Concrete Formwork Shuttering Plywood for Concrete Formwork in Construction Engineering is coated with Film Faced Plywood. The reference standard is Plywood for Concrete Formwork.
Types of Film Faced Plywood Concrete Formwork Shuttering Plywood:
There are generally three types of Concrete Formwork Shuttering Plywood
1. Concrete Formwork Shuttering Plywood (plain board) plywood without surface treatment;
2. Concrete Formwork Shuttering Plywood (abbreviated as coated board) Plywood Treated with resin finish;
3. Concrete Formwork Shuttering Plywood (Film Faced Plywood) plywood coated with dipped adhesive film
Specific Formwork Shuttering Plywood Covering Film Faced Plywood Requirements:
1. Size and tolerance requirements for Film Faced Plywood coated Concrete Formwork Shuttering Plywood:
For concrete Formwork Shuttering Plywood in modular systems, tolerances in length and width are 0-3 mm, and for non-modular templates, tolerances in length and width are <2 mm.
Method for measuring length and width of Concrete Formwork Shuttering Plywood
Detection method of length and width: Measure 2 points of length and width of each plate with a steel tape measure at 100mm from the edge of the plate, take the average value, the difference between the average value and the nominal size is the tolerance (see Figure 1 below).
The allowable thickness deviation for Concrete Formwork Shuttering Plywood shall comply with Table 2.
Thickness tolerance (mm) table 2
Nominal thickness
Allowable deviation between average thickness and nominal thickness
Maximum allowable thickness difference of each plate
≥12mm～＜15mm ±0.5mm 0.8mm
≥15mm～＜18mm ±0.6mm 1.0mm
≥18mm～＜21mm ±0.7mm 1.2mm
≥21mm～＜24mm ±0.8mm 1.4mm
Concrete Formwork Shuttering Plywood Thickness Detection Method: Measure the thickness of Concrete Formwork Shuttering Plywood between 24mm and 50mm from the edge of the plate with a micrometer (or vernier caliper). The measuring point is located in the middle of each corner and edge. Measure 3 points and 1 points respectively on the long and short sides and take an average of 8 points. The difference between the average and the nominal thickness is deviation (see Figure 1 above).
The allowable deviations and warpage limits for the diagonal length of Concrete Formwork Shuttering Plywood are shown in Table 2 and Table 3.
Concrete Formwork Shuttering Plywood Two Diagonal Length Allowable Deviation (mm) Table 2
|
Concrete Formwork Shuttering PlywoodTolerance length |
Difference in length between two diagonals |
| ≤1220
＞1220～≤1830 ＞1830～≤2135 ＞2135 |
3 4 5 6 |
Concrete Formwork Shuttering Plywood Warpage limit table 3
|
Tickness |
Grade |
|
|
A grade Plywood |
B grade Plywood |
|
|
12㎜ and up |
not exceed 0.5% |
not exceed 1% |
Note: Warpage is expressed as the ratio of the maximum chord height of the concrete Formwork Shuttering Plywood diagonal line to the length of the diagonal line.
1. Diagonal difference detection method: Measure the difference between the two diagonals with a steel tape measure.
(2) Warpage detection method: steel ruler is used to measure the diagonal length and wedge gauge (or steel tape gauge) is used to measure the maximum chord height between steel ruler and plate surface. The ratio of the latter to the former is warpage; Diagonal length allowable deviation and warpage limit.
Concrete Formwork Shuttering Plywood must not be more than 0.8m m/m vertical.
Measure the verticality of one side of the right-angle ruler against one side of the Concrete Formwork Shuttering Plywood (see Figure 2) by measuring the distance between the other arm of the right-angle ruler and the edge of the plate (see Figure 2) at a distance of 1000 [1] mm from the plate angle.
6) The verticality of the four edges of Concrete Formwork Shuttering Plywood must not exceed 1.0 m m/m.
Place the ruler against the edge of a plate (or place and straighten the wire at both corners of the plate) and measure the maximum deviation between the ruler (or straighten the wire) and the edge of the plate.
1. Structural Requirements of Concrete Formwork Shuttering Plywood
1) The wood grain of two adjacent layers of veneers shall be perpendicular to each other, and the veneers of symmetrical layers on both sides of the central layer shall be the same tree species or trees with similar physical and mechanical properties and the same thickness.
2) . the uniformity of finished product structure shall be considered. During blank assembly, the total thickness of the surface plate and each layer of veneer with the same fiber direction as the surface plate shall not be less than 40% and not more than 60% of the slab thickness. The number of layers of the Board shall not be less than 7. The thickness of the surface plate shall not be less than 1.2mm, and the thickness of the surface plate of the coated plate shall not be less than 0.8mm.
3) . the surface plate of the same layer shall be the same tree species.
4) Concrete formwork shuttering plywood shall be free of inclusions that may affect its use. The non porous adhesive tape used for splicing shall not be used inside the plywood. If it is used to splice or repair the panel, the adhesive tape shall be removed, except that it is not decorated, and no obvious adhesive tape mark shall be left.
2. Species Requirements of Concrete Formwork Shuttering Plywood
The timber species of concrete formwork shuttering plywood are: masson pine, Yunnan pine, larch, radial pine, poplar, birch, lotus, Liquidambar, pseudo alder, Liu'an, Oakland, clone, abidong, etc.
3. Adhesive Requirements of Concrete Formwork Shuttering Plywood
1) The adhesive of concrete formwork shuttering plywood shall be phenolic resin or resin with equivalent performance.
2) Phenolic resin or resin with equivalent performance shall be used for resin finishing.
3) The resin used for coating shall be phenolic resin or resin with equivalent performance.
Note: phenolic resin is a kind of resin made by condensation polymerization of phenol and formaldehyde under catalyst conditions, neutralization and water washing.
1. Concrete Formwork Shuttering Plywood Film Faced Plywood Grades and Permissible Defects for Concrete
1) Generally, the grade of the finished plate is determined by visual inspection of the allowable defects on the finished plate. The grade depends on the allowable material defects, machining defects and the requirements for splicing.
2) Concrete formwork shuttering plywood (plain board) is divided into two grades according to the visible material defects and processing defects on the finished board: Grade A products (excellent products) and grade B products (qualified products). The allowable defects shall comply with the provisions of table 5.
3) . the concrete formwork shuttering plywood with resin finish is divided into two grades according to the visible processing defects on the finished plate: Grade A products (excellent products) and grade B products (qualified products). The allowable defects shall comply with the provisions of table 6. The appearance quality of the base plate shall meet the corresponding requirements in Table 5.
4) Concrete formwork shuttering plywood (film faced plywood) is divided into two grades according to the visible processing defects on the finished plate: Grade A products (excellent products) and grade B products (qualified products). The allowable defects shall comply with the provisions of table 7. The appearance quality of the base plate shall meet the corresponding requirements in Table 5.
5) The surface of the plate shall be sanded or scraped. If it is agreed by the supplier and the buyer, it can be sanded (scraped) or not sanded (scraped) on one side.
6) Concrete formwork shuttering plywood with film faced plywood resin finish shall be coated with resin on both sides. If the two sides are of different grades, they shall be clearly marked, and the four sides shall be coated with waterproof edge sealing paint.
7) Concrete formwork shuttering plywood (coated board) shall be coated on both sides. If the grades on both sides are different, it shall be clearly marked, and the four sides shall be coated with waterproof edge sealing paint.
2. Physical and Mechanical Properties of Concrete Formwork Shuttering Plywood
The physical and mechanical properties of each grade of concrete formwork shuttering plywood shall comply with the provisions in Table 8.
Physical and mechanical property index values Table 4
|
Item |
|
Thickness（mm） |
|||||
|
≥12～＜15 |
≥15～＜18 |
≥18～＜21 |
≥21～＜24 |
||||
|
Moisture content |
% |
6～14 |
|||||
|
Density |
t/m3 |
Wood Plywood 0.6~0.65 | Bamboo plywood 0.7-0.8 | ||||
|
Bonding strength |
MPa |
≥0.7 |
|||||
|
Static bending strength |
Parallel striation |
MPa |
≥50 |
≥45 |
≥40 |
≥35 |
|
|
Transverse striation |
≥30 |
≥30 |
≥30 |
≥25 |
|||
|
Modulus of elasticity |
Parallel striation |
MPa |
≥6000 |
≥6000 |
≥6000 |
≥6000 |
|
|
Transverse striation |
≥4500 |
≥4500 |
≥4000 |
≥4000 |
|||
|
Dip stripping performance |
|
The cumulative peeling length of each side of the impregnated adhesive film paper veneer and the plywood surface shall not exceed 25mm |
|||||
Note: ① static bending strength: the static bending strength is the ratio of the bending moment and the bending section modulus of the specimen under the maximum load. Taking man-made board as an example, when the man-made board is stressed, it will cause certain bending. This situation is called "static bending". The "static bending strength" refers to the pressure strength that the man-made board can bear when it is stressed and bent to fracture, which is expressed in MPa. ② Modulus of elasticity, also known as elastic coefficient, Young's modulus, is one of the most important and characteristic mechanical properties of elastic materials, and also a representation of the difficulty of deformation of objects, expressed by E. It is defined as the ratio of the stress to the corresponding strain of an ideal material at small deformation.
3.Test method for concrete formwork shuttering plywood
4. The length and width, diagonal, warpage and physical and mechanical properties of concrete formwork shuttering plywood shall be sampled for inspection as required.
Marking, labeling, packaging, transportation and storage of concrete formwork shuttering plywood
The marks, labels, packaging, transportation and storage of concrete formwork shuttering plywood shall comply with the regulations. The grade mark stamped with the number shall be consistent with the grade of the plate.
1. Identification of concrete formwork shuttering plywood
On the lower right corner or side of each concrete formwork shuttering plywood backplane, indelible ink shall be affixed with marks indicating the category, grade, formaldehyde emission level, manufacturer code, inspector code and production date of the concrete formwork shuttering plywood.
Grade marks use "excellent" and "qualified" to represent each grade of concrete formwork shuttering plywood respectively.
Formaldehyde emission levels are marked with E0, E1 and E2 respectively.
Note: formaldehyde is a kind of chemical gas. If the content in the air reaches a certain concentration, it will be harmful to human body. It is mainly used in the manufacturing process of composite materials and plays a bonding role (man-made plates use adhesives and contain formaldehyde). In this way, the formaldehyde contained in the building materials will not volatilize immediately, but slowly volatilize due to different temperature and humidity conditions, with a volatilization time of more than ten years. Living in an environment with excessive formaldehyde concentration for a long time, formaldehyde will cause obvious damage to people's eyes, nose and respiratory system or cause people to suffer from skin diseases. The results of animal experiments also showed that excessive formaldehyde release could lead to nasal cancer and respiratory system cancer.
E0, E1 and E2 all refer to an environmental protection standard of formaldehyde emission limit level
Formaldehyde emission limit of plywood unit: mg / L
Class mark limit (GB) (Europe) scope of use
E0 ≤ 0.5 (0.4) mg/l can be directly used indoors
E1 ≤ 1.5 (1.0) mg/l can be directly used indoors
E2 ≤ 5.0 (4.0) mg/l can be used indoors after finishing
2. Label of concrete formwork shuttering plywood
Each package of concrete formwork shuttering plywood shall be labeled with manufacturer name, address, product name, trademark, product standard number, specification, tree species, category, grade, formaldehyde emission level, number of sheets, production date, etc.
3. Packaging of concrete formwork shuttering plywood
Concrete formwork shuttering plywood shall be packed separately according to different categories, tree species, specifications, grades, formaldehyde emission levels and batch numbers when leaving the factory. To prevent the board surface from being stained, the panel of the outermost Board shall face inward when packaging. Concrete formwork shuttering plywood with special requirements shall be packed according to the agreement between the supplier and the buyer.
4.Transportation and storage of concrete formwork shuttering plywood
Concrete formwork shuttering plywood shall be transported by clean, dry and covered means of transport.
Concrete formwork shuttering plywood shall not be affected by moisture during transportation and storage, and shall prevent human and mechanical damage during handling.
Appendix: concrete formwork shuttering plywood mobilization acceptance procedure
(1) first check that the mark, label and package of concrete formwork shuttering plywood shall comply with the provisions of gb/t9846.6-2004. The grade mark stamped with the number shall be consistent with the grade of the plate. The technical performance must comply with the relevant quality standards (through the storage and inspection of the factory certificate and test report of the mobilized concrete formwork shuttering plywood).
(2) appearance quality inspection standard (through observation and inspection): there shall be no decay, mildew and blister at any part. There shall be no board edge defect or fuzzing. Degumming of veneer per square meter shall not be greater than 0.001m2. The polluted area per square meter shall not be greater than 0.005m2.
(3) refer to the second dimension requirement for specification and dimension inspection.
Post time: Jun-03-2022