CN103232197B - Geopolymer tunnel fireproof coating and preparation method thereof - Google Patents

Abstract

The invention provides a geopolymer tunnel fireproof coating, which is composed of the following raw materials in weight units: 35-45 parts of geopolymer, 10-15 parts of expanded perlite, 17-28 parts of expanded vermiculite, brucite 13-15 parts of fiber, 3-5 parts of sepiolite, 3-5 parts of hydroxymethyl cellulose, 0.03-0.05 parts of fatty alcohol sulfonate air-entraining agent, wherein: the above-mentioned geopolymer is measured in weight units , consists of the following raw materials: 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride, 3 parts of sodium sulfate, and 50 parts of low-calcium fly ash. The geological polymer binder used in the present invention has the characteristics of low material source cost, high bonding strength, and excellent fire resistance and durability; the tunnel fireproof coating of the present invention has long fire resistance limit time, high bonding strength, and freeze-thaw resistance It is a kind of tunnel fireproof coating with good performance.

Description

A kind of geopolymer tunnel fireproof coating and preparation method thereof

technical field

The invention belongs to the field of fireproof coatings, and relates to a tunnel fireproof coating, in particular to a geological polymer tunnel fireproof coating and a preparation method thereof.

Background technique

Tunnel fireproof coating is a special fireproof coating specially designed for tunnel walls and vaults to avoid burning in fire. At present, there are many manufacturers of fireproof coatings for tunnels in my country. Basically, high alumina cement is used as a binder, and lightweight aggregates such as expanded perlite and expanded vermiculite are used to form tunnel fireproof coatings. The typical problem is that this type of tunnel The bonding strength of the fireproof coating is low, the coating is thin and the fire rating is low, the coating is thick and easy to fall off, and the decoration of the fireproof coating is poor.

Geopolymers have the following unique physical and chemical properties:

(1) The source of raw materials is abundant and the price is low. There are abundant reserves of aluminosilicate raw materials in nature. At the same time, industrial slag, fly ash, desulfurization ash, mine tailings and other solid wastes can also be used as aluminosilicate raw materials. While reducing costs, these conventional methods can be disposed of. The substances that are harmful to the environment are processed to achieve the effect of turning waste into treasure.

(2) The material hardens quickly and has high strength. The geopolymerization reaction dehydrates quickly, and the network skeleton is easy to form. Hydration below 20°C for 4 hours, the compressive strength can reach 15-30MPa. The strength of such materials still increases substantially over time.

(3) Good thermal stability and high temperature resistance. Its thermal conductivity is 0.24-0.38W/m K, which is comparable to that of lightweight refractory bricks (0.3-0.4W/m K). The raw materials used are natural aluminosilicate minerals or industrial solid waste, so the material has good fire resistance. It can keep the physical and chemical properties of the material unchanged at a high temperature of 1000 °C.

(4) Good durability. The unique network polymerization structure of geopolymeric materials makes it have better freeze-thaw resistance while maintaining low shrinkage and expansion rates. Therefore, geopolymeric materials have good durability properties.

These unique physical and chemical properties of geopolymers are especially suitable for long-term use as binders in tunnel fireproof coatings. However, usually geopolymers need one or more reactions of water glass solution, metal hydroxide alkali solution and metakaolin, fly ash, slag and other aluminosilicates. In engineering applications, two components are used together Inconvenient and not economical.

Contents of the invention

Aiming at the deficiencies in the prior art, the object of the present invention is to provide a geopolymer tunnel fireproof coating and a preparation method thereof.

In order to realize above-mentioned task, the present invention adopts following technical scheme to realize:

A geopolymer tunnel fireproof coating, which consists of the following raw materials in units of weight: 35-45 parts of geopolymer, 10-15 parts of expanded perlite, 17-28 parts of expanded vermiculite, and 13-15 parts of brucite fiber 3-5 parts of sepiolite, 3-5 parts of hydroxymethyl cellulose, 0.03-0.05 parts of fatty alcohol sulfonate air-entraining agent, wherein:

The geopolymer, in terms of weight unit, consists of the following raw materials: 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride, sodium sulfate 3 parts, 50 parts of low calcium fly ash.

The method for preparing the geopolymer tunnel fireproof coating as described above, the method is carried out according to the steps described below:

Step 1, mix 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride and 3 parts of sodium sulfate according to the parts by weight of the geopolymer formula. Grinding in a ball mill to make fine powder;

Step 2, calcining the fine powder prepared in step 1 at 750° C. for 3 hours;

Step 3, in terms of weight fraction, mix 50 parts of fine powder calcined in step 2 with 50 parts of low-calcium fly ash, and grind it again in a ball mill to make a fine powder below 50 microns to obtain a geopolymer ;

Step 4, according to the formula weight of geopolymer tunnel fireproof coating, 35-45 parts of geopolymer, 10-15 parts of expanded perlite, 17-28 parts of expanded vermiculite, 13-15 parts of brucite fiber, sea foam 3-5 parts of stone, 3-5 parts of hydroxymethyl cellulose and 0.03-0.05 parts of fatty alcohol sulfonate air-entraining agent are stirred and mixed evenly at room temperature to prepare the geopolymer tunnel fireproof coating.

The present invention also has the following technical characteristics:

The weight ratio of the geopolymer tunnel fireproof coating to water is 0.9:1 when used.

Compared with the prior art, the geopolymer tunnel fireproof coating of the present invention has the following technical effects:

(1) Compared with sulphoaluminate cement, high alumina cement and Portland cement, the geopolymer binder used in the present invention has low material source cost, high bonding strength, fire resistance and durability excellent features.

(2) The geopolymer tunnel fireproof coating of the present invention has the characteristics of long fire resistance limit time, high bonding strength and excellent freeze-thaw resistance, and is a tunnel fireproof coating with good performance.

Detailed ways

Geopolymers are activated by alkali to activate the activity of aluminosilicates, and geopolymerization occurs. Generally, aqueous solutions of sodium silicate and sodium hydroxide are used to excite aluminosilicates such as metakaolin, fly ash, and slag. However, if geopolymers are used in tunnel fireproof coatings, the liquid alkali system will bring a lot of inconvenience to transportation and use. The present invention uses low-melting-point sodium salts such as sodium chloride, sodium sulfate and high-melting-point sodium carbonate multi-element eutectic to reduce the melting temperature of sodium carbonate to 600-700°C, and uses highly active silica fume to react with alkali metals at high temperatures The oxide reacts to form sodium silicate, calcium silicate, sodium disilicate or calcium disilicate, and at the same time, with the assistance of alkaline bentonite, kaolin is transformed into highly active metakaolin at 750°C.

Sodium silicate, sodium disilicate, calcium oxide and metakaolin undergo pre-polymerization reaction at high temperature, and finally mix with fly ash to become geological pre-polymer. This geological pre-polymer can make geopolymer tunnel fireproof coating It becomes a single-component coating, which is convenient for transportation. When in use, it only needs to add water to make the geopolymer continue to undergo geopolymerization, and realize the molding of the tunnel fireproof coating.

The use of air-entraining agents can form closed-cell air bubbles in geopolymer fireproof coatings, reducing the thermal conductivity of fireproof coatings.

The tunnel fireproof coating of the invention is not only suitable for fireproofing of various tunnels, but also suitable for fireproofing of various prestressed concrete structures.

According to the above technical scheme, a geopolymer tunnel fireproof coating is composed of the following raw materials in units of weight: 35-45 parts of geopolymer, 10-15 parts of expanded perlite, 17-28 parts of expanded vermiculite, magnesium hydrate 13-15 parts of stone fiber, 3-5 parts of sepiolite, 3-5 parts of hydroxymethyl cellulose, 0.03-0.05 parts of fatty alcohol sulfonate air-entraining agent, of which:

The geopolymer, in terms of weight unit, consists of the following raw materials: 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride, sodium sulfate 3 parts, 50 parts of low calcium fly ash.

The raw material specification requirements in the above formula are as follows:

The particle size of expanded perlite is 2.36mm.

The particle size of expanded vermiculite is 1.18mm～0.6mm.

The brucite fiber length is less than 1 mm.

The fineness of sepiolite is greater than 800 mesh.

Fatty alcohol sulfonate air-entraining agent is produced by Shanghai Daiyu Industrial Co., Ltd.

The Si:Al ratio in low-calcium fly ash is greater than 2.0, and the active glass phase weight content is higher than 40%. The optimal weight ratio of metal oxide M ₂ O and active silica fume SiO ₂ in the mixture of high temperature prepolymerization is 1.3:2.0.

The weight ratio of geopolymer tunnel fireproof coating to water is 0.9:1 when used.

The method for preparing the geopolymer tunnel fireproof coating as described above, the method is carried out according to the steps described below:

Step 1, mix 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride and 3 parts of sodium sulfate according to the parts by weight of the geopolymer formula. Grinding in a ball mill to make fine powder;

Step 2, calcining the fine powder prepared in step 1 at 750° C. for 3 hours;

Step 3, in terms of weight fraction, mix 50 parts of fine powder calcined in step 2 with 50 parts of low-calcium fly ash, and grind it again in a ball mill to make a fine powder below 50 microns to obtain a geopolymer ;

Step 4, according to the formula weight of geopolymer tunnel fireproof coating, 35-45 parts of geopolymer, 10-15 parts of expanded perlite, 17-28 parts of expanded vermiculite, 13-15 parts of brucite fiber, sea foam 3-5 parts of stone, 3-5 parts of hydroxymethyl cellulose and 0.03-0.05 parts of fatty alcohol sulfonate air-entraining agent are stirred and mixed evenly at room temperature to prepare the geopolymer tunnel fireproof coating.

Specific embodiments of the present invention are provided below, and it should be noted that the present invention is not limited to the following specific embodiments, and all equivalent transformations done on the basis of the technical solutions of the present application all fall within the scope of protection of the present invention.

Example 1:

The present embodiment provides the geopolymer tunnel fireproof coating, which consists of the following raw materials in units of weight: 43 parts of geopolymer, 12 parts of expanded perlite, 24 parts of expanded vermiculite, 14 parts of brucite fiber, sepiolite 4 parts, 3 parts of hydroxymethyl cellulose, 0.03 part of fatty alcohol sulfonate air-entraining agent;

The geopolymer, in terms of weight unit, consists of the following raw materials: 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride, sodium sulfate 3 parts, 50 parts of low calcium fly ash.

The various performance parameters of the geopolymer tunnel fireproof coating prepared in this embodiment are shown in Table 1.

Example 2:

The present embodiment provides the geopolymer tunnel fireproof coating, which is composed of the following raw materials in parts by weight: 45 parts of geopolymer, 10 parts of expanded perlite, 22 parts of expanded vermiculite, 13 parts of brucite fiber, sea foam 5 parts of stone, 5 parts of hydroxymethyl cellulose, 0.05 part of fatty alcohol sulfonate air-entraining agent;

The geopolymer, in terms of weight unit, consists of the following raw materials: 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride, sodium sulfate 3 parts, 50 parts of low calcium fly ash.

The various performance parameters of the geopolymer tunnel fireproof coating prepared in this embodiment are shown in Table 1.

Example 3:

The present embodiment provides the geopolymer tunnel fireproof coating, which consists of the following raw materials in units of weight: 35 parts of geopolymer, 12 parts of expanded perlite, 28 parts of expanded vermiculite, 15 parts of brucite fiber, sepiolite 5 parts, 5 parts of hydroxymethyl cellulose, 0.05 part of fatty alcohol sulfonate air-entraining agent;

The geopolymer, in terms of weight unit, consists of the following raw materials: 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride, sodium sulfate 3 parts, 50 parts of low calcium fly ash.

The various performance parameters of the geopolymer tunnel fireproof coating prepared in this embodiment are shown in Table 1.

Example 4:

The present embodiment provides the geopolymer tunnel fireproof coating, which consists of the following raw materials in units of weight: 40 parts of geopolymer, 15 parts of expanded perlite, 20 parts of expanded vermiculite, 15 parts of brucite fiber, sepiolite 5 parts, 5 parts of hydroxymethyl cellulose, 0.04 part of fatty alcohol sulfonate air-entraining agent;

The geopolymer, in terms of weight unit, consists of the following raw materials: 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride, sodium sulfate 3 parts, 50 parts of low calcium fly ash.

The various performance parameters of the geopolymer tunnel fireproof coating prepared in this embodiment are shown in Table 1.

Example 5:

The present embodiment provides the geopolymer tunnel fireproof coating, which is composed of the following raw materials in 100 parts by weight: 45 parts of geopolymer, 15 parts of expanded perlite, 17 parts of expanded vermiculite, 15 parts of brucite fiber, seawater 3 parts of pumice stone, 5 parts of hydroxymethyl cellulose, 0.05 part of fatty alcohol sulfonate air-entraining agent;

The geopolymer, in terms of 100 parts by weight, consists of the following raw materials: 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride, 3 parts of sodium sulfate, 50 parts of low calcium fly ash.

The various performance parameters of the geopolymer tunnel fireproof coating prepared in this embodiment are shown in Table 1.

As can be seen from the above table 1, the tunnel fireproof coatings in embodiment 1, embodiment 2, embodiment 3, embodiment 4 and embodiment 5 all have long fire resistance time, high bonding strength, and freeze-thaw resistance Excellent properties, it is a tunnel fireproof coating with good performance.

Table 1 Tunnel Fireproof Coating Test Results

Claims (3)

1. A geopolymer tunnel fireproof coating is characterized in that, by weight unit, it is made up of the following raw materials: 35 to 45 parts of geopolymer, 10 to 15 parts of expanded perlite, 17 to 28 parts of expanded vermiculite, water 13-15 parts of magnesium stone fiber, 3-5 parts of sepiolite, 3-5 parts of hydroxymethyl cellulose, 0.03-0.05 parts of fatty alcohol sulfonate air-entraining agent, of which: The geopolymer, in terms of weight unit, consists of the following raw materials: 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride, sodium sulfate 3 parts, 50 parts of low calcium fly ash. 2. The geopolymer tunnel fireproof coating according to claim 1, characterized in that the weight ratio of the geopolymer tunnel fireproof coating to water is 0.9:1 when in use. 3. prepare the method for geopolymer tunnel fire-proof coating as described in any one claim in claim 1 and claim 2, it is characterized in that, the method is carried out according to the steps described below: Step 1, mix 17 parts of silica fume, 10 parts of kaolin, 3 parts of calcium-based bentonite, 5 parts of calcium oxide, 10 parts of sodium carbonate, 2 parts of sodium chloride and 3 parts of sodium sulfate according to the parts by weight of the geopolymer formula. Grinding in a ball mill to make fine powder; Step 2, calcining the fine powder prepared in step 1 at 750° C. for 3 hours; Step 3, in terms of weight fraction, mix 50 parts of fine powder calcined in step 2 with 50 parts of low-calcium fly ash, and grind it again in a ball mill to make a fine powder below 50 microns to obtain a geopolymer ; Step 4, according to the formula weight of geopolymer tunnel fireproof coating, 35-45 parts of geopolymer, 10-15 parts of expanded perlite, 17-28 parts of expanded vermiculite, 13-15 parts of brucite fiber, sea foam 3-5 parts of stone, 3-5 parts of hydroxymethyl cellulose and 0.03-0.05 parts of fatty alcohol sulfonate air-entraining agent are stirred and mixed evenly at room temperature to prepare the geopolymer tunnel fireproof coating.