利用密云尾矿废石制备高性能混凝土的基础研究

发布时间：2018-05-13 07:47

本文选题：铁尾矿 + 废石　；参考：《北京科技大学》2015年博士论文

【摘要】：为了开发大宗工业固体废弃物资源化利用的新途径,满足社会对绿色、高性能、高耐久性建筑材料的需求以及推动混凝土行业的可持续发展,本文以精细化综合利用为目标,采用铁尾矿和废石为主要原料依次研发出三种新型绿色高性能混凝土：铁尾矿细骨料混凝土、全尾矿废石骨料高性能混凝土和极细铁尾矿粉混凝土。全部利用铁尾矿砂作为骨料制备出标准养护条件下28d抗压强度达到100MPa的铁尾矿细骨料混凝土,固废总利用率达到89.2%。铁尾矿细骨料混凝土最优配合比为：铁尾矿比例占60%,粉煤灰比例占12%,矿渣比例占14%,水泥熟料比例占10.8%,脱硫石膏比例占3.2%,PC高效减水剂用量为胶凝材料的0.23%,水胶比0.22。在铁尾矿细骨料混凝土基础上加入废石作为粗骨料,制备出塌落度为136mmm,标准养护条件下28d抗压强度达98.54MPa的全尾矿废石骨料混凝土,其尾矿废石掺量达到72%,水泥熟料掺量仅为7.56%,固废总利用率达到92.44%,并且其在抗冻融和抗硫酸盐侵蚀等耐久性方面具有优异的性能。通过XRD、XPS、IR、SEM, TG-DSC、水化放热规律和孔结构测试等分析手段可知,水化各龄期C-S-H凝胶和钙矾石是强度的主要来源。在全尾矿废石骨料混凝土的基础上,采用目前难以利用的极细铁尾矿粉作为矿物掺合料,制备出在标准养护条件下28d抗压强度为88.99MPa的极细铁尾矿粉混凝土,尾矿废石利用率达77.6%。并对极细铁尾矿中所含有的石英、钠长石、拉长石、绿泥石和黑云母五种主要矿物成分进行水化反应活性的研究,结果表明标准养护条件下石英、绿泥石和黑云母反应活性较低,而钠长石和拉长石反应活性较高,其水化产物主要为钙矾石类矿物,对水化硬化浆体的强度有所贡献。将铁尾矿和废石等工业固体废弃物应用于高性能混凝土的研发中,不仅可以降低尾矿废石等固废对环境造成的负面影响,还能减少高性能混凝土原材料的碳足迹,并且提高产品附加值,从而有利于整个行业的可持续发展。
[Abstract]:In order to develop a new way of recycling industrial solid wastes, meet the needs of the society for green, high performance and high durability building materials and promote the sustainable development of concrete industry, this paper aims at fine and comprehensive utilization. Three new types of green high performance concrete were developed by using iron tailings and waste rock as main raw materials: iron tailings fine aggregate concrete, whole tailings waste aggregate high performance concrete and very fine iron tailings powder concrete. Iron tailings fine aggregate concrete with 28d compressive strength up to 100MPa was prepared by using iron tailings as aggregate, and the total utilization ratio of solid waste reached 89.2%. The optimum mix ratio of fine aggregate concrete of iron tailings is 60% of iron tailings, 12% of fly ash, 14% of slag, 10.8 of cement clinker, and 3.2% of desulphurization gypsum. The content of PC superplasticizer is 0.23 and the ratio of water to glue is 0.22. On the basis of iron tailings fine aggregate concrete, waste stone as coarse aggregate was added to prepare the whole tailings waste aggregate concrete with collapse degree of 136mm and compressive strength of 98.54MPa for 28d under standard curing conditions. The content of tailings is 72%, cement clinker is only 7.56, the total utilization ratio of solid waste is 92.44%, and it has excellent durability in the aspects of anti-freezing and anti-sulfate erosion. Through the analysis of XRDX, TG-DSC, hydration exothermic law and pore structure test, it can be seen that C-S-H gel and ettringite are the main sources of strength in different hydration stages. On the basis of total tailings waste aggregate concrete, the extremely fine iron tailings concrete, which is difficult to be used at present as mineral admixture, is prepared under the standard curing conditions with compressive strength of 88.99MPa for 28 days. The utilization ratio of tailings waste rock reaches 77.6%. The hydration activity of quartz, albite, elongite, chlorite and biotite in ultrafine iron tailings was studied. The reaction activity of chlorite and biotite is low, while the reaction activity of albite and elongate is higher. The hydration product is mainly ettringite mineral, which contributes to the strength of hydrated hardened slurry. The application of industrial solid waste such as iron tailings and waste stones in the research and development of high performance concrete can not only reduce the negative impact of solid waste such as tailings on the environment, but also reduce the carbon footprint of raw materials of high performance concrete. And improve the added value of products, which is conducive to the sustainable development of the entire industry.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU528

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