Lightweight plastering gypsum mortar and preparation method thereof

Abstract

The application provides a light plastering gypsum mortar and a preparation method thereof. The light plastering gypsum mortar comprises the following components in parts by weight: 50-65 parts of desulfurized building gypsum, 35-50 parts of aerated concrete waste, 0.02-0.05 parts of a thixotropic lubricant, 0.006-0.015 parts of an air entraining agent, 0.15-0.2 parts of a water-retaining thickening agent and 0.06-0.1 parts of a retarder. The application uses only the aerated concrete block waste and the desulfurized building gypsum as the main raw materials, and through formula design, additive selection and dosage ratio, the light plastering gypsum mortar can consume a large amount of aerated concrete block waste, and completely avoid using the light aggregate (vitrified microbead) prepared by high-temperature calcination and the filler prepared by grinding natural ore, thereby fully embodying the significant progress of the product in green, low-carbon and environmental protection. The light plastering gypsum mortar has the characteristics of high strength, strong adhesion and good workability, and the absolute dry flexural strength can reach 1.8 MPa, the absolute dry compressive strength can reach 4 MPa, the absolute dry tensile bonding strength can reach 0.5 MPa, the bulk density can reach 797 kg / m 3 and the water retention rate can be 73% or higher.

Description

Technical Field

[0001] The invention belongs to the technical field of plaster mortar, and particularly relates to a lightweight plaster gypsum mortar and a preparation method thereof. Background Art

[0002] Traditional building interior wall plastering and leveling materials are primarily cement plaster mortar. Cement plaster mortar, as a leveling material, has characteristics such as large shrinkage and low bond strength, but is prone to cracking and hollowing on the wall after application. Lightweight plaster gypsum mortar, a new building interior wall leveling material, offers advantages such as easy construction, strong adhesion, and resistance to cracking and hollowing, making it a promising alternative to traditional cement plaster mortar.

[0003] At present, in order to reduce its own volume density, 1m3 is usually added to each ton of lightweight plaster gypsum mortar during the production of lightweight plaster gypsum. 3 Lightweight aggregate - vitrified microspheres. Vitrified microspheres are made from perlite minerals calcined at 1200°C, with a density of 80-100 kg / m 3 Its production and preparation process consumes a lot of energy, making it a typical high-energy-consuming product, which is obviously inconsistent with the green product attributes of lightweight plaster gypsum. Therefore, it is necessary to develop a new type of lightweight aggregate to replace vitrified microspheres for the production of lightweight plaster gypsum mortar.

[0004] As a lightweight masonry material, aerated concrete blocks generate a large amount of broken waste during production due to their low strength. Currently, the broken aerated concrete waste is mainly reused in the production of aerated concrete blocks after being crushed and ground. The digestion capacity is limited, and the large amount of accumulated waste occupies limited storage space and needs to be processed urgently. However, the density of aerated concrete waste is usually 500kg / m 3 About, with a density of usually 80-100kg / m 3 Therefore, it is still impossible to use aerated concrete waste in large quantities in the existing technology.

[0005] In summary, how to design a lightweight plaster gypsum mortar that can consume a large amount of aerated concrete waste and obtain high-quality without the need for lightweight aggregate and filler is a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the Invention

[0006] The purpose of the present invention is to provide a lightweight plaster gypsum mortar, which differs from the existing technology in that only waste aerated concrete blocks are added. Through formula design, auxiliary agent selection and dosage ratio, while consuming a large amount of aerated concrete block waste, it can also completely avoid the addition of lightweight aggregate (vitrified microspheres) prepared by high-temperature calcination and fillers prepared by grinding natural minerals, fully reflecting the significant progress in the green, low-carbon and environmentally friendly raw material products.

[0007] To achieve the above object, the present invention provides a lightweight plaster gypsum mortar, which comprises the following components in parts by weight:

[0008] 50-65 parts of desulfurized building gypsum, 35-50 parts of aerated concrete waste, 0.02-0.05 parts of thixotropic lubricant, 0.006-0.015 parts of air-entraining agent, 0.15-0.2 parts of water-retaining thickener, and 0.06-0.1 parts of retarder;

[0009] The lightweight plaster gypsum mortar has an absolute dry flexural strength of 1.8 MPa, an absolute dry compressive strength of 4 MPa, an absolute dry tensile bond strength of 0.5 MPa, and a bulk density of 797 kg / m 3 and below, water retention rate 73% and above.

[0010] In a preferred embodiment, the lightweight plaster gypsum mortar comprises the following components in parts by weight:

[0011] 55-65 parts of desulfurized building gypsum, 35-45 parts of aerated concrete waste, 0.02-0.05 parts of thixotropic lubricant, 0.006-0.015 parts of air-entraining agent, 0.15-0.2 parts of water-retaining thickener, and 0.06-0.1 parts of retarder;

[0012] More preferably, the lightweight plaster gypsum mortar comprises the following components in parts by weight:

[0013] 65 parts of desulfurized building gypsum, 35 parts of aerated concrete waste, 0.05 parts of thixotropic lubricant, 0.015 parts of air-entraining agent, 0.18 parts of water-retaining thickener, and 0.09 parts of retarder.

[0014] In a preferred embodiment, the total weight of the desulfurized building gypsum and aerated concrete waste is 100 parts.

[0015] In a preferred embodiment, the desulfurized building 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.

[0016] In a preferred embodiment, the aerated concrete waste is prepared by crushing and screening damaged aerated concrete blocks, with a fineness of 0.6 mm, a sieve residue of 0, a moisture content of 4%, and a dry density of 500 kg / m 3 In the present invention, considering the construction performance and the subsequent wall smoothness when applying a large amount of lightweight plaster gypsum mortar to the wall after adding water and stirring, aerated concrete waste with a particle size of less than 0.6mm is used. In addition, by designing a reasonable processing aid, the present invention avoids the use of fillers and aggregates, and can set the moisture content of the aerated concrete block waste to 4%, eliminating the need for excessive drying and reducing energy consumption.

[0017] In a preferred embodiment, the thixotropic lubricant is starch ether, and its viscosity is 400-1200mPa . s℃.

[0018] In a preferred embodiment, the air entraining agent is a powdered composite surfactant.

[0019] In a preferred embodiment, the water-retaining thickener is hydroxypropyl methylcellulose ether, and its viscosity is 40,000-100,000 mPa.s.

[0020] In a preferred embodiment, the retarder is a powdered protein gypsum retarder.

[0021] Another object of the present invention is to provide a method for preparing lightweight plaster gypsum mortar. The method requires only uniform mixing of powdery raw materials and then adding water and stirring. This method is simple and efficient, requiring no special equipment or production environment requirements. Furthermore, the powdery raw materials are easy to purchase, store, and transport, making it particularly suitable for large-scale industrial production.

[0022] To achieve the above object, the present invention provides a method for preparing a lightweight plaster gypsum mortar, which specifically comprises the following steps:

[0023] Accurately weigh the following according to the formula: 50-65 parts of desulfurized building gypsum, 35-50 parts of aerated concrete waste, 0.02-0.05 parts of thixotropic lubricant, 0.006-0.015 parts of air-entraining agent, 0.15-0.2 parts of water-retaining thickener, and 0.06-0.1 parts of retarder;

[0024] Stir all the raw materials evenly to obtain mixed powder;

[0025] Add water to the mixed powder and mix evenly to obtain lightweight plaster gypsum mortar.

[0026] In a preferred embodiment, the mass ratio of the powder to water is 1:(0.6-0.65). Since aerated concrete waste typically contains a certain amount of free water, using it in the production of lightweight plaster gypsum can help accelerate the "aging" of the lightweight plaster gypsum mortar and improve the quality stability of the lightweight plaster gypsum mortar product. Therefore, the mass ratio of the powder to water can be within the aforementioned range.

[0027] In a preferred embodiment, the water adding and mixing time is 60-180s, and the water adding and mixing device can be a device conventionally known to 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. The production of traditional lightweight plaster requires a large amount of vitrified microspheres and other aggregates / fillers. Vitrified microspheres are obviously high-energy-consuming products, which are inconsistent with the green and low-carbon properties of lightweight plaster. The present invention uses waste generated during the production of aerated concrete blocks, which are crushed and screened to replace the vitrified microspheres and heavy calcium carbonate in existing lightweight plaster. Through raw material design and dosage ratio, the amount of aerated concrete waste is increased as much as possible, thereby achieving the effect of consuming a large amount of aerated concrete waste.

[0030] 2. In the present invention, by controlling the fineness of aerated concrete block waste and selecting appropriate processing aids, aerated concrete block waste can completely replace aggregate and filler, and a lightweight, high-performance plaster gypsum mortar can be obtained using only desulfurized building gypsum and aerated concrete waste as the main raw materials.

[0031] 3. In the present invention, considering the high bulk density of aerated concrete waste, a suitable amount of composite air-entraining agent is added to further reduce the bulk density of the resulting lightweight plaster when added in large quantities. This can increase the air content of the lightweight plaster, thereby reducing its bulk density. Furthermore, compared to traditional vitrified microspheres, aerated concrete waste has a relatively low roundness. The present invention introduces a thixotropic lubricant to improve the workability of the lightweight plaster, thereby significantly increasing the amount of aerated concrete waste added.

[0032] 4. The lightweight plastering gypsum produced by the present invention features high strength, strong adhesion, and excellent workability. The lightweight plastering gypsum produced by the present invention does not require the addition of energy-intensive lightweight aggregates—vitrified microspheres—or other fillers. Its primary materials are two industrial solid wastes: desulfurized building gypsum and aerated concrete waste. This significantly reduces the production cost and carbon emissions of the lightweight plastering gypsum, highlighting its green, low-carbon, energy-saving, and environmentally friendly properties. Furthermore, through a comprehensive design approach, the lightweight plastering gypsum produced by the present invention, using a large amount of aerated concrete, meets the performance requirements of GB / T 28627-2012, "Plastering Gypsum." DETAILED DESCRIPTION

[0033] 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 embodiments. However, it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0034] The embodiment of the present invention solves the problems in the prior art of low waste consumption of steam pressurized concrete and the need to add aggregates / fillers when preparing lightweight plastering gypsum mortar by providing a lightweight plastering gypsum mortar and a preparation method thereof.

[0035] The technical solution of this application is described in detail below through specific embodiments:

[0036] Unless 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 can be prepared by existing methods. Unless otherwise specified, the reagents used in the present invention are all analytically pure. In the present invention, the aerated concrete waste used comes from Beijing Jingye Aerated Concrete Co., Ltd., and the specific crushing and screening processes can be carried out in a manner conventionally mastered by those skilled in the art, as long as the fineness meets the above requirements. The thixotropic lubricant used is starch ether model 301, purchased from Avibe Company of the Netherlands; the air entraining agent used is powdered composite surfactant model AE-2, purchased from Guangdong Longhu Technology Co., Ltd.; the water-retaining thickener used is hydroxypropyl methylcellulose ether model HPMC40,000, purchased from Shandong Heda Co., Ltd., and the retarder used is powdered protein gypsum retarder model G18N, purchased from Jiangsu Zhaojia Technology Co., Ltd.

[0037] In the present invention, parts by weight may be weight units known in the art such as μg, mg, g, kg, etc., or multiples thereof, such as 1 / 10, 1 / 100, 10 times, 100 times, etc. Example 1

[0038] 1. Weigh the following raw materials:

[0039] 500g desulfurized building gypsum, 500g aerated concrete waste, 0.5g thixotropic lubricant, 0.12g air entraining agent, 2.0g water-retaining thickener, and 0.7g retarder.

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

[0041] 3. Weigh 665g of water and add it to the stirring pot, set aside.

[0042] 4. Add the powder from step 2 to the liquid from step 3 and stir at low speed for 180 seconds using a mortar mixer to obtain lightweight plaster mortar.

[0043] The prepared lightweight plastering gypsum was tested in accordance with GB / T 28627-2012 "Plastering Gypsum". The test results show that the lightweight plastering gypsum developed by the present invention has an absolute dry flexural strength of 1.1 MPa, an absolute dry compressive strength of 2.6 MPa, an absolute dry tensile bond strength of 0.35 MPa, and a bulk density of 710 kg / m 3 , the water retention rate of wet mortar is 78%. Example 2

[0044] 1. Weigh the following raw materials:

[0045] 600g desulfurized building gypsum, 400g aerated concrete waste, 0.5g thixotropic lubricant, 0.15g air entraining agent, 1.9g water-retaining thickener, and 0.8g retarder.

[0046] 2. Mix the above powders evenly and set aside;

[0047] 3. Weigh 635g of water and add it to the stirring pot, set aside.

[0048] 4. Add the powder from step 2 to the liquid from step 3 and stir at low speed for 180 seconds using a mortar mixer to obtain lightweight plaster mortar.

[0049] The prepared lightweight plastering gypsum was tested in accordance with GB / T 28627-2012 "Plastering Gypsum". The test results show that the lightweight plastering gypsum developed by the present invention has an absolute dry flexural strength of 1.5 MPa, an absolute dry compressive strength of 3.0 MPa, an absolute dry tensile bond strength of 0.4 MPa, and a bulk density of 773 kg / m 3 , the water retention rate of wet mortar is 75%. Example 3

[0050] 1. Weigh the following raw materials:

[0051] 650g desulfurized building gypsum, 350g aerated concrete waste, 0.5g thixotropic lubricant, 0.15g air entraining agent, 1.8g water-retaining thickener, and 0.9g retarder.

[0052] 2. Mix the above powders evenly and set aside;

[0053] 3. Weigh 620g of water and add it to the stirring pot, set aside.

[0054] 4. Add the powder from step 2 to the liquid from step 3 and stir at low speed for 180 seconds using a mortar mixer to obtain lightweight plaster mortar.

[0055] The prepared lightweight plastering gypsum was tested in accordance with GB / T 28627-2012 "Plastering Gypsum". The test results show that the lightweight plastering gypsum developed by the present invention has an absolute dry flexural strength of 1.8 MPa, an absolute dry compressive strength of 4.0 MPa, an absolute dry tensile bond strength of 0.5 MPa, and a bulk density of 797 kg / m 3 , water retention rate is 73%.

[0056] Comparative Example 1

[0057] This comparative example provides a lightweight plaster gypsum mortar prepared using vitrified microspheres, and the preparation method comprises the following steps:

[0058] 1. Weigh the following raw materials: 650g ordinary building gypsum, 90g vitrified microspheres, 255g heavy calcium carbonate, 2.4g water-retaining thickener, 1.0g retarder, and 2.0g thixotropic lubricant.

[0059] 2. Mix the above powders evenly and set aside;

[0060] 3. Weigh 630g of water and add it to the stirring pot, set aside.

[0061] 4. Add the powder from step 2 to the liquid from step 3 and stir at low speed for 180 seconds using a mortar mixer to obtain ordinary lightweight plaster gypsum mortar.

[0062] The prepared lightweight plastering gypsum was tested in accordance with GB / T 28627-2012 "Plastering Gypsum". The test results show that the lightweight plastering gypsum developed by the present invention has an absolute dry flexural strength of 1.5 MPa, an absolute dry compressive strength of 3.2 MPa, an absolute dry tensile bond strength of 0.4 MPa, and a bulk density of 850 kg / m 3 , water retention rate 75%.

[0063] It can be seen from Comparative Example 1 that the traditional solution of the prior art not only adds high-energy-consuming vitrified microspheres but also adds fillers, but the performance of the plaster mortar prepared therefrom is obviously inferior to the performance data of the plaster gypsum mortar prepared by all-solid waste and low-energy consumption in the present invention.

[0064] Comparative Example 2

[0065] This comparative example provides a lightweight plaster gypsum mortar prepared using aerated concrete waste, and the preparation method comprises the following steps:

[0066] 1. Weigh the following raw materials:

[0067] 450g desulfurized building gypsum, 550g aerated concrete waste, 0.5g thixotropic lubricant, 0.15g air entraining agent, 1.9g water-retaining thickener, and 0.6g retarder.

[0068] 2. Mix the above powders evenly and set aside;

[0069] 3. Weigh 660g of water and add it to the stirring pot, set aside.

[0070] 4. Add the powder from step 2 to the liquid from step 3 and stir at low speed for 180 seconds using a mortar mixer to obtain lightweight plaster mortar.

[0071] The prepared lightweight plastering gypsum was tested in accordance with GB / T 28627-2012 "Plastering Gypsum". The test results show that the lightweight plastering gypsum developed by the present invention has an absolute dry flexural strength of 1.0 MPa, an absolute dry compressive strength of 2.0 MPa, an absolute dry tensile bond strength of 0.25 MPa, and a bulk density of 652 kg / m 3 , water retention rate is 78%.

[0072] Comparative Example 2 shows that increasing the amount of aerated concrete waste further would not meet the mechanical performance standards for preparing lightweight plaster gypsum mortar. Therefore, the formula and dosage designed in the present invention maximize the consumption of aerated concrete waste while still meeting the standard requirements for plaster mortar. The performance indicators even surpass those of conventional vitrified microsphere technology solutions in the prior art.

[0073] Comparative Example 3:

[0074] This comparative example provides a lightweight plaster gypsum mortar prepared using aerated concrete waste, and the preparation method comprises the following steps:

[0075] 1. Weigh the following raw materials:

[0076] 650g desulfurized building gypsum, 350g aerated concrete waste, 0.5g thixotropic lubricant, 1.8g water-retaining thickener, and 0.9g retarder.

[0077] 2. Mix the above powders evenly and set aside;

[0078] 3. Weigh 640g of water and add it to the stirring pot, set aside.

[0079] 4. Add the powder from step 2 to the liquid from step 3 and stir at low speed for 180 seconds using a mortar mixer to obtain lightweight plaster mortar.

[0080] The prepared lightweight plastering gypsum was tested in accordance with GB / T 28627-2012 "Plastering Gypsum". The test results show that the lightweight plastering gypsum developed by the present invention has an absolute dry flexural strength of 2.1MPa, an absolute dry compressive strength of 4.2MPa, an absolute dry tensile bond strength of 0.55MPa, and a bulk density of 1100kg / m 3 , water retention rate is 72%.

[0081] It can be seen from Comparative Example 3 that if the air entraining agent component is not added, the bulk density of the lightweight plaster gypsum mortar prepared by using aerated concrete waste cannot meet the standard requirements (the national standard requires that the bulk density does not exceed 1000kg / m 3 ).

[0082] In summary, it can be seen that the present invention optimizes and controls raw materials such as desulfurized building gypsum, aerated concrete waste, thixotropic lubricant, air-entraining agent, water-retaining thickener, and retarder, and precisely controls the proportion of each component to prepare a lightweight plastering gypsum mortar whose tensile bond strength meets the requirements of GB / T 28627-2012. The preparation process of the lightweight plastering mortar discards commonly used vitrified microspheres, fillers, and aggregates, and the main raw materials used in the preparation are all industrial solid waste. This is a truly green, low-carbon, lightweight plastering gypsum mortar.

[0083] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A lightweight plaster gypsum mortar, characterized in that: The invention is composed of the following components in parts by weight: 65 parts of desulfurized building gypsum, 35 parts of aerated concrete waste, 0.05 parts of thixotropic lubricant, 0.015 parts of air entraining agent, 0.2 parts of water-retaining thickener, and 0.1 parts of retarder; Wherein, the 2h flexural strength of the desulfurized building gypsum is above 3.0 MPa; The aerated concrete waste is prepared by crushing and screening damaged aerated concrete blocks, and its fineness is 0.6mm, the sieve residue is 0, the moisture content is 4%, and the dry density is 500kg / m 3 ; The thixotropic lubricant is starch ether, and its viscosity is 400-1200mPa·s; The air entraining agent is a powdery composite surfactant; The water-retaining thickener is hydroxypropyl methylcellulose ether, and its viscosity is 40000-100000 mPa·s; The retarder is a powdered protein gypsum retarder.

2. The method for preparing the lightweight plaster gypsum mortar according to claim 1, wherein The specific steps include: Accurately weigh the following according to the formula: 65 parts of desulfurized building gypsum, 35 parts of aerated concrete waste, 0.05 parts of thixotropic lubricant, 0.015 parts of air-entraining agent, 0.2 parts of water-retaining thickener, and 0.1 parts of retarder; Stir all the raw materials evenly to obtain mixed powder; Add water to the mixed powder and mix evenly to obtain lightweight plaster gypsum mortar.

3. The method for preparing the lightweight plaster gypsum mortar according to claim 2, wherein: The mass ratio of the powder to water is 1:(0.6-0.65).