干湿循环作用下锂渣混凝土抗氯离子侵蚀性能的研究

发布时间：2018-03-03 23:25

本文选题：干湿循环　切入点：锂渣　出处：《新疆大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着我国经济水平的提高,基础设施的快速发展,混凝土材料做出巨大贡献的同时,其因氯盐腐蚀引起的耐久性失效,不仅造成了经济的巨大浪费,同时还给资源能源以及环境带来了巨大压力。可持续混凝土的发展要求未来混凝土不但要向长生命周期的方向发展,还要减少资源能源的浪费。在保证其性能的同时有效利用工业废料来代替水泥熟料,不仅节约原材料,同时还会减轻工业废料堆放带来的环境压力。锂渣是生产锂电池所剩的工业废料,新疆是我国乃至全亚洲最大的锂盐生产基地,锂渣年堆积量也居全国为数不多的锂盐厂之首。这种地域产业的局限使锂渣作为混凝土掺合料的研究相对较少。为此,本文以锂渣掺量为主要变量,研究了不同水胶比的混凝土,在浸泡和干湿循环作用下的抗氯离子渗透性能。通过对比侵蚀前后混凝土试件总质量的改变,对不同条件下各锂渣掺量的混凝土抗氯离子渗透性能作出整体评价。得出:相同龄期时,浸泡和干湿循环的混凝土试件内氯离子含量均随着水胶比的增大线性增加。相同水胶比时,浸泡试件内的氯离子渗入总量大于干湿循环试件;同侵蚀环境下掺入锂渣的试件内部氯离子含量均小于空白试件,且锂渣掺量为20%时,内部氯离子含量值最小。同时得出,各试件的单位面积氯离子渗入量与龄期之间呈对数函数形式增长。对受侵蚀后的混凝土试件钻芯取样,依据规程对取样粉末进行水溶性氯离子含量测定,得出各试件内部随着深度的增加氯离子含量减小,且各深度的氯离子含量均随着龄期的延长而变大。相同配比的试件,干湿循环作用时其浅层(0-10mm)氯离子含量较浸泡试件增长迅速,至较深处浸泡试件的氯离子浓度较干湿循环试件大;与空白试件和其它锂渣掺量的试件相比,20%锂渣掺量的混凝土试件内,氯离子浓度均达到最低水平。依实测氯离子浓度与其对应深度的关系,用Origin软件据Fick第二定律对氯离子扩散系数进行拟合。得出,相同水胶比时,浸泡作用的扩散系数大于干湿循环作用;水胶比对氯离子扩散系数的影响较大,锂渣的掺入有效改善了混凝土的渗透性能。随着龄期的增加各试件的扩散系数呈Dt =D1(t1/tn)n 关系衰减,20%锂渣掺量混凝土的时间依懒性指数均大于1,衰减较快。最后,以实测数据对混凝土氯离子扩散系数进行了分层计算和GM(1,1)模拟,对更深层次的氯离子评估提供了方法和依据。
[Abstract]:With the improvement of economic level and the rapid development of infrastructure in our country, the durability failure caused by chloride corrosion not only caused a huge economic waste, but also made a great contribution to concrete materials. At the same time, it also brings great pressure to resources, energy and environment. The development of sustainable concrete requires that in the future, concrete should not only develop in the direction of long life cycle, We also need to reduce the waste of resources and energy. We can not only save raw materials, but also effectively use industrial waste to replace cement clinker while ensuring its performance. At the same time, it will also alleviate the environmental pressure brought by the industrial waste stacking. Lithium slag is the industrial waste surplus from the production of lithium batteries, and Xinjiang is the largest base for lithium salt production in China and even in Asia as a whole. The annual accumulation of lithium slag also ranks first among the few lithium salt plants in China. Due to the limitation of this kind of regional industry, the research on lithium slag as concrete admixture is relatively few. Therefore, the content of lithium slag is the main variable in this paper. The penetration resistance of concrete with different water-binder ratio under the action of wet and dry cycles was studied. The total quality of concrete specimens before and after erosion was compared. An overall evaluation of chloride penetration resistance of concrete with different lithium slag content under different conditions is made. It is concluded that: at the same age, The chlorine ion content in the concrete samples soaked and dry-wet cycle increased linearly with the increase of water-binder ratio. When the water-binder ratio was the same, the total amount of chloride ion infiltration in the soaking specimens was larger than that in the dry-wet cycle specimens. In the same erosion environment, the content of chlorine ions in the samples doped with lithium slag is smaller than that of the blank specimens, and the content of chlorine ions in the samples is the smallest when the content of lithium slag is 20. At the same time, it is concluded that, The amount of chloride ion penetration per unit area of each specimen increased in the form of logarithmic function between the age and the age. The sample was sampled from the drill core of the corroded concrete sample, and the water soluble chloride ion content of the sample powder was determined according to the rules. The results show that the chlorine ion content in each specimen decreases with the increase of depth, and the chloride ion content in each depth increases with the increase of age. The chlorine ion content in the shallow layer of dry and wet cycle increased rapidly than that in the soaking specimen, and the chloride concentration of the sample soaked in the deeper part was larger than that of the wet and dry cycle specimen. Compared with the blank specimen and other samples with lithium slag content, the chloride ion concentration in concrete samples with 20% lithium slag content reaches the lowest level. According to the relationship between the measured chlorine ion concentration and the corresponding depth, According to the second law of Fick, the diffusion coefficient of chloride ion is fitted by Origin software. It is concluded that the diffusion coefficient of soaking is larger than that of dry and wet cycle at the same water / binder ratio, and the influence of water / binder ratio on the diffusion coefficient of chloride ion is greater than that of wet and dry circulation. With the increase of age, the diffusion coefficient of each sample decreases with the increase of age. The time dependent exponent of 20% lithium slag added concrete is larger than 1, and the attenuation is faster. Based on the measured data, the chloride diffusion coefficient of concrete is calculated by stratification and simulated by GM1 / 1), which provides a method and basis for the further evaluation of chloride ions.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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