High-strength anti-cracking mortar and preparation method thereof

Abstract

The application relates to the technical field of building materials, and discloses high-strength anti-cracking mortar and a preparation method thereof, wherein the high-strength anti-cracking mortar comprises the following components in parts by weight: cement 80-90 parts, sand 85-95 parts, fly ash 5-10 parts, sodium silicate 8-15 parts, molybdenum disulfide 8-12 parts, hydroxyethyl cellulose ether 0.3-0.6 parts, water reducing agent 0.01-0.15 parts, and water 60-70 parts. Through the technical scheme, the problems of low strength and poor anti-cracking performance of the mortar in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a high-strength crack-resistant mortar and its preparation method. Background Technology

[0002] With the application and rapid development of modern building materials, there are more new requirements for the performance of building mortar. Many properties of mortar are closely related to mortar cracking. Mortar that is prone to cracking can easily allow external impurities to enter the mortar and cause corrosion to the mortar or building materials, seriously affecting the durability of the mortar and causing it to fall off. At the same time, the current mortar also has the problem of low strength, which limits the application of mortar in the construction field.

[0003] Therefore, the problems of mortar being prone to cracking and having low strength are common and still unsolved technical challenges. If a high-strength, crack-resistant mortar can be obtained, it will be of great significance to broaden the application of mortar in the construction field. Summary of the Invention

[0004] This invention proposes a high-strength crack-resistant mortar and its preparation method, which solves the problems of low strength and poor crack resistance of mortar in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a high-strength crack-resistant mortar, comprising the following components in parts by weight: 80-90 parts cement, 85-95 parts sand, 5-10 parts fly ash, 8-15 parts sodium silicate, 8-12 parts molybdenum disulfide, 0.3-0.6 parts hydroxyethyl cellulose ether, 0.01-0.15 parts water-reducing agent, and 60-70 parts water.

[0006] As a further technical solution, the molybdenum disulfide is molybdenum disulfide modified with vinyl acetate-ethylene copolymer.

[0007] As a further technical solution, the mass ratio of vinyl acetate-ethylene copolymer to molybdenum disulfide in the vinyl acetate-ethylene copolymer modified molybdenum disulfide is 1:5~8.

[0008] As a further technical solution, the preparation method of the vinyl acetate-ethylene copolymer modified molybdenum disulfide includes the following steps: dispersing the molybdenum disulfide in the solution of the vinyl acetate-ethylene copolymer, removing the solvent, and obtaining the vinyl acetate-ethylene copolymer modified molybdenum disulfide.

[0009] As a further technical solution, the solvent of the solution is one of tetrahydrofuran and dichloromethane.

[0010] As a further technical solution, the mass ratio of the vinyl acetate-ethylene copolymer to the solvent is 1:9~10.

[0011] In this invention, by modifying molybdenum disulfide with vinyl acetate-ethylene copolymer, the structural stability of molybdenum disulfide is improved, thereby further enhancing the strength and crack resistance of the mortar.

[0012] As a further technical solution, the hydroxyethyl cellulose ether is a high-viscosity hydroxyethyl cellulose ether and / or a medium-viscosity hydroxyethyl cellulose ether; the viscosity of the high-viscosity hydroxyethyl cellulose ether is 38000~42000 mPa·s; and the viscosity of the medium-viscosity hydroxyethyl cellulose ether is 5500~6500 mPa·s.

[0013] As a further technical solution, when the hydroxyethyl cellulose ether is a high-viscosity hydroxyethyl cellulose ether or a medium-viscosity hydroxyethyl cellulose ether, the mass ratio of the high-viscosity hydroxyethyl cellulose ether to the medium-viscosity hydroxyethyl cellulose ether is 2:1~4.

[0014] In this invention, by using hydroxyethyl cellulose ethers of different viscosities, the internal fluidity of the mortar is balanced, thereby further improving the strength and crack resistance of the mortar.

[0015] As a further technical solution, the cement is one of ordinary silicate cement and slag silicate cement; the sand is ordinary river sand with a particle size of 0.35~0.5mm; and the water-reducing agent is a naphthalene-based water-reducing agent or a polycarboxylate water-reducing agent.

[0016] This invention also proposes a method for preparing the high-strength crack-resistant mortar, comprising the following steps: S1. Mix sand, fly ash, sodium silicate, molybdenum disulfide and hydroxyethyl cellulose ether to obtain mixture A; S2. Mix the mixture A with cement to obtain mixture B; S3. After the mixture B is mixed evenly with the remaining components, a high-strength crack-resistant mortar is obtained.

[0017] The working principle and beneficial effects of this invention are as follows: 1. In this invention, sodium silicate, molybdenum disulfide, and hydroxyethyl cellulose ether are introduced into the mortar. Sodium silicate can undergo a hydration reaction with calcium ions in the cementitious substrate to reduce the internal voids of the mortar, while molybdenum disulfide can provide growth sites for the hydration products of sodium silicate. Sodium silicate and molybdenum disulfide synergistically improve the internal density of the mortar. The addition of hydroxyethyl cellulose ether to the mortar can deposit on the hydration products of sodium silicate, as well as on the surface of molybdenum disulfide and minerals in the cement, interpenetrating and connecting with each other, significantly improving the strength and crack resistance of the mortar. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] In the following examples and comparative examples, the ordinary silicate cement is of type PO 42.5, the slag silicate cement is of type PSA 32.5; the fly ash has a particle size of 200 mesh; the sodium silicate has a particle size of 100 mesh; the molybdenum disulfide has a particle size of 500 nm; the high viscosity hydroxyethyl cellulose ether has a viscosity of 38000~42000 mPa·s; and the medium viscosity hydroxyethyl cellulose ether has a viscosity of 5500~6500 mPa·s.

[0020] Example 1 High-strength crack-resistant mortar comprises the following components by weight: 80 parts ordinary silicate cement, 85 parts sand, 5 parts fly ash, 8 parts sodium silicate, 8 parts molybdenum disulfide, 0.3 parts high-viscosity hydroxyethyl cellulose ether, 0.01 parts water-reducing agent ES9201, and 60 parts water. The preparation method of high-strength crack-resistant mortar includes the following steps: S1. Mix sand, fly ash, sodium silicate, molybdenum disulfide and high-viscosity hydroxyethyl cellulose ether to obtain mixture A; S2. Mix mixture A with ordinary Portland cement to obtain mixture B; S3. After mixing the mixture B with the remaining components evenly, a high-strength crack-resistant mortar is obtained.

[0021] Example 2 High-strength crack-resistant mortar comprises the following components by weight: 85 parts ordinary silicate cement, 90 parts sand, 8 parts fly ash, 12 parts sodium silicate, 10 parts molybdenum disulfide, 0.4 parts high-viscosity hydroxyethyl cellulose ether, 0.08 parts water-reducing agent FDN-C, and 65 parts water. The preparation method of high-strength crack-resistant mortar includes the following steps: S1. Mix sand, fly ash, sodium silicate, molybdenum disulfide and high-viscosity hydroxyethyl cellulose ether to obtain mixture A; S2. Mix mixture A with ordinary Portland cement to obtain mixture B; S3. After mixing the mixture B with the remaining components evenly, a high-strength crack-resistant mortar is obtained.

[0022] Example 3 High-strength crack-resistant mortar comprises the following components by weight: 90 parts slag silicate cement, 95 parts sand, 10 parts fly ash, 15 parts sodium silicate, 12 parts molybdenum disulfide, 0.6 parts high-viscosity hydroxyethyl cellulose ether, 0.15 parts water-reducing agent SY-05, and 70 parts water. The preparation method of high-strength crack-resistant mortar includes the following steps: S1. Mix sand, fly ash, sodium silicate, molybdenum disulfide and high-viscosity hydroxyethyl cellulose ether to obtain mixture A; S2. Mix mixture A with slag silicate cement to obtain mixture B; S3. After mixing the mixture B with the remaining components evenly, a high-strength crack-resistant mortar is obtained.

[0023] Example 4 The only difference between this embodiment and Embodiment 2 is that molybdenum disulfide is replaced with an equal mass of vinyl acetate-ethylene copolymer-modified molybdenum disulfide. The preparation method of vinyl acetate-ethylene copolymer-modified molybdenum disulfide includes the following steps: dispersing molybdenum disulfide in a solution of vinyl acetate-ethylene copolymer, removing the solvent, and obtaining vinyl acetate-ethylene copolymer-modified molybdenum disulfide; wherein, the solvent of the solution is tetrahydrofuran; the mass ratio of vinyl acetate-ethylene copolymer to tetrahydrofuran is 1:9, and the mass ratio of vinyl acetate-ethylene copolymer to molybdenum disulfide is 1:6.

[0024] Example 5 The only difference between this embodiment and Example 4 is that the solvent of the solution is dichloromethane; the mass ratio of vinyl acetate-ethylene copolymer to dichloromethane is 1:10, and the mass ratio of vinyl acetate-ethylene copolymer to molybdenum disulfide is 1:6.

[0025] Example 6 The only difference between this embodiment and Example 5 is that the mass ratio of vinyl acetate-ethylene copolymer to molybdenum disulfide is 1:9.

[0026] Example 7 The only difference between this embodiment and Example 5 is that the mass ratio of vinyl acetate-ethylene copolymer to molybdenum disulfide is 1:5.

[0027] Example 8 The only difference between this embodiment and Example 5 is that the mass ratio of vinyl acetate-ethylene copolymer to molybdenum disulfide is 1:8.

[0028] Example 9 The only difference between this embodiment and Embodiment 8 is that the high-viscosity hydroxyethyl cellulose ether is replaced with an equal mass of medium-viscosity hydroxyethyl cellulose ether.

[0029] Example 10 The only difference between this embodiment and Embodiment 8 is the high-strength crack-resistant mortar, which includes the following components by weight: 85 parts ordinary silicate cement, 90 parts sand, 8 parts fly ash, 12 parts sodium silicate, 10 parts molybdenum disulfide, 0.32 parts high-viscosity hydroxyethyl cellulose ether, 0.08 parts medium-viscosity hydroxyethyl cellulose ether, 0.08 parts water-reducing agent FDN-C, and 65 parts water.

[0030] Example 11 The only difference between this embodiment and Embodiment 8 is the high-strength crack-resistant mortar, which includes the following components by weight: 85 parts ordinary silicate cement, 90 parts sand, 8 parts fly ash, 12 parts sodium silicate, 10 parts molybdenum disulfide, 0.1 parts high-viscosity hydroxyethyl cellulose ether, 0.3 parts medium-viscosity hydroxyethyl cellulose ether, 0.08 parts water-reducing agent FDN-C, and 65 parts water.

[0031] Example 12 The only difference between this embodiment and Embodiment 8 is the high-strength crack-resistant mortar, which includes the following components by weight: 85 parts ordinary silicate cement, 90 parts sand, 8 parts fly ash, 12 parts sodium silicate, 10 parts molybdenum disulfide, 0.27 parts high-viscosity hydroxyethyl cellulose ether, 0.13 parts medium-viscosity hydroxyethyl cellulose ether, 0.08 parts water-reducing agent FDN-C, and 65 parts water.

[0032] Example 13 The only difference between this embodiment and Embodiment 8 is the high-strength crack-resistant mortar, which includes the following components by weight: 85 parts ordinary silicate cement, 90 parts sand, 8 parts fly ash, 12 parts sodium silicate, 10 parts molybdenum disulfide, 0.13 parts high-viscosity hydroxyethyl cellulose ether, 0.27 parts medium-viscosity hydroxyethyl cellulose ether, 0.08 parts water-reducing agent FDN-C, and 65 parts water.

[0033] Comparative Example 1 The only difference between this comparative example and Example 2 is that sodium silicate is not added, but 22 parts of molybdenum disulfide are added.

[0034] Comparative Example 2 The only difference between this comparative example and Example 2 is that molybdenum disulfide is not added, but 22 parts of sodium silicate are added.

[0035] Comparative Example 3 The only difference between this comparative example and Example 2 is that hydroxyethyl cellulose ether is not added.

[0036] According to standard JGJ / T 70-2009 "Standard for Test Methods of Basic Performance of Building Mortar", cubic specimens of the high-strength crack-resistant mortars prepared in Examples 1-13 and Comparative Examples 1-3 were made and placed in an environment with a temperature of (20±2)℃ for (24±2) h. After demolding, they were placed in a standard curing room with a temperature of (20±2)℃ and a relative humidity of 95% for 28 days, and then the cubic compressive strength was tested. The shrinkage rate was measured according to the shrinkage test in standard GB / T 50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete". The test results are shown in the table below.

[0037] By comparing the data of Examples 1-13 and Comparative Examples 1-3, it was found that the mortars prepared in Examples 1-13 had higher compressive strength and lower shrinkage compared with Comparative Examples 1-3. This indicates that the introduction of sodium silicate, molybdenum disulfide and hydroxyethyl cellulose ether into the mortar increases the internal density of the mortar and can significantly improve the strength and crack resistance of the mortar.

[0038] By comparing the data from Examples 2 and Examples 4-8, it was found that the mortars prepared in Examples 4-8 had higher compressive strength and lower shrinkage compared to Example 2. This indicates that by modifying molybdenum disulfide with vinyl acetate-ethylene copolymer and improving the structural stability of molybdenum disulfide, the strength and crack resistance of the mortar can be improved.

[0039] By comparing the data from Examples 2 and 8-13, it was found that the mortars prepared in Examples 9-13 had higher compressive strength and lower shrinkage compared to Examples 2 and 8. This indicates that using hydroxyethyl cellulose ethers of different viscosities to balance the internal fluidity of the mortar can improve its strength and crack resistance.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-strength crack-resistant mortar, characterized in that, The composition comprises the following components in parts by weight: 80-90 parts cement, 85-95 parts sand, 5-10 parts fly ash, 8-15 parts sodium silicate, 8-12 parts molybdenum disulfide, 0.3-0.6 parts hydroxyethyl cellulose ether, 0.01-0.15 parts water-reducing agent, and 60-70 parts water; wherein the molybdenum disulfide is modified molybdenum disulfide with vinyl acetate-ethylene copolymer; and the mass ratio of vinyl acetate-ethylene copolymer to molybdenum disulfide in the modified molybdenum disulfide is 1:5-8.

2. The high-strength crack-resistant mortar according to claim 1, characterized in that, The method for preparing the vinyl acetate-ethylene copolymer modified molybdenum disulfide includes the following steps: dispersing the molybdenum disulfide in the solution of the vinyl acetate-ethylene copolymer, removing the solvent, and obtaining the vinyl acetate-ethylene copolymer modified molybdenum disulfide.

3. The high-strength crack-resistant mortar according to claim 2, characterized in that, The solvent for the solution is one of tetrahydrofuran or dichloromethane.

4. The high-strength crack-resistant mortar according to claim 3, characterized in that, The mass ratio of the vinyl acetate-ethylene copolymer to the solvent is 1:9~10.

5. The high-strength crack-resistant mortar according to claim 1, characterized in that, The hydroxyethyl cellulose ether is a high-viscosity hydroxyethyl cellulose ether and / or a medium-viscosity hydroxyethyl cellulose ether; the viscosity of the high-viscosity hydroxyethyl cellulose ether is 38000~42000 mPa·s; The viscosity of medium viscosity hydroxyethyl cellulose ether is 5500~6500 mPa·s.

6. The high-strength crack-resistant mortar according to claim 5, characterized in that, When the hydroxyethyl cellulose ether is a high-viscosity hydroxyethyl cellulose ether or a medium-viscosity hydroxyethyl cellulose ether, the mass ratio of the high-viscosity hydroxyethyl cellulose ether to the medium-viscosity hydroxyethyl cellulose ether is 2:1~4.

7. The high-strength crack-resistant mortar according to claim 1, characterized in that, The cement is one of ordinary silicate cement or slag silicate cement; the sand is river sand with a particle size of 0.35~0.5mm; the water-reducing agent is a naphthalene-based water-reducing agent or a polycarboxylate water-reducing agent.

8. A method for preparing a high-strength crack-resistant mortar according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Mix sand, fly ash, sodium silicate, molybdenum disulfide and hydroxyethyl cellulose ether to obtain mixture A; S2. Mix the mixture A with cement to obtain mixture B; S3. After the mixture B is mixed evenly with the remaining components, a high-strength crack-resistant mortar is obtained.

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