新型混凝土外加剂的制备和应用研究

发布时间：2018-02-09 23:39

本文关键词： 混凝土外加剂聚羧酸减水剂生产成本硬脂酸盐　出处：《北京工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：混凝土外加剂对于工程建设的贡献巨大。在发达国家中,70%-80%的高性能混凝土均使用外加剂,有些甚至已达到100%。减水剂作为外加剂的一种,也发挥着极其重要的作用。近年来,国内外针对减水剂的研究工作取得了很大进展,各国行业专家不断研制出各种减水剂,并将其复配应用,效果显著。聚羧酸高效减水剂因其低掺量、低坍落度损失、高减水率和不受掺加时间影响等优点,已成为当今世界综合性能最优、应用前景最好的一种减水剂。但是,目前阻碍其迅速发展的因素之一是生产成本较高,其价格一直高于传统的萘系等减水剂。如果建筑工程没有国家的强制性规定,施工方依然会选用低成本、低性能的减水剂,这样势必会影响混凝土性能及工程质量。另外,聚羧酸减水剂对水泥、砂、石的敏感度较高,施工性较差。通过研究,使用硬脂酸盐代替部分聚羧酸主体原料,以解决上述问题。首先,利用相似相容原理,依据HLB值选出一种表面活性剂,将其与硬脂酸盐按不同比例混合,用以改善后者同聚羧酸母液的相容性,通过实验,结合聚羧酸的固含量及生产成本,找到最优配比。然后,添加其他原料,分别复配制出20组不同比例的新型减水剂。依照国家标准测定该减水剂的主要化学成分指标,同时对各化学物质产生的原因进行了分析,并对其形成机理进行了探讨。依据相关标准,参照实验配合比要求,将减水剂掺入混凝土拌合物中,对混凝土主要物理力学性能进行了测定,并综合考虑各项因素,得出最优配方。研究结果显示,新复配成功的聚羧酸减水剂不仅可以减少水泥使用量、节省能源,经济效益明显。而且还能够优化混凝土性能,改善施工条件,社会效益突出。
[Abstract]:Concrete admixtures have made a great contribution to engineering construction. In developed countries, 70% to 80% of high performance concrete uses admixtures, some of which have reached 100%. As an admixture, water reducers also play an extremely important role in recent years. Great progress has been made in the research of water reducing agents at home and abroad. Experts from all over the world have developed various kinds of water reducers and used them in combination with remarkable results. The polycarboxylic acid superplasticizer has lost its slump due to its low content of water reducer. The advantages of high water reducing rate and no influence of mixing time have become a kind of water reducing agent with the best comprehensive performance and the best application prospect in the world today. However, one of the factors hindering its rapid development at present is the high production cost. Its price has always been higher than the traditional naphthalene series water reducer. If the construction project does not have the national mandatory regulation, the construction side will still choose the low cost, the low performance water reducing agent, this will inevitably affect the concrete performance and the engineering quality. In addition, Polycarboxylic acid superplasticizer has a high sensitivity to cement, sand and stone, and has poor workability. Through research, stearate is used to replace some of the main materials of polycarboxylic acid in order to solve the above problems. First, the principle of similarity compatibility is used. According to the HLB value, a surfactant was selected and mixed with stearate in different proportions to improve the compatibility of the latter with polycarboxylic acid mother liquor. Through experiments, the optimum proportion was found by combining the solid content and production cost of polycarboxylic acid. By adding other raw materials, 20 groups of new water reducing agents with different proportions were prepared. The main chemical composition indexes of the water reducer were determined according to the national standards, and the reasons for the production of each chemical substance were analyzed. The formation mechanism is discussed. According to the relevant standards and according to the requirements of experimental mix ratio, the water reducing agent is mixed into concrete mixture, the main physical and mechanical properties of concrete are measured, and various factors are considered synthetically. The results show that the new polycarboxylic acid water-reducing agent can not only reduce cement usage, save energy, but also optimize the performance of concrete, improve the construction conditions, and the social benefits are outstanding.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528.042

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