JT/T 1266-2019Technical conditions of cold sprayed zinc anticorrosive for bridge steel structure (English PDF)

Foreword

This standard is in accordance with GB/T Draft the rules given in 1-2009.

This standard is proposed and managed by the National Technical Committee for Traffic Engineering Facilities (Highway) Standardization (SAC/TC 223).

This standard was drafted. Wuxi Huadong Zinc Shield Technology Co., Ltd., China Railway Construction Bridge Design and Research Institute, China Railway Bridge Survey Design Group Co., Ltd., Shanghai Municipal Engineering Design and Research Institute (Group) Co., Ltd., Shanghai Lin Tongyan Li Guohao Civil Engineering Consulting Co., Ltd., China State Construction Engineering Corporation Design Group Co., Ltd., Zhejiang Transportation Planning and Design Research Institute, Anhui Transportation Planning and Design Research Institute, Suzhou Jiaotong Group Co., Ltd., China Railway Shanqiao Group Co., Ltd., China Railway Baoqiao Group Co., Ltd., Shanghai Jianye Technology Engineering Co., Ltd., Jiangsu China Mining Dazheng Surface Engineering Technology Co., Ltd., Xi'an Municipal Design & Research Institute Co., Ltd., Nanjing Third Yangtze River Bridge Co., Ltd., Jilin Provincial Highway Administration.

1 Scope

This standard specifies the classification, structure, technical requirements, test methods, and quality inspection of cold sprayed zinc anticorrosive coating on the surface of bridge steel structures.

Wait.

This standard is applicable to the cold sprayed zinc anticorrosive coating on the surface of bridge steel structures, and other steel structures can be used for reference.

2 Normative references

The following documents are essential for the application of this document. For dated references, only the dated version applies to this article Pieces. For undated references, the latest version (including all amendments) applies to this document.

GB/T 1725 Determination of non-volatile content in paints, varnishes and plastics GB/T 1728 Determination of drying time of paint film and putty film GB/T 1731 Determination of film flexibility GB/T 1732 Determination of impact resistance of paint film GB/T 1766 Method for rating paint and varnish coatings GB/T 1771 Determination of resistance to neutral salt spray of paints and varnishes GB/T 6742 Paint and varnish bending test (cylindrical shaft) GB/T 8923. 1 Visual evaluation of surface cleanliness of steel surfaces before application of coatings Part 1. Uncoated steel Corrosion level and treatment level on the surface and steel surface after the original coating has been completely removed GB/T 9271 Standard Test Plate for Paints and Varnishes GB/T 9278 Temperature and humidity of paint sample condition adjustment and test GB/T 9286 Cross-cut test for paints and varnishes GB/T 10125 Artificial atmosphere corrosion test Salt spray test GB/T 13288 Surface treatment of steel before coating application Surface roughness of steel after spray cleaning GB/T 13452. 2 Determination of film thickness of paints and varnishes GB/T 16906 Method for determination of resistivity of electrostatic conductive coatings for petroleum tanks GB/T 18570. 3 Surface treatment of steel before coating application Test for evaluation of surface cleanliness Part 3. Steel before coating application Surface dust evaluation (pressure-sensitive adhesive tape method) GB 24409-2009 Limits of harmful substances in automotive coatings GB/T 30789. 3 Evaluation of the aging of colored paint and varnish coatings The number and size of defects and the standard of the degree of uniform change in appearance Part 3. Evaluation of Rust Levels GB/T 30790. 2 Corrosion protection of steel structures by protective paint systems of colored paints and varnishes. Part 2. Environmental classification GB/T 3156. 1. Evaluation of the adhesion/cohesion (breaking strength) of anticorrosive protective coatings of protective coating systems to steel structures and Acceptance criteria Part 1. Pull-open test GB 50205-2001 Code for Construction Quality Acceptance of Steel Structure Engineering HG/T 2454 solvent-based polyurethane coating (two-component) HG/T 3792 Crosslinked fluororesin coating HG/T 3952 Cathodic Electrophoretic Coating JT/T 1266-2019 HG/T 4755 Polysiloxane coating HG/T 4845 Cold Coating Zinc Coating ISO 12944-29.:2018 Corrosion protection of steel structures by protective paint systems for pigmented and varnished parts. Part 9. Offshore construction and construction Protective coating system and laboratory performance test method for related structures

3 Terms and definitions

The following terms and definitions apply to this document.

Cold sprayed zinc material spray zinc material it is suitable for normal temperature spraying construction, has good cathodic protection performance, and can form metal coatings with a dry film total zinc content of more than 95%.

Component materials.

Cold spray zinc sealant cold spray zinc seal it has the function of penetration, sealing, anti-corrosion, insulation and barrier. It is used for coating the rough pores on the surface of cold spray zinc metal coating.

material.

Cold sprayed zinc anticorrosion system cold spyd zinc corrosion protection system According to different corrosive environments and anti-corrosion requirements, various types of composite coatings are matched on the surface of cold sprayed zinc coating, and the cold sprayed zinc coating is cathodic protection and matching the coating barrier protects synergistically and forms a cold spray zinc high durability anticorrosive system.

Total zinc content of dry film tol zn cont of off dry film the mass fraction of all zinc elements including elemental zinc and zinc as a compound (such as zinc oxide) in nonvolatile matter.

4 Classification and structure

4.1 Classification

4.1.1 Cold spray zinc anticorrosive system is divided into.

a) Single-layer self-sealing system. cold sprayed zinc metal coating alone, no additional coating, no. N;

b) Composite coating system. cold sprayed zinc metal coatings are equipped with multiple coatings such as cold sprayed zinc sealant and weather-resistant topcoat.

Is L;

c) Water-based composite coating system. water-based cold sprayed zinc (water-based) cold sprayed zinc sealant, (water-based) weather-resistant top coat and other coatings, codename is W.

4.1.2 Cold spray zinc composite coating system is divided into.

a) Cold spray zinc base coat, codenamed P;

b) cold spray zinc sealant intermediate coating, code M;

c) Weather-resistant topcoat, codenamed F.

4.2 Structure

4.2.1 Cold sprayed zinc single-layer self-sealing layer

Figure 1 shows the composition of the cold sprayed zinc single-layer self-sealing layer.

JT/T 1266-2019

Explanation.

1 --- steel; 2--single-layer self-sealing coating of cold sprayed zinc.

Figure 1 Schematic diagram of cold sprayed zinc single-layer self-sealing coating

4.2.2 Cold spray zinc composite coating system the cold sprayed zinc composite coating system consists of a cold sprayed zinc metal coating, a cold sprayed zinc sealant intermediate coating and a weather-resistant surface coating, as shown in Figure 2.

Explanation.

1 --- steel; 3 --- cold spray zinc sealant intermediate coating;

2 --- cold spray zinc metal coating; 4 --- weather-resistant surface coating.

Figure 2 Schematic of cold spray zinc composite coating

5 Technical requirements

5.1 Materials

5.1.1 Performance requirements of cold sprayed zinc materials the performance requirements of cold sprayed zinc materials shall meet the requirements in Table 1.

Table 1 Performance requirements of cold sprayed zinc materials

Performance requirements

1 No hard lumps in the container, even after stirring

2 No blistering, pinholes, sagging or cracking during construction

3 Non-volatile matter content (%) >=80

4 Lead content (mg/kg) <=30 Total zinc content in non-volatile matter (%) Oily 96 ± 1 Water-based 92 ± 1

6 Drying time (h)

Surface dry <=0. Five Hard work <= 24

7 Flexibility (mm) <=2

8 Impact resistance (cm) 50

9 Crossing test (level) <=1

10 Coating surface resistivity (ohm) <= 105

11 The matching paint film is flat, does not wrinkle, does not bite, and the matching adhesion is not less than 3MPa 12 rapid salt spray test >= 360h without any blistering and rusting

13 Resistance to neutral salt spray >= 4,000h, Ri1 level

JT/T 1266-2019

5.1.2 Performance requirements of cold spray zinc sealant the performance requirements of cold spray zinc sealant should meet the requirements in Table 2.

Table 2 Performance requirements of cold spray zinc sealant

Performance requirements

1 In the state of the container, there is no lumps after stirring, and it is uniform.

2 Non-volatile matter content (%) >=80

3 Drying time (h)

Surface dry <= 2

Hard work <= 24

4 Bendability (mm) <= 2

5 Impact resistance (cm) 50

6 Adhesion (pulling method) (MPa) >=5

5.1.3 Performance requirements for weather-resistant topcoat the weatherproof topcoat performance requirements are as follows.

a) The performance requirements of polysiloxane weather-resistant topcoats shall meet the requirements of HG/T 3792;

b) The performance requirements of fluorocarbon weather-resistant topcoat shall meet the requirements of HG/T 4755;

c) The performance requirements of acrylic polyurethane weather-resistant topcoat shall meet the requirements of HG/T 2454.

5.2 Cold spray zinc anticorrosive coating system

5.2.1 Anticorrosive supporting system

5.2.1.1 Cold sprayed anticorrosive supporting system for the outer surface of steel structure According to the atmospheric environmental conditions of the bridge and the surrounding specific corrosion conditions, combined with the service life, design the cold sprayed zinc anticorrosive body on the outer surface of the steel structure System, see Tables 3, 4, and 5. Corrosive environment according to GB/T 30790. 2 Classification of atmospheric corrosion environment.

a) C3 --- moderately corrosive environment;

b) C4 --- highly corrosive environment;

c) C5 --- very corrosive environment.

Table 3 C3 Cold sprayed zinc anticorrosion supporting system for the outer surface of bridge steel structure in moderately corrosive environment

Variety of coating materials for coating system Number of channels/minimum Dry film thickness (Mm) Total dry film thickness (Mm) Anticorrosive life (year) QD01 Monolayer self-closing system (N) Bottom-in-one coating cold spray zinc/water-based cold spray zinc material 2/85 85 15 ~ 25 QD02 Composite coating system (L) Undercoat (P) Cold sprayed zinc material 1/60 Intermediate coating (M) Cold spray zinc sealant 2/80 Topcoat (F) Acrylic polyurethane topcoat/fluorocarbon topcoat 2/80 220 20 ~ 25 JT/T 1266-2019

Table 3 (continued)

Variety of coating materials for coating system Number of channels/minimum Dry film thickness (Mm) Total dry film thickness (Mm) Anticorrosive life (year) QD03 Environmental protection composite coating System (W) Undercoat (P) Water-based cold spray zinc material Intermediate coating (M) Water-based cold spray zinc sealant 2/80 Topcoat (F) Water-based fluorocarbon topcoat 2/80 220 20 ~ 25 QD04 Composite coating system (L) Undercoat (P) Cold Sprayed Zinc Material 2/70 Intermediate coating (M) Cold spray zinc sealant 2/100 Topcoat (F) Polysiloxane topcoat 2/100 270 20 ~ 30

Table 4 C4 Cold sprayed zinc anticorrosive supporting system for the outer surface of bridge steel structure in high corrosion environment

Variety of coating materials for coating system Number of channels/minimum Dry film thickness (Mm) Total dry film thickness (Mm) Anticorrosive life (year) QD05 Single-layer self-closing System (N) Bottom-in-one coating cold-zinc sprayed/water-based cold-zinc sprayed material 2/120 120 15 ~ 25 QD06 Composite coating system (L) Undercoat (P) Cold Sprayed Zinc Material 2/80 Intermediate coating (M) Cold spray zinc sealant 2/100 Topcoat (F) Fluorocarbon Topcoat 2/80 260 20 to 25 QD07 Composite coating system (L) Undercoat (P) Cold Sprayed Zinc Material 2/80 Intermediate coating (M) Cold spray zinc sealant 2/100 Topcoat (F) Polysiloxane topcoat 2/90 270 20 ~ 25 QD08 Environmental protection composite coating System (W) Undercoat (P) Water-based cold spray zinc material 2/80 Intermediate coating (M) Water-based cold spray zinc sealant 2/120 Topcoat (F) Polysiloxane topcoat 2/90 290 20 to 25

Table 5 C5 Cold sprayed zinc anticorrosion supporting system for the outer surface of bridge steel structure in very corrosive environment

Variety of coating materials for coating system Number of channels/minimum Dry film thickness (Mm) Total dry film thickness (Mm) Anticorrosive life (year) QD09 Composite coating system (L) Undercoat (P) Cold Sprayed Zinc Material 2/80 Intermediate coating (M) Cold spray zinc sealant 2/140 Topcoat (F) Polysiloxane topcoat 2/110 330 15 ~ 25 QD10 Composite coating system (L) Undercoat (P) Cold Sprayed Zinc Material 2/80 Intermediate coating (M) Cold spray zinc sealant 2/150 Topcoat (F) Fluorocarbon Topcoat 2/90 320 15 ~ 25 JT/T 1266-2019

5.2.1.2 Corrosion protection system for internal surface of bridge steel structure in closed environment See Table 6 for supporting systems for internal corrosion protection of bridge steel structures in closed environments.

Table 6 Corrosion protection system for internal surface of bridge steel structure in closed environment

Variety of coating materials under working conditions Number of channels/minimum dry film Thickness (µm) Total dry film thickness (Mm) Anticorrosive life (year) Equipped with a spray coating on the bottom surface of the dehumidifier, cold sprayed zinc/waterborne cold sprayed zinc 2/70 70 30 no spray coating on the bottom surface of the dehumidifier, cold sprayed zinc/water-based cold sprayed zinc 2/85 85 30

5.2.1.3 Anticorrosive supporting system for internal surface of bridge steel structure in non-enclosed environment See Table 7 for supporting systems for internal corrosion protection of bridge steel structures in non-enclosed environments.

Table 7 Anticorrosive supporting system for internal surface of bridge steel structure in non-enclosed environment

Variety of coating materials for corrosive environment Number of channels/minimum dry film Thickness (µm) Total dry film thickness (Mm) Anticorrosive life (year) C3, C4 one-side coating cold spray zinc/water-based cold spray zinc 2/80 80 30 C5 Bottom-in-one coating cold spray zinc/water-based cold spray zinc 2 120 120 120 30

5.2.1.4 Steel bridge surface coating anticorrosive supporting system See Table 8 for the anticorrosive supporting system of steel bridge deck coating.

Table 8 Anticorrosive supporting system for steel bridge surface coating

Variety of coating materials under working conditions Number of channels/minimum dry film Thickness (µm) Total dry film thickness (Mm) Conventional direct paving asphalt or asphalt concrete undercoating cold spray zinc 2 80 80 Designed with a water-repellent coating on the anti-corrosion layer

5.3 Performance requirements of anticorrosive coating system the performance requirements of the anticorrosive coating system are shown in Table 9.

Table 9 Performance requirements of anticorrosive coating systems

Corrosive environment and kind Cyclic alternating corrosion test Salt spray resistance Cathode peel resistance Adhesion (MPa) C3 720h no rust, no peeling, no Cracking and no chalking 2 000h no rust at the scribe line Cracks, does not fall off, does not rust C4 720h no rust, no peeling, no Cracking and no chalking 2 000h no rust at the scribe line, no paint film at the unscribed area Cracks, does not fall off, does not rust 2 000h JT/T 1266-2019

Table 9 (continued)

Corrosive environment and kind Cyclic alternating corrosion test Salt spray resistance Cathode peel resistance Adhesion (MPa) C5 1 440h no rust, no peeling, no Cracking and no chalking 4 000h Unidirectional expansion at the scribe line <= 2mm, not scribed Zone paint film does not crack, peel off, or rust 4 000h 3

5.4 Craftsmanship

5.4.1 Surface treatment 5. 4. 1. 1. Pretreatment before rust removal of steel components Pretreatment of steel components. Steel components should be pretreated before sandblasting and rust removal, including.

a) Rough welds are smooth and polished, and welding spatters are removed with a spatula or a grinder. The weld has a depth of 0. Over 8mm or small defect width Deep undercuts should be repaired and smoothed.

b) Sharp edges are polished with a grinding wheel into a circular arc with a radius of not less than 2 mm.

c) When the difference between the peaks and valleys of the cutting edge is greater than 1mm, it shall be polished to less than 1mm.

d) Surface lamination, cracks and inclusions shall be ground and repaired if necessary.

5.4.1.2 Degreasing

Surface oil stains should be sprayed with a special cleaner or brushed with a soft brush, and all residues should be washed away with a fresh water gun; or alkaline Liquid, flame, etc., and rinse with fresh water until neutral. Small areas of oil can be scrubbed with solvents.

5.4.1.3 Desalination the content of soluble chloride on the surface of steel components after sandblasting should not be greater than 7 µg/cm2. When it exceeds the standard, it should be flushed with high pressure fresh water. When the steel structure when it is determined that it is not exposed to the chloride ion environment, the surface soluble salt test may not be performed; when it is not completely determined, the first test shall be performed.

5.4.1.4 Descaling

The rust removal shall be carried out according to the following requirements.

a) Painting of new components of the factory. The surface treatment of steel components should reach GB/T 8923. 1 Sa2Z grade in the regulations, roughness (RZ) according to the testing method specified in GB/T 13288 should reach 50µm to 80µm; the parts that are not easy to spray to remove rust should be removed by hand and power tools.

Rust to GB/T 8923. 1 St3 in the regulations;

b) Maintenance and painting. first clean up the loose coating around the damaged area, and extend it to the non-damaged area 50mm ~ 80mm.

Mouth, surface treatment to GB/T 8923. 1 St3 in the regulations;

c) Repainting. The surface treatment is in accordance with the requirements of the first painting.

5.4.1.5 Dust removal After the blasting, remove the blasting residue. Use a vacuum cleaner or oil-free, water-free compressed air to clean the surface dust. Spray after cleaning the dust surface cleanliness requirements are not greater than GB/T 18570. Level 3 of the 3 regulations.

5.4.2 Painting requirements Coating according to the following requirements.

a) The ambient temperature of the construction is 5 °C ~ 38 °C, and the relative humidity of the air is less than 85%. When the surface temperature of the steel member is greater than the dew point temperature of 3 °C, Under rain, fog, snow, wind and heavy dust, outdoor construction is not allowed.

b) Coating should be performed within 4 hours after the surface blasting treatment is completed; when the relative humidity of the environment is less than 60%, a delay can be appropriately made, but the longest should not exceed 12h; during this period, if the surface returns to rust, the rust should be removed again.

JT/T 1266-2019

c) Corners and parts that are not easy to be sprayed should be pre-coated with a cold spray zinc material by brushing.

d) For large area spraying, high pressure airless spraying should be used.

e) Slender, small area and complex shape components can be applied by air spray or brush.

5.4.3 Painting interval Cold spray zinc coating interval should not be less than 24h, others should be carried out according to the technical requirements of the material specification.

In the case, it should be painted after brushing.

5.4.4 Coating curing After the coating is completed, the coating film should be put into use after a specified drying time. Avoid rain or water immersion until the coating is completely dry.

Or damage to the coating.

6 Test method

6.1 Materials

6.1.1 Board requirements Cold sprayed zinc coating substrates, substrate treatment, and board making requirements shall be performed in accordance with the provisions of HG/T 4845.

6.1.2 Cold sprayed zinc material Test methods for cold sprayed zinc materials are shown in Table 10.

Table 10 Test methods for cold sprayed zinc materials

Item Test Method

1 State in container Open the container. The material should be uniform and sticky up and down. Stir with a knife or stirring rod.

Hard precipitation, if it is easy to mix evenly by manual stirring, it can be rated as "without hard lumps after mixing, it is in a uniform state"

2 Workability

Under the standard conditions specified in GB/T 9278, spray a cold spray of zinc (50 ± 5) µm, spraying after 24h, spray Apply a second pass of cold spray zinc to (100 ± 10) µm, and observe whether there is blistering, pinholes, sagging, or cracking on the surface of the board.

3 The content of non-volatile matter shall be carried out in accordance with GB/T 1725. The baking temperature is (105 ± 2) ° C, the baking time is 3h, and the sample amount is about 2g

4 Lead content shall be determined in accordance with the provisions of Appendix D of GB 24409-2009.

5 The content of total zinc in non-volatile matter shall be determined in accordance with the regulations of HG/T 4845.

6 Drying time according to GB/T 1728, surface drying according to method B, solid drying according to method A

7 Flexibility according to GB/T 1731

8 Impact resistance according to GB/T 1732

9 Cross-cut test shall be conducted in accordance with GB/T 9286

10 The surface resistivity of the coating shall be carried out in accordance with the provisions of GB/T 16906

11 Compatibility is carried out in accordance with the provisions of HG/T 4845

12 The rapid salt spray test shall be conducted in accordance with GB/T 1771 and in accordance with GB/T 30789. 3 Evaluation

13 Resistance to neutral salt spray is tested in accordance with GB/T 1771 and in accordance with GB/T 3789. 3 Evaluation JT/T 1266-2019

6.1.3 Cold spray zinc sealant the test method of cold spray zinc sealant is shown in Table 11.

Table 11 Test method of cold spray zinc sealant

Item Test Method

1 The state in the container The state in the container should be no lumps after stirring and be in a uniform state

2 The content of non-volatile matter shall be determined in accordance with GB/T 1725

3 Drying time shall be in accordance with GB/T 1728

4 Bendability shall be performed in accordance with GB/T 6742

5 Impact resistance shall be determined in accordance with GB/T 1732

6 Adhesion according to GB/T 3158. Regulation 1

6.1.4 Weather-resistant finish the weathering test method is as follows.

a) Polysiloxane weather-resistant surface coating shall be carried out in accordance with the provisions of HG/T 3792;

b) Fluorocarbon weathering surface coating shall be carried out in accordance with the provisions of HG/T 4755;

c) The acrylic polyurethane weathering surface layer shall be carried out in accordance with the provisions of HG/T 2454.

6.2 Cold spray zinc anticorrosive coating system

6.2.1 The cyclic alternating corrosion test shall be carried out in accordance with the provisions of HG/T 3952.

6.2.2 The salt spray resistance test shall be conducted in accordance with GB/T 1771.

6.2.3 The cathodic peel resistance test shall be carried out in accordance with the provisions of ISO 12944 ~ 9..2018.

6.2.4 The adhesion test of the coating system shall be in accordance with GB/T 3158. 1 provisions.

6.2.5 After the coating system test, the surface defects of the paint film shall be judged in accordance with GB/T 1766.

7 Quality inspection

7.1 Material performance inspection before construction

7.1.1 Material re-inspection shall be carried out before painting construction, which shall be jointly inspected by the constr...