聚羧酸系减水剂复配技术及工程应用

发布时间：2018-02-01 17:44

本文关键词： 聚羧酸减水剂复配技术工程应用混凝土工作性适应性　出处：《石家庄铁道大学》2015年硕士论文　论文类型：学位论文

【摘要】：聚羧酸系减水剂(Polycarboxylate Superplasticizer)是继木质素磺酸盐减水剂和萘系减水剂之后发展而来的第三代高性能减水剂,近几年来,开始广泛用用于混凝土工程之中。聚羧酸减水剂的发展历程尚短,二十一世纪以后伴随着高性能混凝土的出现和发展,人们对混凝土外加剂提出了更高的要求,聚羧酸减水剂步入快速发展时期,人们开始关注和研究聚羧酸的复配技术对混凝土各种性能的影响,就目前来看,聚羧酸减水剂仍然处于不断的完善发展之中。聚羧酸减水剂优点十分突出,比如减水率高、保坍性能优异、引气可控、无过缓凝、经济性高等优点,但是在聚羧酸减水剂工程应用之中也出现了很多问题,比如聚羧酸减水剂与水泥适应性差、对砂石骨料的含泥量敏感、新拌混凝土工作性不稳定等问题,这对聚羧酸减水剂的大规模工程应用提出了挑战。本文主要通过改进聚羧酸减水剂的复配技术来克服聚羧酸减水剂的缺点,扬长避短,以期其在混凝土的工程应用之中发挥更重要的作用。其中聚羧酸减水剂复配技术的改进主要是三大成分的确定:(1)聚羧酸减水剂母液适应性实验以控制变量法为基础,通过观察新拌混凝土(新建宝兰客运专线BLTJ-7标段C45泵送混凝土)工作性,即初始坍落度和坍落度经时损失,确定了山东建科的8#母液250 g和7#母液230 g(每100g PCA中)。(2)缓凝组分的确定以对比性实验为基础,以混凝土贯入阻力仪测定初终凝时间,确定了葡萄糖酸钠及其掺量。(3)引气方式的选择为“先消后引”法,消泡剂和引气剂均为德国赢创德固赛牌(Evonik Degussa),消泡剂和引气剂掺量分别为0.1 g、0.15 g(每100 g PCA中),最终实测混凝土引气量为3.6%。本文也对聚羧酸减水剂在实际工程新建宝兰客运专线中的应用所出现的问题做了有针对性的尝试,对于夏季聚羧酸减水剂易霉变发黑发臭的问题,通过在聚羧酸减水剂中复配入广东华立新牌防腐剂来防止霉变发臭。对于由于砂石骨料质量较差(含泥量较高)导致的新拌混凝土粘聚性差的问题,通过适当提高减水率,复配入增稠剂羟丙基甲基纤维素醚来获得新拌混凝土良好的工作性,改进聚羧酸减水剂的复配技术,进一步提高其在工程领域的适应性。
[Abstract]:Polycarboxylate Superplasticizer. It is the third generation of high performance water reducing agent after the development of lignosulfonate water reducing agent and naphthalene water reducing agent. In recent years, it has been widely used in concrete engineering. The development process of polycarboxylic acid water-reducing agent is still short. After 21th century, the appearance and development of high-performance concrete. People put forward higher requirements for concrete admixtures, polycarboxylic acid water reducer into the rapid development period, people began to pay attention to and study the impact of polycarboxylic acid blending technology on various properties of concrete, from the current point of view. Polycarboxylic acid water reducer is still in the process of continuous development. The advantages of polycarboxylic acid water reducer are very outstanding, such as high water reduction rate, excellent collapse retention performance, air entrainment controllable, no slow coagulation, high economy and so on. However, there are many problems in the application of polycarboxylic acid water reducer, such as poor adaptability between polycarboxylic acid water reducer and cement, sensitive to the content of sand aggregate, unstable workability of fresh concrete, and so on. This is a challenge to the large-scale engineering application of polycarboxylic acid water reducer. In this paper, the shortcomings of polycarboxylic acid water reducer are overcome by improving the compound technology of polycarboxylic acid water reducer. In order to play a more important role in the engineering application of concrete, the improvement of compound technology of polycarboxylic acid water reducer is mainly the determination of three major components: 1). The adaptability experiment of polycarboxylic acid superplasticizer mother liquor is based on the method of controlling variables. The workability of fresh concrete (C45 pumping concrete in BLTJ-7 section of new Baolan passenger dedicated line) was observed, that is, initial slump and slump loss. The retarding components of the 250g and 230g (#number0# g / 100g / 100g PCA) mother liquor in Jianke, Shandong Province, were determined on the basis of comparative experiments. Based on the determination of the initial and final setting time by using the concrete penetration resistance meter, the selection of the gas entraining method of sodium gluconate and its admixture. The defoamer and the air entraining agent were both Evonik Degussaa, and the dosage of defoamer and entrapment were 0.1 g, respectively. 0. 15 g (per 100g PCA). The final measurement of concrete air entrainment is 3.6. This paper also made a targeted attempt on the application of polycarboxylic acid water reducer in the actual project of the new Baolan passenger dedicated line. For the summer polycarboxylic acid superplasticizer is prone to mildew and stink problem. In order to prevent mildew and stink, the polycarboxylic acid superplasticizer is added to the polycarboxylic acid superplasticizer to prevent mildew and stink. The problem of poor cohesion of fresh concrete caused by poor quality of aggregate (with high content of mud) is discussed. The good workability of fresh concrete can be obtained by properly increasing the water reducing rate and adding the thickener hydroxypropyl methyl cellulose ether to improve the blending technology of polycarboxylic acid water reducer and further improve its adaptability in engineering field.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528.042.2

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