Tunnel fire
Tunnel fire prevention features:

Tunnel fire coatings do not contain asbestos and harmful substances, production, use and construction of the coating is not irritating smell.
Fire does not release toxic gas, smoke toxicity reached AQ-1 level, in line with the requirements of environmental protection.
Prepared by the factory, single component packaging, construction site mixing and mixing construction, easy to operate.
Direct spraying and coating construction, quick drying and curing.
The coating is light, strong, strong, resistant to aging and waterproof.

Performance indicators
Serial number project index technical inspection results

In the state of the container after mixing thick liquid, no agglomeration meets the requirements
Drying time (table)/h is less than or equal to 2416
Bond strength /MPa is greater than or equal to 0.10.2
Dry density/kg/m3, 800620 or less
Water resistance after 720h test, the coating does not crack, layer, fall off, allow slight expansion and color change meet the requirements
Acid resistance after 360h test, the coating does not crack, layer, fall off, allow slight expansion and color change meet the requirements
Alkali resistance after 360h test, the coating does not crack, layer, fall off, allow slight expansion and color change meet the requirements
After 15 tests, the coating does not crack, layer, fall off or change color
After 720h test, the coating does not crack, layer, fall off and change color
Thickness of refractory coating /mm20+2mm1221
Fire resistance limit /h2.02.03.0


It is very important to strengthen the fireproof protection of tunnel structure. At present, a feasible method is to apply a layer of special fireproof coating on the concrete surface of tunnel.

Construction technology:
1. Construction machines and tools:

Mortar mixer, special spraying equipment (extruded mortar pump, air compressor), special iron plate for mortar application, cleaning equipment, transportation tools, etc.

2. Construction preparation:

The concrete surface of the tunnel dust, oil and other cleaning, and sprinkling water wetting.
Repair uneven places to ensure the smooth surface of tunnel concrete.
At the same time for the concrete surface is particularly smooth place, the request USES the mortar surface.
The place that leak must fill leak stop water.

3. Basic construction:

Mix water and coating with (0.70 ~ 0.75) : 1 ratio, stir with a blender for 20min (be sure to ensure the mixing time, coating to mix with the use), into a thick slurry.
Use a small amount of slurry to mark the horizontal strip thickness with spacing of 2.5m as the reference for spraying construction
Spray the tunnel from the waist to the top (from the bottom up) with a spray machine, each time the spray thickness of 3 ~ 8.
After the first spray is basically dry, continue to spray the second time, so that the cycle, until the spray to the design thickness.
Because spray surface is not smooth enough, so in the last spray, immediately after the slurry to manually fill leveling, dressing, make the coating surface smooth and smooth, and ensure that the coating reaches the design thickness.
After the completion of the base layer, the coating surface shall be smooth, smooth and clean.

4. Surface construction:

After base course is basic dry thoroughly model, just can undertake surface course construction (taller to the project of requirement, wait like municipal engineering, had better scrape be bored with child in base course surface course before surface course construction).
Surface can be used for the construction of spray gun, wool brush, roller and other machines and tools, spray brush requirements uniform, smooth, no color difference.
The boundaries of different colors should be straight and clear.


Based on the construction experience of hebei waite road bridge maintenance co., LTD., Suggestions are given as follows:

In the actual tunnel construction, it is suggested that the fire resistance limit should be based on the design requirements, choose the total thickness of tunnel fire coating coating, construction should be divided into several times to complete the daub, each daub thickness should be controlled under 8mm, daub thickness should be uniform, do not need to press light, maintain rough surface.
The last coating thickness should not exceed 6mm, its coating surface should be compacted, flat, and gloss, two coating interval time 12-24 hours (the coating surface drying hardening shall prevail), if the interval time is too long, the coating surface should be sprayed with water wet, coating should be glued between, should not appear empty drum phenomenon.
In the process of construction, construction personnel use probe, at any time to detect the thickness of tunnel fire coatings, in order to meet the thickness requirements of construction and design, coating process scattered paint should be cleaned before its solidification.
The thickness of the fire protection coating shall meet the design requirements, the negative deviation of the thickness value of the measuring point shall not be greater than 2mm, and the continuous area of the thickness shortage shall not be greater than 1m2.
Fireproof coating and base material should be firmly bonded, not exposed, loose, delamination and empty drum phenomenon.
When the coating does not completely cover the structure shape, the coating periphery should be coated tightly.
The appearance of fireproof coating shall be smooth and clean.
No leakage of paint.
The thickness deviation per meter shall not be greater than + / - 2mm. Cracks shall not appear in the coating. If there are individual cracks, the width of cracks shall not be greater than 1mm.
When the coating of tunnel fire retardant coating reaches the thickness required by the design, it shall be naturally maintained for 28 days. During the maintenance period, if the weather is hot, dry, or directly irradiated by the sun, the coating surface shall be sprayed with water for maintenance, to prevent water evaporation too fast, and should avoid impact and high-pressure water erosion.


Key words: tunnel fire prevention tunnel fire prevention construction