Application Method for Tunnel Fireproof Coating

Tunnel fire-resistant coating is typically applied using a layered, intermittent construction method, consisting of a base layer (fire-resistant layer) and a surface layer (color layer). During construction and within the first 24 hours post-construction, the ambient temperature must not fall below 4°C to prevent frost damage. Under extremely dry and hot conditions, necessary maintenance conditions should be created to prevent the coating from losing moisture too quickly.

1. Construction Equipment:

Mortar mixers, specialized spraying equipment (screw-type mortar pump, air compressor), iron sheets for mortar application, cleaning tools, transportation vehicles, etc.

2. Construction Preparation:

(1) Clean the surface dust and oil污 from the tunnel concrete, and sprinkle water to moisten.

(2) Repair uneven areas to ensure the tunnel concrete surface is smooth; simultaneously, for particularly smooth concrete surfaces, it is required to apply mortar for leveling.

(3) Ensure leaks are sealed and waterproofed.

3. Field Construction:

(1) Mix water and paint in a ratio of 0.70 to 0.75:1, blend with a mixer for 20 minutes (ensure the mixing time is accurate, use the paint immediately after mixing), forming a thick paste-like consistency.

(2) Create cross-sectional thickness markers in the form of strips spaced 2.5 meters apart using a small amount of paste as a reference for the painting process.

(3) Spray from the tunnel's middle section to the top (from bottom to top) using a spray gun, with each coat thickness ranging from 3 to 8 mm.

After the first coat of di is mostly dry, apply the second coat of di, repeating this process until the desired thickness is achieved.

(5) Due to the uneven smoothness of the coated surface, an immediate hand填补and leveling with paste is required after the last coating application. This ensures the coating surface is smooth and flat, and that the coating thickness meets the design specifications.

Upon completion of the foundation, the coating surface must be smooth, glossy, and clean.

4. Surface Treatment:

After the base layer is fully dried and shaped (typically requiring 3 days), surface work can proceed. For projects with higher requirements, such as municipal engineering, a layer of putty is applied to the base surface before the surface work. The surface can be applied using a spray gun, wool brush, roller, and other equipment, ensuring even, smooth application without color variation. The demarcation lines between different colors must be straight and clear.