What technical indicators and safety issues need to be paid attention to during the construction of tunnel fire retardant coatings?

This paper introduces the fire protection measures of the existing tunnels and the construction technology of the tunnel fireproof coating, and specifically expounds the technical indicators and safety issues that need to be paid attention to in the construction process, and provides some reference suggestions for the construction of the tunnel fireproof coati.

Tunnel is a weak link in the whole road transportation, its safety directly affects the smooth flow of the whole ro.

In order to reduce the losses caused by traffic accidents, fire prevention measures are taken during the construction and maintenance period of the tunn.

By comparison, it is found that spraying fire retardant coatings is the most cost-effective method of fire protecti.

The purpose of this paper is to study the construction technology of tunnel fire retardant coatings, in order to better exert the advantages of tunnel fire retardant coatings through construction control, and improve their fire resistance performance and use effe.

 #1 Scope

Since the main component of the tunnel fire retardant coating is aluminate cement, it can be applied to general civil concrete structure building fire protection and tunnel fire protection spraying projec.

The formula of fire retardant coating is shown in Table 1:

Aluminate cement and rubber powder mainly play the role of bondi.

The vermiculite, mica and perlite in the coating play a role in heat insulation, and hollow glass beads, aluminum hydroxide, magnesium hydroxide, e.

#2 Process Principle

The construction process of tunnel fireproof coating is generally 3-layer interval construction, namely base layer (surface primer), middle layer construction and surface layer (top coating) constructi.

The one-component paint should be mixed with water at a ratio of 1:75, whichever is suitable for mortar pump sprayi.

After stirring and standing for a period of time, the coating is sprayed by a squeeze mortar pu.

 #3 Process flow and operational requirements

1 Construction machinery and material preparation

1 Construction equipment and personnel

a) The mortar mixer is used for mixing tunnel fireproof coatin.

Make sure that the stirred paint has sufficient viscosity, and the water consumption should be modera.

If the water consumption is too small, the viscosity of the paint will increase, the fluidity will be poor, and the load of the pump will be increased during spraying, which will also cause equipment dama.

b) Special spraying equipment (extrusion mortar pump, air compressor) A filter should be added at the feed port of the mortar machine to filter out the large particles in the paint, so as not to damage the spraying equipment or affect the paint sprayi.

c) When the special iron plate for smearing mortar is used to repair the dead corners left by spraying in the tunnel or a small part of the defects in the construction, it is necessary to use the iron plate to hold and stir the appropriate paint to repair .

d) The cleaning tools are mainly water spray equipment or brushes, which are used to clean the spraying equipment after the construction is completed, keep the construction equipment clean and clean, and prevent the paint from adhering to the inner wall of the equipment after drying and curing to block the pipeline, which will affect the next construction applicati.

e) Transport vehicles generally use large trucks to transport fire retardant coatin.

f) The construction personnel need 8 to 10 skilled workers, who can guarantee the quality of the project and save costs in terms of construction experience and construction skil.

2 Construction preparation

First, clean the floating dust and oil on the concrete surface of the tunnel, so that the surface of the tunnel wall is more suitable for bonding with fire-resistant paint, and repair the unevenness of the surface of the tunnel wall with concrete to ensure the smoothness of the tunnel concrete surfa.

At the same time, the surface of the tunnel wall with particularly smooth surface is roughened to make the tunnel fireproof coating easier to bo.

Water leaks and seepage areas in the tunnel must be stopped and repair.

Wet the tunnel wall with water before construction to ensure good adhesion between the paint and the tunnel wa.

3 Basic construction

Mix water and paint roughly in a ratio of 75:1 (mass ratio), stir evenly with a mixer to make the paint into a thick slurry, adjust the ratio of water and paint according to the spraying pressure of the equipment, whichever is suitable for the construction equipment spraying and constructi.

Before spraying, use the stirred slurry to make horizontal strip thickness marks with a spacing of 5 m on the tunnel wall as a reference for the coating thickne.

When applying, apply the sprayer from the waist to the top of the tunnel (from bottom to top), spraying about 5 mm thick each ti.

After the first spray is dry, continue to spray the second time, and so on, until the design thickness is reach.

Due to the high spraying pressure of the equipment during construction, the coating formed by spraying is not smooth enough on the tunnel wa.

In order to improve the aesthetics of the paint coating, generally after the last spraying, manual filling, leveling, trimming and polishing should be carried out immediately with slurry to make the surface of the coating smooth and ensure that the coating reaches the design thickne.

There are also colored paints on the surface to improve the aesthetics and smoothness of the tunn.

4 Surface Construction

The surface layer construction can be carried out after the coating base layer is basically dry and form.

For projects with high surface requirements, such as municipal engineering, it is best to scrape a layer of leveling putty on the surface of the base layer before the surface layer construction to make the surface smoo.

After the surface layer construction, the tunnel wall Bright and cle.

The surface coating generally has a low viscosity and can be applied by equipment spraying, manual brushing or roller coati.

The spraying process is required to be uniform, smooth and without color differen.

The demarcation lines of different colors should be straight and cle.

5 Coating maintenance

When the temperature is above 5 °C, natural curing is generally required for 28 da.

The curing conditions are basically the same as those of ordinary concre.

If the coating is found to be damaged during the curing process, it should be repaired in ti.

 #4 Conclusion

At present, China has become the country with the most tunnels and underground works, the most complex tunnel structure, and the fastest development of tunnel construction in the wor.

In view of the painful lessons of various road fires, tunnel fire safety problems have caused China's transportation, fire protection, safety and security issu.

Supervision and other departments attach great importan.

The construction process is simple and easy to implement, which can ensure the construction quali.

After the completion of the project, the fire resistance of the tunnel can be improved, the overall interlayer structure of the inner wall of the tunnel can be improved, the fire resistance advantages of the tunnel fire retardant coating can be fully exerted, and the driving safety factor of the tunnel can be improv.

This paper has great promotion and application value for guiding the spraying construction of tunnel fire retardant coatin.