Painting gypsum mortar on the surface of the building not only obtains a smooth surface, but also protects the wall. The common problems that occur when plastering gypsum mortar are cracking, hollowing, and falling off. In addition to the low water retention of gypsum mortar, the main reason is also related to the low bonding strength of gypsum mortar. Therefore, the "Quality Acceptance Code for Building Decoration and Renovation Projects" GB50210-2001 stipulates that "the plastering sand layers of the exterior wall and ceiling and between the plastering layers must be firmly bonded", "the plastering layer and the base layer must be firmly bonded" Each plaster layer must be firmly bonded, the plaster layer should be free of delamination and hollowing, and the surface layer should be free of explosive ash and cracks." It can be seen that bonding strength is an important performance indicator of plastering gypsum mortar. Only when the gypsum mortar has a certain bonding stress can the gypsum mortar layer be firmly bonded to the base and will not crack or fall off after long-term use.
Several major problems and prevention measures of gypsum mortar
1. The selection of raw materials for gypsum mortar is very important , Longzhen's graphene plaster gypsum mortar After the gypsum and water react to form dihydrate gypsum, the molecular weight increases and the volume expands. The expanded volume offsets the shrinkage caused by the loss of excess water. The combined volume change is much lower than that of cement gypsum mortar. The various indicators of graphene paint products are far superior to other products.
2. If the base layer is not cleaned properly or the wall surface is too smooth, the hollow surface needs to be treated carefully. The surface should be cleaned and watered to moisten it; If it is too smooth, it should be chiseled or interface agent should be added; the gypsum mortar should maintain good workability and bonding strength; lime plaster or plasticizer should be added appropriately; the overall and local height difference of the cast-in-place board should be within the allowable deviation range; the door The gap between the window and the brick wall should be sealed with gypsum mortar; the surface layer should be left for no less than seven days.
3. If the base ash is too heavy and there are cracks and scratches caused by not being moistened with water, the top ash should be sprinkled with water before being moistened and then compacted. , calendering; pouring concrete into the porous plate should be operated according to regulations and maintained well so that it can play an integral role and avoid cracks.
4. The plastered surface is uneven and the yin and yang angles are not vertical and square (the specific phenomenon is that the surface is uneven and the yin and yang angles are not straight or right angles). This is because the gray cake and ribs were not carefully made when plastering; there were no ribs on both sides of the yin and yang angles, which affected the verticality of the yin and yang angles. The room should be squared, hung, vertical and plastered according to the rules; ribs should be plastered on both sides of the yin and yang corners, and the squareness of the corners should be checked with a square ruler.
5. Blistering and blooming in winter. (The specific phenomenon is blisters, pitting, and blooming of varying sizes on the surface.) This is because the overlay ash was calendered too tightly, and the mortar did not absorb water, causing blistering after calendering. The lime plaster has not been matured for enough time, and there are unripened particles in the ash. After plastering, it continues to mature and expand in volume, causing the surface of the plaster to explode and bloom. The prevention and control measures are that the paper ash covering must be done after 50% to 60% of the base ash is dry, and then calendered after the water is collected; the lime plaster curing time should be more than 15 days, and it is strictly forbidden to use lime plaster containing unripened particles. When quicklime powder is used, it should be cured 3 days before construction. If flowering occurs, it is advisable to remove the loose surface of the flowering part 1-2 days in advance to allow the lime plaster to mature, then use putty to patch it up again, and finally spray grout. </p
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