掺煤矸石混凝土力学及收缩性能研究

发布时间：2018-06-29 01:13

本文选题：煤矸石 + 流动性　；参考：《沈阳建筑大学》2015年硕士论文

【摘要】：煤矸石是煤矿生产过程中采煤、洗煤时排放的工业废渣。目前我国煤矸石累计堆存量已达50多亿吨,占用了大量的土地,同时,煤矸石自然过程中不断排放有害气体,严重污染环境。而利用煤矸石生产混凝土制品,替代混凝土中部分碎石,可以大量减少建筑行业对天然集料的的使用,具有较高的经济效益和社会效益。本课题以煤矸石作为粗集料,替代部分碎石制备掺煤矸石混凝土,系统研究煤矸石掺量、粉煤灰取代率、水胶比、减水剂掺量等因素对掺煤矸石混凝土流动性、力学性能和收缩性能的影响规律。研究结果表明:随着煤矸石掺量的增加,混凝土流动性和力学性能明显下降。混凝土收缩是先增大后减小;随着粉煤灰掺量的增加,混凝土的流动性、力学性能和收缩性能均得到了明显的改善。而粉煤灰对力学性能和收缩性能的影响主要发生在后期;随着水胶比的增大,混凝土的流动性增加,力学性能下降,而水胶比越小,混凝土的收缩越大;随着减水剂掺量的增加,混凝土的流动性和力学性能逐渐增加,而大掺量减水剂对混凝土的早期收缩有有很好的抑制作用,但是对后期收缩影响不利,故减水剂的掺量要控制在合理范围之内;运用正交分析和线性回归分析,得出混凝土力学性能的最佳配合比为粉煤灰掺量为20%、水胶比为0.38、煤矸石掺量为30%,其中水胶比是影响混凝土强度的主要因素,煤矸石掺量次之,粉煤灰取代率影响最小,线性回归方程为Y=99.65889+0.01728X1-124.25X2-0.01897X3。混凝土收缩性能的最佳配合比为粉煤灰掺量为35%、水胶比为0.44、煤矸石掺量为55%、减水剂掺量为1.5%,其中水胶比是影响混凝土收缩应变的主要因素,粉煤灰取代率次之,煤矸石掺量第三,减水剂掺量影响小,线性回归方程为Y=738.20178-0.29528X1-1067.95X2+0.000978X3-0.18912X4。
[Abstract]:Coal gangue is the industrial residue discharged during coal mining and coal washing. At present, the accumulative storage of coal gangue in our country has reached more than 5 billion tons, occupying a large amount of land. At the same time, the natural process of coal gangue constantly releases harmful gas, which seriously pollutes the environment. The use of coal gangue to produce concrete products instead of some crushed stones in concrete can greatly reduce the use of natural aggregates in the construction industry and has higher economic and social benefits. In this paper, coal gangue is used as coarse aggregate instead of some crushed stone to prepare coal gangue concrete. The fluidity of coal gangue concrete is studied systematically, such as coal gangue content, fly ash substitution rate, water binder ratio and water reducing agent ratio, etc. The influence of mechanical properties and shrinkage properties. The results show that the fluidity and mechanical properties of concrete decrease obviously with the increase of coal gangue content. The shrinkage of concrete increases first and then decreases, and with the increase of fly ash content, the fluidity, mechanical properties and shrinkage properties of concrete are obviously improved. The effect of fly ash on the mechanical properties and shrinkage of concrete mainly occurs in the later stage, with the increase of water-binder ratio, the fluidity of concrete increases, the mechanical property decreases, and the smaller the water-binder ratio, the greater the shrinkage of concrete. With the increase of water reducing agent content, the fluidity and mechanical properties of concrete increase gradually. However, the large amount of water reducing agent has a good effect on the early shrinkage of concrete, but it is unfavorable to the late shrinkage. Therefore, the dosage of water reducer should be controlled within a reasonable range, and the orthogonal analysis and linear regression analysis should be used. It is concluded that the optimum mix ratio of concrete mechanical properties is fly ash 20, water binder 0.38, coal gangue 30. The water binder ratio is the main factor affecting the strength of concrete, the coal gangue content is the second, and the fly ash replacement ratio is the least. The linear regression equation is YT 99.65889 0.01728X1-124.25X2-0.01897X3. The optimum mixture ratio of concrete shrinkage performance is 35% fly ash, 0.44 water / binder ratio, 55 coal gangue content and 1.5 water reducing agent. The water binder ratio is the main factor affecting shrinkage strain of concrete, followed by the replacement rate of fly ash. The content of coal gangue was the third, and the content of water reducer had little influence. The linear regression equation was YC 738.20178-0.29528X1-1067.95X2 0.000978X3-0.18912X4.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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