was studied systematically. Further analysis of dissolution was carried out with the help of non-destructive X-ray tomography (X-CTT). The specific contents and conclusions are as follows: 1. The effects of different amount of fly ash and different curing ages (10 months and 3 years) on hardened water are studied respectively. The effect of 6 mol/L / 6M) ammonium nitrate solution on the corrosion resistance of the slurry was studied. The mass loss of the slurry before and after dissolution was measured by weighing method X-CT method and ultrasonic nondestructive testing method, respectively. The dissolution depth and the relative dynamic modulus of the slurry are obtained: with the increase of FA content, the dissolution depth of hardened cement slurry is the smallest when the content of FA is 30%, and the content of FA decreases gradually with the increase of FA content. The X-CT gray image method is consistent with the weighing method in characterizing the change degree of the sample calcium solution. Too much FA will decrease the elastic modulus of the material. The longer the curing age is, the smaller the dissolution amount and the depth of dissolution of the cement paste are. 2. The solution resistance of different amount of silica fume (SF) or granulated slag (SLL) to hardened cement paste is studied. The result shows that the proportion of 30% SF is 30. The lower the depth of dissolution of slurry is, the higher the content of solution is, the smaller the depth of dissolution of slurry is. The higher the content of SF or SL is, the lower the amount of dissolution of slurry is, and the higher the relative dynamic modulus after dissolution is. The higher the water / binder ratio is, the greater the dissolution depth is, and the smaller the dissolution amount is. 3. Based on the imaging principle of X-CT, under specific X-CT scanning conditions, air, deionized water, monocrystalline silicon, silicon, etc. Five homogenized substances, high purity aluminum and single crystal gypsum, are used to calibrate the grayscale values of the phases that may exist in cement based materials, and the concept of CT number is defined, which lays a foundation for further quantitative analysis of the phases in cement based materials.
【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】：TQ172.1

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