粉煤灰与石灰石粉对混凝土浆体流动性能的影响研究

发布时间：2018-03-20 23:09

本文选题：粉煤灰　切入点：石灰石粉　出处：《内蒙古农业大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来,我国建筑行业发展很迅速,混凝土矿物掺合料的利用已经向环保、经济的趋势发展。已有很多学者对粉煤灰作为混凝土掺合料进行研究,并取得了大量成果,粉煤灰作为一种优质的矿物掺合料,其众多优势已得到大量验证,其对混凝土流变性能的改善已得到大多数学者的认可；而石灰石粉作为一种惰性掺合料掺加在混凝土中的研究在近几年才逐渐增多,我国石灰石粉资源比较丰富,对石灰石粉多加利用,不仅可以保护环境,还可以产生良好的社会经济效益；这两种掺合料单独掺加在混凝土的研究已有很多,但石灰石粉与粉煤灰双掺的研究却很少。本文以石灰石粉和粉煤灰作为混凝土掺合料为研究对象,研究了两者对水泥浆体流变性能的影响,探讨了两者对水泥净浆、水泥胶砂及新拌混凝土的工作性能的改善。本文首先设计粉煤灰与石灰石粉单掺及复掺的水泥净浆实验,固定这两种掺合料的掺和量,通过微型坍落度实验和marsh筒实验,研究了在不同状态下这两种掺合料不同比例对水泥净浆流动性能的影响,通过颗分试验分析了水泥净浆组成材料的颗粒级配对水泥净浆流动性能的影响,并根据宾汉姆流体模型中水泥浆体的屈服应力和粘度系数来评价水泥浆体流动性能的优劣。其次,设计粉煤灰和石灰石粉单掺及复掺对水泥胶砂流动度和胶砂流动度经时损失的影响,复掺试验设计思路为固定石灰石粉的掺量,逐渐增加粉煤灰的掺量。试验研究表明石灰石粉的掺加增加水泥胶砂体系的粘稠度,其“填充效应”可在一定程度上增加水泥胶砂的流动度,较大程度的降低水泥胶砂流动度经时损失。其与粉煤灰在不同比例复掺时对水泥胶砂流动度的影响也不同。混凝土试验的水胶比、矿物掺合料的掺量比例与水泥胶砂试验相同,这样可以更好的判断混凝土坍落扩展度与水泥胶砂流动度的相关性,也可为以水泥胶砂流动度来预测混凝土流动性能提供依据；通过电镜扫描来观察混凝土破坏界面的粉煤灰颗粒与石灰石粉颗粒形貌、状态,为两者改善混凝土浆体流动性能的理论分析提供依据。
[Abstract]:In recent years, the construction industry in China has developed rapidly, and the use of concrete mineral admixture has been developed to the trend of environmental protection and economy. Many scholars have studied fly ash as concrete admixture, and obtained a lot of achievements. Fly ash as a kind of high quality mineral admixture, its numerous advantages have been verified, and the improvement of concrete rheological properties has been approved by most scholars. However, the study of limestone powder as an inert admixture in concrete has increased gradually in recent years, and the resources of limestone powder in our country are relatively rich, so more use of limestone powder can not only protect the environment, but also improve the quality of limestone powder. It can also produce good social and economic benefits; there has been a lot of research on the addition of these two admixtures to concrete alone. In this paper, the influence of limestone powder and fly ash on the rheological properties of cement paste is studied, and the effect of both on cement paste is discussed. Improvement of working performance of cement mortar and fresh concrete. In this paper, first of all, the experiment of cement paste with fly ash and limestone powder is designed, the mixing amount of these two admixtures is fixed, and the experiment of micro slump and marsh tube is carried out. The effect of the two admixtures on the flow performance of cement paste was studied under different conditions. The effect of particle gradation of cement paste composition on the flow performance of cement paste was analyzed through particle tests. According to the yield stress and viscosity coefficient of cement paste in Bingham fluid model, the flow performance of cement paste is evaluated. Secondly, the influence of fly ash and limestone powder on the flowability of cement mortar and the loss of flowability of cement sand is studied. The design idea of compound mixing test is to fix the content of limestone powder. The experimental results show that the "filling effect" can increase the fluidity of cement sand to a certain extent by increasing the viscosity of cement sand system with the addition of limestone powder. The flow loss of cement sand is reduced to a large extent, and the effect on the flowability of cement mortar is different from that of fly ash when it is mixed with fly ash in different proportion. The water / binder ratio and mineral admixture ratio of concrete test are the same as that of cement sand test, which can better judge the correlation between concrete collapse expansion and cement sand flow. It can also provide the basis for predicting the fluidity of concrete based on the flowing degree of cement sand, and observe the morphology and state of fly ash and limestone particles at the failure interface of concrete by scanning electron microscope. It provides the basis for the theoretical analysis of improving the flow performance of concrete paste.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528.041

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