What are the factors that cause the aging of external wall insulation materials?

The factors that cause the aging of the building exterior wall insulation system in daily life are: thermal stress, wind pressure, seismic force, water or water vapor, and fire. The specific analysis is as follows: 1. Thermal stress. The thermal expansion and cold contraction caused by the change of temperature difference will cause the volume change of the 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 the outer wall of high-rise buildings. Compared with multi-storey or one-story buildings, high-rise buildings receive stronger sunlight on the outer layer, greater thermal stress and greater deformation. Therefore, in the design of thermal insulation and anti-cracking structures, the selection of thermal insulation materials should meet the principle of flexibility and gradual change. The deformation capacity of the material should be higher than that of the inner layer material. 2. Wind pressure. Generally speaking, positive wind pressure generates thrust, and negative wind pressure generates suction, which will cause great damage to the outer insulation layer of high-rise buildings. In other words, it is required that the insulation layer has no cavity, and the air layer is eliminated, 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 condition of wind pressure, especially negative wind pressure. 3. Seismic force. Seismic forces can cause extrusion, shearing or twisting deformation of high-rise building structures and thermal insulation surfaces, and the greater the rigidity of thermal insulation surfaces, the greater the seismic force it can withstand, and the more serious the damage may be. This requires that the external thermal insulation material of the outer wall of high-rise buildings must meet the principle of flexible gradient under the premise of considerable adhesion, so as to disperse and absorb seismic stress, reduce the load on the surface of the thermal insulation layer as much as possible, and prevent thermal insulation under the influence of seismic force. The layers are extensively cracked, peeled off or even peeled off. 4. Water or steam. In order to avoid the damage of water or water vapor to high-rise buildings, external thermal insulation materials with good hydrophobicity and good water vapor permeability should be selected to avoid condensation on the wall or increased moisture content in the thermal insulation layer during the migration of water or water vapor. It can improve the rainwater erosion resistance and freeze-thaw resistance of the outer insulation layer of high-rise buildings. 5. Fire. High-rise buildings have higher fire rating requirements than multi-storey buildings, and the thermal insulation layer of high-rise buildings should have better fire resistance, and should have the characteristics of preventing the spread of fire and preventing the release of smoke or toxic gases in case of fire, the material strength and The volume should not be reduced too much, and the surface layer should not burst or collapse, otherwise, it will cause harm to the residents or firefighters, and cause great difficulties to the rescue work.