Under what circumstances is it easy to cause cracking of the surface layer?
1. When the surface density of the alkali-resistant glass fiber mesh cloth is insufficient or the warp and weft lines are not straight, it will form insufficient restraint during the expansion and contraction of the surface layer, and even produce "broken lines", which cannot play the role of restraining the "tendon", and it is easy to cause cracking of the surface layer;
2. The alkali-resistant glass fiber mesh cloth is not butted, dry-lapped, and overlapped too little, and the alkali-resistant glass fiber mesh is not close to the insulation board, which will cause the alkali-resistant glass fiber mesh cloth to be unable to be effectively composite-bonded with the anti-cracking mortar, and cannot form an anti-cracking protective layer with good deformation resistance, which affects the deformation stress transmission and anti-cracking and impact resistance, and is easy to produce straight and long cracks;
How to use mesh cloth correctly to prevent cracking?
1. Use qualified alkali-resistant glass fiber mesh cloth, and it is strictly forbidden to butt and dry-lap the alkali-resistant glass fiber mesh cloth, and the overlap should be no less than 50㎜. The first floor wall, door and window openings and external corners should be reinforced with double-layer alkali-resistant fiberglass mesh cloth, and the four corners of the opening should be covered with alkali-resistant fiberglass mesh cloth at 45°. A 2m high metal corner guard is set at the external corner of the first floor wall.
2. Use qualified polymer plastering mortar. Strict on-site construction process. The plastering mortar should be cured twice. First, apply the bottom mortar 2-3mm, press the mesh cloth into the mortar, and compact it flat. Wrinkles on the mesh cloth are strictly prohibited. Before the bottom plastering mortar solidifies, apply another layer of plastering mortar with a thickness of 1-2mm, which is only enough to cover the mesh cloth and slightly see the outline of the mesh cloth. Avoid rubbing the surface mortar continuously to avoid hollowing. When the polymer plastering mortar has not fully reached the final normal strength, prevent it from being soaked in water, frozen, or losing water too quickly to cause cracks.
