Construction of energy-saving wall insulation technology and application of new materials Yin Wu 1. External wall insulation technology and energy-saving materials In the building, the heat loss of the external protection structure is large, and the wall of the external protection structure also occupies a large share. Therefore, the development of building wall reform and wall energy-saving technology is one of the most important aspects of building energy-saving technology. The development of external wall insulation technology and energy-saving materials is the main way to achieve building energy conservation. The internal insulation construction of the external wall is to add insulation layer inside the external wall structure. The internal insulation construction speed is fast, the operation is convenient and flexible, and the construction progress can be guaranteed. The internal insulation application time is long, the technology is mature, and the construction technology and inspection standards are relatively perfect. About 25% of the engineering applications in the external wall insulation construction in 2QQ1 apply internal insulation technology. The internal thermal insulation technologies that have been widely promoted include: reinforced gypsum composite polystyrene insulation board, polymer mortar composite polyphenylene insulation board, reinforced cement composite polystyrene insulation board, interior wall paste polystyrene board plastering plaster and styrene granule insulation The practice of adding slurry and anti-cracking mortar into the mesh cloth. However, the internal heat preservation will occupy more area of ​​use. The "heat bridge" problem is not easy to solve, it is easy to cause cracking, it will affect the construction speed, affect the secondary decoration of the residents, and the inner wall suspension and fixed objects are also easy to damage the internal insulation structure. The technical irrationality of internal insulation determines that it must be replaced by external insulation.
1.1 External thermal insulation technology and its characteristics External thermal insulation is a kind of building insulation energy-saving technology that is currently being promoted. Compared with internal thermal insulation, external thermal insulation has reasonable technology and obvious advantages. The thermal insulation material with the same specifications, the same size and performance is better than the internal thermal insulation. The external thermal insulation technology is not only suitable for new structural engineering, but also suitable for the renovation of old buildings. It has a wide application range and high technical content. The external thermal insulation package is on the outer side of the main structure, which can protect the main structure and prolong the life of the building; effectively reduce the construction. The structural thermal bridge increases the effective space of the building; at the same time eliminates condensation and improves the comfort of living.
12 At present, the most mature exterior wall insulation technologies are mainly as follows: the external insulation materials are rock (mineral) cotton, glass wool felt, polystyrene foam board (referred to as polystyrene board, EPS, XPS), ceramsite concrete composite Polyphenylene stone decorative insulation board, wire mesh frame sandwich wall board, etc. Among them, polystyrene board has been widely used in the external wall insulation plug-in technology all over the world because of its excellent physical properties and low cost. The plug-in technology uses a bonding mortar or a special fixing member to stick and hang the heat insulating material on the outer wall, and then wipes the crack resistant mortar, presses the glass fiber mesh cloth to form a protective layer, and finally adds a decorative surface.
Another method is to use a special fixing member to fix various insulation boards which are not easy to absorb water on the outer wall, and then suspend the aluminum board, natural stone, colored glass and the like on the pre-made keel to directly form the decorative surface. The external insulation of the office building of the Bank of China, designed by Mr. Pei Ming, is the design adopted. This type of external thermal insulation installation takes time, the construction is difficult, and the construction takes up the lead time, and the construction can only be carried out after the main experience is completed. When carrying out high-rise construction, the safety of construction workers is not easily guaranteed.
1.2.2 Polystyrene board and wall one-time casting molding This technology is to build polystyrene board into the building formwork in the concrete frame-shear system, on the outside of the wall to be flexed, and then flexing concrete, concrete and polystyrene. The plate is once molded into a composite wall. This technology solves the main problems of external thermal insulation, and its advantages are obvious. Since the main body of the outer wall and the thermal insulation layer survive once, the work efficiency is improved, the construction period is greatly shortened, and the safety of the construction personnel is ensured. Moreover, in the winter construction, the polystyrene board plays a role of heat preservation, which can reduce the external insulation and insulation measures. However, when scratching concrete, pay attention to uniform and continuous scratching. Otherwise, due to the influence of concrete side pressure, the polystyrene board will be deformed and staggered after demoulding, which will affect the subsequent construction. The built-in polystyrene board can be a double-sided steel mesh or a single-sided steel mesh. The connection between the double-sided steel mesh polystyrene board and the concrete mainly relies on the inner steel wire mesh frame and the outer reinforcement of the wall and the adhesion of the concrete and the polystyrene board, and the bonding performance is good and the safety is high. The connection between the polystyrene board and the concrete of the single-sided steel mesh mainly depends on the adhesion of the concrete and the polystyrene board, and the anchoring force of the obliquely inserted steel bar, the L-shaped steel and the concrete wall, and the bonding performance is also good. Compared with the double steel mesh, the single-sided wire mesh technology saves man-hours and materials by eliminating the outer wire mesh and the outer side of the plate before the installation of the insulation board. Its cost can be reduced by about 10%. However, both of these methods use a steel wire mesh frame, which has a high cost, and the steel is a good conductor of heat, and direct heat transfer will reduce the thermal insulation effect of the wall.
We have carried out experimental research on concrete and non-grid polystyrene board one-time composite wall. The test results show that it is entirely possible to directly use concrete as a bonding agent to adhere polystyrene board under the condition that the amount of cement slurry in concrete is suitable. When we treated the back side of the polystyrene board, its adhesion to concrete was further improved (the average bond strength could reach 0.07 MPa, and the damage occurred in the polystyrene board). This technology eliminates the wire mesh frame, its insulation performance is improved, and the cost of the plate is again reduced. After the demonstration of its long-term durability, it can be promoted in the project.
1.2.3 Polystyrene granule insulation slurry external wall insulation The waste polystyrene plastic (abbreviated as EPS) is processed and crushed into particles of 0.54 mm, and the thermal insulation mortar is prepared as a light aggregate. The technology includes an insulation layer, a crack resistant protective layer and a barrier protective surface layer (or a surface layer anti-seepage and anti-cracking two-in-one mortar layer). Among them, ZL rubber powder polystyrene granule insulation materials and technology were listed as national-level construction methods by the Ministry of Construction in 1998. This method is currently widely recognized as an exterior wall insulation technology. The construction technology is simple, can reduce labor intensity and improve work efficiency; it is not affected by structural quality differences, and the wall surface does not need to be repaired and leveled when the defective wall is constructed, and the thermal insulation slurry can be directly used to supplement, avoiding other Insulation construction technology is due to the phenomenon that the leveling plaster is too thick and falls off. At the same time, the technology solves the problem that the interface layer is easy to debond and empty, and the surface layer is easy to crack due to the poor use conditions in the external wall insulation project, thereby realizing an important breakthrough in the external wall insulation technology. Compared with other external insulation, the cost is lower when the same insulation effect is achieved, which can reduce the construction cost of the house. For example, compared with polystyrene board external insulation, it can be reduced by about 25 yuan per square meter. This technology is used in the high-rise exterior wall insulation project of Tianjin Yunxiao New Residence. In addition, in the energy-saving insulation wall technology, the wall is made into a sandwich layer, and perlite, wood chips, mineral wool, glass wool, polystyrene foam, polyurethane foam (also can be foamed in the field) are filled into the interlayer. Forming an insulating layer.
2. Application of new wall materials China's new wall materials have developed rapidly. In 1987, the output of new wall materials was 18.45 billion standard bricks. By 1997, it increased to 184.88 billion standard bricks, a 10 times increase. The proportion of materials in the total amount of wall materials is more variety of new wall materials, mainly including bricks, blocks, plates, such as clay hollow bricks, clay bricks mixed with waste, non-clay bricks, building blocks, aerated concrete, light Quality plates, composite plates, etc., but in small quantities, the proportion of existing wall materials is still small. Only by promoting the rapid development of various new body materials according to local conditions can we change the unreasonable product structure of wall materials, achieve energy conservation, protect cultivated land, utilize industrial waste residue, and promote construction technology.
In the past 0 years, I have introduced foreign production technology and equipment from China. The wall material industry in China has begun to embark on the road of development of many varieties, and initially formed a wall material system based on block plates, such as concrete hollow blocks and paper. Gypsum board, fiber cement sandwich panels, etc., but the proportion of various light boards and composite boards representing the modern level of wall materials is still small, less than 1% of the total wall material, and industrial developed countries. Compared to the relatively backward 4050 years. The main performances are: low product grade, small enterprise scale, backward technology and equipment, and poor supporting ability. One of the important reasons for the slow development of new wall materials is that the restrictions on solid clay bricks are not enough. There are no specific measures to protect the land resources. The cost of manufacturing clay bricks at the expense of destroying the land is extremely low, so that any new wall materials are at the price. Can't compete with it. After the implementation of the new tax system in 1994, only 6% of the value-added tax was imposed on clay brick producers, and many new wall materials, especially lightweight panels, had to pay 17% of the value-added tax bureau. Unfavorable situation in the development of materials. In response to this situation, the Office of the Wall Materials Innovation of the Ministry of Construction, the Ministry of Agriculture, the Ministry of Land and Resources and the National Building Materials Bureau actively guided local governments to vigorously carry out wall material innovation work, and combined with the actual situation in various places, introduced a number of wall reforms. The policy has effectively promoted the development of new wall materials.
The new building wall materials are divided into six categories: (1) non-clay bricks, including non-clay sintered porous bricks and hollow bricks with a hole ratio greater than 25%, concrete hollow bricks and hollow blocks, sintered shale bricks; (2) building bricks Blocks, including ordinary concrete small hollow blocks, light aggregate concrete small hollow blocks, autoclaved aerated concrete blocks and gypsum blocks; (3) building plates, including glass fiber reinforced cement lightweight porous partition wall slabs, Fiber reinforced low alkali cement building slab, autoclaved aerated concrete slab, light aggregate concrete slab, steel grid cement sandwich panel, gypsum wallboard, metal and sandwich panel, composite lightweight sandwich panel, Strips; (4) wall materials containing not less than 30% of industrial waste, crop straw, garbage, river silt; (5) prefabricated and currently flexed concrete walls; (6) steel structure and glass curtain wall.
As a new type of building wall material promoted by the state, compared with traditional clay solid bricks, many performances on the technical level have great advantages. Its characteristics mainly include the following aspects: thermal insulation performance is good, such as aerated concrete block, steel wire frame fire core board, keel gypsum board, etc.; anti-seepage water is good as brick and block type wall material and gypsum board Sound insulation performance is better, such as coal ash sintered bricks, autoclaved lime sand bricks, etc.; low energy consumption, new building wall materials require much lower raw materials and energy consumption than traditional clay solid bricks; high strength grade; light weight It is good for base treatment and earthquake resistance. In addition, the new building wall material can shorten the construction period, save mortar, and thus increase the use area.
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