聚羧酸减水剂配制自密实混凝土性能试验研究

发布时间：2018-04-26 10:18

本文选题：自密实混凝土 + 钢管自密实混凝土　；参考：《清华大学》2013年硕士论文

【摘要】：本文通过试验，，对聚羧酸减水剂配制自密实混凝土的性能试验做出了研究。通过一定方法合成两种聚羧酸减水剂，将两种减水剂按照一个最优的比例配合成一种涵盖两种聚羧酸优点的减水剂，进而讨论了该聚羧酸减水剂和胶凝材料的相容性规律，并通过自密实混凝土的强度试验，得出了一组自密实混凝土的最佳配比。合成高减水性聚羧酸的原材料中，对净浆初始流动度、30min流动度、60min流动度以及净浆流动度损失的影响因素是丙烯酸、甲基丙烯磺酸钠以及丙烯酸羟乙酯。对砂浆初始流动度、60min流动度、流动度损失的影响因素是丙烯酸羟乙酯、丙烯酰胺、甲基丙烯磺酸钠、双氧水；通过试验得出合成高保塑性聚羧酸减水剂所需的最佳引发剂掺量、引发试验所需要的聚合温度、保温时间、聚合反应加料方法等。通过试验研究，为降低胶凝材料的用量，减小混凝土内部温升，添加了粉煤灰和超细矿粉等矿物掺合料来增加自密实混凝土的后期强度和自密实性。通过正交试验三水平四因素（水胶比，粉煤灰，超细矿粉，砂率）确定了自密实混凝土最优配合比。通过对自密实混凝土和易性的研究，得出影响自密实混凝土坍落度的最大因素是掺合料和砂率，其次是聚羧酸减水剂，最后是纤维素醚型增稠剂。对自密实混凝土坍落扩展度影响最大的因素是增稠剂，其次是聚羧酸减水剂，第三是砂率，最后是掺合料；对自密实混凝土坍落扩展时间影响最大的因素是聚羧酸减水剂，其次是砂率、增稠剂，最后为掺合料。针对自密实混凝土体积稳定性问题，本文通过试验找出最优的膨胀剂掺量，并在试验中加入了SAP即吸水性树脂，通过调整SAP和膨胀剂的掺量找出一个最优方案使后期达到较好的膨胀效果。由于吸水性树脂SAP能在自密实混凝土中起到蓄水池的作用，养护期间能够源源不断的提供水分，有利于膨胀剂发挥膨胀作用，弥补了混凝土自收缩，获得良好的体积稳定性，为自密实混凝土在钢管中应用时避免脱空并达到协同工作提供了解决方案。
[Abstract]:In this paper, the properties of self-compacting concrete prepared by polycarboxylic acid superplasticizer are studied. Two polycarboxylic acid water reducers were synthesized by a certain method, and the two water reducers were combined in an optimal proportion to form a water reducing agent covering the advantages of two kinds of polycarboxylic acids. The compatibility of the polycarboxylic acid superplasticizer and the cementitious material was discussed. Through the strength test of self-compacting concrete, the optimum proportion of self-compacting concrete is obtained. In the raw materials for the synthesis of high water-reducing polycarboxylic acid, the factors affecting the initial fluidity of the pulp and the loss of the fluidity of the pulp for 30 min and 60 min are acrylic acid, sodium methacrylate sulfonate and hydroxyethyl acrylate. The factors affecting the flow loss of mortar are hydroxyethyl acrylate, acrylamide, sodium methpropylene sulfonate and hydrogen peroxide, and the optimum initiator dosage for the synthesis of high conserving plastic polycarboxylic acid water reducer is obtained. Polymerization temperature, holding time, polymerization reaction feeding method and so on. In order to reduce the amount of cementitious material and reduce the internal temperature rise of concrete, mineral admixtures such as fly ash and ultrafine mineral powder are added to increase the later strength and self-compactness of self-compacting concrete. The optimum mix ratio of self-compacting concrete was determined by orthogonal test with three water and four factors (water-binder ratio, fly ash, ultrafine ore powder, sand ratio). Through the study of self-compacting concrete and its easiness, it is concluded that the biggest factors affecting the slump of self-compacting concrete are admixture and sand rate, followed by polycarboxylic acid water-reducing agent, and finally cellulose ether thickener. The thickening agent is the most important factor affecting the collapse expansion of self-compacting concrete, followed by the polycarboxylic acid water reducer, the third is the sand rate, and the last is the admixture, and the most important factor affecting the collapse expansion time of the self-compacting concrete is the polycarboxylic acid water-reducing agent. Sand ratio, thickener, and admixture are the second. In order to solve the problem of volume stability of self-compacting concrete, the optimal amount of expansive agent was found out through experiments, and SAP was added to the test, that is, absorbent resin. By adjusting the content of SAP and expansion agent, an optimal scheme was found to achieve better expansion effect in the later stage. Because the water-absorbent resin SAP can act as a reservoir in self-compacting concrete, it can supply water continuously during curing, which is beneficial to the expansion of expansive agent, which makes up for the self-shrinkage of concrete and obtains good volume stability. It provides a solution for avoiding void removal and achieving cooperative work when self-compacting concrete is applied in steel pipe.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528

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