Tunnel fireproof material and preparation method thereof

Abstract

The invention belongs to the field of fireproof materials, and particularly discloses a tunnel fireproof material and a preparation method thereof.The tunnel fireproof material comprises a dry powder coating and water, and the weight ratio of the water to the dry powder coating is (0.75-0.8): 1; the dry powder coating comprises the following raw materials in percentage by mass: 40%-50% of cement, 20%-30% of expanded vermiculite, 8%-12% of expanded perlite, 10%-12% of sepiolite, 8%-10% of a flame retardant, 1%-3% of dispersible latex powder, 0.1%-0.3% of PP fibers and 0.01%-0.02% of an SY-05 air entraining agent. According to the invention, cement is taken as a main binder, various lightweight fillers are cemented together, and the fireproof material is applied to fireproof protection of highway, railway and subway tunnel constructions and can also be applied to firewalls of petrochemical engineering and the like, heat conduction is effectively reduced by changing the flame retardant, the heating rate of a protective base layer is reduced, the fire endurance of the fireproof material is improved, and the fireproof performance of the fireproof material is improved. The fireproof material does not generate any toxic gas and waste in a construction process and a fire disaster, and is safe and environment-friendly.

Description

Technical Field

[0001] The invention belongs to the field of fireproof materials, and in particular relates to a tunnel fireproof material and a preparation method thereof. Background Art

[0002] With the rapid development of the economy, the railway, highway and urban subway networks are constantly improving, and there are more and more tunnel projects. Tunnels are not only channels for transportation, but also channels for power cables, optical cables, and even water pipes and oil pipes. Therefore, once a fire accident occurs in a tunnel, it will cause adverse social impacts. Reinforced concrete, which is the main building in the tunnel, is a non-combustible material, but it has a large thermal conductivity and a low fire resistance limit. If a fire occurs in a tunnel, the fire temperature will reach more than 1000 degrees Celsius within less than 10 minutes. The reinforced concrete will quickly lose its bearing capacity and collapse, making evacuation and fire fighting quite difficult, which can easily cause heavy casualties and property losses. Therefore, the tunnel structure must be fire-protected.

[0003] Traditional fire prevention measures include:

[0004] Concrete addition: using additional concrete with a thickness of more than 50 mm as a sacrificial layer to maintain the integrity of the tunnel structure; adding polypropylene fibers to the concrete. Polypropylene fibers melt at high temperatures to form interconnected tiny holes. The water vapor in the concrete is discharged through the small holes, reducing the pressure in the concrete and avoiding the explosion of the concrete to a certain extent; installing a fire extinguishing system, and pasting tunnel-specific fireproof panels with low thermal conductivity made of inorganic materials on the tunnel lining.

[0005] The above-mentioned fire prevention measures are limited in scope of application due to their low fire resistance, complicated construction works and high project costs. In recent years, the most commonly used method of tunnel fire protection is to apply fire retardant coatings on the tunnel lining. When a fire occurs, the tunnel fire retardant coatings undergo rapid physical and chemical changes, which can reduce the flammability of the surface of the coated material and block the rapid spread of the fire. In addition, when applied to the surface of metal components such as steel or non-metallic components such as concrete, in addition to playing the role of rust prevention, acid and alkali resistance and corrosion resistance, it can also slow down the transfer of heat to the components when encountering fire, keep the surface temperature of the components from rising too high within a certain period of time, so that the components can normally bear the structural load.

[0006] However, current tunnel fireproofing materials have problems such as thick coating, low bonding strength, poor water resistance, and coating toxicity safety hazards, which cannot meet the requirements of use. Summary of the invention

[0007] The purpose of the present invention is to provide a tunnel fireproofing material and a preparation method thereof, so as to solve the problems of thick coating, low bonding strength, poor water resistance and potential safety toxicity of coating in the current tunnel fireproofing materials mentioned in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A tunnel fireproofing material comprises dry powder coating and water, wherein the weight ratio of the water to the dry powder coating is 0.75-0.8:1, and the dry powder coating raw materials include: 40%-50% cement, 20%-30% expanded vermiculite, 8%-12% expanded perlite, 10%-12% sepiolite, 8%-10% flame retardant, 1%-3% dispersible latex powder, 0.1%-0.3% PP fiber, and 0.01%-0.02% SY-05 air entraining agent.

[0010] Preferably, the cement is PS42.5 cement, and the cement includes at least one of ordinary Portland cement and high alumina cement.

[0011] Preferably, the expanded vermiculite has a bulk density of 150, a particle size of 1 to 4 mm, and a moisture content of less than 1%.

[0012] Preferably, the expanded perlite has a bulk density of 80, a particle size of 1 to 4 mm, and a moisture content of less than 1%.

[0013] Preferably, the PP fiber has a diameter of 100 to 150 um and a length of 8 to 10 mm.

[0014] Preferably, the flame retardant includes at least one of magnesium hydroxide and aluminum hydroxide.

[0015] A method for preparing a tunnel fireproof material comprises: adding the dry powder coating and water in proportion into a JJ-5 type mixer and stirring them evenly to obtain the tunnel fireproof material.

[0016] Preferably, the JJ-5 type mixer rotates at 140±5 rpm, revolves at 62±5 rpm, and the stirring time is 3 to 6 minutes.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention uses cement as a main binder to bond various lightweight fillers together, and at the same time adds flame retardants and various additives thereto. The lightweight filler can effectively reduce heat conduction, the flame retardant can reduce the temperature of the tunnel fire retardant coating in a fire, and effectively protect the substrate. The dispersible latex powder plays a role in significantly improving workability, construction performance and adhesion. It is applied to the fire protection of highway, railway and subway tunnel structures, and can also be used for fire walls of petrochemical projects. By changing the flame retardant, the heat conduction is effectively reduced, the heating rate of the protective base layer is reduced, and the fire resistance limit of the fireproof material is improved. During the construction process and in the fire, the fireproof material does not generate any toxic gas and waste, and is safe and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0020] Figure 1 It is a block diagram of the material composition of the present invention. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0024] As attached Figure 1 As shown:

[0025] Embodiment 1: This embodiment provides a tunnel fireproof material, including dry powder coating and water, the weight ratio of water to dry powder coating is 0.75-0.8:1, and the mass ratio of dry powder coating raw materials includes: 45% cement, 25% expanded vermiculite, 10% expanded perlite, 12% sepiolite, 10% flame retardant, 3% dispersible latex powder, 0.2% PP fiber, and 0.01% SY-05 air entraining agent.

[0026] The cement is PS42.5 cement, and the cement includes at least one of ordinary Portland cement and high-alumina cement. The expanded vermiculite has a bulk density of 150, a particle size of 1 to 4 mm, and a water content of less than 1%.

[0027] The bulk density of expanded perlite is 80, the particle size is 1 to 4 mm, and the moisture content is less than 1%.

[0028] The diameter of PP fiber is 100-150um and the length is 8-10mm.

[0029] Main indicators of PP fiber:

[0030] Material Polypropylene Fiber Type Bundle monofilament proportion 0.91 tensile strength >358Mpa Acid and alkali resistance Very high Elastic modulus >3.5Gpa Melting point >165℃ Fiber diameter 100-400μm Security Non-toxic materials Water absorption none Thermal conductivity Very low Tensile limit >15％ Low temperature resistance powerful Specification 19mm, 9mm, 6mm, 3mm

[0031] Dispersible latex powder indicators:

[0032] Polymer composition VAC / veoVa / E Solid content ≥98.0％ Ash 10±2 Bulk density (g / L) 400-600 Average particle size (um) 85±15 50% aqueous solution viscosity (pa.s) 2.0-5.0 pH 5-8 Minimum film forming temperature (℃) 5 Appearance White powder, free flowing

[0033] The flame retardant includes at least one of magnesium hydroxide and aluminum hydroxide.

[0034] A method for preparing a tunnel fireproof material comprises: adding dry powder coating and water in proportion into a JJ-5 type mixer and stirring evenly to obtain the tunnel fireproof material.

[0035] The JJ-5 mixer has an autorotation speed of 140±5rpm, an orbital speed of 62±5rpm, and a stirring time of 3 to 6 minutes.

[0036] From the above, we can know that the physical properties of SY-5 air entraining agent are as follows: triterpenoid saponins have large molecules and are not easy to crystallize. Most of them are white or milky white amorphous powders, and only a few are crystals; most of the sapogenins have intact crystals; most of the saponins have bitter and spicy tastes, and are hygroscopic; triterpenoid saponins have the effect of reducing the surface tension of aqueous solutions, and their aqueous solutions can produce persistent foam when they are often shaken strongly, which will not disappear due to heating; triterpenoid saponins have high melting points and often decompose before melting, and the decomposition point is mostly between 200℃-300℃; they are soluble in water, easily soluble in hot water, aqueous enol, hot methanol and hot ethanol, and almost insoluble or difficult to dissolve in other solvents;

[0037] Chemical structure of SY-5 air entraining agent: The chemical structure of triterpenoid saponins is complex, usually composed of multiple carbon atoms, with specific chemical bonds and functional groups; Melting point and boiling point: The melting point of triterpenoid saponins is usually between 175-177℃, and the boiling point is 885.0±65.0℃at760mmHg; Density and polarizability: The density of triterpenoid saponins is about 1.3±0.1g / cm 3 , polarizability is 81.0±0.510^-24cm 3 ;

[0038] Tunnel fireproof materials are mainly used for fire protection of highway, railway and subway tunnel structures, and can also be used for fire walls of petrochemical projects. The main mechanism is: cement is used as the main binder to bond various lightweight fillers together, and flame retardants and various additives are added to them; lightweight fillers can effectively reduce heat conduction; flame retardants can reduce the temperature of tunnel fireproof coatings in fires and effectively protect the substrate; water reducers and dispersible latex powders play a role in significantly improving workability, construction properties and adhesion;

[0039] The tunnel fireproof material is made of cement compound, in which ordinary silicate cement provides good bonding strength, and high-alumina cement can also be appropriately added to improve the fire resistance limit; it can reduce costs and improve the bonding strength of fireproof materials, and the bonding strength is about 0.2MPa;

[0040] By changing the flame retardant, the heat conduction can be effectively reduced, the heating rate of the protective base layer can be reduced, and the fire resistance limit of the fireproof material can be increased, that is, the fire resistance limit is 3h when the thickness is 20mm;

[0041] During the construction process and in a fire, the fireproof material does not produce any toxic gas or waste, and is safe and environmentally friendly.

[0042] experiment:

[0043] The experimental instruments include: fire retardant coating tester XSF-01, oven 202-1AB, hanging alcohol torch J2610, digital thermometer XMD-12, pull-out strength tester SW-4B, refrigerator Casarte, mortar mixer JJ-05, constant temperature and humidity incubator HWS;

[0044] Experimental method: Weigh dry powder coating and water according to the proportion, mix them using a method for preparing tunnel fireproof materials, and measure the dry density, fire resistance and bonding strength of the mixture;

[0045] The fire resistance was determined using the chamber combustion method, specifically: first prepare a concrete column with a diameter of 44 mm and a height of 100 mm, apply the mixed coating to the bottom of the column, and then maintain for 28 days; set a thermocouple at the connection between the concrete and the fire retardant coating, set a thermocouple 25 mm into the concrete from the connection between the concrete and the fire retardant coating, and set a thermocouple 10 mm from the surface of the fire retardant coating to the alcohol torch;

[0046] The dry density is determined as follows: inject the mixed coating into a plastic tube with a diameter of 43mmx47mm, gently shake and tamp it to make it smooth, and remove the plastic tube after 24 hours; after one week in an environment of 15-20℃, place it in an oven at (60±5)℃ to dry for 48 hours, and use a caliper and an electronic balance to measure the volume and mass of the specimen and then calculate the dry density.

[0047] The bonding strength test is as follows: place a frame on a 70mm×70mm×20mm mortar block, fill the frame with the paint mixture (internal dimensions 40mm×40mm×3m), smooth the surface with a scraper and immediately remove the frame to obtain a test plate. Curing is carried out in a standard environment for 14 days. On the tenth day of curing, evenly apply a high bonding strength adhesive on the surface of the test plate, and then gently stick the steel connector on it. Carefully remove any excess adhesive that overflows around the connector, and then place it in a ventilated and dry environment for 3 days. After curing for 14 days, measure the maximum tensile strength, i.e., bonding strength, on a tensile testing machine (SW-4B) at a tensile speed of 5mm / min along the vertical direction of the specimen surface; the average value of the 5 experimental values ​​after eliminating gross errors is taken as the result. Experimental Example 1: Weigh dry powder coating and water according to the proportion, mix them using a method for preparing tunnel fireproof materials to obtain a mixture, apply the mixture on the smooth surface of the specimen bottom plate (conforming to the fiber-reinforced low-alkalinity cement building slab specified in JC / T 626) and cure for 28 days, and after the curing is completed, apply a 1:1 mixture of rosin and paraffin on the edges and back of the specimen, and the edge sealing width of the specimen is 2-3mm, and then immerse the specimen with the short side facing down in a glass container filled with tap water, 3 hydrochloric acid aqueous solution and saturated calcium hydroxide solution, and the immersion depth is 2 / 3 of the long side of the specimen; during the experiment, the specimen should be observed every 24 hours to determine whether the coating has cracking, delamination, shedding, swelling and discoloration, and record it until the specified time is reached; used to determine water resistance, acid resistance, alkali resistance and moisture and heat resistance, and the result is that at least 2 of the 3 specimens meet the technical requirements and are judged to be qualified;

[0048] Weigh dry powder coating and water according to the proportion, mix them by a method for preparing tunnel fireproof materials to obtain a mixture, use the mixture to prepare test pieces, set 4 prepared test pieces as a group, keep 1 piece as a control sample, and place the other 3 test pieces at room temperature for 24 hours: place the test pieces in tap water at 23±2℃ for 18 hours, then place the test pieces in a low temperature box at -20±2℃ for 3 hours, then take the test pieces out of the low temperature box and immediately place them in a constant temperature box at 50±2℃ for 3 hours, this is one cycle, and repeat the experiment in this way; during the experiment, the test piece should be observed once at the end of each cycle to determine whether the coating has cracking, delamination, shedding, swelling and discoloration, and record it until the specified number of cycles is reached; used to determine freeze-thaw cycle resistance, the result is that at least 2 of the 3 test pieces meet the technical requirements and are qualified;

[0049] Experimental Example 2: The above experimental method was used to conduct an experiment. The ratio of fireproof materials was the same as that of Example 1. The effects of different cement dosages on the bonding strength, fire resistance and dry density of fireproof materials were measured, as shown in the following table:

[0050] Cement dosage % 30 35 40 45 50 55 60 65 70 75 Bond strength MPa 0.07 0.11 0.15 0.16 0.18 0.18 0.18 0.19 0.2 0.22 Fire resistance min 204 189 175 165 151 142 120 103 93 80 <![CDATA[Dry density kg / m 3 > 420 500 580 630 680 730 850 1000 1230 1520

[0051] Results: With the increase of cement dosage, the bonding strength and dry density of fireproof materials gradually increased, especially when the cement dosage was more than 55%, the dry density increased sharply and the bonding strength increased slowly; this was because the cement with larger bulk density filled the gaps between the particles of the thermal insulation material with smaller bulk density, resulting in a dense structure. With the increase of cement dosage, the relative dosage of the thermal insulation material became smaller and the fire resistance gradually decreased. Therefore, considering the fire resistance, bonding strength and dry density, the most suitable cement dosage is 40% to 50%.

[0052] Experimental Example 3: The above experimental method was used to conduct an experiment. The ratio of fireproof materials was the same as that in Example 1. The effects of the amount of high-alumina cement and ordinary Portland cement in cement on the bonding strength, fire resistance and dry density of the fireproof materials were determined, as shown in the following table:

[0053] High alumina cement: ordinary silicate cement 1:0 7:3 5:5 3:7 0:1 Bond strength MPa 0.05 0.06 0.07 0.12 0.16 Fire resistance min 260 255 243 193 165 <![CDATA[Dry density kg / m 3 > 570 580 613 621 630

[0054] Results: With the increase of high alumina cement dosage, the fire resistance gradually increases and the dry density gradually decreases; this shows that the bulk density of high alumina cement is smaller than that of ordinary Portland cement, and the fire resistance of high alumina cement is higher than that of ordinary Portland cement; however, when the amount of high alumina cement is too much, the bonding strength of the fire retardant coating will be reduced and cannot reach the standard requirement; ordinary Portland cement can also achieve the required fire resistance and is cheaper, so ordinary Portland cement is selected, but a certain amount of high alumina cement can be added as needed to improve the fire resistance.

[0055] Experimental Example 4: The above experimental method was used to conduct an experiment. The ratio of the fireproof material was the same as that in Example 1. The effect of the amount of expanded perlite on the bonding strength, fire resistance and dry density of the fireproof material was determined, as shown in the following table:

[0056] Expanded perlite dosage% 0 5 8 10 12 15 Bond strength MPa 0.48 0.41 0.38 0.34 0.27 0.14 Fire resistance min 115 121 153 170 179 181 <![CDATA[Dry density kg / m 3 > 820 753 699 681 631 543

[0057] Results: With the increase of the amount of expanded perlite, the fire resistance gradually increased, while the bonding strength and dry density gradually decreased. In particular, when the amount of expanded perlite was higher than 15%, the bonding strength did not meet the standard requirements; when the amount was lower than 5%, the dry density and fire resistance did not meet the standard requirements; therefore, the appropriate amount of expanded perlite is 8% to 12%.

[0058] Experimental Example 5: The above experimental method was used to conduct an experiment. The ratio of fireproof materials was the same as that in Example 1. The effect of the amount of sepiolite on the bonding strength, fire resistance and dry density of the fireproof materials was determined, as shown in the following table:

[0059] Sepiolite dosage% 0 6 8 10 12 14 16 Bond strength MPa 0.20 0.28 0.30 0.32 0.34 0.33 0.30 Fire resistance min 161 165 168 168 170 168 168 <![CDATA[Dry density kg / m 3 > 563 584 621 643 681 723 758

[0060] Results: With the increase of the amount of sepiolite, the fire resistance tends to increase a little bit, and the bonding strength gradually increases; because sepiolite is not only a thermal insulation material, but also has a similar role as a binder, and when the amount of sepiolite is higher than 14%, the dry density of the fireproof material cannot reach the standard requirement; therefore, the appropriate amount of sepiolite is 10% to 12%.

[0061] Experimental Example 6: The above experimental method was used to conduct an experiment. The ratio of fireproof materials was the same as that in Example 1. The effects of different flame retardants and their dosages on the bonding strength, fire resistance and dry density of fireproof materials were determined, including the effects of different flame retardants and their dosages on the bonding strength MPa, as shown in the following table (Table 1):

[0062] Flame retardant dosage% 0 6 8 10 12 14 A1(OH) 0.31 0.32 0.34 0.34 0.33 0.33 Mg(OH) 0.30 0.31 0.34 0.33 0.33 0.32

[0063] The effects of different flame retardants and their dosage on the fire resistance min are shown in the following table (Table 2):

[0064] Flame retardant dosage% 0 6 8 10 12 14 16 A1(OH) 121 132 148 170 173 174 175 Mg(OH) 121 128 135 150 153 153 154

[0065] Effect of different flame retardants and their dosage on dry density kg / m 3 The impact is shown in the following table (Table 3):

[0066] Flame retardant dosage% 0 6 8 10 12 14 A1(OH) 673 671 679 681 700 723 Mg(OH) 665 669 671 675 695 713

[0067] Results: From Table 1, it can be seen that the bonding strength does not change significantly with the change of the amount of flame retardant; From Table 2, it can be seen that with the increase of the amount of flame retardant, the fire resistance improves sharply, and the flame retardant effect of A1(OH) is more obvious than that of Mg(OH); This is because the heat absorbed by the thermal decomposition of A1(0H) (470kCa1 / kg) is much greater than that absorbed by the thermal decomposition of Mg(OH) (184kCa1 / kg) under high temperature conditions; It can be seen that it is more advantageous to use A1(OH) as a flame retardant than Mg(OH) to improve the fire resistance of fire retardant coatings; From Table 3, it can be seen that when the amount of A1(OH) is higher than 12%, the dry density of the fire retardant material will not meet the standard requirement value, therefore, the appropriate amount of A1(OH) is 8% to 12%.

[0068] Experimental Example 7: The above experimental method was used to conduct an experiment. The ratio of the fireproof material was the same as that of Example 1. The effects of different amounts of PP fibers added on the performance of the fireproof material were measured, as shown in the following table:

[0069] Fiber addition % 0 0.1 0.2 0.3 0.5 Bond strength MPa 0.33 0.32 0.34 0.33 0.28 Fire resistance min 161 163 170 175 172 Appearance (coating thickness 15mm) Light cracking Minor cracking normal normal normal

[0070] As a result, when the PP fiber addition amount is less than 0.3%, the bonding strength does not change significantly, and the fire resistance performance tends to increase slightly; when the PP fiber addition amount is higher than 0.5%, the changes in bonding strength and fire resistance performance are not obvious; when no PP fiber is added, cracks appear on the surface of the coating, but this does not occur after the addition; therefore, the appropriate addition amount of PP fiber is 0.1% to 0.3%.

[0071] Experimental Example 8: The above experimental method was used to conduct an experiment. The ratio of fireproof materials was the same as that of Example 1. The effects of different air entraining agents on the performance of fireproof materials were measured. When SDS and SY-O5 were used as air entraining agents, the fluidity of the fireproof coating mixture and the introduction of bubbles were observed by naked eyes, as shown in the following table:

[0072] Air entraining agent addition% SDS (0.1%~0.05%) SY-05(0.01%~0.02%) Liquidity Difference good Bubble size big Small Bubble stability Difference good

[0073] The effect of SY-05 addition on the bonding strength, dry density and fluidity of fireproof materials is shown in the following table:

[0074] SY-05 addition amount% 0 0.01 0.02 0.03 0.04 0.05 Bond strength MPa 0.42 0.34 0.32 0.24 0.22 0.21 <![CDATA[Dry density kg / m 3 > 711 681 649 580 530 450 Liquidity Difference good good good good good

[0075] Results: With the increase of SY-05 addition, the bonding strength and dry density gradually decreased, and the fluidity became better. It can be seen that in order to improve the performance of fireproof materials and the fluidity of coating mixtures, the most appropriate amount of SY-05 addition is 0.01% to 0.02%.

[0076] Experimental Example 9: The above experimental method was used to conduct an experiment. The ratio of fireproof materials was the same as that of Example 1. The effects of different water amounts and stirring times on the performance of fireproof materials were measured. The effects of water amounts on the performance of fireproof materials are shown in the following table:

[0077] Water / dry powder coating 0.7 0.75 0.8 0.85 0.9 1 Mixture state Difference good good Difference Difference Difference Bond strength MPa 0.40 0.37 0.33 0.23 0.12 - <![CDATA[Dry density kg / m 3 > 736 675 653 532 424 - Fire resistance min 162 172 163 133 105 -

[0078] Results: When the water / dry powder coating ratio is lower than 0.7, construction is difficult; when the water / dry powder coating ratio is higher than 0.85, the bonding strength, dry density and fire resistance of the material will be sharply reduced; therefore, the appropriate water:dry powder coating ratio is 0.75-0.8.

[0079] The influence of stirring time on the performance of fire retardant coating is shown in the following table:

[0080] Mixing time min 3 6 9 12 <![CDATA[Dry density kg / m 3 > 675 665 631 587 Bond strength MPa 0.39 0.34 0.31 0.28

[0081] Results: When the stirring time is 3 to 6 minutes, the bonding strength and dry density can reach a certain level; when the stirring time exceeds 9 minutes, the dry density and bonding strength gradually decrease; this is because the stirring time is too long and more bubbles are introduced into the mixture.

[0082] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangement, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of performing the function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to numerous modifications still falling within the scope of the appended claims.

[0083] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0084] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0085] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A tunnel fireproof material, characterized in that: The invention comprises dry powder coating and water, wherein the weight ratio of the water to the dry powder coating is 0.75-0.8:1, and the raw materials of the dry powder coating include: 40%-50% cement, 20%-30% expanded vermiculite, 8%-12% expanded perlite, 10%-12% sepiolite, 8%-10% flame retardant, 1%-3% dispersible latex powder, 0.1%-0.3% PP fiber and 0.01%-0.02% SY-05 air entraining agent.

2. A tunnel fireproof material according to claim 1, characterized in that: The cement is PS42.5 cement, and the cement includes at least one of ordinary Portland cement and high alumina cement.

3. A tunnel fireproof material according to claim 1, characterized in that: The expanded vermiculite has a bulk density of 150, a particle size of 1 to 4 mm, and a moisture content of less than 1%.

4. A tunnel fireproof material according to claim 1, characterized in that: The expanded pearlite has a bulk density of 80, a particle size of 1 to 4 mm, and a moisture content of less than 1%.

5. The tunnel fireproof material according to claim 1, characterized in that: The PP fiber has a diameter of 100 to 150 um and a length of 8 to 10 mm.

6. A tunnel fireproofing material according to claim 1, characterized in that: The flame retardant includes at least one of magnesium hydroxide and aluminum hydroxide.

7. A method for preparing a tunnel fireproof material according to any one of claims 1 to 6, characterized in that: include: The dry powder coating and water are put into a JJ-5 mixer according to a certain proportion and stirred evenly to obtain the tunnel fireproofing material.

8. The method for preparing a tunnel fireproof material according to claim 7, characterized in that: The JJ-5 type mixer rotates at 140±5 rpm, revolves at 62±5 rpm, and the stirring time is 3 to 6 minutes.

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