1. Hollowing

The main reasons are:

① The base layer is not clean. Such as dust and loose objects, release agents and oil stains attached to the surface of the base layer. If these debris are not thoroughly removed, it will affect the bonding between the plaster layer and the base layer.

② There are recesses or the plastering is too thick at one time. Before the mortar dries, the mortar layer has been separated from the base layer due to gravity.

③ Improper interface treatment or no interface treatment. The base surface is too smooth. The shrinkage of the mortar cannot be suppressed, resulting in the detachment of the mortar layer from the base layer.

The base layer should be cleaned before plastering. And start watering the wall 2-3 days in advance. Construction can only be carried out after the water seepage depth reaches 10 mm. If there are deep recesses, the mortar should be filled in advance. In addition, the interface mortar should be sprayed in advance.

2. Delamination

It is mainly due to the overdrying of the bottom ash layer. Prevention and control methods In addition to construction according to the requirements of the specifications, if the base layer is found to be dry, it should be moistened with water and the surface layer should be applied after the base layer is thoroughly moistened.

3. Explosion of ash

The main reason is that the material quality is poor, with impurities or soil. The quality of the materials should be carefully checked before construction, and the sand should be screened through a fine sieve before use.

4. Cracks

The main reason is that the plaster layer is too thick and no anti-cracking measures are taken. Or cracks are caused by hollowing. If the plaster surface is very thick, the bottom layer should be filled first during construction. Or spray anti-cracking agent after the base ash is applied.

If the cement plaster mortar has the above situation, it should be reworked and repaired. During the repair, the delamination, hollowing, explosion of ash and cracks should be cleaned up, and then local plastering should be performed according to the requirements of the specifications.

HPMC for plaster mortar