China National Standard for concrete form plywood was first published in 1999, revised in 2008, and revised in 2018 to GB/T 17656-2018.
It was first proposed by State Forestry and Grassland Administration of China.
The new standard was lead by China Forestry Science Academe Wood Industry Institute. Also some plywood manufacturers, glue manufacturers, construction companies, universities, are involved in the draft of the standard.
GB/T 17656-2018 stipulates terms, defination, classification, test method, marking, packaing, transportation and storage of plywood for concrete forming.
2. Related Standards
- GB/T 9846-2015 Ordinary Plywood
- GB/T 17657-2013 Physical and chemical test method of wood based panels
- GB/T 18259 Terms for wood panels and decorative surfaces
- GB/T 19367 Size measurement of wood based panels
3. Terms and Defination
3.1 Plywood For Concrete Form
Plywood that can pass water boiling test and can be used for concrete forming cast
3.2 Modular System
The form plywood can be classified into three types according to its surfaces
4.1 Raw Face Plywood
4.2 Phenolic Faced Plywood
4.3 Phenolic Coated Film Faced Plywood
5.1 Wood Species
The veneer used for concrete forming plywood can be Pinus massoniana, Pinus yunnanensis, Larix gmelinii, Radiata pine, poplar, eucalyptus, birch, luan, Aucoumea, Keruing, Gurjan, Apitong, etc.
5.2 Panel Structure
Wood grain of adjacent veneers should cross with each other. Same layer should use same wood species veneer. Any tape used for fixing plywood should be removed.
5.3 Adhesive Glue
The glue for concrete form plywood shoud use phenolic resin or similar glue.
5.4 Plywood Sizes
915*1830mm, 1220*1880mm, 915*2135mm, 1220*2440mm, 1250*2500mm
Length and width tolerances are +-2mm
5.5 Visual Quality
Overlap of film in the film faced plywood is not permitted. The largest crystalation of film should not be bigger than 100 mm2.
Plywood should be sanded unless stipulated in sales contract.
Film faced plywood shoud have 2 faces with film. Both sides film should be same quality.
5.6 Physical Performance
Moisture content 5-14%
Bonding strength >=0.70MPa
6. Test Method
3 pieces of 600*600mm samples are cut from a whole piece of film faced plywood. Mark the directions of samples.
Use visual the check the defects of the plywood.
Moisture Content test by GB/T 17657-2013.