Abstract: With the construction curtain wall works such as glass curtain wall, aluminum curtain wall, stone curtain wall and synthetic plate, etc., resulting in a large number of building sealant use. This article through the current national standards and technical standards, from the sealant application principle and sealant standard angle of the construction sealant and construction sealant performance to be discussed for designers, engineering and technical personnel and sealant manufacturers reference.
Key words: building structure sealant performance requirements silicone sealant design
[China curtain wall network sealant application principle and the standard angle of sealant on the construction sealant and building structure sealant performance for the designer, engineering and technical personnel and sealant manufacturers reference.
First, the sealant sealant used in the construction joints to seal, the building on a variety of joints by the temperature, external force and other factors affect the change, the sealant in the joints must withstand the changes in the joints and the environment Influence (water, light, cold, hot) without being destroyed. The primary consideration of the sealant is elasticity, and the characterization of the quality of the sealant is displacement. Architectural Seal Schemes The world’s most influential sealant standards are: ASTMC920 “Elastic Sealant Specification” and ISO11600 “Building Structures – Sealants – Classification Requirements”. China’s standards for sealants such as GB / T14683, JC / T881 a JC / T885 and other major reference to the development of ISO11600. ISO11600 and ASTMC920 in the product classification is quite different. ISO11600 classification ASTMC920 grading “displacement capability” displacement capability) 25LM100 / 5025HM5020ML. 35.20HM2512.5E12.512.5P7.5P I think ASTMC920 classification of the sealant is more scientific, from l00 / 50 to l2.5 level, the quality of the sealant separation, and ISO11600 grading from 25 to 7.5, 25 or more sealant can not distinguish between the high modulus (Ⅲ), low modulus (LM) grading in the design and selection on how to distinguish between the description, and 20 and 25 between the very small difference between the designer Selection of guidance is of little significance.
Second, the seam design Architects usually use two methods to determine the size of the adhesive and choose sealant: (1) by the beautiful, easy processing and other requirements to determine the width of the sealant, and then calculated by the amount of change in the gum ( Temperature, load and other factors), and then select the appropriate sealant. Such as glue change 12%, can choose l2.5 level sealant, such as rubber joints change 22%, can choose 25 sealant; (2) selected sealant, through the sealant displacement ability to determine the seams width. In most of our design in the first way to determine the width of the seam. In practice, there is a case where the size of the seam is unreasonably caused by the failure of the seal. The reason is usually the design according to the first method, but the displacement ability of the unseparated sealant is matched, or the displacement ability of the sealant can not be achieved The level claimed by the business.
Third, the silicone structure sealant silicone adhesive for the glass curtain wall structure assembly, the glass bonded to the main structure, bear the wind load and glass load load, structural adhesive must have sufficient strength to bear these loads. General architectural designers in the design of the curtain wall structure when the glue on the structure of plastic to take 0.14MPa, requiring structural adhesive strength greater than 0.7YPa, so you can reach 5 times the safety factor. Structural adhesive Another important performance is the elastic modulus, the designer needs to calculate the thickness of the structural joint according to the elastic modulus, low modulus of the sealant is not suitable for structural adhesive, low modulus plastic under the action of wind load or heavy load Will produce a large displacement, which is not allowed for glass curtain wall construction. But the modulus of the structural adhesive should not be too high, because the structural adhesive must be adapted to the temperature caused by the deformation of the rubber joints. Structural glue must have a certain degree of flexibility. The standards for structural adhesives are: ASTMCl184; GB16776; ETAGO02. These three standards are similar, mainly considering the structural adhesive in a variety of conditions under the strength, adhesion, while paying attention to the modulus of the structural adhesive.
Fourth, the structural adhesive and sealant performance requirements of the difference; Strength of the structural glue can give the curtain wall a greater safety factor; Structural glue and sealant are essentially different from the structure of plastic in the building is to control the change in plastic joints, must have high modulus, and sealant is to adapt to changes in rubber (high displacement capacity), can not use sealant performance indicators (such as lower Modulus, displacement capacity) to require structural adhesive; The displacement ability of the structural glue (used to calculate the structural seam thickness) and the sealant’s ability to displace (for calculating the width of the seam) is two completely different concepts. The sealant’s ability to adjust the sealant is to seal the seal The change in the grade of the structural adhesive is the strain value of the structural adhesive when the stress is 0.14YPa. It is wrong to judge the elasticity of the structural adhesive with the displacement ability index of the sealant. 【end】
Post time: Feb-25-2017