Gypsum-based autoclaved aerated concrete adhesive mortar and preparation method thereof

Abstract

The invention provides gypsum-based autoclaved aerated concrete adhesive mortar and a preparation method thereof, and relates to the technical field of building materials. The gypsum-based autoclaved aerated concrete adhesive mortar is prepared from the following components in parts by weight: 30 to 45 parts of building desulfurized gypsum, 20 to 35 parts of inorganic filler, 30 to 45 parts of dried sand, 1.5 to 3.0 parts of active filler, 0.2 to 0.3 part of water-retaining thickening agent, 0.05 to 0.1 part of retarder, 0.05 to 0.1 part of cellosilk and 0.001 to 0.003 part of air entraining agent. According to the autoclaved aerated concrete adhesive mortar, the building desulfurized gypsum is used as a main raw material, the filler, the sand, the cellosilk and the processing aid are used as auxiliary raw materials, and the main raw material and the auxiliary raw materials are uniformly mixed according to a specific proportion, so that the autoclaved aerated concrete adhesive mortar which is high in strength, strong in adhesive force and good in constructability is prepared. A large amount of industrial by-product building desulfurized gypsum can be consumed, and a high-performance mortar product can be obtained from green, environment-friendly and low-carbon raw materials. The performance indexes of the gypsum-based adhesive mortar prepared by the invention all meet the requirements of JC / T 890-2017 'Special Mortar for Autoclaved Aerated Concrete Wall'.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and particularly relates to a gypsum-based autoclaved aerated concrete bonding mortar and a preparation method thereof. Background Art

[0002] Autoclaved aerated concrete board is a porous crystalline autoclaved aerated material made of cement, lime, silica sand and other raw materials through high temperature, high pressure and steam curing. It is widely welcomed by the market for its excellent fire resistance, heat preservation, sound insulation, heat insulation and green environmental protection advantages. However, since this material is mainly used as a non-load-bearing partition wall, theoretical gaps will inevitably appear during its splicing and use, and it also faces bonding problems during the actual construction process. At present, conventional cement-based bonding mortars and ordinary mortars used for insulation boards, gypsum blocks or other bonding materials have poor adaptability due to the lack of targeted design for the characteristics of autoclaved aerated concrete materials. After being used in autoclaved aerated concrete boards, cracking and unstable performance are very likely to occur. Therefore, the development of a bonding mortar that can meet the construction requirements of autoclaved aerated concrete has become a problem that needs to be solved urgently by technical personnel in the construction industry.

[0003] At present, the annual output of desulfurized gypsum, an industrial by-product, in my country is increasing year by year. With the rapid development of urban construction, gypsum products are also being updated. The construction industry is also changing from traditional on-site masonry partition walls to the use of autoclaved aerated concrete slabs as partition walls. This change has not only strongly promoted the development of the industry, but also promoted the rise of the autoclaved aerated concrete bonding mortar industry. If the autoclaved aerated concrete bonding mortar can be prepared with gypsum as the base to completely replace the traditional cement content, it can not only reduce the amount of high-energy cement and increase the consumption of industrial by-products, but also make a substantial contribution to responding to the energy-saving and emission reduction policies vigorously promoted by the country.

[0004] In Chinese Patent 202210614284.8, a gypsum-based lightweight sound-insulating prefabricated groove insulation board bonding mortar and a preparation method are disclosed. The bonding mortar uses building gypsum as raw material, and is compounded with artificial sand, cement and other materials to obtain a bonding mortar for bonding gypsum-based lightweight sound-insulating prefabricated groove insulation boards. Because it is used as a thick bonding material between the base layer and the module during the construction of the gypsum-based heating module, the bonding between the gypsum-based prefabricated groove board and the base layer requires thick bonding, and there are certain requirements for the slump of the bonding material. The use of traditional bonding gypsum cannot meet the slump requirements, so coarse aggregate needs to be introduced into the mortar system. The artificial sand used has a large particle size, the cement material has poor thermal stability, and is prone to shrinkage and cracking, which makes it impossible to use it as the adhesive material required for the bonding of autoclaved aerated concrete. The application field is completely different from the present invention.

[0005] In Chinese Patent 202010738644.6, a gypsum mortar for interior wall masonry and a method of using the same are disclosed. The bonding mortar uses modified building gypsum as raw material, and is compounded with machine-made sand, vitrified microspheres, and other materials to obtain a bonding mortar for bonding concrete hollow block walls. Because it is a bonding mortar for interior wall blocks and the bonding layer is a concrete hollow block, and high-energy-consuming vitrified microspheres are used as fillers, there is a difference between the bonding interface and the porous crystalline structure of autoclaved aerated concrete, which makes it impossible to be used as the adhesive material required for bonding autoclaved aerated concrete, and its application field is completely different from the present invention.

[0006] In Chinese Patent 201910804805.4, a calcined-free phosphogypsum bonding mortar and a preparation method thereof are disclosed. The bonding mortar uses β-hemihydrate gypsum as a raw material, and is compounded with calcined-free phosphogypsum, cement and other materials to obtain a bonding mortar for mutual bonding between gypsum blocks and strips, and bonding between gypsum blocks, strips and cement walls. Because the blocks and strips involved are gypsum-based, which is different from the structure of autoclaved aerated concrete, and cement materials with poor thermal stability and easy shrinkage and cracking are added, it cannot be used as the adhesive material required for bonding autoclaved aerated concrete, and its application field is completely different from the present invention.

[0007] In summary, there is no high-quality cement-free bonding mortar in the prior art that is tailored to the material properties of autoclaved aerated concrete and can meet the construction requirements of autoclaved aerated concrete. In view of this, the present invention is proposed. Summary of the invention

[0008] The object of the present invention is to provide a gypsum-based autoclaved aerated concrete bonding mortar. In view of the problems that the autoclaved aerated concrete bonding mortar prepared with cement as raw material in the prior art leads to high process energy consumption and high construction cost. The present invention uses building desulfurization gypsum as the main raw material, and fillers, sand, fiber filaments and processing aids as auxiliary raw materials, and mixes them evenly in a specific proportion, so as to prepare a kind of autoclaved aerated concrete bonding mortar that has high strength, strong bonding force and good construction performance. It can not only consume a large amount of industrial by-product building desulfurization gypsum, but also obtain high-performance mortar products with green, environmentally friendly and low-carbon raw materials. The performance indicators of the bonding mortar prepared by the present invention all meet the requirements of JC / T 890-2017 "Autoclaved Aerated Concrete Wall Special Mortar".

[0009] To achieve the above object, the present invention provides a gypsum-based autoclaved aerated concrete bonding mortar, which comprises the following components in parts by weight: 30-45 parts of building desulfurized gypsum, 20-35 parts of inorganic filler, 30-45 parts of dried sand, 1.5-3.0 parts of active filler, 0.2-0.3 parts of water-retaining thickener, 0.05-0.1 parts of retarder, 0.05-0.1 parts of fiber filaments, and 0.001-0.003 parts of air-entraining agent.

[0010] In a preferred embodiment, the total weight of the building desulfurization gypsum, inorganic filler, dried sand and active filler is 100 parts.

[0011] In a preferred embodiment, the following components are included by weight: 35-45 parts of building desulfurization gypsum, 25-35 parts of inorganic filler, 30-40 parts of drying sand, 1.5-2.5 parts of active filler, 0.2-0.3 parts of water-retaining thickener, 0.05-0.1 parts of retarder, 0.05-0.1 parts of fiber, and 0.001-0.003 parts of air entraining agent.

[0012] In a preferred embodiment, the following components are included by weight: 45 parts of building desulfurization gypsum, 23 parts of inorganic filler, 30 parts of dried sand, 2.0 parts of active filler, 0.3 parts of water-retaining thickener, 0.1 parts of retarder, 0.08 parts of fiber, and 0.002 parts of air entraining agent.

[0013] In a preferred embodiment, the gypsum-based autoclaved aerated concrete bonding mortar has an absolute dry flexural strength of 3.5 MPa, an absolute dry compressive strength of 7.0 MPa, an absolute dry tensile bonding strength of 0.47 MPa, and a bulk density of 1288.6 kg / m 3 , the water retention rate can reach 89.7%.

[0014] In a preferred embodiment, the building desulfurization gypsum is a 3.0-grade β-type building gypsum that meets the requirements of GB / T9776, and its 2h flexural strength is above 3.0 MPa.

[0015] In a preferred embodiment, the inorganic filler is stone powder, the fineness of which is 200 mesh, the residue on the sieve is 2.6%, and the dry density is 1115.0 kg / m 3 .

[0016] In a preferred embodiment, the dried sand is 40-140 mesh sand, with a mud content of 2.0%, a sieve residue of 1.0%, a moisture content of 0.10%, and an apparent density of 1464.3 kg / m 3 .

[0017] In a preferred embodiment, the active filler is lime, the chemical composition is Ca(OH)2, the fineness is 200 mesh, the sieve residue is 0%, and the dry density is 528.1 kg / m 3 .

[0018] In a preferred embodiment, the water-retaining thickener comprises hydroxypropyl methylcellulose ether, and the viscosity thereof is 40,000-100,000 mPa.s.

[0019] In a preferred embodiment, the retarder comprises a powdered protein-based gypsum retarder.

[0020] In a preferred embodiment, the fiber filaments include PP polypropylene fibers, with a single fiber equivalent diameter of ≤48 μm, a moisture content of ≤10%, good dispersibility in water, and no fiber bundles.

[0021] In a preferred embodiment, the air entraining agent comprises a powdered composite surfactant.

[0022] Another object of the present invention is to provide a method for preparing gypsum-based autoclaved aerated concrete bonding mortar, which only requires uniform mixing of powdery raw materials and then adding water and stirring. The preparation method is simple and efficient, and has no special requirements on equipment and production environment. In addition, the powdery raw materials are easy to purchase, store and transport, and are particularly suitable for large-scale industrial production and preparation.

[0023] To achieve the above object, the present invention provides a method for preparing gypsum-based autoclaved aerated concrete bonding mortar, which specifically comprises the following steps:

[0024] Step 1: Weigh all raw materials according to the formula, stir evenly to obtain a mixed powder;

[0025] Step 2: Add water to the mixed powder and mix evenly to obtain gypsum-based autoclaved aerated concrete bonding mortar.

[0026] In a preferred embodiment, in step 2, the mass ratio of the powder to water is 1:(0.22-0.26).

[0027] In a preferred embodiment, in step 2, the water adding and mixing time is 60-180s, and the water adding and mixing device can be a device conventionally known by those skilled in the art, such as a cement mortar mixer.

[0028] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0029] 1. In the prior art, the production raw materials of traditional autoclaved aerated concrete bonding mortar need to consume a large amount of cement, while the present invention uses building desulfurized gypsum as the main cementitious material, and other auxiliary raw materials are also prepared by low-carbon technology, which conforms to the green and environmentally friendly building concept. The autoclaved aerated concrete bonding mortar solution provided by the present invention can not only consume a large amount of industrial by-product building desulfurized gypsum, but also reduce the production energy consumption and raw material cost of the bonding mortar.

[0030] 2. The gypsum-based autoclaved aerated concrete bonding mortar prepared by the present invention has the characteristics of high strength, strong bonding force and good workability. The performance indicators of the obtained product meet the requirements of JC / T 890-2017 "Autoclaved aerated concrete wall special mortar". DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with specific implementation methods, but it should be understood that the protection scope of the present invention is not limited by the specific implementation methods.

[0032] The embodiment of the present invention provides a gypsum-based autoclaved aerated concrete bonding mortar and a preparation method thereof, thereby solving the technical problem in the prior art that the autoclaved aerated concrete bonding mortar can only achieve a good bonding effect by using high-energy consumption cement as a raw material.

[0033] The technical solution of the present application is described in detail below through specific embodiments:

[0034] If not otherwise specified, the technical means used in the present invention are conventional means well known to those skilled in the art, and the various raw materials, reagents, instruments and equipment used in the present invention can be purchased on the market or prepared by existing methods. The reagents used in the present invention are analytically pure unless otherwise specified. In the present invention, the aerated concrete panels and blocks used are from Beijing Jingye Aerated Concrete Co., Ltd. The building desulfurization gypsum used is a 3.0 grade β-type building gypsum that meets the requirements of GB / T9776, and its 2h flexural strength is above 3.0MPa; the inorganic filler used is stone powder, and its fineness is 200 mesh, the sieve residue is 2.6%, and the dry density is 1115.0kg / m 3 The dried sand used is 40-140 mesh sand, with a mud content of 2.0%, a sieve residue of 1.0%, a moisture content of 0.10%, and an apparent density of 1464.3kg / m 3 The active filler used is gray calcium, the chemical composition is Ca(OH)2, purchased from Shaanxi Shuntong Calcium Industry Co., Ltd.; the water-retaining thickener used is hydroxypropyl methylcellulose ether, the model is HPMC40,000, purchased from Shennan Technology (Tianjin) Co., Ltd.; the retarder used is a powdered protein retarder, the model is GR20, purchased from Tianjin Tianying New Building Materials Co., Ltd.; the fiber filament is PP fiber, the model is PP-6, purchased from Shennan Technology (Tianjin) Co., Ltd.; the air entraining agent is a powdered composite surfactant, the model is OSB, purchased from Clariant of Germany.

[0035] In the present invention, parts by weight may be μg, mg, g, kg or other weight units known in the art, or multiples thereof, such as 1 / 10, 1 / 100, 10 times, 100 times or the like.

[0036] Example 1

[0037] A method for preparing gypsum-based autoclaved aerated concrete bonding mortar comprises the following steps:

[0038] 1. Weigh the following raw materials:

[0039] 300g of building desulfurization gypsum, 235g of inorganic filler, 450g of dried sand, 15g of active filler, 2g of water-retaining thickener, 0.8g of retarder, 0.5g of fiber, and 0.01g of air-entraining agent.

[0040] 2. Mix the above powders evenly and set aside;

[0041] 3. Weigh 250g of water and add it to the stirring pot for later use;

[0042] 4. Add the powder in step 2 to the liquid in step 3, and stir at a low speed for 180 seconds using a mortar mixer to obtain a gypsum-based autoclaved aerated concrete bonding mortar.

[0043] The prepared gypsum-based autoclaved aerated concrete bonding mortar was tested with reference to JC / T 890-2017 "Autoclaved aerated concrete wall special mortar". After testing, the gypsum-based autoclaved aerated concrete bonding mortar developed by the present invention has a 28d absolute dry flexural strength of 3.0Mpa, a 28d absolute dry compressive strength of 6.0Mpa, a 28d absolute dry tensile bonding strength of 0.35Mpa, and a bulk density of 1273kg / m 3 , water retention rate is 82.6%.

[0044] Example 2

[0045] A method for preparing gypsum-based autoclaved aerated concrete bonding mortar comprises the following steps:

[0046] 1. Weigh the following raw materials:

[0047] 400g of building desulfurization gypsum, 235g of inorganic filler, 350g of dried sand, 15g of active filler, 2.5g of water-retaining thickener, 0.8g of retarder, 0.5g of fiber, and 0.01g of air-entraining agent.

[0048] 2. Mix the above powders evenly and set aside;

[0049] 3. Weigh 255g of water and add it to the stirring pot, set aside;

[0050] 4. Add the powder in step 2 to the liquid in step 3, and stir at a low speed for 180 seconds using a mortar mixer to obtain a gypsum-based autoclaved aerated concrete bonding mortar.

[0051] The prepared gypsum-based autoclaved aerated concrete bonding mortar was tested with reference to JC / T 890-2017 "Autoclaved aerated concrete wall special mortar". After testing, the gypsum-based autoclaved aerated concrete bonding mortar developed by the present invention has a 28d absolute dry flexural strength of 3.3Mpa, a 28d absolute dry compressive strength of 6.5Mpa, a 28d absolute dry tensile bonding strength of 0.41Mpa, and a bulk density of 1278.9kg / m 3, water retention rate is 86.4%.

[0052] Example 3

[0053] A method for preparing gypsum-based autoclaved aerated concrete bonding mortar comprises the following steps:

[0054] 1. Weigh the following raw materials:

[0055] 450g of building desulfurization gypsum, 230g of inorganic filler, 300g of dried sand, 20g of active filler, 3.0g of water-retaining thickener, 1.0g of retarder, 0.8g of fiber, and 0.02g of air-entraining agent.

[0056] 2. Mix the above powders evenly and set aside;

[0057] 3. Weigh 260g of water and add it to the stirring pot, set aside;

[0058] 4. Add the powder in step 2 to the liquid in step 3, and stir at a low speed for 180 seconds using a mortar mixer to obtain a gypsum-based autoclaved aerated concrete bonding mortar.

[0059] The prepared gypsum-based autoclaved aerated concrete bonding mortar was tested with reference to JC / T 890-2017 "Autoclaved aerated concrete wall special mortar". After testing, the gypsum-based autoclaved aerated concrete bonding mortar developed by the present invention has a 28d absolute dry flexural strength of 3.5Mpa, a 28d absolute dry compressive strength of 7.0Mpa, a 28d absolute dry tensile bonding strength of 0.47Mpa, and a bulk density of 1288.6kg / m 3 , water retention rate is 89.7%.

[0060] Comparative Example 1

[0061] A method for preparing gypsum-based autoclaved aerated concrete bonding mortar comprises the following steps:

[0062] 1. Weigh the following raw materials:

[0063] 450g of building desulfurization gypsum, 530g of inorganic filler, 20g of active filler, 3.0g of water-retaining thickener, 1.0g of retarder, 0.8g of fiber, and 0.02g of air-entraining agent.

[0064] 2. Mix the above powders evenly and set aside;

[0065] 3. Weigh 260g of water and add it to the stirring pot, set aside;

[0066] 4. Add the powder in step 2 to the liquid in step 3, and stir at a low speed for 180 seconds using a mortar mixer to obtain a gypsum-based autoclaved aerated concrete bonding mortar.

[0067] The prepared gypsum-based autoclaved aerated concrete bonding mortar was tested with reference to JC / T 890-2017 "Autoclaved aerated concrete wall special mortar". After testing, the gypsum-based autoclaved aerated concrete bonding mortar developed by the present invention has a 28d absolute dry flexural strength of 2.5Mpa, a 28d absolute dry compressive strength of 5.6Mpa, a 28d absolute dry tensile bonding strength of 0.3Mpa, and a bulk density of 1298.7kg / m 3 , water retention rate 89.1%.

[0068] Comparative Example 2

[0069] A method for preparing gypsum-based autoclaved aerated concrete bonding mortar comprises the following steps:

[0070] 1. Weigh the following raw materials:

[0071] 450g of building desulfurization gypsum, 250g of inorganic filler, 300g of dried sand, 3.0g of water-retaining thickener, 1.0g of retarder, 0.8g of fiber, and 0.02g of air-entraining agent.

[0072] 2. Mix the above powders evenly and set aside;

[0073] 3. Weigh 260g of water and add it to the stirring pot, set aside;

[0074] 4. Add the powder in step 2 to the liquid in step 3, and stir at a low speed for 180 seconds using a mortar mixer to obtain a gypsum-based autoclaved aerated concrete bonding mortar.

[0075] The prepared gypsum-based autoclaved aerated concrete bonding mortar was tested with reference to JC / T 890-2017 "Autoclaved aerated concrete wall special mortar". After testing, the gypsum-based autoclaved aerated concrete bonding mortar developed by the present invention has a 28d absolute dry flexural strength of 3.1Mpa, a 28d absolute dry compressive strength of 6.2Mpa, a 28d absolute dry tensile bonding strength of 0.36Mpa, and a bulk density of 1281.1kg / m 3 , water retention rate is 88.7%.

[0076] Comparative Example 3

[0077] A method for preparing gypsum-based autoclaved aerated concrete bonding mortar comprises the following steps:

[0078] 1. Weigh the following raw materials:

[0079] 450g of building desulfurization gypsum, 400g of inorganic filler, 150g of dried sand, 3.0g of water-retaining thickener, 1.0g of retarder, 0.8g of fiber, and 0.02g of air-entraining agent.

[0080] 2. Mix the above powders evenly and set aside;

[0081] 3. Weigh 260g of water and add it to the stirring pot, set aside;

[0082] 4. Add the powder in step 2 to the liquid in step 3, and stir at a low speed for 180 seconds using a mortar mixer to obtain a gypsum-based autoclaved aerated concrete bonding mortar.

[0083] The prepared gypsum-based autoclaved aerated concrete bonding mortar was tested with reference to JC / T 890-2017 "Autoclaved aerated concrete wall special mortar". After testing, the gypsum-based autoclaved aerated concrete bonding mortar developed by the present invention has a 28d absolute dry flexural strength of 2.8Mpa, a 28d absolute dry compressive strength of 5.9Mpa, a 28d absolute dry tensile bonding strength of 0.32Mpa, and a bulk density of 1271.5kg / m 3 , water retention rate is 88.6%.

[0084] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A gypsum-based autoclaved aerated concrete bonding mortar, characterized in that: By weight, it includes the following components: 30-45 parts of building desulfurization gypsum, 20-35 parts of inorganic filler, 30-45 parts of dried sand, 1.5-3.0 parts of active filler, 0.2-0.3 parts of water-retaining thickener, 0.05-0.1 parts of retarder, 0.05-0.1 parts of fiber, and 0.001-0.003 parts of air entraining agent.

2. The gypsum-based autoclaved aerated concrete bonding mortar according to claim 1, characterized in that: The total weight of the building desulfurization gypsum, inorganic filler, dried sand and active filler is 100 parts.

3. The gypsum-based autoclaved aerated concrete bonding mortar according to claim 2, characterized in that: The gypsum-based autoclaved aerated concrete bonding mortar has an absolute dry flexural strength of 3.5 MPa, an absolute dry compressive strength of 7.0 MPa, an absolute dry tensile bonding strength of 0.47 MPa, and a bulk density of 1288.6 kg / m 3 , the water retention rate can reach 89.7%.

4. The gypsum-based autoclaved aerated concrete bonding mortar according to claim 1, characterized in that: The building desulfurization gypsum is a 3.0-grade β-type building gypsum that meets the requirements of GB / T9776, and its 2h flexural strength is above 3.0 MPa.

5. The gypsum-based autoclaved aerated concrete bonding mortar according to claim 1, characterized in that: The inorganic filler is stone powder, the fineness of which is 200 mesh, the sieve residue is 2.6%, and the dry density is 1115.0kg / m 3 .

6. The gypsum-based autoclaved aerated concrete bonding mortar according to claim 1, characterized in that: The dried sand is 40-140 mesh sand, with a mud content of 2.0%, a sieve residue of 1.0%, a moisture content of 0.10%, and an apparent density of 1464.3 kg / m 3 .

7. The gypsum-based autoclaved aerated concrete bonding mortar according to claim 1, characterized in that: The active filler is limestone, the chemical composition is Ca(OH)2, the fineness is 200 mesh, the sieve residue is 0%, and the dry density is 528.1 kg / m 3 .

8. The gypsum-based autoclaved aerated concrete bonding mortar according to claim 1, characterized in that: The water-retaining thickener includes hydroxypropyl methylcellulose ether, and its viscosity is 40000-100000mPa.s; the retarder includes powdered protein gypsum retarder; the fiber filaments include PP polypropylene fibers, the single filament equivalent diameter is ≤48μm, the water content is ≤10%, the dispersibility in water is good, and there is no fiber bundle; the air entraining agent includes a powdered composite surfactant.

9. The method for preparing the gypsum-based autoclaved aerated concrete bonding mortar according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Weigh all raw materials according to the formula, stir evenly to obtain a mixed powder; Step 2: Add water to the mixed powder and mix evenly to obtain gypsum-based autoclaved aerated concrete bonding mortar.

10. The method for preparing the gypsum-based autoclaved aerated concrete bonding mortar according to claim 9, characterized in that: In step 2, the mass ratio of the powder to water is 1:(0.22-0.26).