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毕业论文网 > 毕业论文 > 材料类 > 无机非金属材料工程 > 正文

超胶凝水泥性能研究毕业论文

 2021-05-06 01:05  

摘 要

节能减排和可持续发展这几年来越来越受到社会的重视,特别是在水泥行业,这样一个高能耗、高资源、高排放的工业。随着我国经济不断发展和城镇化建设的加快,水泥、砂石等建筑材料的消耗日益增加。然而,面对现代混凝土 “低水胶比、高流态”的要求,技术上还存在有重大问题:在现代混凝土体系中,有约30%未水化的水泥,这些未水化的水泥颗粒仅作为微集料填充在孔隙之中,浪费了大量资源。更糟糕的是,若未水化的水泥颗粒数量很多,更会造成混凝土体系中的界面过渡区产生Ca(OH)2富集,对混凝土的强度和耐久性都会造成不利影响。

针对上述问题,提出了超胶凝水泥的概念,通过添加微研磨介质和表面改性剂,对水泥颗粒进行整形,调整优化级配,来提高水泥的胶凝效率。采用微研磨介质整形、粒度分析、强度测试、SEM形貌观测等实验和分析手段,本文主要对超胶凝水泥的制备方法、宏观力学性能、水化进程及水化产物等方面进行了研究。

结果表明:当微研磨介质含量相同时随着整形时间的增加,颗粒粒径明显减小;在微研磨介质含量相同的组中,随着研磨时间的增加,水泥净浆的3d、7d、28d抗压强度是逐渐降低的,但是普遍还是高于空白组;砂浆(30%微研磨介质)的3d强度、7d强度和28d强度先降低后升高,表明在水泥颗粒过细情况下,对净浆强度有削弱的趋势,水泥粒径在一个合适的颗粒区内对砂浆的强度贡献值达到最大。水泥细度细,与水接触面积大,水化快,同时水泥晶格扭曲、缺陷多,也有利于水化。细度过细,往往使早期水化进程加快、强度提高,但对后期强度没有多大益处。

关键字:超胶凝水泥 微研磨介质 水泥水化

Abstract

Energy saving and emission reduction and sustainable development in recent years more and more attention from the society. Especially in the cement industry, such a high energy consumption, high resources, high emissions of industrial. With the continuous development of China's economy and the acceleration of urbanization, building materials, such as cement, sand and gravel consumption is increasing. However, in the face of modern concrete "low water binder ratio, high flow" of the requirements, there are still major problems in technology: In the modern concrete system, there are about 30% of the non hydrated cement, these non hydrated cement particles are only filled with micro aggregates in the pores and waste a lot of resources. Worse, if there is a lot of water without hydration of cement particles, it will cause the interface transition zone in the concrete system to produce Ca (OH) 2 enrichment, the strength and durability of concrete will be adversely affected.

In view of the above problems, the concept of super gel cement was put forward. This is a kind of particle shaping and finishing, gradation adjustment and optimization, surface modification and charge balance technology based on, through the cement particle processing, to improve the cement coagulation efficiency, reduce the high resources, energy consumption and high carbon emissions of cement clinker. In this paper, the preparation and the performance of many aspects are studied.

The results showed that the particle size was decreased with the increase of the plastic time when the micro.grinding media was the same. Under the same micro.grinding media, with the shaping time increased, the 3D strength, 7d strength and 28d strength of the cement paste have gradually decreased, but higher than the blank sample. Mortar (30% micro grinding media) 3D strength, 7d strength and 28d strength first decreased and then increased. In the case that the cement particles are too small, weaken the trend of strength of paste, the cement particle size is the largest contribution to the strength of the mortar in a suitable particle area. The fineness of cement is small, and the water contact area is large, and the hydration is fast. At the same time, there are many defects in the crystal lattice, and it is also beneficial to the hydration of the cement. The fineness of meticulous, often make the early hydration process accelerate and improve the strength, but not much benefit to the later strength.

Keywords: super.gel, micro.grinding media, hydration

目 录

摘要 I

Abstract II

1 绪论 1

1.1超胶凝水泥的研究背景 1

1.1.1混凝土发展历程 1

1.1.2混凝土中存在的问题 1

1.1.3混凝土中水泥的水化情况 2

1.1.4 水泥的发展历程 3

1.1.5 水泥胶凝性改善途径 3

1.2超胶凝水泥的概念、技术和意义 4

1.2.1 超胶凝水泥的概念 4

1.2.2 超胶凝水泥的技术 5

1.2.2.1 表面改性技术 5

1.2.2.2 低碳制备技术 6

1.2.3 超胶凝水泥的研究意义 6

2超胶凝水泥的制备和粒径测试 8

2.1超胶凝水泥的制备 8

2.2超胶凝水泥的粒径分析 8

2.2.1 水泥粒度负压筛分仪 8

2.2.2 马尔文激光粒度仪 9

3超胶凝水泥制备的净浆强度 15

3.1超胶凝水泥制备净浆 15

3.2抗压强度测试分析 16

4超胶凝水泥水化产物SEM 19

4.1 3d水化产物SEM 20

4.2 7d水化产物SEM 22

5 结论 23

6 展望 24

参考文献 25

致谢 26

第一章 绪论

1.1超胶凝水泥的研究背景

1.1.1混凝土发展历程

混凝土发展至今已有100多年,其强度一直在提升。本世纪60年代,美国、英国等国家所使用的混凝土大部分都是41MPa,1972年至62MP a,1982年至75MP a,1987年达到117M P a,1991年达到133M Pa。现在 140MPa的混凝土应用已经出现了。[1]

首先要说的提到的是无宏观缺陷水泥材料(MDF),牛津大学、日本及美国先后对其进行了研究。该水泥是通过在普通水泥中加入水溶性树脂,在放入搅拌机中搅拌,最后热压成型。这些手段可以降低颗粒之间的应力作用,以消除宏观缺陷。最后得到的产品强度可达280MPa,弹性模量达50GPa。但是,由于这种材料有不少的确定,如基本无流动性,成型困难,收缩性能差等,所以至今仍未得以实用化。

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