Research on the application of RE-composite thermal insulation technology on aerated concrete blocks â–¡ Shi Song 1 Xu Ronghua 1 Tian Mei 2 (1 Jiangsu Nantong Liujian Construction Group Co., Ltd. Rugao 226500; 2 Jiangsu Hetai Real Estate Co., Ltd. Nanjing 210000) Excessive material configuration and construction process have overcome the traditional practice of relying on the glass fiber mesh to eliminate cracks, so that the external insulation material does not fall off, does not hollow, does not crack, and ensures the quality of the project.
Published in February 2006 1 Overview With the implementation of energy efficiency design standards for public buildings, the thermal performance of a single wall material (typically 190 m thick) does not meet the prescriptive indicators of energy-saving design standards except for aerated concrete blocks. The "requirements, therefore the external wall must meet the prescriptive requirements" must be insulated. There are two kinds of wall insulation: external insulation and internal insulation. In recent years, the practice of wall insulation in the north shows that although the two insulation methods are the same in the thermal performance and thickness of the insulation, the internal insulation is "hot". The deadly problems such as “bridge†and condensation have been used less and less in engineering in recent years. The external thermal insulation system has the function of protecting the main structure and extending the service life of the building because its insulation layer is placed outside the outer wall. It can prevent the phenomenon of heat bridge and condensation condensation, and does not occupy indoor space and increase the use area. Therefore, it is widely used in new buildings, renovation and expansion of civil buildings and various buildings for heating and air conditioning.
The Jiangsu Hetai Building project undertaken by our company decided to apply RE composite insulation technology on solid aerated concrete blocks according to the public building energy-saving design standard GE50189-2005. This is a new attempt, because RE composite insulation technology, regardless of Whether it is in the national norm, or local regulations, there are KP1, KM, lime sand brick, concrete, etc. at the grassroots level, but there is no solid aerated concrete block, so this is another bold attempt.
Nantong Liujian (226500), No. 256 Fushou Road, Rugao City, Tel (0513) Received 2005- 2RE-type composite insulation and related materials physical and mechanical properties requirements, configuration methods, external insulation materials placed on the outside of the wall, directly Contact with the outside world, the temperature difference is large, therefore, the thermal insulation material not only has good resistance heat transfer performance, that is, large thermal resistance, small heat transfer coefficient, and resistance to weather resistance, durability and insulation system of the thermal insulation material. Cracking, fireproofing, waterproofing, ventilation, shock resistance, and wind pressure resistance have high requirements.
The R-type insulating material is a one-component powdery material composed of an inorganic cementitious material such as silicate, a filler and EPS (polystyrene) particles and having a volume content of not less than 75% and a plurality of admixtures. When it is used, it is stirred with water to form a viscous slurry, which is applied to the working surface and dried to be used as a material for the heat insulating layer (hereinafter referred to as an insulating material).
R丨丨 type insulation material for exterior insulation system. 1R type thermal insulation material, its physical and mechanical properties should meet the requirements of the following table (see Table 1.2R type insulation material configuration, according to the volume of the mixer, pre-calculate the quantity that can be input once, when mixing the insulation material should be based on the ambient temperature and The dry moisture of the base layer determines the water-cement ratio. The dry powder water is generally 1:0.65 (weight ratio), first pour the water into the mixer, and then pour the insulation material into the mixer. The mixing time is calculated from the second mortar than the ordinary mortar. The mixing time should be more than doubled, the consistency should be controlled within the range of 5~7cm, and it can be used with the mixing, generally within 4h. The ash in 4h can be used to remove the impurity lumps by 1:4 (weight ratio) and new material. Blend, continue to use after mechanical stirring.
Table 1R.E-type thermal insulation material physical and mechanical properties No. Item name unit RE-ll performance index Appearance quality dry powder gray ash color foam particles fibrous dry powder loose bulk density dry powder EPS particle content material hardening dry apparent density thermal conductivity (Normal temperature and dry state) Compressive strength (standard 28d) water absorption (excluding the surface layer of water for 1h) tensile strength (standard 28d) softening coefficient (standard 28d) dry linear shrinkage (standard 28d) water Vapor permeability coefficient combustion performance grade B1 grade 3 external insulation material cracking problem and its prevention and treatment measures The anti-cracking problem of the external insulation system is also one of the key technical problems of external insulation. The external thermal insulation system has different temperature-dependent properties due to different materials of thermal insulation materials, mortar, brick wall or concrete. Under the influence of external temperature difference, the temperature stress generated by the material is different, and the temperature strain generated by the material is not equal. The temperature strain occurs between different material layers and cracking occurs, resulting in water seepage, which greatly reduces the thermal insulation performance of the thermal insulation material, and loses the thermal insulation performance after a long time. Therefore, the prevention or effective control of the cracking of the external thermal insulation system is generally carried out by using a crack-resistant mortar and a reinforcing rib such as a glass fiber mesh cloth between the two materials to improve the temperature-resistant performance of the external thermal insulation system. The tensile strength of the mesh cloth material is a key indicator. Therefore, the mandatory provisions of Article 4.0.10 of GT144-2005 stipulate that the tensile breaking strength of the glass fiber mesh cloth shall not be less than 750N50mm. The alkali-resistant tensile breaking strength retention rate shall not be less than 50% of this project uses RE anti-cracking and anti-seepage agent.
RE anti-cracking and anti-seepage agent, a powdery material compounded by inorganic cementitious materials such as silicate, filler, short fiber and various admixtures. When used, it is mixed with sand and water to stir into a viscous slurry. It is applied to the working surface. After drying, it can meet certain deformation and maintain the mortar without cracking and penetration resistance. (hereinafter referred to as anti-cracking mortar) RE anti-cracking and anti-seepage agent: used to configure plastering mortar, its physical and mechanical properties should meet the requirements of Table 2.
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4 The problem of the external thermal insulation material falling off and its prevention and control measures First, the external thermal insulation is affected by the wind load, especially the high-rise building. The external wall of the building is subjected to a large wind load, and the wall part will generate a large negative wind pressure (suction), plus The external thermal insulation material is easy to produce and fall off due to its own weight; the second is that the external thermal insulation material is mostly organic material, while the base material is usually inorganic material of various bricks, blocks or concrete, and the two materials are incompatible with each other. Poor sex is easy to fall off. Therefore, the bond between the insulation layer and the base layer must have a certain strength during the design. At present, there are two kinds of connection methods of special adhesive glue bonding or anchor nail mechanical fixing, which is used to ensure reliable and firm bonding of the external thermal insulation system. Standard G144-2005 lists 4 mandatory provisions of 4.0.2, 4.0.5 and 4.0.8, which stipulates that “the on-site bonding strength of the external thermal insulation system shall not be less than 01 Ma, and the adhesive and cement mortar shall be pulled. The tensile bond strength shall not be less than 0.6 Ma in the dry state and not less than 0.4 Ma after 48 h of water immersion. The bond strength with the EPS plate shall not be less than 01 Ma in the dry state and 48 h after soaking, and the damage site shall be located in the EPS plate." This project uses RE interface treatment agent.
RE interface treatment agent, a powdery material compounded with inorganic cementitious materials such as silicate, mineral aggregates and various admixtures. Used to enhance the bond strength between the base layer and the insulation layer.
RE interface treatment agent: used to configure the interface treatment mortar, its physical and mechanical properties should meet the requirements of Table 3.
Table 3R.E interface pharmacodynamics performance No. Item name Unit performance index Appearance Gray-brown powder-like compression-shear bond strength Original strength (standard 28d) Water resistance (standard 21d soaking 劢 freeze resistance (standard 28dS freeze-thaw cycle) The interface treatment agent is added with water on site, stirred into a uniform slurry, and the consistency should meet the construction requirements.
The physical and mechanical properties of the R-type insulation material external wall insulation system shall comply with the provisions of Table 4.
Table 2R.E Anti-cracking and anti-seepage agent Physical and mechanical properties No. Item name Unit performance index Appearance Dry powder is containing fiber ash Uncovering powdery compressive strength Tensile bond strength (bonded with RE1 temperature material)>0.2 (1 destruction interface Should be located in the RE-insulation layer impervious to water (immersed in water for 2h impervious to dry linear shrinkage (standard 28d crack resistance wind speed, 24) wedge body thickness below 5m without crack water absorption (excluding facing layer water soak 2h anti-crack mortar Configuration: anti-cracking and anti-seepage agent: medium sand: water is 1:3:075 (weight ratio). Consistency is controlled at 68cm, generally within 2h. Table 4R.E-External wall insulation system physical and mechanical properties No. Project unit performance index resistance Impact 10, non-collision parts above the second wall of the building, etc. 3 Wind pressure load resistance Wind pressure value Rd is not less than 5 times the wind load standard value W required by the design.
Weather resistance high temperature rain cycle 80 times, heating and refrigerating cycle 20 times without cracks, empty drum, shedding insulation layer water vapor permeability resistance should meet the design requirements Thermal resistance should meet the design requirements Tensile strength of the surface layer impervious to water (immersed 2h not After 30 freeze-thaw cycles of water-permeable and freeze-thaw resistance, the protective layer has no empty drums and falls off, and there is no crack that can penetrate water into the surface of the insulation layer. The tensile bond strength between the protective layer and the insulation layer is not less than the ai5 failure interface. Should be located in the insulation layer water absorption (excluding the surface layer water soak 2h), the bonding strength of the facing brick 5 exterior layer should be used for the coating insulation layer is mostly lightweight porous material, the shear strength is low, so the high-rise building thermal insulation system It is not advisable to use facing bricks for the facing layer. For example, the height of the facing brick should not exceed 24m, and there must be reliable fixing measures to prevent the brick from falling off and hurting people. This project does not paste the brick and uses the mortar.
6 The basic structure of the paint exterior wall exterior insulation system (7 design requirements (the grid layer is set according to the building facade design requirements no more than the thickness of the plaster layer layer, after the site installation to form a division joint (see) .
Through the multi-disciplinary meeting of the owner, design, supervision and construction, although the aerated concrete block external wall can meet the energy-saving requirements, in order to overcome the cold bridge phenomenon at the beam, column, ring beam and structural column, the thickness of the insulation layer is determined. Construction 81 construction process, door and window frame surrounding caulking - wall cleaning hanging vertical, sleeve, plastering cake, blasting ash layer control line watering pre-wet coating interface treatment agent wipe the first time insulation material watering maintenance wipe Two times insulation materials inspection flatness, verticality, thickness installation grids - watering wet - wipe anti-crack mortar - watering maintenance acceptance - finish layer construction.
82 Construction points (1) The base layer is 10#/alkaline water for the concrete wall to remove surface oil, then rinse the lye with clean water and dry. Water the wall before wet the interface. The interface treatment agent construction method is divided into a coating method and a brushing method. The coating method is uniformly applied to the surface of the base layer by a roller brush or a paint brush, and the interface treatment agent is not suitable for flowing, and then the heat insulating material is applied. Pulling the interface treatment agent with a brush, a broom and other tools on the concrete or other base layer, pull the rough into a rough surface, and then apply the insulation material after hardening.
(2) The base layer is aerated concrete wall should be watered two days in advance, more than two times a day, so that the depth of seepage is 8~10mm. The last time before plastering should be watered 1 h in advance, and the interface treatment agent is used to smear 1 interface treatment agent is not dried and then the insulation material is applied. Gray cake blasting is made of insulation material to make gray cake blasting.
(3) The construction of the insulation layer shall be carried out by hand plastering or mechanical spraying. It shall be carried out separately. The thickness of each insulation shall not be more than 10mm. When it is applied, it shall be smoothed and compacted. After the initial insulation of the insulation material, the water is moistened for the next plastering. The time interval between layered plastering is generally above 24h. When the thickness reaches the reinforced surface, first use a large bar to flatten and then use iron to wipe the surface.
In the construction of the insulation layer, the insulation material layer should be applied to the outer wall of the door and window opening. The cement mortar is used to make the slope on the top surface of the part protruding from the wall surface, and the drip line should be made below.
(4) Insulation layer maintenance: After the initial insulation of the insulation layer, the water is moistened. The time interval of watering can be determined according to the dry condition of the environment, and the surface should be free from blushing. The watering maintenance should not be less than 7d. (5) The joint construction using the plastic support with the thickness not greater than the thickness of the surface layer is used. The treatment agent is adhered to the surface of the thermal insulation layer, and a grid is formed after installation on site.
(6) Anti-cracking mortar surface layer construction Anti-cracking mortar surface layer plastering must be carried out after the insulation layer is fully solidified, generally in the case of 7d or by hand pressing the surface. Watering the day before the construction is wet. Water again 1 hour before plastering. When the anti-cracking mortar is applied, it is smoothed with iron and then flattened with a plastic trowel.
Anti-cracking mortar should be used with mixing, and the parking time should not exceed 3h. Floor ash should not be recycled.
(7) Anti-cracking mortar surface protection material should be watered and cured after initial setting. The watering maintenance should not be less than 7d. The interval between watering and curing can be determined according to the dry condition of the environment, and the surface does not appear white.
8.3 Precautions Yearly publication (1) Before the plastering of the external wall insulation construction, the pipe grooves and holes that have been dug on the wall shall be repaired and improved. Check whether the position of the door and window frame is correct, whether the installation is firm, the gap between the door and window frame and the wall is filled with flexible sealing material such as polyurethane, the outside is painted with 1:3 cement mortar, and the gap between the wall and column is applied with burlap or steel mesh reinforcement. .
(2) When the temperature is higher than 35C or the lowest temperature in 24h is lower than 5C, it is not suitable for construction, and construction is not allowed on rainy days. During rainy construction, effective rain protection measures should be taken. Antifreeze measures should be taken during construction in winter. Avoid sun exposure during construction in summer and set sunscreen on scaffolding when needed.
(3) Since the RE-composite thermal insulation technology is a netless system, the yin and yang angle does not require an additional reinforcement layer, which brings convenience to the construction.
(4) At the entrance and exit of the door and window, pay attention to the detailed structure (see).
9 Conclusion By applying RE composite external thermal insulation technology for the first time on the aerated concrete block exterior wall, the cold bridge phenomenon at the ring beam and the structural column is overcome, and the traditional material relies on the full paste through strict material configuration and construction process. The practice of eliminating cracks in the glass fiber network ensures that the external thermal insulation material does not fall off, is not hollow, and does not crack, which ensures the quality of the project and clears an obstacle in the process of creating a Luban Award for the Hetai Building Project.
(Finish)
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