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Affected by climatic conditions, consumption levels, and aesthetic habits in many parts of China, the exterior wall of decorative tiles has been loved by many real estate developers and residents. However, it is unavoidable to worry about the accident when the facing bricks are empty and fall off.
In the past ten years, the central government's energy conservation policy has been earnestly implemented throughout the country, and the external thermal insulation composite wall has become the preferred form of wall insulation. Is it safe to use the decorative bricks attached to the lightweight and low-strength insulation materials? This has become the focus of attention in the industry.
The facing brick directly attached to the outer wall surface is subjected to two external loads: one is the self-weight of the facing brick and the adhesive, which is about 0.25 kN/m2; the other is the wind load (mainly negative wind pressure), in Beijing area, The calculated maximum negative wind pressure at a height of 20 meters from the ground is about 2.1 kN/m2, and about 3.6 kN/m2 at a height of 100 meters from the ground (in coastal areas, this value may reach 8-9 kN/m2). It depends on the bonding strength of the adhesive to the outer wall surface. According to the national industry standard "Construction and Acceptance Regulations for Exterior Wall Finishing Bricks", the exterior wall facing brick works are tested by the bonding strength of the facing bricks, and the drawing strength is not less than 0.4 MPa, ie 400 kN/m2. It can be seen that the initial adhesion provided by the acceptance-qualified project has a sufficient safety factor to overcome the external load. Therefore, most exterior wall facing brick works can be used safely for a long time.
The reason why the facing bricks fall off in individual projects is because the temperature change and moisture migration in the years have weakened the bonding strength between the facing bricks and the outer wall. There are two main reasons for this: First, severe and repeated temperature changes on the outer wall surface produce large temperature difference stress at the interface of different thermal expansion coefficients; second, because the adhesive construction is not full, facing bricks or caulking The water absorption rate of the agent is too high, the water vapor permeation is blocked, and the like, and water accumulation is formed inside the facing brick, causing frost heaving damage in the cold region in winter. To avoid this problem, we should thoroughly understand and conscientiously implement the "Construction and Acceptance Procedures for Exterior Wall Finishing Bricks". The "Procedure" puts forward several notable problems in the basic design rules: 1 The shrinkage deformation caused by temperature change during use is often one of the main factors that cause the exterior wall facing brick to drum and fall off. 2 Set expansion joints to prevent deformation of the wall structure and cracking and falling off caused by temperature deformation of the exterior wall facing brick itself. 3 It adopts flexible waterproof material caulking, which can absorb deformation and increase the impermeability of the veneer. If the seam of the 4 facing bricks is too small, it will easily fall off under the action of temperature stress. The procedure is defined as "width should not be less than 5mm". The "Procedure" also emphasizes that the bonding strength test of the facing bricks should be carried out according to the "Inspection Standard for Bonding Strength of Building Finishing Tiles". Other research results show that: to reduce the shear stress caused by temperature difference at the interface, to prevent the tile from falling off, flexible adhesive should be used as much as possible; appropriate adhesive layer thickness should be used; low elastic modulus and small size ceramic tile should be used as much as possible; The spacing of the tile veneer joints should be appropriately reduced; the water vapor permeability of the composite wall should be calculated to avoid the use of insulation materials and facing bricks with poor air permeability, and for light-filled walls such as aerated mortar. Gas or gas barrier measures.
The tiling on the external thermal insulation composite wall, the bonding strength of the facing brick and the external thermal insulation system still needs to reach 0.4 MPa, and the self-weight of the external thermal insulation system with the facing brick and the negative wind pressure are connected by the external thermal insulation system and the structural wall. Force to bear. Therefore, three problems need to be solved: First, can the bonding strength of the facing brick and the external thermal insulation system reach 0.4 MPa? Second, can the coupling force between the external thermal insulation system and the structural wall overcome the dead weight of the external thermal insulation system with the facing brick and the negative wind pressure transmitted? The third is because there is a layer of insulation system in between, how to solve the new problems caused by this?
(1) Not long ago, we did a batch of tile drawing tests. Part of the glass fiber mesh reinforced mortar is used. The varieties, specifications and layers of the glass fiber mesh used in the 8 sets of test pieces are different. The drawing strength is up to 0.46 MPa, the lowest is 0.36 MPa, and the average is 0.40 MPa. According to the standard requirements, it is accurate to one decimal place. All meet the requirements of not less than 0.4 MPa. The other group uses a steel mesh with different varieties, specifications and wire diameters to reinforce the mortar. The tensile strength is up to 0.74 MPa, the lowest is 0.51 MPa, and the average is 0.66 MPa. The controversial question is: Where is the slit cut before drawing? "Inspection Standard for Bonding Strength of Building Finishing Tiles" states that "the fracture should be cut from the surface of the facing brick to the surface of the substrate". Some people stressed that it is necessary to cut the surface of the structural wall; it is also argued that it can only cut the surface of the composite thermal insulation wall, that is, the surface of the crack resistant mortar, because the facing brick is attached to the base surface of the composite thermal insulation wall. Recently, the controversy has subsided, and most people agree with the latter view.
(2) The connection between the exterior insulation system with the facing brick and the structural wall is generally a combination of bonding and mechanical anchoring. For new construction, it is often based on bonding. For the most widely used post-adhesive polystyrene board external thermal insulation system, the polystyrene board is adhered to the structural wall with adhesive. The relevant standard requirements: the tensile bond strength of the adhesive and the structural wall is not less than 0.40 MPa. The tensile bond strength of the binder and the polystyrene board is not less than 0.10 MPa, the bonding area ratio is not less than 40%; the tensile strength of the polystyrene board is not less than 0.10 MPa; the surface mortar and the polystyrene board are The tensile bond strength is not less than 0.10 MPa. It can be seen that the weakest connection between the external thermal insulation system and the structural wall is at the interface between the adhesive and the polystyrene board, and the minimum adhesion force here is not less than 0.04 MPa, that is, 40 kN/m 2 . Obviously, there is a great safety factor in overcoming the negative wind pressure at a height of 100 meters from the ground. The self-weight of the exterior insulation system with facing bricks is generally around 0.5 kN/m2, so don't worry too much. As for the role of mechanical anchors, it has not been included.
(3) The insulation board and the plaster on the middle of the sandwich bring two new problems:
First, since the existence of the enhanced mesh plays a key role in the drawing strength of the tile, the durability of the reinforcing mesh becomes the key to prevent the facing brick from falling off for a long time. Glass fiber is susceptible to alkali corrosion, and the cement mortar it is in is just an alkaline environment. To prevent the glass fiber from being greatly corroded by alkali corrosion and affecting the reinforcing effect, the glass fiber mesh with alkali resistance meeting the standard requirements should be selected. Although the reinforcement of the uncorroded steel mesh is more prominent, its rust prevention problem requires special attention. Sometimes the wire mesh seen at the construction site is zinc plated, but the rust point can be observed without the wall. This is very dangerous. According to our experimental research, the steel wire mesh or galvanized wire woven mesh which is hot-dip galvanized after welding should be selected; the thickness of the galvanized layer must exceed a minimum value; if possible, the plating material with better rust prevention effect should be selected; Try to avoid bending during transportation and construction; the inner and outer sides of the steel mesh should be wrapped with a certain thickness of mortar protection layer.
Second, under the self-weight of the facing brick, adhesive and plastering mortar, the polystyrene board is sheared and deformed to cause horizontal cracks in the plastering mortar. The intrusion of water will affect the durability of the facing brick bonding. The prevention and control method is to set a horizontal expansion joint at a certain height, and the brackets installed in the joints are responsible for their own weight; the density of the polystyrene board can also be appropriately increased to reduce the deformation.
Aluminum Opener is the second popular Opener in our factory; it allowed many colors, because the process of the color is anodic treatment, it won`t fell. Also, in order to protect the logo, we suggest that laser engraving is the best choice, but if the logo much difficulty, printing also acceptable. Each Aluminum Bottle OpenerKeychain packed into a polybag is the standard packing method. But also we could provide paper box or plastic box and velvet box for Beer Can Opener.
Description of Aluminum Opener:
Item: Aluminum Opener
Process: Stamping with anodic treatment
Design: Customized (2DD)
Material: Aluminum
Size: Standard size or custom size
Thickness: Standard size or customized
Color: Custom (any Pantone color in our stock, like red, blue, green, black, white, silver adn orange.)
Attachment: Metal chain
MOQ: 1000pcs
Usage: Bottle Opener
Packing: 1pc/polybag/box
QC Control: 100% inspection before packing, spot inspection before shipment
After-sale service: Free replacement if find out any short or defective goods within 90 days after shipment
Sample time: 7-12 days
Production time: 18-20 days
Shipment: TNT/UPS/DHL/FEDEX/BOAT
Payment: 100% in advance for small orders; 30% deposit, 70% before shipment for big orders.
Aluminum Opener
Aluminum Opener,Beer Can Opener,Aluminum Bottle Opener,Aluminum Bottle Opener Keychain
Artilanyard Co., Ltd. , http://www.grmgifts.com