plastering project construction quality has always been an important focus for project delivery and owners' house inspection, especially the hollow cracking problem of the plastering layer ranks first in the owner's quality complaints. How to control the hollow cracking risk of the plastering layer is an important task for our engineers. Zhongtian Jiujian Quality Month Micro Classroom "Causes of Plastering Hollow and Prevention and Control Measures" Analyze and summarize the control of hollow cracking problems in the plastering layer. Please follow the editor to find out.
. Causes of hollowing
. Insufficient raw material control
. Insufficient stone powder in the machine sand in the mortar, it is too sticky and inconvenient to operate, and it is easy to cause cracks and hollowing of the wall after the plastering is completed; on-site workers have added mortar king , mortar essence and even washing powder to facilitate operation, causing insufficient strength to cause hollowing.
. The base layer treatment is not in place, and it is not watered and wet
The base layer treatment has no special supervision and acceptance, and the nodes in key areas are not in place, and the next process is entered with "illness". There is too much floating slurry on the concrete surface and no interface erosion is washed; the wall is not watered 1 day in advance before plastering, and the base wall is not watered in advance (2 days, once in the morning and evening) before plastering.
blocking and not compacting
top plug is not in place
, no network processing
junction of different structures and pipe groove repairs are not hung.
junction of different materials is not
The wire tube groove is not
. The pulping is not standardized, and the maintenance is not in place.
pulping is uneven and missed. The pulping area does not meet the requirements and the effect does not meet the standards; the pulping strength is not met in time after the pulping, resulting in the pulping strength not meeting the standards.
. The fiberglass fiber web is not set as required
plastered wall fiberglass fiber web laying rate is less than 100%, and is not set on the upper part of the plastering surface layer, which does not have the effect of anti-cracking and hollowing.
, maintenance
The maintenance cycle is insufficient, the number of maintenance times per day is too small, and the water loss is too fast, causing hollowing and cracking.
. Pre-control measures for hollowing and cracking
. Raw material control
strictly controls the quality of mortar entering the site, inspects and inspects the site on vehicles, and firmly demands the exit of the site for problematic mortar; the stone powder in the machine sand in the mortar should be controlled at about 10%, which is conducive to ease and stickiness and facilitates workers' operation. During the construction process, a dedicated person controlled the mortar. Once it was discovered that the workers had added mortar king, mortar essence or washing powder and other admixtures privately.
, process control
Base processing
Screw eye, channel steel holes, and wall-connecting holes are sealed according to requirements; structural defects are repaired and dealt with in a timely manner.
screw hole seal
Base layer processing
On-site blocking
blocking
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Blocking diagram
net hanging measures
After the junction and grooves of different materials, the gap between the flue and the wall is filled with full and compact, and the wire mesh is hung fully. The width of the glass fiber mesh/wire mesh and the substrate is ≥150mm on each side, flat and without warping, and the overlap width between the mesh is ≥100mm.
Network at the junction of different materials2
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The wire tube slot is hung in the net
The wire tube slot is hung in the net
Pitch requirements
▶ Homemade wire mesh patter: Cut the 15mm×15mm×1mm wire mesh into about 200mm×2400mm, then fold it into 200mm×300mm, and finally use DN25 galvanized pipe as the handle to fix the folded wire mesh to the end of the galvanized pipe. After the wire mesh is finished, the pulping effect test is carried out on the wall, and after meeting the requirements, the pulping operation is entered.
▶ Before pulping, water the wall one day in advance to moisten. The wetting standard is to seep into the masonry 8~10mm.
▶ Use construction glue, cement and appropriate amount of fine sand to prepare slurry in a certain proportion for slurry. Control the consistency of the slurry, the slurry spots have no drops, the slurry distribution points are uniform, the burrs are 3-5mm, and the coverage area reaches more than 95% of the entire wall.
▶ Maintenance in time after final setting, and the strength should be smooth and it is best to keep it off. Put it on your hands and feel stinging. This can improve the adhesion of the base and effectively reduce hollowing.
surface layer anti-cracking
plastered surface layer adds anti-cracking fiberglass web, set on the upper part of the surface layer, lift the slurry and retract the surface, and do not rub it hard (otherwise, the layer is hollow); when the surface layer is constructed from bottom to top, do not rush the upper part, wait for all the gas behind the surface layer to be discharged (otherwise, the bubbles will be hollowed out).
Timely maintenance
After the plastering is completed, personnel are arranged to water and maintain it in a timely manner depending on the weather conditions. The wall watering should be left without blind spots, so that the plastering surface can fully absorb water. It is generally carried out after 12 hours at room temperature, no less than 3 times a day (appropriately increase the frequency in summer), and the maintenance cycle should be no less than 7 days.
water gun maintenance
spray maintenance
plastering hollow cracking not only affects the quality of use and visual appearance, but also takes labor and time-consuming, and requires a lot of manpower and material resources. Strengthening preliminary planning and process control is the key to solving the problem.
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