A kind of gypsum-based steel structure fireproof mortar and its production method

Abstract

The present invention relates to a kind of gypsum-based steel structure fireproof mortar and preparation method, raw material is 80-125 parts of gypsum, 20-45 parts of heavy calcium powder, 25-55 parts of vitrified microspheres, 2-6 parts of propyltrimethoxysilane; additive is appropriate; each raw material contained in the additive is mixed and stirred for 10-15min during preparation to obtain a mixed additive; gypsum, heavy calcium powder and mixed additive are added to a forced mixer, stirred for 10-20min, and a glue powder is obtained; propyltrimethoxysilane is heated to 110-130°C, sprayed on the surface of vitrified microspheres, mixed and stirred, hydrophobic vitrified microspheres are obtained, and then mixed with the glue powder, stirred, and a fireproof mortar is obtained. The steel structure fireproof mortar of the present invention has the characteristics of good fireproof and heat-insulating performance, light weight, high strength, low thermal conductivity, low water absorption, good flexibility, and good construction performance.

Description

Technical Field

[0001] The invention relates to a steel structure fireproof mortar and a production method thereof, belonging to the technical field of steel structure fireproof materials. Background Art

[0002] Steel structure fireproof mortar is used to bond fireproof mortar to steel structure, generally composed of inorganic cementitious materials, fine aggregate and other admixtures. With the development of modern construction industry, people pay more and more attention to the performance of steel structure fireproof mortar.

[0003] As a new type of fireproof material, the existing vitrified microsphere insulation mortar is a dry powder fireproof mortar composed of vitrified microspheres, cement and admixtures. It has sound insulation, heat insulation and fireproof properties and is widely used in house insulation and steel structure fireproofing projects. However, the crack resistance of ordinary vitrified microsphere fireproof mortar is poor. The vitrified microsphere fireproof mortar is constructed by wet method. After the mortar is applied to the steel structure, it will produce a large drying shrinkage ratio, resulting in cracks in the fireproof mortar, which is easy to leak and cause the performance of the fireproof system to decline.

[0004] Therefore, there is an urgent need to develop a fireproof, highly adhesive, lightweight and heat-insulating steel structure fireproof mortar for indoor use. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a steel structure fireproof mortar for indoor use and a production method thereof, wherein the mortar has the characteristics of good fireproofing and heat insulation performance, light weight, high strength, low thermal conductivity, low water absorption, good flexibility, and good construction performance.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A gypsum-based fireproof mortar for steel structures, comprising the following raw materials in parts by weight: 80-125 parts of gypsum, 20-45 parts of heavy calcium powder, 25-55 parts of vitrified microspheres, 2-6 parts of propyltrimethoxysilane, and an appropriate amount of additives;

[0008] The additive comprises: 0.002-0.01 parts of retarder, 0.2-0.5 parts of bentonite, 0.01-0.03 parts of starch ether, 0.002-0.1 parts of touch lubricant, 0.005-0.01 parts of polyvinyl alcohol, 3-8 parts of cement, 0.2-3 parts of cellulose hydroxypropyl methyl ether and 5-10 parts of EVA type redispersible latex powder.

[0009] The compressive strength of gypsum is greater than 15MPa, the flexural strength is greater than 7MPa, the radionuclide internal exposure index is not greater than 1.0; the external exposure index is not greater than 1.0. The particle size of heavy calcium powder is 325 mesh, the whiteness is 95%, and the calcium carbonate content is 98%. The closed porosity of vitrified microspheres is 85-95%, and the bulk density is 100±5kg / m3. It is made of vitrified microspheres of two particle sizes, one passing through a 70 mesh sieve and the other passing through a 90 mesh sieve, with a mixing ratio of 1:3.

[0010] The production method of gypsum-based steel structure fireproof mortar comprises the following steps:

[0011] (1) Weigh each raw material component according to the raw material ratio and set aside;

[0012] (2) Mixing and stirring the raw materials contained in the additive for 10-15 minutes to obtain a mixed additive for later use;

[0013] (3) Add gypsum, heavy calcium powder and mixed additives into a forced mixer and stir for 10-20 minutes to obtain a rubber powder for later use;

[0014] (4) Propyl trimethoxysilane is heated to 110-130° C., then sprayed onto the surface of the glass microspheres, mixed and stirred for 10-15 minutes to obtain hydrophobic glass microspheres, and then mixed with the rubber powder and stirred for 10-15 minutes to obtain the fireproof mortar.

[0015] Beneficial effects of the present invention

[0016] 1. Excellent fireproof performance. The steel structure fireproof mortar of the present invention mainly adopts inorganic non-combustible materials such as gypsum, heavy calcium powder, and vitrified microspheres, which can effectively improve the fireproof performance of the steel structure fireproof mortar, and the combustion performance of the fireproof mortar can reach A1 level.

[0017] 2. Good thermal insulation and bonding properties. The present invention adopts gypsum as the main cementing material of the fireproof mortar, and at the same time, latex powder is added to improve the strength and bonding properties of the cementing material, so that the dry density of the mortar is reduced on the basis of ensuring the compressive strength, so that the mortar has higher strength, lower thermal conductivity and better bonding properties, thereby ensuring that the mortar has good thermal insulation and heat preservation properties, good bonding compatibility with steel structures, and no hollowing and cracking will occur.

[0018] 3. The present invention adopts EVA rubber powder with good flexibility as a cementitious material additive and adds bentonite and the like to improve performance. The product quality is stable and the breakage rate of the vitrified microspheres in the mortar during the construction process is reduced.

[0019] 4. Low water absorption. The present invention selects high-quality vitrified microspheres, mixes with a variety of raw materials, and optimizes the ratio of each component, thereby reducing the water absorption of vitrified microspheres and extending their service life; selects EVA latex powder, which has low ash content and high strength; and selects cellulose hydroxypropyl methyl ether, which has excellent water retention performance.

[0020] 5. The present invention uses gypsum and other organic and inorganic substances as raw materials, effectively utilizes industrial and mining waste materials, and does not add toxic and harmful substances, which is green and environmentally friendly.

[0021] 6. The fireproof mortar of this invention has excellent performance. The experimental results show that the dry bulk density of the fireproof mortar of this invention is less than 415kg / m 3 , compressive strength greater than 0.55MPa, thermal conductivity less than 0.085W / (mk), bonding strength greater than 0.101MPa, softening coefficient greater than 0.88, and hydrophobicity greater than 95%.

[0022] 7. The fireproof mortar of the present invention has a wide range of raw materials, low cost, simple production process, easy operation, convenient use, good construction performance, can meet the needs of different building materials, and has good social and economic benefits. DETAILED DESCRIPTION

[0023] The specific implementation modes of the present invention are further described in detail below in conjunction with the embodiments.

[0024] The performance requirements of the raw materials used in the embodiments of the present invention are as follows:

[0025] Plaster of Paris: compressive strength greater than 15MPa, flexural strength greater than 7MPa, radionuclide internal irradiation index (IRa) less than 1.0; external irradiation index (Ir) less than 1.0;

[0026] Heavy calcium powder: particle size is 325 mesh, whiteness is 95%, calcium carbonate content is 98%;

[0027] Vitrified microspheres: closed porosity 85-95%, vitrified microspheres that pass through a 70-mesh sieve and vitrified microspheres that pass through a 90-mesh sieve are mixed in a ratio of 1:3, and the bulk density is 100±5kg / m 3 .

[0028] Example 1 A fireproof mortar for steel structure and its production method

[0029] The raw materials include the following components by weight: 107 parts of gypsum, 35 parts of heavy calcium powder, 55 parts of vitrified microspheres, 2 parts of propyltrimethoxysilane; and appropriate amounts of additives;

[0030] The additive composition includes: 0.002 parts of retarder, 0.2 parts of bentonite, 0.03 parts of starch ether, 0.002 parts of touch lubricant, 0.005 parts of polyvinyl alcohol, 3 parts of cement, 2 parts of cellulose hydroxypropyl methyl ether, and 5 parts of EVA type redispersible latex powder.

[0031] The production method comprises the following steps:

[0032] (1) Weigh each raw material component according to the raw material ratio and set aside;

[0033] (2) Mix and stir the components of the additive for 10-15 minutes to obtain a mixed additive for later use;

[0034] (3) Add gypsum, heavy calcium powder and mixed additives into a forced mixer and stir for 10-20 minutes to obtain a rubber powder for later use;

[0035] (4) Propyl trimethoxysilane is heated to 110-130° C., then sprayed onto the surface of the glass microspheres, mixed and stirred for 10-15 minutes to obtain hydrophobic glass microspheres, and then mixed with the rubber powder and stirred for 10-15 minutes to obtain the fireproof mortar.

[0036] Construction method: When constructing the mortar, first add water to the mortar, stir evenly, spray it on the beams and columns of the steel structure, and cure at room temperature for 7-14 days; after the curing is completed, proceed to the next step of construction.

[0037] Example 2 A fireproof mortar for steel structure and its production method

[0038] Raw material composition: 90 parts of gypsum, 42 parts of heavy calcium powder, 50 parts of vitrified microspheres, 4 parts of propyltrimethoxysilane; 0.008 parts of retarder, 0.4 parts of bentonite, 0.02 parts of starch ether, 0.01 parts of touch lubricant, 0.008 parts of polyvinyl alcohol, 5 parts of cement, 2 parts of cellulose hydroxypropyl methyl ether, and 7 parts of EVA type redispersible latex powder.

[0039] The production and construction method of the fireproof mortar are the same as in Example 1.

[0040] Example 3 A fireproof mortar for steel structure and its production method

[0041] Raw material composition: 95 parts of gypsum, 25 parts of heavy calcium powder, 45 parts of vitrified microspheres, 5 parts of propyl trimethoxy silane; 0.01 parts of retarder, 0.5 parts of bentonite, 0.01 parts of starch ether, 0.1 parts of touch lubricant, 0.01 parts of polyvinyl alcohol, 6 parts of cement, 2.5 parts of cellulose hydroxypropyl methyl ether, 6 parts of EVA type redispersible latex powder. The production and construction methods of fireproof mortar are the same as those in Example 1.

[0042] Experimental Example 1

[0043] The raw material formula of the steel structure fireproof mortar of the present invention is used as the experimental material, and the feeding ratio of the vitrified microspheres to the rubber powder is changed to obtain different dry bulk densities. The dosage of other raw materials is the same as that of Example 1, and the influence of different raw material ratios on the strength is verified. The results are shown in Table 1.

[0044] Rubber powder refers to a mixture of gypsum, heavy calcium powder and mixed additives in the raw materials.

[0045] Experiments show that increasing the amount of rubber powder and reducing the amount of glass beads can improve the strength, but will reduce the fireproof effect; while reducing the amount of rubber powder and increasing the amount of glass beads can improve the fireproof effect, but will reduce the strength.

[0046] From Table 1, we can see that the dry bulk density is 400kg / m 3 The compressive strength is 0.552MPa, the bonding strength is 0.101MPa, and the fire resistance is good.

[0047] The amount of rubber powder and vitrified microspheres refers to the amount of rubber powder and vitrified microspheres per cubic meter of raw materials.

[0048] Table 1 Effect of different dry bulk density fireproof mortar on compressive strength and bonding strength

[0049]

[0050] Experimental Example 2

[0051] The various performance indicators of the steel structure fire retardant mortar of Examples 1-3 were tested, with reference to standards such as "GB14907-2018" steel structure fire retardant coating and "GB8624-2006", and the test results are shown in Table 2.

[0052] The steel structure fireproof mortar of the present invention mainly adopts inorganic materials and has good fireproof performance. According to the water resistance test, the coating has no delamination, bubbling and falling off after the product is tested for 24 hours. The thermal insulation efficiency deviation is 10%-15%. According to the freeze-thaw cycle resistance test, the coating has no cracking, peeling and bubbling after 15 tests. The product has good thermal insulation effect and excellent crack resistance and waterproof performance.

[0053] Table 2 Performance comparison of the mortar of the present invention and commercially available products

[0054]

[0055] The commercially available product in Table 2 has a formula of: 900 parts of gypsum, 100 parts of vitrified microspheres, 2 parts of gypsum retarder, 5 parts of glass fiber, and 5 parts of thixotropic agent.

Claims

1. A gypsum-based fireproof mortar for steel structures, characterized in that: The raw materials include the following parts by weight: 80-125 parts of gypsum, 20-45 parts of heavy calcium powder, 25-55 parts of vitrified microspheres, 2-6 parts of propyltrimethoxysilane, and appropriate amounts of additives; The additive comprises: 0.002-0.01 parts of retarder, 0.2-0.5 parts of bentonite, 0.01-0.03 parts of starch ether, 0.002-0.1 parts of touch lubricant, 0.005-0.01 parts of polyvinyl alcohol, 3-8 parts of cement, 0.2-3 parts of cellulose hydroxypropyl methyl ether and 5-10 parts of EVA type redispersible latex powder.

2. The gypsum-based steel structure fireproof mortar according to claim 1, characterized in that: The plaster of Paris has a compressive strength greater than 15 MPa, a flexural strength greater than 7 MPa, a radioactive nuclide internal exposure index less than 1.0, and an external exposure index less than 1.

0.

3. The gypsum-based steel structure fireproof mortar according to claim 1, characterized in that: The particle size of the heavy calcium powder is 325 meshes, the whiteness is 95%, and the calcium carbonate content is 98%.

4. The gypsum-based steel structure fireproof mortar according to claim 1, characterized in that: The closed porosity of the vitrified microspheres is 85-95%, and the bulk density is 100±5kg / m 3 It is a mixture of two sizes of vitrified microbeads, one passing through a 70-mesh sieve and the other passing through a 90-mesh sieve, with a mixing ratio of 1:

3.

5. A method for producing a gypsum-based fireproof mortar for steel structures according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Weigh each raw material component according to the raw material ratio and set aside; (2) Mixing and stirring the raw materials contained in the additive for 10-15 minutes to obtain a mixed additive for later use; (3) Add gypsum, heavy calcium powder and mixed additives into a forced mixer and stir for 10-20 minutes to obtain a rubber powder for later use; (4) Propyl trimethoxysilane is heated to 110-130° C., then sprayed onto the surface of the glass microspheres, mixed and stirred for 10-15 minutes to obtain hydrophobic glass microspheres, and then mixed with the rubber powder and stirred for 10-15 minutes to obtain the fireproof mortar.

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