GB/T 17656-2018 in English
VALIDPlywood for concrete form
- Issued on:2018-05-14
- Implemented on:2018-12-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$214.00
《GB/T 17656-2018混凝土模板用胶合板》由TC198（全国人造板标准化技术委员会）归口，主管部门为国家林业和草原局。
Introduction
In-depth interpretation of the national standard GB/T 17656-2018 for plywood for concrete formwork
1. Background and significance of the standard
GB/T 17656-2018 "Plywood for Concrete Formwork" is a national standard formulated for concrete formwork materials widely used in construction. This standard was issued in 2018, replacing the old version of the standard in 2008. It mainly revised and supplemented the definition of terms, classification, technical requirements and inspection methods.
2. Scope and applicability of the standard
This standard applies to plywood for concrete formwork made of wood veneer. The specific scope includes:
- Material requirements: including the species of wood, adhesive type, etc.
- Structural requirements: including the number of layers, core thickness ratio, and technical indicators of the surface board and core board.
- Physical and mechanical properties: covering key parameters such as moisture content, bonding strength, static bending strength, elastic modulus, etc.
3. Classification and structural requirements
Plywood for concrete formwork is divided into three categories according to surface treatment: unfaced plain board, resin-faced coated board and impregnated paper-coated board. The structural requirements include:
| Project | Technical requirements |
|---|---|
| Number of layers | Minimum 7 layers, maximum unlimited |
| Surface plate thickness | ≥1.2mm (plain plate), ≥0.8mm (film-faced plate) |
| Core layer ratio | The total accounts for 40%-60% of the slab thickness |
4. Physical and mechanical properties requirements
The following is a comparison table of key physical and mechanical properties:
| Item | Nominal thickness range (mm) | ||||
|---|---|---|---|---|---|
| 12≤t<15 | 15≤t<18 | 18≤t<21 | 21≤t<24 | ||
| Moisture content (%) | 5～14 | ||||
| Bond strength (MPa) | ≥0.70 | ||||
| Static bending strength along the grain (MPa) | ≥50.0 | ≥45.0 | ≥40.0 | ≥35.0 | |
| Elastic modulus along the grain (MPa) | ≥6000 | ≥5000 | |||
5. Implementation suggestions and precautions
Precautions when selecting plywood:
- Choose the appropriate type (plain board, glue-coated board or film-faced board) according to the needs of the formwork project.
- Check the appearance quality to ensure that there are no obvious defects, especially holes and cracks that affect use.
- Check the physical and mechanical performance indicators, focusing on static bending strength and elastic modulus.
- Store and transport strictly in accordance with the standards to avoid deformation or moisture.
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