赤泥及其水泥固化土的特性研究

发布时间：2018-01-21 00:58

  本文关键词： 赤泥 赤泥水泥固化土 电阻率 无侧限抗压强度　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：工业氧化铝生产过程中产生大量赤泥,赤泥堆放对土壤造成严重危害,为解决赤泥大量堆积及综合利用等问题,将赤泥应用于道路基层材料,代替部分水泥固化土,减少赤泥堆放并降低路用水泥的成本。本文将通过了解赤泥电阻率特性为其提供理论依据。通过室内试验,研究赤泥电阻率与电流频率、含水率、龄期、孔隙率以及应变之间的关系,证明电阻率法研究赤泥应用的可行性。工程场地中的土体易被酸碱性废水污染,降低固化土路基的工作性能,从而引起工程事故的产生。基于这一担忧,本文以酸碱污染为典型,与赤泥水泥固化土形成不同污染程度和类型的污染土,以此来模拟工程中酸碱污染路基的情况。以赤泥和水泥为固化剂,采用酸碱溶液调节水的p H值,模拟酸碱污染固化土。探讨了电流频率、养护龄期和酸碱溶液对固化土电阻率的影响,成型方式、养护龄期和酸碱溶液对固化土无侧限抗压强度影响,以及电阻率与抗压强度之间的关系。基于以上问题,主要研究结论如下:(1)对赤泥和赤泥水泥固化土试块进行电阻率测试时,电流频率对电阻率有相同的变化规律。50Hz≤电流频率f50kHz时,随电流频率的不断升高,电阻率快速降低;50kHz≤电流频率f≤1MHz时,随电流频率的不断升高,电阻率变化趋势变缓。为减少电流频率对测试的影响,在下文中将选用电流频率f=50kHz时的电阻率进行分析。(2)赤泥电阻率随含水率的增加而降低。不同孔隙率下,含水率较小时,随龄期的延长,赤泥电阻率先升高后降低;含水率较大时,赤泥电阻率随龄期的变化较小。在含水率一定的情况下,赤泥电阻率随孔隙率的增大,呈现先急速减小又增大的变化规律。赤泥电阻率随应变的增加而降低。(3)赤泥水泥固化土电阻率随龄期的变化规律,会因成型方式的不同发生改变,立即成型试样的电阻率随龄期变化曲线划分为三个阶段:升高阶段(1d≤t14d)、降低阶段(14d≤t21d)、平缓阶段(21d≤t≤28d),静置4h成型试样的电阻率随龄期的增加而增大。溶液呈酸性时,电阻率随p H的增大而增大;溶液呈碱性时,固化土电阻率随p H的增大而减小。(4)静置4h成型试样的赤泥水泥固化土无侧限抗压强度有明显降低的趋势。立即成型试样的抗压强度随龄期的变化分为两个阶段:快速增长阶段(7d≤t14d)、缓慢增长阶段(14d≤t≤28d);随龄期的增加,静置4h成型试样的抗压强度呈线性增加。掺入酸性溶液立即成型试样的抗压强度随p H的增大而减小,掺入碱性溶液的抗压强度随p H的增大而增大;掺入酸性、碱性溶液静置4h成型试样的抗压强度随p H的增大,均先增大后减小。在同一p H下,静置4h成型试样的抗压强度与电阻率有良好的线性相关性。
[Abstract]:In order to solve the problem of red mud accumulation and comprehensive utilization, red mud is applied to road base material in order to solve the problem that a large amount of red mud is produced in the process of production of industrial alumina, and red mud stacking causes serious harm to soil. Instead of some cement solidified soil, it can reduce the red mud stacking and reduce the cost of road cement. This paper will provide the theoretical basis by understanding the characteristics of the red mud resistivity. Through laboratory tests, the resistance and current frequency of red mud will be studied. The relationship among water content, age, porosity and strain proves the feasibility of using resistivity method to study the application of red mud. The soil in engineering site is liable to be polluted by acid and alkaline wastewater, and the working performance of solidified soil subgrade is reduced. Based on this concern, the acid-base pollution is typical, and different pollution degree and type of contaminated soil are formed with red mud cement solidified soil. In order to simulate the acid-alkali pollution of roadbed in engineering, using red mud and cement as curing agent, adjusting pH value of water with acid-base solution, simulating acid-base pollution solidified soil, the current frequency is discussed. The influence of curing age and acid-base solution on the resistivity of solidified soil, forming mode, curing age and acid-base solution on unconfined compressive strength of solidified soil. And the relationship between resistivity and compressive strength. Based on the above problems, the main conclusions are as follows: 1) when the resistivity of red mud and red mud cement solidified soil samples are tested. When the current frequency is less than 50 kHz, the resistivity decreases rapidly with the increasing of current frequency. When 50 kHz 鈮，

本文编号：1449967