Which factors will cause the aging of exterior wal

2022-07-30
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What factors will cause the aging of exterior wall thermal insulation materials

nowadays, high-rise buildings will be installed with exterior wall thermal insulation panels in construction, which can not only play a role in thermal insulation, but also protect the external wall, and can prolong the service life of brick concrete materials for the exterior wall. However, with the extension of service time, the exterior wall insulation materials will also age. What are the reasons for its aging? Here we briefly introduce a preset tension value, which can be roughly divided into five aspects

1. Thermal stress. The thermal expansion and cold contraction caused by the change of temperature difference will cause the volume change of non structural structure, so that it is always in an unstable state. Therefore, thermal stress is one of the main destructive forces of the external insulation layer of high-rise buildings. Compared with multi-storey or bungalow buildings, because the outer layer of high-rise buildings receives more sunlight, the thermal stress is greater, and the deformation is also greater. Therefore, in the design of thermal insulation and crack resistance structure, the selection of thermal insulation materials should meet the principle of flexible gradual change, and the deformation capacity of outer layer materials should be higher than that of inner layer materials

2. Wind pressure. Generally speaking, the positive wind pressure generates thrust and the negative wind pressure generates suction, which will cause great damage to the external insulation layer of high-rise buildings. This requires that the external insulation layer should have considerable wind pressure resistance. In terms of wind pressure resistance, the insulation layer should have no cavity and eliminate the air layer, so as to avoid the damage to the insulation layer caused by the volume expansion of the air layer in the insulation layer under the wind pressure, especially the negative wind pressure

3. Seismic force. Seismic force will lead to extrusion, shear or distortion of high-rise building structure and thermal insulation surface. Thermal insulation surface can also conduct impact test on metal materials. The greater the rigidity, the greater the seismic force, and the more serious the damage may be caused. This requires that the external thermal insulation materials of high-rise buildings must meet the principle of flexible gradual change on the premise of considerable adhesion, so as to disperse and absorb the seismic stress, reduce the load on the surface of the thermal insulation layer as far as possible, and prevent the thermal insulation layer from cracking, peeling off or even falling off in a large area under the influence of the seismic force

4, water or steam. In order to avoid the damage of water or steam to high-rise buildings, external insulation materials with good hydrophobicity and water vapor permeability should be selected to avoid the phenomenon of wall condensation or the increase of internal moisture content of insulation layer during the migration of water or steam, and improve the improved magnetic separation effect, rain water erosion resistance and freeze-thaw resistance of external insulation layer of high-rise buildings

5. Fire. The fire rating of high-rise buildings is higher than that of multi-storey buildings. The insulation layer of high-rise buildings should have better fire resistance function, and should have the characteristics of preventing the spread of fire and the release of smoke or toxic gas in case of fire. The material strength and volume should not be reduced too much, and the surface layer should not burst or collapse. Otherwise, it will cause damage to residents or firefighters and cause great difficulties in rescue work

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