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57-3.02 MATERIALS

57-3.02A General


Plastic lumber must:

1. Be produced continuously and homogeneously without joints

2. Be straight and true and free from twist, curvature, bulging, or other deformations

3. Have a smooth outer layer with no visible voids

4. Not vary from the dimensions shown by more than 1/2 inch for cross-sectional dimensions or 1 inch for the length

5. Have total resistance to marine borers and dry rot

6. Not swell, shrink, or crack

7. Comply with the requirements shown in the following table:




Quality characteristic

Test method

Requirement

Density (kg/m3, min)

ASTM D792,

Test Method A
Skin: 880

Core: 680

Water absorption

(weight increase, percent, max)
ASTM D570

1.0 at 2 hours;

3.0 at 24 hours

Brittleness, (at -40 °C)

ASTM D746

Skin: No break

Hardness

ASTM D2240, Type D

Skin: 45–75

UV deterioration (hardness change, percent after 500 hours of exposure, max)

ASTM D4587a

ASTM D2240, Type D
Skin: 10

Abrasion

ASTM D4060:

Cycles: 10,000

Wheel: CS17

Load: 1 kg
Skin:

Weight loss: < 500 mg

Wear index: 2.5–3.0


Chemical resistance

(weight increase, percent)
ASTM D543:

Practice A,

Procedure 1


Sea water: < 1.5

Gasoline: < 7.5

No. 2 diesel: < 6.0


Coefficient of thermal expansion (per degree C, max)

ASTM D696

0.00009

Ignition temperature (°C)

ASTM D1929

> 340

aASTM D4329 using UVA 340 bulbs operating at a UV intensity of 0.77 W/m2/nm measured at 340 nm. The exposure cycle must be 4 hours of ultraviolet (UV) exposure at 60 °C and 4 hours of condensate (CON) exposure at 40 °C.

Stiffness and yield stress in bending of plastic lumber must have at least the values shown in the following table:

Cross section size

(inches)


Stiffness EI

(kip-sq ft)
Yield stress in bending

(psi)


8 x 10

932

4,650

8 x 12

883

3,775

10 x 10

1,764

3,900

10 x 12

1,830

3,625

12 x 12

2,892

3,050

NOTE: These values are for the weak axis of rectangular sections.

For the exterior voids at each exposed end of plastic lumber:

1. Maximum dimension of any void must not exceed 1 inch.

2. Total number of voids with a maximum dimension greater than 1/4 inch must not exceed 4.
For the interior voids in the cut sections of each segment of plastic lumber:

1. Maximum dimension of any void in a cut section must not exceed 1/2 inch.

2. Total area of voids in a cut section must not exceed 5 percent of the total cross-sectional area.
Permanently mark each piece of plastic lumber with the manufacturer's name.

Ship and store plastic lumber in a way that minimizes scratching or damage to the outer surfaces.


57-3.02B Reinforced Recycled Plastic Lumber


Reinforced RPL must consist of recycled plastic reinforced with fiberglass reinforcing bar elements, fiberglass filaments, or a combination of both.

Reinforced RPL must be a recycled product.

Fabricate reinforced RPL from one or more of the following thermoplastics:

1. High-density polyethylene

2. Medium-density polyethylene

3. Low-density polyethylene

4. High-density polypropylene
Reinforced RPL must have a dense outer skin at least 3/16 inch thick surrounding a less dense core. The plastic for the outer skin must be mixed with colorants to match color no. 37030 or 30097 of FED-STD-595 and must contain a UV inhibitor and antioxidants.

Fiberglass reinforcing bar elements must comply with the requirements shown in the following table:



Quality characteristic

Test method

Requirement

Flexural strength (psi, min)

ASTM D790

70,000

Compression modulus (psi, min)

ASTM D695

40,000

Tensile strength (psi, min)

ASTM D638

70,000

Fiberglass filaments must comply with the requirements shown in the following table:

Quality characteristic

Test method

Requirement

Density (kg/m3)

ASTM D792

2,560–2,592

Mechanical, single filament tensile strength (MPa)

ASTM D3822

3,450–3,790

Tensile modulus of elasticity (MPa)

ASTM D3822

69–72

All reinforced RPL must contain the same type of reinforcement.

57-3.02C Composite Plastic Lumber


CPL may be substituted for reinforced RPL.

Fabricate the shell for CPL from polyester or epoxy resin reinforced with E-glass and mixed with colorants, UV inhibitors, and antioxidants. The CPL coating must match color no. 37030 or 30097 of FED-STD-595.

The core material for CPL must be lightweight aggregate polymer concrete.

CPL must comply with the physical quality characteristics specified for reinforced RPL and the requirements shown in the following table:



Quality characteristic

Test method

Requirement

Density of concrete core

(kg/m3, min)
ASTM D792

1,762

28-day compressive strength of concrete core (psi, min)

ASTM C579

5,000

Structural strength of shell:

Tensile strength, tensile modulus (percent loss)

Flexural strength, flexural modulus (percent loss)

ASTM D638


ASTM D790

Less than 10 after UV deterioration test specified for plastic lumber

Dry film thickness of coating

(mils, min)
--

15

Color change of coating

ASTM D4587,

Test Cycle 2
No visible color change when tested for 800 hours

Initial adhesion of coating (psi, min)

ASTM D4541

150

Decrease in initial adhesion of coating, decrease (percent)

ASTM D4541

ASTM D1183,

Test Condition Da


No more than 10 following 2 exposure cycles

aUse a low temperature phase at 4 ± 5 °F and high temperature phase at 140 ± 5 °F.

Seal the cut ends of CPL with a cap securely held in place with an adhesive recommended by the manufacturer. The adhesive must show no more than a 10 percent decrease in strength when tested under ASTM D3164 following 2 cycles of exposure under ASTM D1183, Test Condition D, with a low temperature phase of -16 ± 3 degrees C and a high temperature phase of 60 ± 3 degrees C.

57-3.02D Unreinforced Recycled Plastic Lumber


Unreinforced RPL may be substituted for reinforced RPL for chocks, filler blocks, and other nonstructural members shown. Unreinforced RPL must comply with the specifications for reinforced RPL, except fiberglass reinforcement is not required and stiffness tests do not apply.



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