Discussion on construction technology of building exterior wall insulation and application of energy-saving materials

Zhang Lixin Wen Changjun (Hegang Jingwei Building Co., Ltd., Hegang 154100, Heilongjiang) 1 Analysis of the internal insulation technology of the external wall The internal insulation of the wall is the use of benzene board, thermal insulation mortar and other insulation materials on the inner side of the outer wall, so that the building can reach Construction method for heat preservation and energy saving. The construction method has the advantages of convenient construction, low requirements on the verticality of the external wall of the building, and the construction progress. However, an obvious drawback of the internal insulation of the external wall is that the presence of a structural cold (heat) bridge causes the local temperature difference to be too large, resulting in condensation.

In addition, in the winter heating, summer cooling buildings, the indoor temperature varies with day and night and the season is usually about (about 10c), this temperature change causes the building interior walls and floors to linear deformation and volume search is not large. However, the temperature variation caused by the external temperature and the radiant heat of the sun on the outer wall and the roof is large.

When the outdoor temperature is lower than the indoor temperature, the external wall shrinks faster than the internal thermal insulation system; when the outdoor temperature is higher than the indoor temperature, the external wall expands faster than the internal thermal insulation system. This repeated deformation makes the internal thermal insulation system always on an unstable wall foundation. Under the repeated action of the deformation stress, the external wall is not only vulnerable to temperature and stress damage, but also easy to cause internal thermal insulation system. The empty drum cracked.

2 Internal and external mixed insulation technology analysis of internal and external mixed insulation, is the construction of the construction site in the evening, the use of external insulation, the construction of the insulation of the building is not convenient.

From the point of view of construction operation, the mixed heat preservation can improve the construction speed, the inner wall that can not be protected by the external wall insulation, and the cold (hot) bridge part of the board at the junction of the wall is effectively protected, so that the building is in the heat preservation. However, mixed insulation has serious damage to the building structure. The structural wall of the building is mainly affected by the indoor temperature, and the temperature change is relatively small. Therefore, the wall is in a relatively stable temperature field, and the temperature difference deformation stress generated is relatively small; The structural wall of the building is mainly affected by the outdoor ambient temperature, and the temperature fluctuation of the room is large, so the wall is in a relatively unstable temperature field, and the temperature difference deformation stress generated is relatively large. The heat preservation method of local tempering and local internal insulation is used to make different deformation speeds and deformation sizes of different parts of the main body of the whole building. The building structure is in a more unstable environment, and the crack is generated by the annual temperature difference structure deformation. , thereby shortening the life of the entire building.

It is unreasonable to use the combination of internal and outdoor insulation in the engineering insulation practice, which is more harmful than the internal insulation. This method has been rarely used.

3Composite sandwich insulation technology analysis composite sandwich insulation wall, is divided into outer leaf wall and inner leaf wall during construction, middle ± true filling insulation material, (generally EPS board, bulk weight 18kg/m320kg/m3) Construction method.

From the point of view of construction operation, the method has the advantages of convenient construction, reliable thermal insulation effect, less influence of temperature difference, and relatively small temperature deformation deformation stress. The method can effectively solve the cracking of the decorative surface of the external wall of the thermal insulation wall, and the decorative material. Technical problems such as shedding, and the fire performance of the building is significantly improved compared to the external wall insulation. In view of the above advantages, local areas are still used in large quantities. However, this technology also has some defects, such as building details, nodes, and insulation treatment is difficult; it is not conducive to the maintenance and maintenance of the building. In the case of Heilongjiang Province, the design period of the fK process is 25 years, and the structural design period is 50 years. Because the inner and outer leaf walls will be insulated, if the sandwich insulation ages to reach the service life, it will not be able to replace the repair. At one point, the inner and outer leaf walls are connected by the tie-through members that pass through the insulation layer, and the earthquake resistance is relatively weak. This method is not suitable for areas with high seismic resistance.

4External wall thermal insulation technology analysis 4.1 The technology is mature and the construction methods are various. It is suitable for all kinds of buildings with mature EPS board and EPS module exterior wall 保温 h insulation technology, spraying rigid foam polyurethane exterior wall insulation technology, rubber powder EPS Granular insulation slurry external wall insulation technology and paste insulation composite veneer insulation technology, etc., various methods are simple to use, high reliability, and mature acceptance specifications.

4.2 Wide range of applications. Xi h insulation is not only suitable for heating buildings in the northern winter insulation area but also for air-conditioned buildings in the southern summer heat-insulated areas. It is used for new buildings and also for energy-saving renovation of existing buildings.

4.3 insulation effect is obvious. Since the insulation material is placed on the outer wall of the building, the "thermal bridge" effect on various parts of the building can be basically eliminated. Thereby fully utilizing the efficiency of the lightweight and efficient insulation material, compared with the external wall insulation and sandwich insulation wall, it can use a thinner insulation material to achieve higher energy saving effect.

4.4 Protect the main structure. The insulation layer placed on the building's eve greatly reduces the influence of the natural temperature, humidity, and purple squad on the main structure. As the number of building layers increases, the effect of temperature on the vertical direction of the building has drawn attention. Foreign research data show that due to the influence of temperature on the structure, the outward expansion and contraction of the building may cause cracking of some non-structural parts inside the building. The outer wall adopts the thermal insulation technology to reduce the stress generated inside the structure.

5.1 Selection of insulation materials. In the current construction, the use of thermal insulation materials is mainly composed of compacted benzene board, polystyrene board and polystyrene granule insulation material. The compacted benzene board has a weaker crack resistance than the polystyrene board than the polystyrene board. The polystyrene granule is the main raw material thermal insulation material, which is made of rubber powder and rubber powder poly benzene particles. As a bonding material of polystyrene particles, the rubber powder material generally uses slaked lime. Fly ash. Silicone powder-cement is the main component of inorganic gelling system. The thermal conductivity of this type of material is generally 0.06 WW4 and the difference is 16 times compared with the crack resistant mortar.

5.2 Enhanced network selection. As the key reinforcement material for the soft compensation of crack-resistant protective layer, Glass Fiber mesh cloth has been rapidly developed in the application of exterior wall insulation technology. On the one hand, it can effectively protect the tensile strength of the layer. On the other hand, since the stress can be effectively dispersed, the crack which can be originally generated is dispersed into many fine cracks. Thereby forming a crack resistance effect. Due to the insulation layer, the cracking mortar is alkaline. The long-term alkali resistance of glass fiber mesh cloth has a decisive significance against cracks.

5.3 Selection of protective layer materials. Because the cement mortar has high strength, large shrinkage, and insufficient flexibility and deformation, it directly acts on the outside of the insulation layer, and has poor weather resistance and causes cracking. In order to solve this problem, it is necessary to use a special crack-resistant mortar and a reasonable reinforcing net, and add a proper amount of fiber to the mortar.

5.4 No cavity structure to improve the stability of the system. In the design of the use of polystyrene board for the h h insulation. The insulation layer is mainly subjected to gravity and wind pressure. Due to the limitation of the strength of the polystyrene board, the insulation layer is cracked or even peeled off. In order to improve the strength of the insulation board, the bonding area should be increased as much as possible, and no cavity should be used to meet the requirements of wind pressure and resistance. 6 External wall insulation construction points When the base wall is constructed and accepted, the insulation can be carried out. Layer construction, the specific construction process is: cleaning, leveling the base layer - elastic, hanging control line installation, leveling the bottom end plate, material tools, preparation, bonding, glue, bonding, tunding, grid cloth, benzene board inspection, leveling and filling board Seam-grinding and leveling installation mouldings (made of benzene board) or grid-seam-nail anchoring-insulation layer acceptance.

The construction process looks very simple, but in fact it is very complicated to operate. Under the premise of requiring the quality of the materials to be qualified, the actual operation of the construction personnel also requires a certain level of technical and responsible. Otherwise, it will directly affect the quality of the entire system.

The protective layer is generally “one cloth and two pulp”. In the part with enhanced requirements, it is “two cloths and three pulps”.

During the construction of the protective layer, the overturned mesh cloth and the reinforced mesh cloth should be laid first, and then the standard wall construction of the wall should be carried out. Special parts such as the corners of the wall that are easy to collide, the entrance and exit of the door and window, and the junction of different material substrates should be strengthened. Measures.

Building exterior wall insulation is a new construction method in recent years. Due to the defects in the design of internal insulation, mixed insulation and other methods, it is recommended to use the ah h insulation or composite sandwich insulation, and select the material according to the principle of layer-by-layer grading and flexible release stress. And construction methods to achieve the purpose of insulation and crack resistance. At the same time, we should vigorously develop and update energy-saving materials, so that the external wall protection technology can be better developed and better played its role, thus realizing building energy conservation.

(Finish)

POM plastics,lalso named Acetals(paraformaldehyde) (semel - Stirling),