复配聚羧酸系减水剂对混凝土性能的影响

发布时间：2018-03-04 03:16

  本文选题：聚羧酸系减水剂　切入点：消泡剂　出处：《南昌航空大学》2014年硕士论文　论文类型：学位论文

【摘要】：聚羧酸系减水剂具有掺量低、减水率高、保坍性能强等优点，在商品混凝土生产中得到广泛应用。然而将聚羧酸系减水剂单独与混凝土拌合时，经常会出现与水泥适应性不好的现象，导致混凝土拌合物和易性差、坍落度损失大等问题，难以满足施工要求。因此，聚羧酸系减水剂一般需要与其他外加剂复配使用。 本文通过试验，对聚羧酸系减水剂和其他外加剂的复配对混凝土性能的影响进行了较为系统的研究，并得出相应结论。主要有： （1）聚羧酸系减水剂和不同的缓凝剂复配对混凝土拌合物凝结时间、坍落度及损失、混凝土抗压强度的影响。随着柠檬酸钠掺量的增大，混凝土拌合物的凝结时间延长、混凝土抗压强度降低，葡萄糖酸钠掺量的增大也可以延长混凝土拌合物的凝结时间，但对混凝土28d强度影响不大。二者对混凝土均有辅助塑化作用和保坍作用。 （2）聚羧酸系减水剂和不同的引气剂复配以及改变引气方式对混凝土含气量及损失、抗压强度和抗氯离子渗透性能的影响。随着德固赛或三萜皂甙掺量的增加，混凝土的抗压强度降低，含气量增大，但气泡易聚合后逸出。与德固赛相比，三萜皂甙引气效果更显著。改变引气方式后，混凝土含气量经时损失减小，气泡较稳定；德固赛掺量为0.01‰~0.04‰、三萜皂甙为0.06‰~0.10‰时，混凝土的抗氯离子渗透性能有所提高。 （3）聚羧酸系减水剂和外加剂优化配比。通过四种复配组合的对比分析，可以得出德固赛、葡萄糖酸钠、竹本油脂和聚羧酸系减水剂复配后与水泥适应性较好，混凝土各方面性能最优，且德固赛的最佳掺量为0.03‰，，葡萄糖酸钠的最佳掺量为0.06%。 本文研究成果可以为混凝土外加剂配比设计提供参考。
[Abstract]:Polycarboxylic acid superplasticizer has been widely used in the production of commercial concrete because of its advantages of low content, high water reducing rate and strong collapsibility. However, when the polycarboxylate water reducer is mixed with concrete alone, The poor adaptability to cement often leads to poor mixing and ease of concrete, large slump loss and so on, so it is difficult to meet the construction requirements. Therefore, polycarboxylic acid series water reducers usually need to be combined with other admixtures. In this paper, the effects of polycarboxylic acid superplasticizer and other admixtures on concrete properties are studied systematically, and the corresponding conclusions are drawn. 1) the effects of polycarboxylic acid series water reducer and different retarder on the setting time, slump and loss of concrete mixture, and the compressive strength of concrete. With the increase of sodium citrate content, the setting time of concrete mixture is prolonged. The compressive strength of concrete decreases, and the increase of sodium gluconate content can also prolong the setting time of concrete mixture, but it has little effect on the strength of concrete for 28 days. Both of them have auxiliary plasticizing and collapsing effect on concrete. 2) the effects of polycarboxylic acid superplasticizer and different air entraining agent on the air content and loss, compressive strength and chloride ion permeability of concrete by changing the way of air entraining, with the increase of Degusai or triterpenoid saponins, The compressive strength of concrete decreases, the gas content increases, but the bubble is easily polymerized and escapes. Compared with Degusai, triterpenoid saponins are more effective in entraining air. After changing the way of entraining, the loss of air content in concrete decreases and the bubble is more stable. When the dosage of Degusai was 0.01 鈥

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