TB/T 3522-2018 in English

This standard systematically stipulates the technical requirements for the entire life cycle of railway protective fences, with the focus on:

• Material specifications: concrete strength ≥ C30, metal mesh galvanizing amount 270g/m²
• Durability indicators: reinforced concrete components ≥ 30 years, metal mesh ≥ 15 years
• Process control: welding point shedding rate <4%, mesh deviation ±3.0mm

4.2.1 Concrete raw materials

Cement is used>42.5 grade silicate cement, coarse aggregate is 5-16mm continuous graded crushed stone, water-cement ratio ≤0.40. Special attention:

• Chloride ion content ≤0.06%
• Sulfur trioxide content ≤4.0%
• Frost resistance grade ≥F250

4.2.6 Steel requirements

The steel bar is HPB300/HRB335 grade, the barbed wire core is φ6.5mm high wire, and the blade is 0.5mm thick Q195 steel plate.

4.3.3 Concrete pouring

Key parameter control:

1. Pouring time of single component≤20 minutes
2. Formwork temperature5-35℃
3. Mold temperature5-30℃

4.3.6 Welding requirements

Tensile strength of mesh welding point＞1kN, resistance welding process is adopted, and the following shall be carried out after welding:

• Weld slag cleaning
• Deformation correction
• Flatness detection

6.1 Type inspection

Trigger conditions include:

• New production line put into operation
• Resume production after 6 months of suspension
• Major changes in materials/processes

6.2 Factory inspection

Required inspection items for each batch:

7.2 Storage specifications

Component storage requirements:

• Handrail ≤10 layers, 6 pads/layer
• Columns ≤ 5 layers, 3 pads/layer
• The cover can be removed only when the ambient temperature difference is ≤15℃

Special environmental response

For saline-alkali/freeze-thaw areas:

1. Galvanizing amount increased to 270g/m²
2. Add preservatives to concrete
3. Add chloride ion diffusion coefficient detection