硅质铁尾矿粉用作混凝土掺合料的应用研究

发布时间：2018-04-30 21:32

本文选题：硅质铁尾矿粉 + 混凝土掺合料　；参考：《清华大学》2013年硕士论文

【摘要】：硅质铁尾矿是铁矿开采过程中排出的废料，可造成环境污染。以硅质铁尾矿为基材进行磨细加工，达到一定细度可制备粉体材料--硅质铁尾矿粉。本文研究硅质铁尾矿粉作为混凝土掺合料的可行性以及其对混凝土性能的影响，，试图开发新品种混凝土掺合料，探索硅质铁尾矿资源化应用的新途径。本文进行了硅质铁尾矿的矿物组成、化学成分和易磨性等材料特性试验研究；不同细度硅质铁尾矿粉的活性指数以及和粉煤灰、矿渣粉不同比例复合的活性指数试验研究；不同水胶比、不同掺量和不同复合比例的混凝土强度试验研究；掺硅质铁尾矿粉的混凝土的拌合物性能、力学性能、耐久性能和体积稳定性的试验研究。并选择合适的工程进行了实际应用。得出如下结论： 1、本次研究的铁尾矿属典型的高硅鞍山型铁尾矿，其易磨性指数高于水泥熟料，与矿渣或钢渣相当。 2、比表面积400m~2/kg以上的硅质铁尾矿粉具有微弱水硬性，但不具备火山灰性。硅质铁尾矿粉的活性指数低于矿渣粉和粉煤灰。掺加比例相同时，硅质铁尾矿粉与矿渣粉复合后的活性指数高于其与粉煤灰复合后的活性指数，细度对其活性指数的影响不显著。与粉煤灰复合相比，硅质铁尾矿粉与矿渣粉复合有利于其活性的发挥。 3、比较不同水胶比、不同掺合料掺量和不同复合比例的硅质铁尾矿粉与矿渣粉复合双掺混凝土的抗压强度规律时发现，随着复合掺合料掺量的增加，同龄期混凝土早期强度逐渐减低，但后期强度增幅明显。随水胶比的降低，同龄期混凝土单位强度贡献率增大；低水胶比条件下更有利于掺合料活性的发挥。 4、硅质铁尾矿粉与矿渣粉复合双掺后，改善了混凝土的工作性能、力学性能和耐久性能，并能减少混凝土收缩，硅质铁尾矿粉的细度对混凝土的力学性能影响不显著。 5、加强硅质铁尾矿的选材，粉磨、运输、应用等各环节的质量控制，采用合理的配合比，达到一定细度的硅质铁尾矿粉作为混凝土掺合料，已在实际工程中应用，混凝土的拌合物性能和硬化混凝土性能均能满足设计要求。
[Abstract]:Siliceous iron tailings are wastes discharged during iron ore mining, which can cause environmental pollution. The siliceous iron tailings can be prepared by grinding the siliceous iron tailings to a certain degree of fineness. In this paper, the feasibility of siliceous iron tailings as concrete admixture and its influence on concrete properties are studied. A new kind of concrete admixture is developed, and a new approach to the application of siliceous iron tailings is explored. In this paper, the mineral composition, chemical composition and grindability of siliceous iron tailings were studied, and the activity index of siliceous iron tailings with different fineness and different ratio of fly ash and slag powder were studied. Experimental study on the strength of concrete with different water / binder ratio, different content and different composite ratio, and experimental study on the mixing properties, mechanical properties, durability and volume stability of concrete mixed with siliceous iron tailing powder. The suitable project is selected for practical application. The following conclusions are drawn: 1. The iron tailings studied in this paper are typical high silicon Anshan iron tailings, and their grindability index is higher than that of cement clinker, which is equivalent to slag or steel slag. 2. The siliceous iron tailings with specific surface area above 400m~2/kg have weak hydrohardness but no pozzolanic property. The activity index of siliceous iron tailings is lower than that of slag and fly ash. The activity index of siliceous iron tailings mixed with slag powder was higher than that of fly ash when the ratio was the same, but the fineness had no significant effect on the activity index. Compared with fly ash, the combination of siliceous iron tailings and slag powder is beneficial to its activity. 3. When comparing the compressive strength law of the concrete with different water / binder ratio, different admixture content and different compound ratio, it is found that with the increase of the amount of the compound admixture, the compressive strength of the concrete mixed with the siliceous iron tailing powder and the slag powder is increased. The early strength of concrete of the same age period decreases gradually, but the increase of later stage strength is obvious. With the decrease of water-binder ratio, the contribution rate of concrete per unit strength increases at the same age, and the low water-binder ratio is more favorable for the exertion of admixture activity. 4. After the compound addition of siliceous iron tailing powder and slag powder, the working performance, mechanical property and durability of concrete are improved, and the shrinkage of concrete is reduced. The fineness of siliceous iron tailings powder has no significant effect on the mechanical properties of concrete. (5) strengthening the quality control of the selection, grinding, transportation and application of siliceous iron tailings, adopting reasonable mix ratio and achieving certain fineness of siliceous iron tailings as concrete admixtures, has been applied in practical projects. The performance of concrete mixture and hardened concrete can meet the design requirements.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528.041

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