【作者】 李天鹏；

【导师】 张彩文；

【作者基本信息】 河北理工学院 ， 材料学， 2003， 硕士

【摘要】 冀东熟料磨制的水泥,强度及其他一些物理性能都很好,但是配制的混凝土坍落度经时损失较大,尤其是在添加高效减水剂后更为严重,因而大大限制了冀东水泥在高性能混凝土上的应用。本课题研究的目的就是探讨冀东水泥配制的混凝土坍落度经时损失较大的原因,并通过实验寻找切实可行的解决办法。本研究分析了冀东熟料与启新熟料的化学组成,并通过XRD、SEM和能谱分析等近代测试手段对这两种熟料进行对比。从矿物组成看,两者没有太大的差异,但两种熟料中铝酸盐矿物的结晶形态明显不同。因此导致冀东熟料磨制的水泥初始水化速度比启新熟料磨制的水泥快得多,大量拌合水迅速转化为水化产物的化学结合水和表面物理吸附水。同时由于大量水化产物粒子聚集在熟料颗粒周围形成絮凝结构,又将部分游离水封闭在絮凝结构中,使用于流动的游离水进一步减少。水化初始用于流动的游离水量的迅速降低,就是冀东水泥配制的混凝土坍落度经时损失严重的根本原因。本研究通过建立数学模型,对各种存在状态的水,进行了定量计算。从而对坍落度经时损失的原因作了定量表述。本研究考察了各种因素对胶砂流动度经时损失的影响,并提出了胶砂流动度经时损失较小的水泥组成。实验结果表明,在不改变熟料组成的条件下,通过调整石膏种类和数量、混合材种类和数量、水泥细度、可溶性碱和外加剂等等,能够在一定程度上减小浆体的流动度经时损失,同时水泥的其他物理性能也没有受到损害。更多还原

【Abstract】 The cement made from Jidong clinker has high strength both in early stage and late stage, but the concrete slump loss is very rapid, especially when the superplasticizer is added in. Therefore, the cement can hardly be used in HPC. The aim of this study is to find the reasons of the rapid slump loss and to seek some feasible measures to improve the slump loss.The XRD patterns show that there are no obvious differences between Jidong clinker and Qixin clinker, and what are the same be shown from the data of chemical compositions and mineral compositions. But the SEM photos indicate that there are some prominent distinction in the aluminate minerals between Jidong clinker and Qixin clinker, which result in the higher hydration reaction rate of Jidong cement than that of Qixin cement in the initial stage, thus more free water is converted into chemically boned water and physically absorbed water, and more free-water is closed in the flocculent structures. All above lead to the free-water that contributes to the fluidity decreases more of Jidong cement than that of Qixin cement. The reduction of the free water that contributes to the fluidity leads the rapid slump loss. The quantity of the water that exists in different state is calculated by the mathematical models, thus the slump loss can be estimated in quantity.Various factors, which have the effect on the fluidity, are examined. The cement composition with lesser fluidity loss is put forward. The experiment results indicate that without changing the clinker compositions, the slump loss can be controlled only by adjusting the amount and the type of gypsum, mixtures, the soluble alkali and the organic additions and the cement fineness etc. In the other hand there are no disadvantages to the other cement physical properties.更多还原