HPMC Water Retention

HPMC Water retention

Effect of Hydroxypropyl Methyl Cellulose on Performance of Plastering Mortar for Aerated Concrete

Aerated concrete blocks have their own characteristics: high porosity, high water absorption, and ordinary mortar on the aerated concrete plastering.As the ordinary mortar water retention capacity is poor, which affected the normal condensation of hardening mortar. So that aerated concrete plaster layer prone to hollowing, cracking or even fall off and so on. Therefore, in order to solve these problems, some research has been made on the plaster mortar for aerated concrete: from the point of view of the water retaining agent, the effect of the water retaining agent on the performance of the aerated concrete plaster mortar and the mechanism of action are still very little, especially The effect of cellulose ether-based water retaining agent on the performance of plastering mortar for aerated concrete is also lacking. Therefore, the effect of hydroxypropylmethylcellulose and carboxymethylcellulose ether (CMC) on the performance of plastering mortar for aerated concrete was studied in this paper. The mechanism of action was also discussed.

The ability of fresh mortar to maintain moisture is called water retention. Water retention also refers to the nature of the composition of the mortar is not easy to separate. Mortar water retention in the (autoclaved aerated concrete masonry mortar and mortar) industry standard [4] with the level of said. The goodness of the mortar is relatively small. Autoclaved aerated concrete masonry mortar and mortar mortar with the thickness of ≤ 20mm is appropriate.

(1) CMC and HPMC can be added into the mortar, which can play the dual role of water retention and thickening. With the increase of the content, the stratification of mortar decreases, CMC is ion ether ether, (OH) 2 reaction, CMC to improve the retention of mortar is not obvious, and the amount of more; and HPMC is a non-ionic cellulose ether, stable performance, when the mortar is very small, only one-tenth of the CMC content You can greatly reduce the degree of mortar, play a very good water retention.

(2) CMC and HPMC mixed with mortar, will introduce bubbles, especially when HPMC content is very small will introduce a large number of tiny bubbles, these bubbles in the mortar, such as ball bearing-like role, so that the new mortar and easy The air is improved, but a large number of bubbles reduce the wet weight of the mortar, and the slurry hardened in the slurry after the formation of pores, making the mortar internal structure loose, and thus the mortar strength is also significantly reduced.

(3) The addition of HPMC in the mortar, the decrease of the flexural strength of the mortar is small, and the compressive strength decreases greatly, and the flexure ratio curve increases, indicating that the addition of the HPMC can improve the toughness of the mortar. Mortar mechanized construction in the country has been trying to promote for many years, but has not made substantial progress. In addition to skepticism about the subversive changes that will be brought to the traditional construction of mechanized construction, it is mainly due to the fact that in the traditional mode, the mortar of the site is likely to cause a blockage in the mechanized construction due to the problem of particle size and performance Failure, not only affect the progress of the construction, but increased the construction intensity, and thus breed the fear of the workers, for the promotion of mechanized construction increased the difficulty.