GB/T 24721.1-2023Glass fiber reinforced plastic product for highway - Part 1: General rule (English PDF)

Foreword

This document was issued on 17 March 2023 by the State Administration for Market Regulation; Standardization Administration of the PRC and takes effect on 1 July 2023.

It is a GB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

1 Scope

GB/T 24721.1-2023 is the common part of the series on glass fibre reinforced plastic products used along highways, and it holds what the product parts would otherwise each have to repeat. It classifies the products by moulding process, moulded and pressed laminates among them, then sets technical requirements that begin with the raw materials, including the performance indices the unsaturated polyester resin has to meet, before moving on to the finished product. The test methods clause is the longest: it fixes specimen conditioning and the laboratory environment first, so that results from two laboratories can be compared at all, and then the individual tests. Inspection rules decide how a lot is sampled and when it is accepted or rejected, and a closing clause covers marking, packaging, transport and storage. Roadside items of this kind live outdoors for years under sun, rain and temperature swing, and a resin or a laminate that was never tested under stated conditions fails quietly, well after the road is open and long after the invoice is paid. Needed by manufacturers of highway GFRP products, by the design and procurement staff who write the tender, and by the laboratories that test to the product parts of the series.

This document specifies the classification, technical requirements, test methods, inspection

rules, as well as marking, packaging, transportation and storage requirements for glass fiber

reinforced plastic product for highway.

This document is applicable to the production, inspection and usage of glass fiber reinforced

plastic product for highway (hereinafter referred to as “glass fiber reinforced plastics”).

2 Normative References

The contents of the following documents constitute indispensable clauses of this document

through the normative references in the text. In terms of references with a specified date, only

versions with a specified date are applicable to this document. In terms of references without a

specified date, the latest version (including all the modifications) is applicable to this document.

GB/T 1446 Fiber-reinforced Plastics Composites - The Generals for Determination of

Properties

GB/T 1447 Fiber-reinforced Plastics Composites - Determination of Tensile Properties

GB/T 1448 Fiber-reinforced Plastics Composites - Determination of Compressive Properties

GB/T 1449 Fiber-reinforced Plastics Composites - Determination of Flexural Properties

GB/T 1451 Fiber-reinforced Plastics Composites - Determination of Charpy Impact Properties

GB/T 1463 Test Methods for Density and Relative Density of Fiber Reinforced Plastics

GB/T 1634.3-2004 Plastics - Determination of Temperature of Deflection under Load - Part 3:

High-strength Thermosetting Laminates

GB/T 2408 Plastics - Determination of Burning Characteristics - Horizontal and Vertical Test

GB/T 2573 Test Method for Aging Properties of Glass Fiber Reinforced Plastics

GB/T 3854 Test Method for Hardness of Reinforced Plastics by means of a Barcol Impresser

GB/T 3857 Test Method for Chemical Resistance of Glass Fiber Reinforced Thermosetting

Plastics

GB/T 8237 Liquid Unsaturated Polyester Resin for Fiber Reinforced Plastics

GB/T 8627 Test Method for Density of Smoke from the Burning or Decomposition of Building

Materials

GB/T 8924 Test Method for Flammability Characteristics of Fiber Reinforced Plastics - Oxygen

Index Method

GB/T 9286 Paints and Varnishes - Cross-cut Test

GB/T 16422.2 Plastics - Methods of Exposure to Laboratory Light Sources - Part 2: Xenon-arc

Lamps

GB/T 16422.3 Plastics - Methods of Exposure to Laboratory Light Sources - Part 3: Fluorescent

UV Lamps

GB/T 17470 Glass Fiber Mats - Chopped Strand and Continuous Filament Mats

GB/T 18369 Glass Fiber Roving

GB/T 18370 Glass Fiber Woven Roving

GB/T 18371 Glass Filament Yarn

GB/T 20428 Granite Surface Plates

GB/T 22040-2008 Technical Requirements and Determination of Weathering Quality for

Plastics of Highway Furnitures

JT/T 495 Sampling Methods for Highway Safety Facilities Quality Inspection

3 Terms and Definitions

This document does not have terms or definitions that need to be defined.

4 Product Classification

4.1 In accordance with different molding processes, glass fiber reinforced plastics products are

divided into:

a) Molded and pressed glass fiber reinforced plastics;

b) Winded glass fiber reinforced plastics;

c) Pultruded glass fiber reinforced plastics;

d) Rolled glass fiber reinforced plastics;

e) Molded glass fiber reinforced plastics;

f) Hand lay-up glass fiber reinforced plastics;

g) Other formed glass fiber reinforced plastics.

4.2 In accordance with different flame-retardant properties, glass fiber reinforced plastics

products are divided into:

a) Level-1 flame-retardant properties, which is used in environments with high flame-

retardant requirements, that is, closed or semi-closed structures with a continuous

length of not less than 1,000 m;

b) Level-2 flame-retardant properties, which is used in environments with relatively high

flame-retardant requirements, that is, closed or semi-closed structures with a

continuous length of less than 1,000 m;

c) Level-3 flame-retardant properties, which is used in environments with general flame-

retardant requirements, that is, full open environments.

4.3 In accordance with different weather resistance properties, glass fiber reinforced plastics

products are divided into:

a) Common weather-resistant type, which is used in environments without special strong

ultraviolet light exposure;

b) Anti-ultraviolet weather-resistant type, which is the type of products exposed to

normal sunlight environment and need to be painted on the outer wall.

5 Technical Requirements

5.1 Raw Materials

5.1.1 Resin

The performance index of unsaturated polyester resin shall comply with the requirements of

GB/T 8237.

5.1.2 Reinforcing materials

The performance index of reinforcing materials shall comply with the requirements of GB/T

17470, GB/T 18369, GB/T 18370 and GB/T 18371, and high-alkali glass fiber products shall

not be used.

5.2 Appearance Quality

5.2.1 For specimens with no coating on the surface, the surface shall be smooth, and uniform

in color and luster; there shall be no defects such as wrinkles, cracks, particles, gummosis, resin

shall comply with the stipulations of various product standards.

5.3.6 Resistance to chemical media

5.3.6.1 Gasoline resistance

After being subject to the test of the specified time in 6.11.1, the specimen shall not manifest

traces of softening, wrinkles, blisters, cracks, dissolution, exposure of reinforcing materials and

solvent immersion, etc. on the surface; the retention rate of flexural strength of the material

shall comply with the stipulations of various product standards.

5.3.6.2 Acid resistance

After being subject to the test of the specified time in 6.11.2, the specimen shall not manifest

traces of softening, wrinkles, blisters, cracks, dissolution, exposure of reinforcing materials and

solvent immersion, etc. on the surface; the retention rate of flexural strength of the material

shall comply with the stipulations of various product standards.

5.3.6.3 Alkali resistance

After being subject to the test of the specified time in 6.11.3, the specimen shall not manifest

traces of softening, wrinkles, blisters, cracks, dissolution, exposure of reinforcing materials and

solvent immersion, etc. on the surface.

5.4 Environmental Adaptability

5.4.1 Damp heat resistance

After being subject to 240 h of damp heat resistance test, the specimen shall not manifest traces

of discoloration or erosion on the surface; the retention rate of flexural strength of the material

shall comply with the stipulations of various product standards.

5.4.2 Low-temperature impact resistance

After being subject to the low-temperature impact resistance test in 6.12.2, with the impact

point as the center, outside the area with a radius of 6 mm, the specimen shall not manifest

phenomena of cracking, delamination, peeling or other damages on the surface.

5.4.3 Low-temperature drop resistance

After being subject to the low-temperature drop test in 6.12.3, the specimen shall manifest no

phenomena of breakage, cracking or damages on the surface.

5.5 Weather Resistance

5.5.1 Resistance to artificial accelerated aging (xenon arc light source)

After being subject to 950 h of artificial accelerated aging test with xenon arc lamp, the

specimen without coating shall manifest no phenomena of obvious aging, such as: exposure of

reinforcing materials, discoloration, cracking and pulverization, etc. on the surface, and the

retention rate of flexural strength of the material shall comply with the stipulations of various

product standards; the specimen with coated surface shall comply with the appearance

requirements of GB/T 22040-2008, and the retention rate of flexural strength of the material

shall comply with the stipulations of various product standards.

5.5.2 Resistance to artificial accelerated aging (fluorescent ultraviolet light source)

After being subject to 600 h of artificial accelerated aging test with fluorescent ultraviolent light

source, the specimen shall not manifest defects, such as: pulverization, blistering and peeling,

on the outer coating.

5.5.3 Resistance to natural exposure

After being subject to 5 years of natural exposure test, the specimen without coating shall

manifest no phenomena of obvious aging, such as: exposure of reinforcing materials,

discoloration, cracking and pulverization, etc. on the surface, and the retention rate of flexural

strength of the material shall comply with the stipulations of various product standards; the

specimen with coated surface shall comply with the appearance requirements of GB/T 22040-

2008, and the retention rate of flexural strength of the material shall comply with the stipulations

of various product standards.

6 Test Methods

6.1 Specimen Conditioning and Test Environment Conditions

Unless it is otherwise specified, the specimen shall be subject to 24 h of state conditioning in

accordance with the stipulations of GB/T 1446, and be tested under the following conditions:

a) Ambient temperature: 23 C  2 C;

b) Relative humidity of test environment: 50%  10%.

6.2 Reagents

The reagents shall include:

a) Solid reagent: NaOH (chemically pure);

b) Liquid reagents: H2SO4 (chemically pure), gasoline (92#).

6.3 Test Instruments and Equipment

The main instruments and equipment used for the test shall include:

a) Mechanical properties testing machine: shall comply with the stipulations of GB/T

1446;

6.6.5 Density

In accordance with the method of GB/T 1463, conduct the test. Regularly shaped product

specimens should adopt the geometric method; specially shaped product specimens may adopt

the buoyancy method.

6.6.6 Barcol hardness

In accordance with the method of GB/T 3854, conduct the test.

6.6.7 Load deformation temperature

In accordance with the method of GB/T 1634.3-2004, conduct the test. The span is set to 100

mm, and the maximum bending stress uses Method A, which is 1.80 MPa.

6.7 Flame-retardant Properties

6.7.1 Oxygen index

In accordance with the method of GB/T 8924, conduct the test.

6.7.2 Vertical combustion

In accordance with the method of GB/T 2408, conduct the test.

6.8 Smoke Density

In accordance with the method of GB/T 8627, conduct the test.

6.9 Adhesion Performance

In accordance with the method of GB/T 9286, conduct the test.

6.10 Water Resistance

In accordance with the method of GB/T 2573, conduct the test. The test water shall be distilled

water or deionized water, and the test water temperature is 23 C  2 C or 40 C  2 C. After

720 h of test, check the appearance quality of the specimen, determine the flexural strength of

the specimen and calculate the retention rate of flexural strength. The water temperature of the

arbitration test is 23 C  2 C.

6.11 Resistance to Chemical Media

6.11.1 Gasoline resistance

In accordance with the method of GB/T 3857, conduct the test. The test solvent is 92# gasoline.

After soaking at room temperature at 10 C ~ 35 C for 360 h, check the appearance quality of

the specimen, determine the flexural strength of the specimen and calculate the retention rate

of flexural strength.

6.11.2 Acid resistance

In accordance with the method of GB/T 3857, conduct the test. The test solvent is 30% sulfuric

acid solution. After soaking at room temperature at 10 C ~ 35 C for 360 h, check the

appearance quality of the specimen, determine the flexural strength of the specimen and

calculate the retention rate of flexural strength.

6.11.3 Alkali resistance

In accordance with the method of GB/T 3857, conduct the test. The test solvent is 10% sodium

hydroxide solution. After soaking at room temperature at 10 C ~ 35 C for 168 h, check the

appearance quality of the specimen.

NOTE: if there is a special service environment for the above-mentioned chemical solvent

resistance tests, the concentration of the test solvent and the test cycle shall be determined

by both parties through negotiation.

6.12 Environmental Adaptability

6.12.1 Damp heat resistance

In accordance with the method of GB/T 2573, conduct the test. Select the constant damp heat

test conditions. The temperature is 60 C  2 C and the relative humidity is 93%  2%. Carry

out the test with 24 h as a test cycle and conduct not less than 10 consecutive cycles. After the

test, check the appearance quality of the specimen, determine the flexural strength of the

specimen and calculate the retention rate of flexural strength.

6.12.2 Low-temperature impact resistance

Place the specimen with a length of not less than 300 mm or not less than 50% of the total

length of the sample in a low-temperature test chamber. After the temperature drops to 40 C

 2 C, maintain the temperature constant for 2 h, then, take out the specimen; immediately use

a steel ball with a mass of 1 kg  50 g to freely drop to impact the specimen at a distance of 1

m directly above the specimen; observe the test results.

6.12.3 Low-temperature drop resistance

Place the specimen whose length is not less than 300 mm in the low-temperature test chamber.

When the actual length of the sample is less than 300 mm, put the whole sample into the low-

temperature test chamber. After the temperature drops to 40 C  2 C, maintain the

temperature constant for 2 h, then, take out the specimen; with the length direction of the

specimen or the front of the specimen parallel to the ground, from a height of 1 m, let it freely

fall to the hard ground; observe the test results.

6.12.4 Weather resistance

6.12.4.1 Resistance to artificial accelerated aging (xenon arc light source)

7.1.2 Inspection conditions

The type inspection shall be carried out every two years. Under one of the following

circumstances, type inspection shall also be carried out:

a) Newly designed and trial-manufactured products;

b) During the official production, if there are major changes in raw materials and

processes that may affect product properties;

c) When the exit-factory inspection results are significantly different from the previous

type inspection;

d) When the production has been suspended for more than half a year, then, resumed.

7.1.3 Determination rules

During the type inspection, when one of the indicators does not comply with the requirements,

then, double samples shall be taken from the same batch of products to conduct a re-inspection

on the indicator. If it is still disqualified in the re-inspection results, then, the product shall be

determined as disqualified in the type inspection, otherwise, it shall be determined as qualified.

7.2 Exit-factory Inspection

7.2.1 General requirements

The products shall pass the inspection of the producer’s quality inspection department and be

attached with a product quality certificate before exiting the factory.

7.2.2 Batch

Products with the same formula, raw materials, processes and production conditions can

constitute a batch.

7.2.3 Sampling method

In accordance with the stipulations of JT/T 495, conduct the test.

7.2.4 Inspection items

Comply with the stipulations of various product standards.

7.2.5 Determination rules

During the exit-factory inspection, when one of the indicators does not comply with the

requirements, then, double samples shall be taken to conduct a re-inspection on the indicator.

If the samples in the re-inspection are still disqualified, then, the batch shall be determined as

disqualified.

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