多因素作用下锂渣混凝土渗透性系数的定量分析

发布时间：2018-09-18 14:28

【摘要】：锂渣作为工业生产锂盐的副产品,长时间以来都被当作废料弃用,如能在混凝土中合理的利用锂渣不仅有利于环境的保护而且能有利于建筑结构的发展。新疆地区属于严寒盐渍地地区,混凝土在长期服役过程中因为环境因素作用,耐久性问题日益严重。所以本文在冻融循环作用下、自然浸泡作用下探究不同锂渣粉掺量对混凝土气体渗透性能、氯离子渗透性能的影响,在此基础上探究气体渗透系数与电通量之间的相关性,氯离子扩散系数与电通量之间的关系,通过压汞法探究了锂渣粉对混凝土孔结构的影响、锂渣混凝土渗透性能与孔结构参数的关系;最后利用相关理论推导适用于Autoclam渗透仪的扩散系数公式。本文首先测定不同强度等级锂渣混凝土在各龄期的抗压强度和气体渗透系数,并测定28d时的电通量值,结果表明:在锂渣粉掺量10%时,各强度等级混凝土的28d抗压强度提升明显;混凝土在一定锂渣掺量下,其气体渗透系数和电通量值有明显降低。且发现气体渗透系数与龄期之间存在良好的函数关系、电通量值与初始电流相关性较好。其次本文在快速冻融法的基础上,测定锂渣混凝土的质量损失、抗压强度、气体渗透系数、电通量值,结果表明:抗压强度和冻融次数有良好的数学关系,随冻融次数增加抗压强度按一定比例损失;气体渗透系数、电通量值与冻融次数之间均为一次函数关系,气体渗透系数与电通量值都随着冻融次数的增加而增加,掺入锂渣粉能降低混凝土电通量值;气体渗透系数与电通量值相关较好,气体渗透系数随电通量值增加而增加。基于自然浸泡法探究氯离子扩散系数,结果表明:氯离子扩散系数随着NaCl浓度的增加而增加,随着浸泡时间的增加而降低;锂渣混凝土在NaCl溶液中浸泡一定时间后,其氯离子扩散系数与28天电通值均会随锂渣掺量的增加而降低。最后本文在压汞法的基础上,测定掺锂渣混凝土的临界孔径、最可几孔径、平均孔径、孔隙率,结果表明:临界孔径、最可几孔径均随龄期增加而减小,锂渣粉的掺入会减小临界孔径大小,增大最可几孔径。气体渗透系数和电通量均随临界孔径增加而增加。C30、C60分别在掺量为20%、30%时有最大的孔曲折度。
[Abstract]:Lithium slag, as a by-product of industrial production of lithium salt, has been used as waste material for a long time. If lithium slag can be used reasonably in concrete, it is not only beneficial to the protection of environment but also to the development of building structure. Xinjiang is a cold and salinized area. The durability of concrete is becoming more and more serious due to environmental factors in the long service. Therefore, under the action of freeze-thaw cycle and natural immersion, this paper explores the influence of different amount of lithium slag powder on the permeability of concrete gas and chloride ion, and on this basis explores the correlation between gas permeability coefficient and electric flux. The influence of lithium slag powder on pore structure of concrete and the relationship between permeability of lithium slag concrete and pore structure parameters were investigated by mercury injection method. Finally, the diffusion coefficient formula suitable for Autoclam osmometer is derived by using relevant theory. In this paper, the compressive strength and gas permeability coefficient of lithium slag concrete of different strength grades at different ages are measured, and the electric flux value of 28 days is measured. The results show that when the amount of lithium slag powder is 10, The 28d compressive strength of concrete of different strength grades is obviously increased, and the gas permeability coefficient and electric flux value of concrete with a certain amount of lithium slag are obviously decreased. It is found that there is a good functional relationship between the gas permeability coefficient and the age, and the electric flux has a good correlation with the initial current. Secondly, on the basis of rapid freeze-thaw method, the mass loss, compressive strength, gas permeability coefficient and electric flux of lithium slag concrete are measured. The results show that there is a good mathematical relationship between compressive strength and freeze-thaw times. With the increase of freezing and thawing times, the compressive strength is lost in a certain proportion, the gas permeability coefficient, electric flux value and freeze-thaw number are all first function relations, the gas permeability coefficient and electric flux value all increase with the increase of freeze-thaw times. The electric flux value of concrete can be reduced by adding lithium slag powder, the gas permeability coefficient is better correlated with the electric flux value, and the gas permeability coefficient increases with the increase of the electric flux value. Based on the natural immersion method, the chloride diffusion coefficient was investigated. The results show that the chloride diffusion coefficient increases with the increase of NaCl concentration and decreases with the increase of immersion time, and the lithium slag concrete is immersed in NaCl solution for a certain time. The chloride diffusion coefficient and 28 days electric flux value will decrease with the increase of lithium slag content. Finally, on the basis of mercury injection method, the critical pore size, maximum pore size, average pore size and porosity of lithium-doped slag concrete are determined. The results show that the critical pore size and the most available pore size decrease with the increase of age. The addition of lithium slag powder can decrease the critical pore size and increase the maximum pore size. The gas permeability coefficient and the electric flux increase with the increase of critical pore size. C30C60 has the largest pore zigzag when the content is 20%.
【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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