Proposed Scope This test method covers the determination of creep properties of structural adhesives in wood-to-wood bonds when a standardized specimen is subjected to shearing stresses at various levels of static load, constant temperature, and relative humidity. Apparatus and procedures are provided for shear deformation (creep) of adhesive bonds under static load. This test method is used under the indicated conditions to evaluate creep properties of a structural wood adhesive. The test method is used to evaluate creep performance of adhesives suitable for the bonding of wood, including treated wood, into structural wood products for general construction, for marine use, or for other uses where a high-strength general construction, creep-resistant, durable adhesive bond is required. Individual block shear specimens are prepared from adhesively bonded laminations, subjected to a constant load under various combinations of temperature and relative humidity, and the amount of creep measured. Creep of structural wood adhesives as measured by this test method may not be comparative to other ASTM methods and is limited to the conditions of the test and procedures contained herein.
Based upon a significant amount of laboratory work, current Test Methods and Standards such as ASTM D3535 and CSA O112.9-04 have been determined as not appropriate to evaluate structural wood adhesives for creep resistance under conditions of high moisture content and temperature. The multi-joint test specimen in these methods is not dimensionally stable under extreme environmental conditions of moisture/temperature. This instability has been documented, in many cases to cause premature failure of the specimen with mode of failure entirely within the wood substrate. The standard will be used to evaluate a structural wood adhesive for resistance to creep under controlled combined conditions of temperature and humidity in order to provide an assurance the test adhesive is suitable for specific bonded wood products and the environment to which they are subjected and conditions under which they are expected to perform. Users will be testing laboratories; specifiers of adhesive testing such as ASTM D14.30, CSA SC05 on wood adhesives, wood product standards such as ASTM DO7 and numerous code agencies both within the US, North America and possibly ISO standards.
The title and scope are in draft form and are under development within this ASTM Committee.
Citing ASTM Standards
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