普通预拌砂浆性能的研究

发布时间：2018-03-28 22:18

本文选题：纤维素醚（HPMC）　切入点：可分散乳胶粉　出处：《济南大学》2013年硕士论文

【摘要】：随着建筑技术发展，人们对施工效率、环境保护及建筑质量提出了更高要求，工业化生产的预拌砂浆得到快速发展。为改善砂浆工作性，纤维素醚、可分散乳胶粉、纤维、减水剂等作为添加剂，在预拌砂浆中起到必不可少的作用。砂级配是影响砂浆质量的关键因素，如何利用添加剂弥补砂级配不合理对砂浆性能的影响也是需要面对的课题。本实验分别研究了纤维素醚（HPMC）、可分散乳胶粉、纤维、减水剂及砂颗粒组成对砂浆性能的影响规律，主要研究结果如下：（1）添加HPMC可提高砂浆保水率，降低稠度损失率，延长凝结时间。添加0.3%HPMC，可提高砂浆保水率达到94%，稠度损失率低于10%；砂浆折压比随龄期增长先降低后增加，在28d时折压比最小，添加HPMC砂浆后期折压比增长更为显著，添加0.2%HPMC，砂浆28d折压比均高于0.35；砂浆凝结时间随HPMC粘度增加而增大，，添加0.5%H1凝结时间延长至900min；添加H4砂浆56d、108d基本无收缩，但是纤维素醚掺量、粘度过大会增加砂浆收缩率。HPMC的加入会大幅降低砂浆强度和流动度。（2）添加胶粉，砂浆强度会出现一定程度降低，韧性得到明显改善，添加P1、P2、P3、P4、P5分别在1.0%、1.5%、2.0%、1.0%、2.0%时，对砂浆韧性改善效果最显著，折压比分别达到0.26、0.28、0.29、0.29、0.30；粘结强度随胶粉掺量增加而增加，掺加0.2%P1和P5分别达到0.036MPa、0.035MPa。（3）随纤维掺量增加，开裂面积和强度降低，砂浆需水量增加，砂浆韧性得到改善，其中以长径比最大的9mm聚丙烯纤维和木纤维改善效果最好，掺量在0.3%时，28d折压比分别达到0.33、0.30，9mm聚丙烯纤维和木纤维分别在0.3%和0.05%时砂浆收缩率最低。（4）聚羧酸减水剂在单一粒径砂配制砂浆中起不到减水作用，相反会增加砂浆离析泌水。＜0.3mm粒径砂添加减水剂、HPMC对砂浆强度没有明显的改善效果，0.3mm-0.6mm、0.6mm-1.18mm与1.18mm-2.36mm粒径砂同时添加减水剂与HPMC，相对单掺其中一种，强度和韧性改善更为显著，28d抗压强度分别达到5.1MPa、8.1MPa、7.7MPa，抗折强度分别为2.2MPa、2.8MPa、2.5MPa；无论添加减水剂、HPMC与否，由0.6mm-1.18mm粒径砂配制的砂浆强度最大。（5）成功复配砂浆添加剂，使其对不同细度模数砂配制的砂浆保水率及韧性改善都优于市售砂浆添加剂。
[Abstract]:With the development of building technology, higher requirements for construction efficiency, environmental protection and building quality have been put forward, and ready-mixed mortar produced in industrial production has developed rapidly. In order to improve the workability of mortar, cellulose ether can disperse latex powder and fiber, As additives, water-reducing agents play an essential role in ready-mixed mortar. Sand gradation is a key factor affecting mortar quality, and how to make up for the influence of additive on mortar performance is also a problem to be faced with. In this experiment, the effects of cellulose ether, dispersible latex powder, fiber, water reducer and sand particle composition on the properties of mortar were studied. The main results are as follows:. (1) adding HPMC can increase the water retention rate of mortar, reduce the loss rate of consistency and prolong the setting time. Adding 0.3HPMCcan increase the water retention rate of mortar up to 94and the loss rate of consistency is lower than 100.The ratio of break to pressure of mortar decreases first and then increases with the increase of age, and the ratio of broken pressure to pressure is the smallest at 28 days. In addition of 0.2HPMC, the ratio of break to pressure was higher than 0.35 in 28 days. The setting time of mortar increased with the increase of HPMC viscosity, and the setting time of adding 0.5%H1 was prolonged to 900min, and H4 mortar had no shrinkage at 56d ~ 108d. However, the addition of cellulose ether and viscosity increased the shrinkage of mortar. HPMC significantly reduced the strength and fluidity of mortar. (2) the strength of mortar decreases to a certain extent and the toughness of mortar is improved obviously by adding rubber powder. When adding P1P2P2P3P3P4P5, the mortar toughness is improved most obviously at 1.0%, 1.5% and 2.0%, respectively, with a ratio of 0.260.280.290.290.0.30, and the bond strength increases with the increase of the content of rubber powder, and the strength of the mortar increases with the increase of the content of rubber powder. The strength of the mortar increases with the increase of the content of rubber powder, and the ratio of bending to pressure is 0.260.280.280.290.290.30, respectively. The addition of 0.2%P1 and P5 reached 0.036 MPA and 0.035 MPA, respectively. 3) with the increase of fiber content, the cracking area and strength decrease, the water requirement of mortar increases, and the toughness of mortar is improved. Among them, 9mm polypropylene fiber and wood fiber with the largest aspect ratio have the best effect. The shrinkage of mortar was the lowest when the ratio of 0.33 ~ 0.30 ~ 9 mm polypropylene fiber and wood fiber reached 0.33 ~ 0.30 ~ 9mm and 0.05% respectively at 0.3d / 28d when the content was 0.3% and 0.05% respectively. (4) polycarboxylic acid water reducer can not reduce water in single size sand. On the contrary, the segregation and bleeding of mortar will be increased. < 0.3mm particle size sand adding water reducer has no obvious improvement effect on mortar strength. The addition of water reducer and 1.18mm-2.36mm particle size sand together with 0.3mm-0.6mm-1. 18mm is relatively only mixed with one of them. The compressive strength and flexural strength of the mortar were 5.1MPa / 8.1MPa / 7.7MPa and 2.2MPa / 2.8MPa / 2.5MPa, respectively, and the strength of mortar prepared with 0.6mm-1.18mm particle size sand was the highest, regardless of adding water reducer or not. 5) the water retention and toughness improvement of mortar prepared with different fineness modulus sand is better than that of commercial mortar additive.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU578.1

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