铁尾矿砂替代天然砂的实验研究

发布时间：2018-06-02 07:25

本文选题：铁尾矿砂 + 砂浆　；参考：《燕山大学》2014年硕士论文

【摘要】：开采矿产资源产生了数量巨大的资源垃圾——尾矿砂，尾矿占用土地、污染环境，甚至危及百姓生命财产。与此同时，建筑与道路等基础设施投资日益加大，天然砂材料紧缺，国家出台政策防治乱采乱挖，寻找合理的替代材料刻不容缓。尾矿砂作为放错了地方的资源，如果能成为替代材料，，不仅能盘活土地、减小污染，还能降低材料成本，创造经济效益和社会效益，促进社会的可持续发展。本文分析了铁尾矿砂的成分及特性，通过一系列试验，确定了其用于建筑砂浆和道路基层的工程材料上的可能性。首先，研究将铁尾矿砂等体积取代天然砂对普通砂浆性能的影响程度和规律，确定铁尾矿砂配制普通砂浆的适宜掺量。通过对砂浆的流动性、表观密度、抗压强度和抗冻性的试验分析，发现当铁尾矿砂等体积取代天然砂时，随着单位体积内尾矿砂掺量增多，流动性先增大后减小，砂浆分层度基本上能保持在10mm~20mm之间，抗冻性等符合性能要求。合适的配比可以使混合砂浆符合性能要求，砂浆密实度增加，水泥充分骨料，抗压强度增大。试验表明，水泥砂浆配合比1:4，铁尾矿砂替代天然砂比例为60%时最佳。其次，参考二灰土和二灰碎石的配比，设计二灰矿砂中的二灰与铁尾矿砂的配合比。通过研究二灰矿砂基层混合料的无侧限抗压强度、击实试验、抗冻性和耐水性能，发现二灰矿砂强度主要由石灰和粉煤灰反应生成的胶凝物稳定结构提供，随着石灰含量的增加强度先增加后降低。铁尾矿砂在二灰矿砂中起骨料作用，掺量过多后混合料中空隙率过大，二灰无法充分填实空隙，结构密实度降低，抗压强度下降。二灰矿砂的强度、抗冻性、耐水性均随龄期增长而增强。最终确定二灰矿砂最佳配比为二灰：尾矿砂为30:70。通过对同配比二灰矿砂与二灰土、二灰碎石的性能对比分析，确定了二灰矿砂能够应用各等级、各类城市道路的底基层、二级和二级以下公路的基层。
[Abstract]:Mining mineral resources produces a huge amount of garbage-tailings, which occupy land, pollute environment and even endanger people's life and property. At the same time, the investment in infrastructure such as construction and road is increasing day by day, and the natural sand material is in short supply. As the resources in the wrong place, tailings can not only invigorate the land, reduce the pollution, but also reduce the cost of materials, create economic and social benefits, and promote the sustainable development of society. In this paper, the composition and characteristics of iron tailings are analyzed. Through a series of tests, the possibility of using them as engineering materials for building mortar and road base is determined. Firstly, the influence degree and law of replacing natural sand with iron tailings in equal volume on the performance of ordinary mortar are studied, and the suitable amount of iron tailings to prepare ordinary mortar is determined. Through the experimental analysis of the fluidity, apparent density, compressive strength and frost resistance of mortar, it is found that when iron tailings replace natural sand in volume, the fluidity increases first and then decreases with the increase of tailings content per unit volume. Mortar delamination can be maintained between 10mm~20mm, frost resistance and other performance requirements. The mix mortar can meet the requirements of performance, the compactness of mortar increases, the cement aggregate is sufficient and the compressive strength increases. The test results show that when the mix ratio of cement mortar is 1: 4 and the ratio of iron tailings instead of natural sand is 60%, it is the best one. Secondly, according to the ratio of lime-lime soil and lime-fly ash gravel, the mixture ratio of lime-fly ash and iron tailings is designed. By studying the unconfined compressive strength, compaction test, frost resistance and water resistance of lime-fly ash base mixture, it is found that the strength of lime-lime ore sand is mainly provided by the stable structure of cement produced by the reaction of lime and fly ash. With the increase of lime content, the strength increased first and then decreased. Iron tailings play an aggregate role in the lime-ash ore sand. When the content of iron tailings is too high, the porosity in the mixture is too large, the structure compactness is reduced and the compressive strength is decreased because the lime-fly ash can not fully fill the void. The strength, frost resistance and water resistance of lime-fly ash ore are increased with the increase of age. Finally, it is determined that the optimum ratio of lime-ash ore sand is lime-fly ash and that of tailings is 30: 70. By comparing and analyzing the properties of lime-fly ash ore sand and lime-lime soil and lime-ash gravel, it is determined that lime-ash ore sand can be applied to the base course of all kinds of urban roads, and the base of roads below the second grade and the second grade.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U414

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