Composite gypsum-based self-leveling mortar and preparation method thereof

Abstract

The application relates to the technical field of building gypsum, and discloses a composite gypsum-based self-leveling mortar and a preparation method thereof, which comprises phosphorus building gypsum, a composite additive and auxiliary materials; according to the mass fraction, the composite additive comprises 0.05-0.3% of a reinforcing agent, 0.02-0.2% of a defoaming agent, 0.03-0.2% of a gypsum retarder, 0.02-0.2% of a stabilizer, 0.01-0.1% of a toning agent and 0.05-0.4% of a flow aid; the auxiliary materials comprise 2-20% of dried sand, 0.01-0.5% of calcium oxide, 0.1-2% of calcium carbonate, 1-6.5% of ceramic microspheres and 0.1-0.5% of anti-cracking fibers; and the balance is phosphorus building gypsum. The application controls the types and dosages of the raw material components of the gypsum-based self-leveling mortar, so that the components can be combined with each other; and the material performance defects of the current self-leveling mortar taking phosphorus building gypsum as the main gel material, such as low strength, easy cracking and poor fluidity, can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building gypsum, in particular to a composite gypsum-based self-leveling mortar and a preparation method thereof. BACKGROUND

[0002] After being mixed with water, the self-leveling mortar can obtain a high flatness base surface through self-flowing or spreading with a trowel, has the beneficial properties of convenient construction and fast hardening speed, and is widely used in the floor laying of industrial plants, workshops, shopping malls and the like.

[0003] The self-leveling mortar is mainly made of building gypsum as the main cementitious material, supplemented by alkaline materials such as cement, sand and additives. However, the existing gypsum-based self-leveling mortar has the following problems:

[0004] (1) Low strength. Common gypsum-based self-leveling mortar often introduces cement as an auxiliary filler, but cement is alkaline and will affect the hydration degree of gypsum to varying degrees according to the amount of cement and the performance of the material system, resulting in a significant reduction in the effective strength of gypsum itself, and ultimately making the strength of the gypsum-based self-leveling mortar low, whether it is the early strength of construction or the strength during the drying process and after drying and hardening, it is difficult to meet the strength requirements of JC / T 1023-2021 "Gypsum-based self-leveling mortar".

[0005] (2) Easy to crack. Most gypsum-based self-leveling mortars are prone to obvious cracking during the curing process after forming or during use, especially in areas with external corners, and the cracks are difficult to repair in subsequent stages.

[0006] (3) Fast and large loss of fluidity. According to the requirements of JC / T 1023-2021 "Gypsum-based self-leveling mortar", the gypsum-based self-leveling mortar should meet the requirement of 30 min fluidity greater than 140 mm. Currently, the gypsum-based self-leveling mortar is mostly improved in the initial fluidity to meet the relevant requirements of fluidity, but this method further reduces the strength of the mortar and even makes it difficult to ensure the construction feasibility, and after standing for a period of time, it is prone to problems such as water bleeding, delamination and blackening.

[0007] Currently, although technical means that can solve any of the problems of low strength, cracking or severe loss of fluidity have been proposed, such as the patent with publication number CN115159946A, which relates to a high-strength gypsum-based sand-free self-leveling mortar. According to the description, it has more significant compressive strength. However, it still cannot achieve the effects of high strength, good fluidity and less cracking. SUMMARY

[0008] The present application aims to solve the technical problems of:

[0009] In the existing gypsum-based self-leveling mortar technical field, high-strength gypsum-based self-leveling mortar, good fluidity gypsum-based self-leveling mortar, and less cracking gypsum-based self-leveling mortar can be respectively realized, but for the material performance of the above aspects, it is impossible to realize that the performances of the gypsum-based self-leveling mortar all have a high level effect, that is, in actual application, there is always a problem of material performance defects.

[0010] The technical scheme adopted by the present application is:

[0011] The application provides a composite gypsum-based self-leveling mortar, which comprises phosphorus building gypsum, a composite additive and auxiliary materials.

[0012] The composite additive comprises 0.05-0.3% of a reinforcing agent, 0.02-0.2% of a defoaming agent, 0.03-0.2% of a gypsum retarder, 0.02-0.2% of a stabilizer, 0.01-0.1% of a toning agent and 0.05-0.4% of a flow agent in terms of mass fraction.

[0013] The auxiliary materials comprise 2-20% of dried sand, 0.01-0.5% of calcium oxide, 0.1-2% of calcium carbonate and 0.1-0.5% of anti-cracking fibers.

[0014] Preferably, the reinforcing agent is selected from one or more of a polycarboxylic acid reinforcing agent, a melamine reinforcing agent, a lignin sulfonate reinforcing agent and a naphthalene sulfonate reinforcing agent.

[0015] Preferably, the defoaming agent is selected from one or more of a polyether defoaming agent, a silicone defoaming agent and a modified polyether defoaming agent.

[0016] Preferably, the gypsum retarder is selected from one or more of a protein retarder, an amino acid retarder and a composite retarder.

[0017] Preferably, the stabilizer is selected from one or more of a redispersible latex powder, polyvinyl alcohol, instant putty glue powder, cellulose ether and guar gum.

[0018] Preferably, the flow agent is selected from one or more of magnesium stearate, potassium stearate, talc, magnesium aluminum silicate and colloidal silicon dioxide.

[0019] Preferably, the anti-cracking fiber is selected from one or more of polypropylene fiber, carbon fiber, plant fiber and basalt fiber.

[0020] Preferably, in the dried sand, 1-8% of the dried sand has a particle size of 20-80 mesh, and 5-18% of the dried sand has a particle size of 80-150 mesh.

[0021] Preferably, the preparation method of the auxiliary materials comprises the following steps:

[0022] Take the dried sand, in turn through the first fine grinding, first screening, second fine grinding, second screening treatment, then the screening of different particle size of the dried sand mixture is obtained; adding calcium oxide, calcium carbonate, ceramic microspheres and anti-cracking fiber, stirring and mixing, auxiliary material is obtained.

[0023] The preparation method of the composite gypsum-based self-leveling mortar as described above comprises the following steps:

[0024] S1 respectively preparing a composite additive and an auxiliary material;

[0025] S2 weighing phosphorus building gypsum and auxiliary material, stirring and mixing; then under the stirring state, the composite additive is added at a uniform speed, and is mixed uniformly to obtain the composite gypsum-based self-leveling mortar.

[0026] The beneficial effects of the present application are reflected in:

[0027] The composite gypsum-based self-leveling mortar in the application takes alpha-phosphorus building gypsum as the main cementitious material, introduces a composite additive containing a reinforcing agent and the like, and an auxiliary material containing multiple raw materials such as dried sand, controls the types and amounts of the components of the raw materials, and makes them work together, so that the material performance defects such as low strength, easy cracking and poor fluidity of the current self-leveling mortar taking phosphorus building gypsum as the main cementitious material can be solved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The absolute dry surface of the self-leveling mortar in Example 3 is photographed;

[0029] Figure 2 The absolute dry surface of the self-leveling mortar in Comparative Example 2 is photographed. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme in the embodiments of the application will be clearly and completely described below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0031] The application provides a composite gypsum-based self-leveling mortar, which comprises phosphorus building gypsum, a composite additive and an auxiliary material.

[0032] The composite additive comprises 0.05-0.3% reinforcing agent, 0.02-0.2% defoaming agent, 0.03-0.2% gypsum retarder, 0.02-0.2% stabilizer, 0.01-0.1% toner and 0.05-0.4% flow aid by mass fraction.

[0033] The auxiliary material comprises 2-20% of dried sand, 0.01-0.5% of calcium oxide, 0.1-2% of calcium carbonate, 1-6.5% of ceramic microspheres and 0.1-0.5% of anti-cracking fibers;

[0034] The balance is phosphorus building gypsum, the phosphorus building gypsum adopts alpha-phosphorus building gypsum and / or beta-phosphorus building gypsum, preferably alpha-phosphorus building gypsum.

[0035] In the application, the reinforcing agent is selected from one or more of polycarboxylic acid reinforcing agent, melamine reinforcing agent, lignin sulfonate reinforcing agent, naphthalene sulfonate reinforcing agent and the like, and preferably is a polycarboxylic acid water reducing agent containing hydroxymethyl, hydroxyethyl or hydroxypropyl.

[0036] The defoaming agent is selected from one or more of polyether defoaming agent, silicone defoaming agent, modified polyether defoaming agent and the like.

[0037] The gypsum retarder is selected from one or more of protein retarder, amino acid retarder, composite retarder and the like.

[0038] The stabilizer is selected from one or more of redispersible latex powder, polyvinyl alcohol, instant putty powder, cellulose ether, guar gum and the like.

[0039] The flow aid is selected from one or more of magnesium stearate, potassium stearate, talc, magnesium aluminum silicate, colloidal silicon dioxide and the like, and when magnesium stearate or potassium stearate is used, emulsifying material is supplemented to avoid the magnesium stearate or potassium stearate floating on the surface of the material system and improve water resistance.

[0040] The anti-cracking fiber is selected from one or more of polypropylene fiber, carbon fiber, plant fiber, basalt fiber and the like.

[0041] In the application, the preparation method of the ceramic microspheres comprises the following steps:

[0042] The silica powder is taken, 2-10wt% of sodium carbonate and / or calcium carbonate is added, and ball milling is carried out to obtain an initial powder;

[0043] The initial powder is placed at a distance of 0.18-0.35m from a high-temperature flame gun, the pressure is controlled to be 0.8-1MPa, the medium gas is oxygen, and jet heating is carried out at 2200-2750℃, and the smelting product is sent into water to obtain crude ceramic;

[0044] The crude ceramic is further separated by oscillation, dried to obtain ceramic microspheres.

[0045] In the application, the dried sand satisfies: 1-8wt% of the dried sand has a particle size of 20-80 mesh, and 5-18wt% of the dried sand has a particle size of 80-150 mesh.

[0046] The application further provides a preparation method of the composite gypsum-based self-leveling mortar, comprising the following steps:

[0047] (1) preparing a composite additive:

[0048] measuring the components of the composite additive by quantity,

[0049] (2) preparing an auxiliary material:

[0050] taking the dried sand, sequentially performing first fine grinding, first screening, second fine grinding, second screening, and mixing the dried sand with different particle sizes obtained by screening; adding calcium oxide, calcium carbonate, ceramic microspheres and anti-cracking fibers, and stirring at a speed of 30-50 rpm for 45-60 min to obtain the auxiliary material.

[0051] (3) preparing the composite gypsum-based self-leveling mortar:

[0052] respectively measuring the phosphorus building gypsum and the auxiliary material, and placing them in a mixing container and stirring uniformly; then adding the composite additive at a uniform speed under stirring and mixing uniformly to obtain the composite gypsum-based self-leveling mortar.

[0053] <EMBODIMENT>

[0054] Preparation of ceramic microspheres: the ceramic microspheres prepared by the above process are used as one of the raw material components of the auxiliary material in the composite gypsum-based self-leveling mortar, and a plurality of groups of composite gypsum-based self-leveling mortar samples are prepared by the following examples.

[0055] Example 1

[0056] measuring 2 parts of polycarboxylic acid reinforcing agent, 1.5 parts of silicone defoaming agent, 1.5 parts of protein retarder, 1.5 parts of polyvinyl alcohol, 0.5 parts of toner and 2 parts of magnesium stearate by mass fraction; mixing the above raw materials, placing them in a 120 rpm stirrer and stirring for 30 min to obtain the composite additive.

[0057] taking another batch of dried sand, first performing first fine grinding and screening with a 120 mesh screen; then performing second fine grinding and screening with a 40 mesh screen; mixing the first screened coarse material, the 120 mesh material and the 40 mesh material in a mass ratio of 16:3:1 to obtain the dried sand to be used;

[0058] adding 0.05 parts of calcium oxide, 0.12 parts of calcium carbonate, 0.35 parts of ceramic microspheres and 0.04 parts of carbon fibers to 1 part of the dried sand to be used, and stirring at a speed of 45 rpm for 60 min to obtain the auxiliary material.

[0059] Take 8 parts of alpha-phosphorus building gypsum and the auxiliary material prepared above, place in a stirrer, stir at 300 rpm for 15 min; then under stirring, add 0.12 parts of composite additive, continue to stir for 20 min, to obtain a composite gypsum-based self-leveling mortar.

[0060] Example 2

[0061] According to the mass fraction, respectively take 1.5 parts of polycarboxylic acid reinforcing agent, 1 part of silicone defoaming agent, 1.5 parts of protein retarder, 1.5 parts of polyvinyl alcohol, 0.5 parts of toner and 2 parts of magnesium stearate; mix the above raw materials, place in a 120 rpm stirrer, stir for 30 min, to obtain a composite additive.

[0062] Take the initial dry sand, first fine grinding, sieving with a 120 mesh screen; then secondary fine grinding, sieving with a 40 mesh screen; according to the mass ratio of 46:3:1, respectively take the first sieved coarse material, 120 mesh material, 40 mesh material, mix to obtain the dry sand to be used;

[0063] Then add 0.05 parts of calcium oxide, 0.12 parts of calcium carbonate, 0.3 parts of ceramic microspheres and 0.03 parts of carbon fiber to 1 part of the dry sand to be used, stir at a speed of 45 rpm for 60 min, to obtain an auxiliary material.

[0064] Take 8 parts of alpha-phosphorus building gypsum and the auxiliary material prepared above, place in a stirrer, stir at 300 rpm for 15 min; then under stirring, add 0.13 parts of composite additive, continue to stir for 20 min, to obtain a composite gypsum-based self-leveling mortar.

[0065] Example 3

[0066] According to the mass fraction, respectively take 2 parts of polycarboxylic acid reinforcing agent, 1.5 parts of silicone defoaming agent, 1.5 parts of protein retarder, 1.5 parts of polyvinyl alcohol, 0.5 parts of toner and 2 parts of magnesium stearate; mix the above raw materials, place in a 120 rpm stirrer, stir for 30 min, to obtain a composite additive.

[0067] Take the initial dry sand, first fine grinding, sieving with a 120 mesh screen; then secondary fine grinding, sieving with a 40 mesh screen; according to the mass ratio of 46:3:1, respectively take the first sieved coarse material, 120 mesh material, 40 mesh material, mix to obtain the dry sand to be used;

[0068] Then add 0.01 parts of calcium oxide, 0.12 parts of calcium carbonate, 0.15 parts of ceramic microspheres and 0.4 parts of carbon fiber to 1 part of the dry sand to be used, stir at a speed of 45 rpm for 60 min, to obtain an auxiliary material.

[0069] Take 8 parts of β-phosphorus building gypsum and the auxiliary material prepared above, place in the stirrer, stir at 300 rpm for 15 min; again in the state of stirring, add 0.13 parts of composite additive, continue to stir for 20 min, get composite gypsum-based self-leveling mortar.

[0070] Example 4

[0071] According to the mass fraction, respectively take 2 parts of lignin sulfonate reinforcing agent, 1.5 parts of polyether defoaming agent, 1.5 parts of amino acid retarder, 1.5 parts of polyvinyl alcohol, 0.5 parts of toning agent and 2 parts of magnesium stearate; the above raw materials are mixed, placed in a 120 rpm stirrer, stirred for 30 min, to get a composite additive.

[0072] Take another initial dry sand, first fine grinding, sieving with 120 mesh screen; then secondary fine grinding, sieving with 40 mesh screen; according to the mass ratio of 16:3:1, respectively take the first sieved coarse material, 120 mesh material, 40 mesh material, mix to get the ready-to-use dry sand;

[0073] Add 0.05 parts of calcium oxide, 0.12 parts of calcium carbonate, 0.35 parts of ceramic microspheres and 0.4 parts of carbon fiber to 1 part of the ready-to-use dry sand, stir at 45 rpm for 60 min to get the auxiliary material.

[0074] Take 8 parts of α-phosphorus building gypsum and the auxiliary material prepared above, place in the stirrer, stir at 300 rpm for 15 min; again in the state of stirring, add 0.15 parts of composite additive, continue to stir for 20 min, get composite gypsum-based self-leveling mortar.

[0075] Example 5

[0076] According to the mass fraction, respectively take 2.8 parts of lignin sulfonate reinforcing agent, 1.85 parts of polyether defoaming agent, 1.85 parts of amino acid retarder, 1.5 parts of polyvinyl alcohol, 0.5 parts of toning agent and 2 parts of magnesium stearate; the above raw materials are mixed, placed in a 120 rpm stirrer, stirred for 30 min, to get a composite additive.

[0077] Take another initial dry sand, first fine grinding, sieving with 120 mesh screen; then secondary fine grinding, sieving with 40 mesh screen; according to the mass ratio of 16:3:1, respectively take the first sieved coarse material, 120 mesh material, 40 mesh material, mix to get the ready-to-use dry sand;

[0078] Add 0.05 parts of calcium oxide, 0.12 parts of calcium carbonate, 0.35 parts of ceramic microspheres and 0.4 parts of carbon fiber to 1 part of the ready-to-use dry sand, stir at 45 rpm for 60 min to get the auxiliary material.

[0079] Take 8 parts of alpha-phosphorus building gypsum and the auxiliary material prepared above, place in the stirrer, stir at 300 rpm for 15 min; again in the stirring state, add 0.12 parts of composite additive, continue to stir for 20 min, get composite gypsum-based self-leveling mortar.

[0080] Example 6

[0081] According to the mass fraction, respectively take 2 parts of polycarboxylic acid reinforcing agent, 1.5 parts of silicone defoaming agent, 1.5 parts of protein retarder, 1.5 parts of redispersible latex powder, 0.5 parts of toner and 2 parts of talc; the above raw materials are mixed and placed in a 120 rpm stirrer for 30 min to obtain a composite additive.

[0082] Take the initial dry sand, first fine grinding, sieving with a 120 mesh screen; then fine grinding again, sieving with a 40 mesh screen; according to the mass ratio of 16:3:1, respectively take the first sieved coarse material, 120 mesh material, 40 mesh material, mix to get the ready-to-use dry sand;

[0083] Add 0.05 parts of calcium oxide, 0.12 parts of calcium carbonate, 0.35 parts of ceramic microspheres and 0.4 parts of carbon fiber to 1 part of the ready-to-use dry sand, stir at 45 rpm for 60 min to get the auxiliary material.

[0084] Take 8 parts of alpha-phosphorus building gypsum and the auxiliary material prepared above, place in the stirrer, stir at 300 rpm for 15 min; again in the stirring state, add 0.12 parts of composite additive, continue to stir for 20 min, get composite gypsum-based self-leveling mortar.

[0085] Example 7

[0086] According to the mass fraction, respectively take 2 parts of polycarboxylic acid reinforcing agent, 1.5 parts of silicone defoaming agent, 1.5 parts of protein retarder, 0.8 parts of redispersible latex powder, 0.5 parts of toner and 0.8 parts of talc; the above raw materials are mixed and placed in a 120 rpm stirrer for 30 min to obtain a composite additive.

[0087] Take the initial dry sand, first fine grinding, sieving with a 120 mesh screen; then fine grinding again, sieving with a 40 mesh screen; according to the mass ratio of 16:3:1, respectively take the first sieved coarse material, 120 mesh material, 40 mesh material, mix to get the ready-to-use dry sand;

[0088] Add 0.05 parts of calcium oxide, 0.12 parts of calcium carbonate, 0.35 parts of ceramic microspheres and 0.4 parts of carbon fiber to 1 part of the ready-to-use dry sand, stir at 45 rpm for 60 min to get the auxiliary material.

[0089] Take 8 parts of alpha-phosphorus building gypsum and the auxiliary material prepared above, place in a stirrer, stir at 300 rpm for 15 min; then under stirring, add 0.13 parts of composite additive, continue to stir for 20 min, to obtain a composite gypsum-based self-leveling mortar.

[0090] <Comparative Example>

[0091] Comparative Example 1

[0092] According to the mass fraction, take 0.05 parts of polycarboxylic acid reinforcing agent, 0.1 parts of silicone defoaming agent, 0.1 parts of protein retarder, 0.15 parts of polyvinyl alcohol, 0.05 parts of toning agent and 0.2 parts of magnesium stearate; mix the above raw materials, place in a 120 rpm stirrer, stir for 30 min, to obtain a composite additive.

[0093] Take another initial dry sand, first fine grinding, sieving with a 120 mesh screen; then secondary fine grinding, sieving with a 40 mesh screen; according to the mass ratio of 16:3:1, take the first sieved coarse material, 120 mesh material and 40 mesh material respectively, mix to obtain the dry sand to be used;

[0094] Add 0.01 parts of calcium oxide, 0.02 parts of calcium carbonate and 0.04 parts of glass fiber to 0.1 parts of the dry sand to be used, stir at a speed of 45 rpm for 60 min, to obtain an auxiliary material.

[0095] Take 40 parts of alpha-phosphorus building gypsum and the auxiliary material prepared above, place in a stirrer, stir at 300 rpm for 15 min; then under stirring, add 0.12 parts of composite additive, continue to stir for 20 min, to obtain a composite gypsum-based self-leveling mortar.

[0096] Comparative Example 2

[0097] According to the mass fraction, take 2 parts of polycarboxylic acid reinforcing agent, 1.5 parts of silicone defoaming agent, 1.5 parts of protein retarder, 1.5 parts of polyvinyl alcohol, 0.5 parts of toning agent and 2 parts of magnesium stearate; mix the above raw materials, place in a 120 rpm stirrer, stir for 30 min, to obtain a composite additive.

[0098] Take another initial dry sand, first fine grinding, sieving with a 120 mesh screen; then secondary fine grinding, sieving with a 40 mesh screen; according to the mass ratio of 16:3:1, take the first sieved coarse material, 120 mesh material and 40 mesh material respectively, mix to obtain the dry sand to be used;

[0099] Add 0.05 parts of calcium oxide, 0.12 parts of calcium carbonate, 0.35 parts of ceramic microspheres and 0.4 parts of glass fiber to 1 part of the dry sand to be used, stir at a speed of 45 rpm for 60 min, to obtain an auxiliary material.

[0100] Take 70 parts of alpha-phosphorus building gypsum, 15 parts of cement and 10 parts of the auxiliary material prepared above, place them in a stirrer, and stir at 300 rpm for 15 min; then, under stirring, add 1.5 parts of the composite additive, and continue stirring for 20 min to obtain a composite gypsum-based self-leveling mortar.

[0101] Comparative Example 3

[0102] According to the mass fraction, 80 parts of alpha-phosphorus building gypsum, 10 parts of 150-mesh dried sand, 0.05 parts of calcium oxide, 2 parts of calcium carbonate, 2 parts of ceramic microspheres, 1 part of glass fiber, 0.4 parts of polycarboxylic acid reinforcing agent, 0.2 parts of silicone defoaming agent, 0.1 parts of protein retarder, 1 parts of polyvinyl alcohol, 0.5 parts of toning agent and 0.5 parts of magnesium stearate were taken respectively, stirred at 300 rpm for 40 min to obtain a self-leveling mortar.

[0103] <Experimental Example>

[0104] Samples: Examples 1-7, Comparative Examples 1-3

[0105] The self-leveling mortar samples prepared in Examples 1-7 and Comparative Examples 1-3 were taken respectively, and the relevant material properties were determined according to the requirements of JC / T 1023-2021 "Gypsum-based self-leveling mortar" in the corresponding manner, and the test results are as follows in Table 1:

[0106] Table 1 Material performance of different self-leveling mortar samples

[0107]

[0108] From Table 1 above, it can be seen that:

[0109] 1. The self-leveling mortar samples prepared in Examples 1-7 have a significantly higher compressive strength after 28 days under normal construction and maintenance conditions than the self-leveling mortar samples in Comparative Examples 1-3, and all exceed 25 MPa, fully meeting the requirements of JC / T 1023-2021 "Gypsum-based self-leveling mortar" on strength, reaching the c25 standard grade.

[0110] 2. After adding an equal amount of water to the above self-leveling mortar samples to make a slurry, the initial flow degree was determined, and the 30 min flow degree was tested after standing for 30 min. The results showed that the samples in Examples 1-7 had a flow degree of more than 140 mm at the initial stage and at 30 min, and the 30 min flow degree decreased to a lesser extent, and no bleeding and layering occurred. Although Comparative Examples 1-3 also had a high flow degree at the initial stage, the flow degree decreased significantly at 30 min, and bleeding began to occur, i.e., they could not meet the requirement of JC / T 1023-2021 "Gypsum-based self-leveling mortar" of more than 140 mm.

[0111] 3、The cracking degree of the samples in Examples 1-7 is obviously lower than that in Comparative Examples 1-3, because: in Examples 1-7, the gypsum-based self-leveling mortar is prepared without introducing cement, thus the normal hydration process of gypsum can be ensured, and the gypsum can reach a relatively high self-strength; in addition, the dried sand with a specific particle size and other auxiliary materials are added, the materials are more uniform through the mutual matching of particles, and the finally formed mortar material system has excellent anti-cracking performance.

[0112] In summary, the composite gypsum-based self-leveling mortar provided by the present application has light thickening ability and lubricating flow effect, that is, the stability of the material system can be ensured to avoid water bleeding, and the mortar liquid can maintain good flowability within a certain time to realize sufficient self-leveling effect, which is convenient for actual construction and other treatments; and in application, no obvious cracking occurs in a large area, and even in the sun corner which is prone to cracking, no obvious cracks occur.

[0113] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A composite gypsum-based self-leveling mortar, characterized in that, It includes phosphorus building gypsum, composite additives and auxiliary materials, and the phosphorus building gypsum uses α-phosphorus building gypsum and / or β-phosphorus building gypsum; By mass fraction, the compound additives include 0.05-0.3% reinforcing agent, 0.02-0.2% defoamer, 0.03-0.2% gypsum retarder, 0.02-0.2% stabilizer, 0.01-0.1% colorant, and 0.05-0.4% flow aid; The auxiliary materials include 2-20% dried sand, 0.01-0.5% calcium oxide, 0.1-2% calcium carbonate, 1-6.5% ceramic microspheres, and 0.1-0.5% crack-resistant fiber; the crack-resistant fiber is selected from one or more of polypropylene fiber, carbon fiber, plant fiber, and basalt fiber; in the dried sand, 1-8 wt% of the dried sand has a particle size of 20-80 mesh, and 5-18 wt% of the dried sand has a particle size of 80-150 mesh.

2. The composite gypsum-based self-leveling mortar according to claim 1, characterized in that, The reinforcing agent is selected from one or more of polycarboxylic acid reinforcing agents, melamine reinforcing agents, lignin sulfonate reinforcing agents, and naphthalene sulfonate reinforcing agents.

3. The composite gypsum-based self-leveling mortar according to claim 1, characterized in that, The defoamer is selected from one or more of polyether defoamers, silicone defoamers, and modified polyether defoamers.

4. The composite gypsum-based self-leveling mortar according to claim 1, characterized in that, The gypsum retarder is selected from one or more of protein retarder, amino acid retarder, and composite retarder; Among them, the amino acid retarder is an amino acid retarder containing acidic amino acid groups.

5. The composite gypsum-based self-leveling mortar according to claim 1, characterized in that, The stabilizer is selected from one or more of the following: redispersible latex powder, polyvinyl alcohol, instant putty powder, cellulose ether, and guar gum.

6. The composite gypsum-based self-leveling mortar according to claim 1, characterized in that, The flow aid is selected from one or more of magnesium stearate, potassium stearate, talc, magnesium aluminum silicate, and colloidal silica.

7. The composite gypsum-based self-leveling mortar according to any one of claims 1 to 6, characterized in that, The preparation method of the auxiliary material includes the following steps: Take dried sand and process it in sequence through initial fine grinding, initial sieving, secondary fine grinding, and secondary sieving. Then mix the dried sand of different particle sizes obtained from sieving. Add calcium oxide, calcium carbonate, ceramic microspheres, and crack-resistant fibers, stir and mix well to obtain auxiliary materials.

8. The method for preparing the composite gypsum-based self-leveling mortar according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1 prepares composite additives and auxiliary materials respectively; S2 Weigh out the phosphorus-based building gypsum and auxiliary materials, and stir them until well mixed; then, while stirring, add the composite additive at a uniform speed and mix well to obtain the composite gypsum-based self-leveling mortar.

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