High-anti-crack self-leveling dry-mixed mortar, preparation method and construction method thereof

Abstract

The present application relates to the technical field of building material preparation, and particularly relates to a high-anti-cracking self-leveling dry powder mortar, a preparation method thereof and a construction method thereof. The present application uses gypsum to replace cement and is combined with fly ash and steel slag powder to form a composite cementitious material, and uses incinerator slag to replace natural sand as fine aggregate to prepare the high-anti-cracking self-leveling dry powder mortar, thereby opening up a new way for resource utilization of solid waste. Moreover, the prepared self-leveling dry powder mortar has good anti-cracking capacity, good workability and water retention; the construction layer is quickly solidified, and the maintenance period is short; after construction, the bonding force is strong, and the self-leveling dry powder mortar is not shrunk, not hollow, and has a smooth and flat surface.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building material preparation, and particularly relates to a high-anti-cracking self-leveling dry powder mortar and a preparation method and a construction method thereof. BACKGROUND

[0002] The self-leveling mortar is a dry-mixed powder material composed of various active components, has very good fluidity and self-leveling ability, can be used by mixing with water on site, and is widely applied to indoor floor and industrial floor leveling engineering of public buildings such as residences, hospitals and supermarkets.

[0003] The self-leveling mortar material is generally divided into organic and inorganic types. The organic self-leveling material is mainly an epoxy resin self-leveling material, has good construction performance, but has high price and high construction requirement, and has poor wear resistance. The inorganic self-leveling material is divided into a gypsum-based self-leveling material and a cement-based self-leveling material. The cement-based self-leveling material uses cement as a cementing material, has high production cost, is easy to crack, and has poor anti-cracking ability. The gypsum-based self-leveling material uses building gypsum to replace part or all of cement, has improved anti-cracking performance compared with the cement-based self-leveling material, but the improvement range needs to be further improved. SUMMARY

[0004] Therefore, the present application aims to provide a high-anti-cracking self-leveling dry powder mortar and a preparation method and a construction method thereof. The self-leveling dry powder mortar provided by the present application has good anti-cracking ability, and opens up a new way for resource utilization of solid waste.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions.

[0006] The present application provides a high-anti-cracking self-leveling dry powder mortar, which comprises the following components in total mass of 100%:

[0007]

[0008] The content of the hemihydrate gypsum in the gypsum is greater than or equal to 95% by mass percentage, the content of the dihydrate gypsum is less than or equal to 2% by mass percentage, and the content of the anhydrous gypsum is 0% by mass percentage.

[0009] Preferably, the content of the retarder comprises 35-45% of aminoacetic acid, 15-25% of malic acid and 35-45% of ethylenediaminetetraacetic acid disodium by mass percentage.

[0010] Preferably, the particle size of the gypsum is 35-50 microns, and the gypsum is obtained by calcining and grinding desulfurization gypsum.

[0011] Preferably, the particle size of the steel slag powder is 30-45 microns.

[0012] Preferably, the particle size of the fly ash is 10-30 microns.

[0013] Preferably, the particle size composition of the incineration slag is that the mass ratio of 10-30 mesh, 30-60 mesh, 60-90 mesh and 90-120 mesh particles is 25%.

[0014] Preferably, the water reducing agent is a polycarboxylic acid superplasticizer, and the water reducing rate is > 35%.

[0015] Preferably, the defoaming agent is an organic silicon type powder defoaming agent, and the thickening agent is hydroxypropyl methyl cellulose.

[0016] The application provides a preparation method of the high-anti-cracking self-leveling dry powder mortar.

[0017] The application provides a construction method of the high-anti-cracking self-leveling dry powder mortar or the high-anti-cracking self-leveling dry powder mortar prepared by the preparation method.

[0018] The application provides a high-anti-cracking self-leveling dry powder mortar, which comprises the following components in a total mass of 100%: 35-45% of gypsum, 5-10% of steel slag powder, 5-10% of fly ash, 40-50% of incineration slag, 0.1-0.3% of a retarder, 0.1-0.3% of a thickening agent, 0.5-1.5% of a water reducing agent and 0.01-0.15% of a defoaming agent; the content of hemihydrate gypsum in the gypsum is greater than or equal to 95%, the content of dihydrate gypsum is less than or equal to 2%, and the content of anhydrous gypsum is 0%. The gypsum is used to replace cement and is combined with fly ash and steel slag powder to form a composite cementitious material, so that the self-leveling dry powder mortar has certain water resistance, which is beneficial to reducing cracking. In addition, the gypsum has a slight expansion effect, can reduce shrinkage and prevent cracks, so that the self-leveling dry powder mortar has high anti-cracking capability.

[0019] Further, the existing gypsum-based material usually needs to be mixed with a retarder to adjust the setting time for construction, but the retarder will cause serious loss of the strength of the gypsum-based material when the retardation effect occurs; the application adopts a composite retarder with a small addition amount, good retardation effect and small loss of the strength of the gypsum-based material, and the obtained self-leveling dry powder mortar has good strength (including compressive strength, flexural strength and tensile bonding strength).

[0020] In addition, the high anti-cracking self-leveling dry powder mortar prepared by the application mainly uses desulfurization gypsum, steel slag powder, fly ash and incinerator slag as main raw materials, so that the production cost of the high anti-cracking self-leveling dry powder mortar can be reduced, and a new way for the resource utilization of the solid waste such as desulfurization gypsum, steel slag powder, fly ash and incinerator slag is opened up.

[0021] The high anti-cracking self-leveling dry powder mortar provided by the application can be produced on a large scale in a factory, the high anti-cracking self-leveling dry powder mortar is a dry powder material, can be packaged in bags, has a long storage period and is convenient for transportation, water can be added at a certain proportion at a construction site, and the water-cement ratio is controlled, so that machine spraying construction can be performed, and the construction can be performed at-5℃ or above in winter without affecting the construction quality requirements.

[0022] The high anti-cracking self-leveling dry powder mortar has good workability and water retention, a fast curing speed of a construction layer, a short maintenance cycle (solidification after 1 hour of construction, a compressive strength of 19 MPa or above after 24 hours, and normal temperature maintenance), strong adhesion after construction, no shrinkage, no hollowing, and a smooth and flat surface. DETAILED DESCRIPTION

[0023] The application provides a high anti-cracking self-leveling dry powder mortar, and the total mass is 100%, and the high anti-cracking self-leveling dry powder mortar comprises the following components:

[0024]

[0025] The content of the hemihydrate gypsum in the gypsum is ≥95%, the content of the dihydrate gypsum is ≤2%, and the content of the anhydrous gypsum is 0% in terms of mass percentage.

[0026] The high anti-cracking self-leveling dry powder mortar provided by the application comprises 35-45% of gypsum, and the gypsum can be 35%, 37%, 38%, 40%, 42%, 44% or 45% in specific embodiments. In the application, the content of the hemihydrate gypsum in the gypsum is ≥95%, the content of the dihydrate gypsum is ≤2%, and the content of the anhydrous gypsum is 0% in terms of mass percentage; in specific embodiments, the content of the hemihydrate gypsum in the gypsum can be 95%, 96%, 97%, 98%, 98.5%, 99%, 99.5% or 100%, and the content of the dihydrate gypsum can be 0%, 0.5%, 1%, 1.5% or 2%. In related technologies, building gypsum is used as a cementing material, and the building gypsum is prepared by calcining and dehydrating natural gypsum or industrial by-product gypsum at a certain temperature, wherein the content of the hemihydrate gypsum is ≥60%, and it is difficult to reach such a high content of 95%. The gypsum with the above composition has a slight expansion effect and can reduce shrinkage, but the water resistance of the gypsum-based material is poor, and the cooperation of fly ash and steel slag powder improves the water resistance to a certain extent, and the improvement of the water resistance is also beneficial to preventing cracking.

[0027] In the present application, the particle size of the gypsum is preferably 35-50 μm. In the present application, the gypsum is preferably obtained by grinding the calcined desulfurization gypsum. The present application does not have special requirements for the conditions of the calcination, and it is enough to meet the conditions that the content of the stable gypsum triphase (hemihydrate gypsum, dihydrate gypsum, anhydrous gypsum) after the calcination is: the content of the β-type hemihydrate gypsum is ≥ 95%, the content of the dihydrate gypsum is ≤ 2%, and the content of the anhydrous gypsum is 0%. In the present application, the calcined gypsum is preferably cooled to below 50 ℃ before the grinding. The present application does not have special requirements for the speed of the grinding, and the speed of the grinding known in the art can be adopted. In the examples of the present application, the speed of the grinding is specifically 15 t / h. In the present application, the desulfurization gypsum is the waste residue generated after the flue gas desulfurization of the coal-fired power plant, and the main component is calcium sulfate dihydrate. The present application uses the desulfurization gypsum as the main raw material, and realizes the resource utilization of the desulfurization gypsum.

[0028] The high-anti-cracking self-leveling dry powder mortar provided by the present application comprises 5-10% of steel slag powder, which can be 5%, 6%, 7%, 8%, 9% or 10% in specific examples. In the present application, the particle size of the steel slag powder is preferably 30-45 μm, and the mass content of metallic iron in the steel slag powder is preferably < 0.5%. Since the slag and iron are wrapped together in the steel slag, the content of iron is controlled to be below 0.5% by removing iron, so that the particle size of the steel slag powder can be ground to 30-45 μm. In the present application, the steel slag powder is preferably obtained by grinding and repeatedly removing iron from the converter or electric furnace steel slag meeting the YB / TO22 standard. The present application does not have special requirements for the grinding, and the grinding process known in the art can be adopted, for example, the pre-grinding closed-circuit system taking the column mill as the main equipment and the final grinding closed-circuit system taking the K-type powder separator as the main equipment. In the present application, the steel slag powder is used as a composite cementitious material together with gypsum and fly ash to improve the water resistance of gypsum.

[0029] The high-anti-cracking self-leveling dry powder mortar provided by the present application comprises 5-10% of fly ash, which can be 5%, 6%, 7%, 8%, 9% or 10% in specific examples. In the present application, the particle size of the fly ash is preferably 10-30 μm. The present application does not have special requirements for the source of the fly ash, and the commercially available product can be used, or the fly ash can be prepared by the method known in the art. In the examples of the present application, the fly ash discharged from the coal-fired power plant is put into a QM-480-600 horizontal high-fine grinding tester, the rotating speed is adjusted to 48 rpm, and the grinding is performed for 10 minutes; the ground fly ash is then put into an OS-I type ultra-fine classifier, the rotor linear speed is adjusted to 100 m per second, the automatic feeding button is started, and the air selection and classification are performed, so that the fly ash with a particle size of 10-30 μm is obtained after 1 hour. In the present application, the fly ash is used as a composite cementitious material together with gypsum and steel slag powder to improve the water resistance of gypsum.

[0030] The high-anti-cracking self-leveling dry-mixed mortar provided by the application comprises 40-50% of incineration slag, which can be 40%, 42%, 44%, 45%, 46%, 48% or 50% in specific embodiments. In the application, the particle size grading composition of the incineration slag preferably comprises 25% of 10-30 mesh particles, 25% of 30-60 mesh particles, 25% of 60-90 mesh particles and 25% of 90-120 mesh particles. The application controls the particle size of the incineration slag, so that the incineration slag of different sizes can fill the gaps between each other, and the density of the self-leveling dry-mixed mortar can be increased.

[0031] The incineration slag is a solid residue of molten material produced in the garbage incineration process, which mainly comprises SiO2, Al2O3, CaO and MgO, and also contains iron and aluminum, copper and other metals. Since the main physical components of the slag are hard, the slag can ensure a certain strength when used as aggregate. In the application, the incineration slag needs to meet the GB / T25032-2010 “Domestic Waste Incineration Slag Aggregate” standard, has good firmness, stable chemical properties, good durability, certain strength and can meet the utilization requirements of aggregate.

[0032] In the application, the incineration slag is preferably processed by a process well known in the art. In the embodiments, the incineration slag produced by garbage incineration is crushed by a crusher to a particle size of 10 mm, treated by a magnetic separator, and the iron is removed and collected by the magnetic separator. The slag after preliminary iron removal is then fed into an eddy current separator to separate the non-ferrous metals in the slag. The slag after iron and non-ferrous metal removal and separation is crushed by a crusher to a particle size of 5 mm, and then subjected to iron removal and non-ferrous metal treatment, followed by water washing, drying treatment, and then vibration screening to obtain slag aggregate with particle sizes of 10-30 mesh, 30-60 mesh, 60-90 mesh and 90-120 mesh, respectively, for use.

[0033] In the application, the incineration slag is used to replace natural sand as fine aggregate to prepare high-anti-cracking self-leveling dry-mixed mortar.

[0034] The high anti-cracking self-leveling dry powder mortar provided by the application comprises 0.1-0.3% of a retarder, which can be 0.1%, 0.15%, 0.2%, 0.25% or 0.3% in specific embodiments. The retarder preferably comprises 35-45% of glycine, 15-25% of malic acid and 35-45% of disodium ethylenediaminetetraacetate in terms of mass percentage. In specific embodiments, the content of glycine in the retarder can be 35%, 37%, 40%, 43% or 45%, the content of malic acid can be 15%, 17%, 20%, 22% or 25%, and the content of disodium ethylenediaminetetraacetate can be 35%, 37%, 40%, 43% or 45%. Because of the fast setting of gypsum-based materials, a retarder is usually added to adjust the setting time for construction. However, the retarder will cause serious loss of the strength of the gypsum-based material while retarding the setting. The application uses a composite retarder, which has good retarding effect, requires a small amount of addition and causes small loss of the strength of the gypsum-based material.

[0035] The high anti-cracking self-leveling dry powder mortar provided by the application comprises 0.1-0.3% of a thickening agent, which can be 0.1%, 0.15%, 0.2%, 0.25% or 0.3% in specific embodiments. In the application, the thickening agent is preferably hydroxypropyl methyl cellulose. In the application, the thickening agent plays the roles of thickening, water retention, bonding and improving the workability, and can improve the water retention, bonding strength of the mortar and the anti-cracking property of the mortar.

[0036] The high anti-cracking self-leveling dry powder mortar provided by the application comprises 0.1-0.3% of a water reducing agent, which can be 0.1%, 0.15%, 0.2%, 0.25% or 0.3% in specific embodiments. In the application, the water reducing agent is preferably a polycarboxylic acid superplasticizer, and the water-reducing rate is preferably >35%. The use of the polycarboxylic acid superplasticizer in the application can significantly reduce the water consumption of the mortar, reduce the water-cement ratio of the mortar, thereby improving the fluidity, stability and compactness of the mortar, and helping to improve the compressive strength, tensile bonding strength of the mortar and the anti-cracking property of the mortar.

[0037] The high anti-cracking self-leveling dry powder mortar provided by the application comprises 0.01-0.15% of a defoaming agent, which can be 0.01%, 0.03%, 0.05%, 0.08%, 0.10%, 0.12% or 0.15% in specific embodiments. In the application, the defoaming agent is preferably a silicone type powder defoaming agent. The use of the silicone type powder defoaming agent in the application has strong defoaming capacity and fast speed, does not affect the basic properties of the system after being added, has good stability and can increase the compactness of the mortar.

[0038] The application provides a preparation method of the high anti-cracking self-leveling dry powder mortar described in the above scheme, which comprises the following steps: mixing components to obtain the high anti-cracking self-leveling dry powder mortar.

[0039] In the present application, the mixing preferably comprises: first mixing the gypsum, the steel slag powder, the fly ash, the retarder, the thickening agent, the water reducing agent and the defoaming agent, and second mixing the incineration slag into the resultant mixture.

[0040] In the present application, the first mixing and the second mixing are preferably carried out under stirring, and the present application does not specially limit the time and the stirring rate of the first mixing and the second mixing, as long as the purpose of uniform mixing can be achieved. In the embodiments of the present application, the time of the first mixing and the second mixing is both 5 min, the stirring rate of the first mixing is 60-75 rpm, and the stirring rate of the second mixing is 55-70 rpm. In the present application, the mixing is preferably carried out in a mixer.

[0041] The high anti-cracking self-leveling dry powder mortar is preferably packed in a warehouse at 50 kg per package.

[0042] The present application provides a construction method of the above high anti-cracking self-leveling dry powder mortar, comprising the following steps: coating after mixing the high anti-cracking self-leveling dry powder mortar and water; the mass ratio of the water to the high anti-cracking self-leveling dry powder mortar (i.e. the water-cement ratio) is 0.20-0.23:1.

[0043] In specific embodiments, the water-cement ratio can be 0.20:1, 0.21:1, 0.22:1 or 0.23:1.

[0044] The present application does not have special requirements for the coating method, and a coating method well known in the art can be used, such as spraying. The present application preferably uses large pumping equipment and special spraying equipment for construction. This construction method is fast and efficient, reduces labor intensity, improves the construction environment, saves construction cost, and also ensures excellent construction quality. The present application can adjust and control the spraying thickness of the high anti-cracking self-leveling dry powder mortar according to actual needs. The high anti-cracking self-leveling dry powder mortar provided by the present application has good anti-cracking ability, and can be constructed above -5℃ in winter without affecting the construction quality requirements. The high anti-cracking self-leveling dry powder mortar can be applied to various floors indoors.

[0045] The high anti-cracking self-leveling dry powder mortar of the present application has good workability and water retention; the construction layer solidifies quickly and can be solidified after 1 hour of construction; the curing period is short, and the curing period is 24 hours at normal temperature; the adhesion after construction is strong, and there is no shrinkage, no hollowing, and the surface is smooth and flat.

[0046] The high anti-cracking self-leveling dry powder mortar provided by the present application and the preparation method and construction method thereof will be described in detail below in conjunction with embodiments, but they should not be understood as limiting the scope of protection of the present application.

[0047] Example 1

[0048] This example is to prepare 100 kg high crack resistance self-leveling dry powder mortar, its preparation method is as follows:

[0049] The amount of each raw material is:

[0050] Gypsum (particle size is 35-50 μm, content of hemihydrate gypsum is 97%, content of dihydrate gypsum is 1%, content of anhydrous gypsum is 0%) 44 kg, steel slag powder (particle size is 30-45 μm, mass content of metallic iron is <0.5%) 7.15 kg, fly ash (particle size is 10-30 μm) 5 kg, incineration slag (particle size is 10-30 mesh, 30-60 mesh, 60-90 mesh, 90-120 mesh, and slag aggregate of each accounts for 25%) 42 kg, composite retarder (consists of aminoacetic acid 0.12 kg, malic acid 0.6 kg, and ethylenediaminetetraacetic acid disodium 0.12 kg) 0.3 kg, thickening agent (hydroxypropyl methyl cellulose) 0.25 kg, polycarboxylic acid high efficiency water reducing agent (water reducing rate >35%) 1.2 kg, and organic silicon type powder defoaming agent 0.1 kg.

[0051] The above-mentioned proportioning and batching are weighed, the gypsum, steel slag powder, fly ash, composite retarder, thickening agent, water reducing agent and defoaming agent are put into a mixer in sequence to be stirred and mixed, and are fully mixed uniformly, the stirring and mixing time is 5 min, and the stirring rate is 60-75 rpm, then the incineration slag is put into the mixer to be stirred and mixed, the stirring and mixing time is 5 min, and the stirring rate is 55-70 rpm, and the high crack resistance self-leveling dry powder mortar is obtained. Then 50 kg is packed and stored in a warehouse.

[0052] Example 2

[0053] This example is to prepare 100 kg high crack resistance self-leveling dry powder mortar, its preparation method is as follows:

[0054] The amount of each raw material is: gypsum (particle size is 35-50 μm, content of hemihydrate gypsum is 95%, content of dihydrate gypsum is 2%, content of anhydrous gypsum is 0%) 37 kg, steel slag powder (particle size is 30-45 μm, mass content of metallic iron is <0.5%) 7.7 kg, fly ash (particle size is 10-30 μm) 9 kg, incineration slag (particle size is 10-30 mesh, 30-60 mesh, 60-90 mesh, 90-120 mesh, and slag aggregate of each accounts for 25%) 45 kg, composite retarder (consists of aminoacetic acid 0.04 kg, malic acid 0.02 kg, and ethylenediaminetetraacetic acid disodium 0.04 kg) 0.1 kg, thickening agent (hydroxypropyl methyl cellulose) 0.2 kg, polycarboxylic acid high efficiency water reducing agent (water reducing rate >35%) 0.9 kg, and organic silicon type powder defoaming agent 0.1 kg.

[0055] The ingredients are weighed according to the above ratio, and the gypsum, steel slag powder, fly ash, composite retarder, thickening agent, water reducing agent and defoaming agent are sequentially put into a mixer for stirring and mixing, and are fully mixed and uniform, the stirring and mixing time is 5 min, and the stirring rate is 60-75 rpm, then the incinerator slag is put into the mixer for stirring and mixing, the stirring and mixing time is 5 min, and the stirring rate is 55-70 rpm, and high anti-cracking self-leveling dry powder mortar is obtained. Then 50 kg is packed in a bag and stored in a warehouse.

[0056] Example 3

[0057] This example takes the preparation of 100 kg of high anti-cracking self-leveling dry powder mortar as an example, and the preparation method is as follows:

[0058] The amount of each raw material is:

[0059] Gypsum (particle size 35-50 μm, content of hemihydrate gypsum 96%, content of dihydrate gypsum 1.5%, content of anhydrous gypsum 0%) 40 kg, steel slag powder (particle size 30-45 μm, mass content of metallic iron <0.5%) 5 kg, fly ash (particle size 10-30 μm) 6 kg, incinerator slag (particle size 10-30 mesh, 30-60 mesh, 60-90 mesh, 90-120 mesh slag aggregate each accounting for 25%) 48 kg, composite retarder (consisting of aminoacetic acid 0.08 kg, malic acid 0.04 kg, and disodium ethylenediaminetetraacetate 0.08 kg) 0.2 kg, thickening agent (hydroxypropyl methyl cellulose) 0.1 kg, polycarboxylic acid superplasticizer (water-reducing rate >35%) 0.6 kg, and silicone type powder defoaming agent 0.1 kg.

[0060] The ingredients are weighed according to the above ratio, and the gypsum, steel slag powder, fly ash, composite retarder, thickening agent, water reducing agent and defoaming agent are sequentially put into a mixer for stirring and mixing, and are fully mixed and uniform, the stirring and mixing time is 5 min, and the stirring rate is 60-75 rpm, then the incinerator slag is put into the mixer for stirring and mixing, the stirring and mixing time is 5 min, and the stirring rate is 55-70 rpm, and high anti-cracking self-leveling dry powder mortar is obtained. Then 50 kg is packed in a bag and stored in a warehouse.

[0061] Comparative Example 1

[0062] The difference from Example 1 is that the gypsum is replaced by commercially available building gypsum powder with a fineness of 80-200 mesh, of which hemihydrate gypsum is 75%, and the rest is the same as Example 1.

[0063] Comparative Example 2

[0064] The self-leveling mortar formula of the related art is used, and desulfurized building gypsum powder and portland cement are used as cementitious materials, and river sand is used as aggregate, specifically:

[0065] The amount of each raw material is: desulfurization building gypsum powder (particle size 45-60 μm, of which hemihydrate gypsum is 80%) 48 kg, 42.5 Portland cement 5 kg, heavy calcium powder 5.55 kg, river sand (particle size 0.16-0.63 mm) 39 kg, protein-based retarder 0.3 kg, polyvinyl alcohol 0.4 g, cellulose ether 0.2 kg, polycarboxylic acid water reducing agent (water reducing rate > 35%) 1.4 kg, silicone powder defoaming agent 0.15 kg.

[0066] The self-leveling dry powder mortar prepared in the examples and the comparative examples was tested for performance according to the method in JC / T 1023-2021 “Gypsum-based self-leveling mortar”, and the test results are shown in Table 1.

[0067] Table 1 Technical performance indicators of high crack resistance self-leveling dry powder mortar

[0068]

[0069] As can be seen from the results in Table 1, the crack resistance of the self-leveling dry powder mortar prepared by the present application is better than that of the comparative examples, which is manifested by the small size change rate. This is because the gypsum used in the present application has a stable gypsum three-phase (i.e. the content of β-type hemihydrate gypsum is ≥ 95%, the content of dihydrate gypsum is ≤ 2%, and the content of anhydrous gypsum is 0%), and the present application uses gypsum instead of cement and combines with fly ash and steel slag powder to form a composite cementitious material, so that the gypsum-based material has a certain water resistance, and at the same time, the gypsum-based material has a slight expansion effect, which reduces the shrinkage and does not produce cracks. In addition, in terms of fluidity, bending strength and compressive strength, the self-leveling dry powder mortar prepared by the present application is also better than that of the comparative examples. However, the commercially available building gypsum used in Comparative Example 1 does not have these properties, and the self-leveling dry powder mortar prepared by it has poor performance. In addition, Comparative Example 2 uses desulfurization building gypsum powder and Portland cement as cementitious materials, and river sand as aggregate, and the self-leveling dry powder mortar prepared by it also has poor crack resistance and strength.

[0070] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A high crack-resistant self-leveling dry powder mortar, characterized in that, The total mass, calculated on a 100% basis, includes the following components: By mass percentage, the gypsum contains ≥95% hemihydrate gypsum, ≤2% dihydrate gypsum, and 0% anhydrous gypsum. The retarder comprises, by weight percentage, 35-45% glycine, 15-25% malic acid, and 35-45% disodium ethylenediaminetetraacetate; The particle size of the steel slag powder is 30-45 μm; The incinerator slag has a particle size distribution of 25% by mass for 10-30 mesh, 30-60 mesh, 60-90 mesh, and 90-120 mesh particles.

2. The high crack-resistant self-leveling dry powder mortar according to claim 1, characterized in that, The gypsum has a particle size of 35–50 μm; the gypsum is obtained by calcining and grinding desulfurized gypsum.

3. The high crack-resistant self-leveling dry powder mortar according to claim 1, characterized in that, The particle size of the fly ash is 10–30 μm.

4. The high crack-resistant self-leveling dry powder mortar according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate high-efficiency water-reducing agent with a water reduction rate of >35%.

5. The high crack-resistant self-leveling dry powder mortar according to claim 1, characterized in that, The defoamer is an organosilicon powder defoamer; the thickener is hydroxypropyl methylcellulose.

6. The method for preparing the high crack-resistant self-leveling dry powder mortar according to any one of claims 1 to 5, characterized in that, The process includes the following steps: mixing the components to obtain the high crack-resistant self-leveling dry powder mortar.

7. A construction method for the high crack-resistant self-leveling dry mortar according to any one of claims 1 to 5 or the high crack-resistant self-leveling dry mortar prepared by the preparation method according to claim 6, comprising the following steps: The high crack-resistant self-leveling dry powder mortar is mixed with water and then coated; the mass ratio of water to high crack-resistant self-leveling dry powder mortar is 0.20 to 0.23:1.

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