Cement-based self-leveling mortar for crack-resistant and wear-resistant ground and preparation method of cement-based self-leveling mortar

Abstract

The invention discloses cement-based self-leveling mortar for an anti-crack wear-resistant floor and a preparation method of the cement-based self-leveling mortar, and belongs to the technical field of cement-based self-leveling mortar. According to the mortar prepared by the invention, through strict pretreatment steps, the purity and the particle size of the raw materials are ensured to meet the requirements, personal errors in the construction process are reduced, and the quality of the mortar is improved; a step-by-step stirring method is adopted, so that all the components are uniformly dispersed, and the fluidity and flatness of the mortar are improved; lignosulfonate is added into the raw materials to serve as a bio-based water reducer, so that the water consumption is reduced, the fluidity of the mortar is improved, and the environment-friendly performance is good; the prepared modified nanoscale silicon dioxide is good in dispersity, the crack resistance and wear resistance of the mortar can be improved, and the water reducing property of the mortar can be further improved, so that the flowability is improved; therefore, the prepared mortar is good in fluidity and excellent in crack resistance and wear resistance, and has important application significance in the technical field of cement-based self-leveling mortar.

Description

Technical Field

[0001] The invention belongs to the technical field of cement-based self-leveling mortar, and in particular, relates to a cement-based self-leveling mortar for crack-resistant and wear-resistant floors and a preparation method thereof. Background Art

[0002] Cement-based self-leveling mortar is a building material used for ground leveling. It is composed of cement, fine aggregate, additives, etc. It forms a fluid slurry with excellent fluidity after mixing with water. It has the advantages of high early strength, good wear resistance, easy laying, simple construction, fast construction speed, short construction period, thin leveling layer thickness, dual functions of load bearing and decoration, etc. Due to its excellent performance, it is widely used in the ground engineering of various open spaces and offices such as new or renovated industrial plants, workshops, commercial stores, exhibition halls, gymnasiums, hospitals, warehouses, basements, parking lots, etc. However, the existing self-leveling mortar is prone to cracks when used for a long time or subjected to external forces, which affects the beauty and service life of the ground. In addition, ordinary self-leveling mortar is prone to wear in areas with high loads or frequent use, resulting in surface damage. At the same time, the existing ordinary self-leveling mortar has poor fluidity and is difficult to spread evenly during construction, which affects the construction quality and efficiency. Therefore, it is urgent to solve the above problems to meet the higher demands in the field of cement-based self-leveling mortar technology. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a cement-based self-leveling mortar for crack-resistant and wear-resistant floors and a preparation method thereof.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for preparing a cement-based self-leveling mortar for crack-resistant and wear-resistant floors comprises the following steps:

[0006] Cement, quartz sand, modified nano-scale silica, high-hardness fine ceramic particles and anti-cracking fibers are pretreated in sequence, dry-mixed and a plasticizer is added after the pretreatment, and finally a bio-based water reducer, an acrylic emulsion and water are added for wet mixing to obtain a cement-based self-leveling mortar for anti-cracking and wear-resistant floors.

[0007] Furthermore, the weight percentage of each component is: 50% cement, 25% quartz sand, 2% modified nano-scale silica, 5% high-hardness fine ceramic particles, 1% bio-based water reducer, 2% acrylic emulsion, 0.5% anti-cracking fiber, 0.5% plasticizer, and 14% water.

[0008] Furthermore, the preprocessing comprises the following steps:

[0009] The cement and quartz sand are sieved separately to remove impurities and ensure that their particle sizes meet the requirements; the modified nano-scale silica is dried at 100°C for 2 hours to prevent agglomeration; the high-hardness fine ceramic particles are cleaned with clean water and then dried at 100°C for 2 hours to ensure that the surface is clean and free of oil and dirt; the anti-cracking fiber is cut to the required length to ensure uniform distribution, thereby obtaining pretreated cement, quartz sand, modified nano-scale silica, high-hardness fine ceramic particles and anti-cracking fiber.

[0010] Further, the dry mixing comprises the following steps:

[0011] In a clean mixer, add pretreated cement and quartz sand, stir at low speed for 3 minutes to ensure uniform mixing; then add pretreated modified nano-scale silica and high-hardness fine ceramic particles, continue to stir at low speed for 4 minutes to evenly disperse these fine particles; then add pretreated anti-cracking fiber and plasticizer, stir at low speed for 3 minutes to ensure uniform distribution of the fiber and sufficient mixing of the plasticizer to obtain a dry mixed mixture.

[0012] Further, the wet mixing comprises the following steps:

[0013] The bio-based water reducer and acrylic emulsion are pre-mixed evenly to form a liquid additive; the liquid additive is slowly added to the dry-mixed mixture, and water is gradually added at the same time, and stirred at high speed for 4-5 minutes until the mortar reaches the required fluidity and flatness, thereby obtaining a cement-based self-leveling mortar for crack-resistant and wear-resistant floors.

[0014] Furthermore, the cement is ordinary Portland cement.

[0015] Furthermore, the particle size of the quartz sand ranges from 0.1 mm to 1.5 mm.

[0016] Furthermore, the hardness of the high-hardness fine ceramic particles is greater than Mohs hardness 7, and the particle size range is 50 μm.

[0017] Furthermore, the bio-based water reducer is lignin sulfonate.

[0018] Furthermore, the solid content of the acrylic ester emulsion is 50%.

[0019] Furthermore, the anti-cracking fiber is polypropylene fiber.

[0020] The use of lignin sulfonate as a bio-based water reducer not only reduces water consumption and improves the fluidity of the mortar, but also has good environmental performance and can adapt to construction needs under different environmental conditions. Through strict pretreatment steps, the purity and particle size of the raw materials are ensured to meet the requirements, which reduces human errors in the construction process and improves the quality of the mortar. At the same time, a step-by-step mixing method is adopted, first dry mixing and then wet mixing, to ensure that the components are evenly dispersed, thereby improving the fluidity and smoothness of the mortar.

[0021] Furthermore, the modified nano-scale silicon dioxide is prepared by the following steps:

[0022] S1. Add nano-silica with an average particle size of 50 nm, ethanol aqueous solution and hydrochloric acid solution into a flask, stir and mix, then ultrasonically treat for 45 minutes, then add silane coupling agent KH-580, stir and heat to 70°C, keep warm for 2 hours, then stir and heat to 80°C, keep warm for 5 hours, the reaction is completed, cool, filter, wash with acetone, and vacuum dry to obtain pre-modified nano-silica; the ratio of nano-silica, ethanol aqueous solution, hydrochloric acid solution, and silane coupling agent KH-580 is 1g:100mL:10mL:3.7g;

[0023] The surface of nano-silica contains a large number of hydroxyl groups, which can react with the silane coupling agent KH-580 to introduce mercapto groups on the nano-silica to obtain pre-modified nano-scale silica.

[0024] S2, in a three-necked flask equipped with a stirring device, add 8-aniline-1-naphthalenesulfonic acid and toluene, slowly drip NaOH solution (mass fraction 12%), adjust pH to 7, generate 8-aniline-1-naphthalenesulfonic acid sodium, rotary evaporation to remove water, then pass nitrogen into the device, add allyl chloride and triethylamine, warm to 75 ℃, insulation reaction 5h, the reaction is complete, after the temperature in the reaction bottle drops to 30 ℃, filter, rotary evaporation, and then purify by column chromatography (eluent adopts a mixed solvent of benzene / ether, the volume ratio of the two is 2: 1), rotary evaporation to remove the eluent, vacuum drying to obtain an intermediate; the ratio of the amount of 8-aniline-1-naphthalenesulfonic acid, toluene, allyl chloride, and triethylamine is 29.9g:100mL:7.6g:15mL;

[0025] Sodium 8-aniline-1-naphthalenesulfonate and allyl chloride undergo nucleophilic substitution to generate an intermediate;

[0026] S3, pre-modified nano-scale silica was mixed with N, N-dimethylformamide, magnetic stirring was turned on, and the pre-modified nano-scale silica was stirred for 15 minutes to disperse the pre-modified nano-scale silica uniformly, AIBN (azobisisobutyronitrile) and the intermediate were added, and the temperature of the system was maintained at 60°C, and the reaction was kept warm for 8 hours. After the reaction was completed, the mixture was washed with anhydrous ethanol for 3-4 times, freeze-dried, and ground to obtain modified nano-scale silica; the ratio of the amount of pre-modified nano-scale silica, N, N-dimethylformamide, azobisisobutyronitrile, and the intermediate was 1.0g:100mL:0.1g:7.3g;

[0027] Under the action of AIBN, the thiol groups on the pre-modified nano-scale silica and the unsaturated carbon-carbon double bonds on the intermediate undergo a thiol-ene click reaction to obtain modified nano-scale silica.

[0028] Nano-silica nanoparticles are highly active and can significantly improve the density, wear resistance and crack resistance of mortar, reduce the generation of microcracks, and extend the service life of mortar. In addition, by modifying nano-silica and grafting different functional groups and molecular structures on its surface, the dispersibility of nano-silica can be enhanced due to the steric hindrance between molecules, so that the performance of nano-silica can be fully exerted. The introduced -SO3- and sulfonate groups play a role in efficient dispersion to produce a high water reduction rate, forming intermolecular hydrogen bonds to produce a water reduction effect, which can synergize with bio-based water reducers to further improve the water reduction and the fluidity of cement. Finally, the modified nano-silica contains a rigid benzene ring structure, which improves the mechanical properties and further improves the crack resistance of the mortar.

[0029] Furthermore, the present invention provides a construction method, comprising the following steps:

[0030] 1. Base surface treatment: Before construction, use a wire brush or high-pressure water gun to clean the base surface to ensure that the base surface is clean, flat, free of oil and dust;

[0031] 2. Laying mortar: Lay the prepared anti-crack and wear-resistant floor cement-based self-leveling mortar evenly on the base surface, and use a special scraper to scrape it flat to ensure that the mortar surface is flat;

[0032] 3. Exhaust treatment: Use a vibrating rod or roller to gently vibrate or roll on the mortar surface to remove bubbles in the mortar to prevent bubbles from affecting the flatness and strength of the mortar;

[0033] 4. Maintenance: After the construction is completed, cover with plastic film and carry out appropriate maintenance according to the ambient temperature and humidity. Generally, the maintenance time is more than 24 hours to ensure that the mortar is completely cured.

[0034] Beneficial effects of the present invention:

[0035] 1. The mortar prepared by the present invention undergoes strict pretreatment steps to ensure that the purity and particle size of the raw materials meet the requirements, reduce human errors during the construction process, and improve the quality of the mortar;

[0036] 2. The step-by-step mixing method is adopted to ensure uniform dispersion of each component and improve the fluidity and flatness of the mortar;

[0037] 3. Adding lignin sulfonate as a bio-based water reducer to the raw materials not only reduces water consumption and improves the fluidity of the mortar, but also has good environmental performance;

[0038] 4. The prepared modified nano-scale silica has good dispersibility, which can improve the crack resistance and wear resistance of the mortar, and can further improve the water reduction of the mortar, thereby improving fluidity;

[0039] Therefore, the mortar prepared by the present invention has good fluidity, excellent crack resistance and wear resistance, and has important application significance in the technical field of cement-based self-leveling mortar. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described below in conjunction with the accompanying drawings.

[0041] Figure 1 The present invention is a flowchart of a preparation method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Embodiment 1

[0044] Preparation of modified nano-scale silica:

[0045] S1. Add 1 g of nano-scale silica with an average particle size of 50 nm, 100 mL of ethanol aqueous solution and 10 mL of hydrochloric acid solution into a flask, stir and mix, and then ultrasonically treat for 45 minutes, then add 3.7 g of silane coupling agent KH-580, stir and heat to 70°C, keep warm for 2 hours, then stir and heat to 80°C, keep warm for 5 hours, the reaction is completed, cool, filter, wash with acetone, and vacuum dry to obtain pre-modified nano-scale silica;

[0046] S2, in a three-necked flask equipped with a stirring device, 29.9g8-aniline-1-naphthalenesulfonic acid and 100mL toluene were added, NaOH solution (mass fraction 12%) was slowly added dropwise, PH was adjusted to 7, 8-aniline-1-naphthalenesulfonic acid sodium was generated, water was removed by rotary evaporation, nitrogen was then introduced into the device, 7.6g allyl chloride and 15mL triethylamine were added, the temperature was raised to 75°C, and the reaction was kept warm for 5h. The reaction was completed, and the temperature in the reaction bottle was reduced to 30°C, filtered, rotary evaporated, and then purified by column chromatography (eluent adopts a mixed solvent of benzene / ether, and the volume ratio of the two is 2:1), the eluent was removed by rotary evaporation, and vacuum dried to obtain an intermediate;

[0047] S3. Mix 1.0 g of pre-modified nano-scale silica with 100 mL of N,N-dimethylformamide, turn on magnetic stirring, stir for 15 minutes to evenly disperse the pre-modified nano-scale silica, add 0.1 g of AIBN and 7.3 g of the intermediate, maintain the temperature of the system at 60°C, and react for 8 hours. After the reaction is completed, wash with anhydrous ethanol three times, freeze-dry, and grind to obtain modified nano-scale silica.

[0048] Embodiment 2

[0049] according to Figure 1 The process of preparing mortar:

[0050] 1. Pretreatment: 50 kg of ordinary Portland cement and 25 kg of quartz sand with a particle size of 0.1 mm were sieved separately to remove impurities and ensure that their particle sizes met the requirements; 2 kg of modified nano-scale silica prepared in Example 1 was dried at 100° C. for 2 hours to prevent agglomeration; 5 kg of high-hardness fine ceramic particles with a hardness greater than Mohs hardness 7 and a particle size of 50 μm were washed with clean water and then dried at 100° C. for 2 hours to ensure that the surface was clean and free of oil stains; 0.5 kg of polypropylene fiber was cut to a desired length to ensure uniform distribution, thereby obtaining pretreated cement, quartz sand, modified nano-scale silica, high-hardness fine ceramic particles and polypropylene fiber;

[0051] 2. Dry mixing: In a clean mixer, add pretreated cement and quartz sand, stir at low speed for 3 minutes to ensure uniform mixing; then add pretreated modified nano-scale silica and high-hardness fine ceramic particles, continue to stir at low speed for 4 minutes to evenly disperse these fine particles; then add pretreated polypropylene fiber and 0.5 kg polycarboxylic acid plasticizer, stir at low speed for 3 minutes to ensure uniform distribution of fibers and full mixing of plasticizers to obtain a dry-mixed mixture;

[0052] 3. Wet mixing: pre-mix 1 kg of lignin sulfonate and 2 kg of acrylate emulsion with a solid content of 50% to form a liquid additive; slowly add the liquid additive to the dry-mixed mixture, and gradually add 14 kg of water, stirring at high speed for 4-5 minutes until the mortar reaches the required fluidity and flatness to obtain a cement-based self-leveling mortar for crack-resistant and wear-resistant floors.

[0053] Comparative Example 1

[0054] Commercially available cement mortar was used.

[0055] Comparative Example 2

[0056] Ordinary nano-scale silicon dioxide of the same mass is used to replace the modified nano-scale silicon dioxide in Example 3, and the remaining steps are the same as those in Example 3.

[0057] The second embodiment and the first and second comparative examples were constructed, and the construction steps were as follows:

[0058] Surface treatment: Before construction, use a wire brush or high-pressure water gun to clean the surface to ensure that the surface is clean, flat, and free of oil and dust;

[0059] Laying mortar: evenly lay the prepared self-leveling mortar on the base surface, and use a special scraper to scrape it flat to ensure that the mortar surface is flat;

[0060] Exhaust treatment: Use a vibrating rod or roller to gently vibrate or roll the mortar surface to remove bubbles in the mortar to prevent bubbles from affecting the flatness and strength of the mortar;

[0061] Maintenance: After the construction is completed, cover with plastic film and carry out appropriate maintenance according to the ambient temperature and humidity. Generally, the maintenance time is more than 24 hours to ensure that the mortar is completely cured;

[0062] The performance tests of the constructed samples were carried out as follows;

[0063] Compressive strength test: The compressive strength test is carried out according to the national standard GB / T 17671-1999;

[0064] Wear resistance test: The wear resistance test is carried out using the national standard GB / T 1768-2007 wear resistance testing machine;

[0065] Crack resistance test: The national standard GB / T 16777-2008 tensile test or bending test is used to evaluate the crack resistance of the mortar.

[0066] Fluidity test: The national standard GB / T 2419-2016 is used to conduct the fluidity test of cement mortar;

[0067] The measured results are shown in the following table:

[0068]

[0069] It can be seen from the above table that the fluidity, crack resistance and wear resistance of the mortar prepared in the embodiment of the present invention are higher than those of the comparative example. Therefore, the present invention has important application significance in the technical field of cement-based self-leveling mortar.

[0070] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0071] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing a cement-based self-leveling mortar for crack-resistant and wear-resistant floors, characterized in that: The steps include: Cement, quartz sand, modified nano-scale silica, high-hardness fine ceramic particles and anti-cracking fibers are pretreated in sequence, dry-mixed and a plasticizer is added after the pretreatment, and finally a bio-based water reducer, an acrylic emulsion and water are added for wet mixing to obtain a cement-based self-leveling mortar for anti-cracking and wear-resistant floors.

2. The method for preparing a crack-resistant and wear-resistant cement-based self-leveling mortar for flooring according to claim 1, characterized in that: The weight percentage of each component is: 50% cement, 25% quartz sand, 2% modified nano-scale silica, 5% high-hardness fine ceramic particles, 1% bio-based water reducer, 2% acrylic emulsion, 0.5% anti-cracking fiber, 0.5% plasticizer, and 14% water.

3. The method for preparing a crack-resistant and wear-resistant cement-based self-leveling mortar for flooring according to claim 1, characterized in that: The modified nano-scale silicon dioxide is prepared by the following steps: S1. Add nano-scale silica with an average particle size of 50 nm, ethanol aqueous solution and hydrochloric acid solution into a flask, stir and mix, then ultrasonically treat for 45 minutes, add silane coupling agent KH-580, stir and heat to 70°C, keep warm for 2 hours, stir and heat to 80°C, keep warm for 5 hours, and after the reaction is completed, cool, filter, wash and vacuum dry to obtain pre-modified nano-scale silica; S2, in a three-necked flask, add 8-aniline-1-naphthalenesulfonic acid and toluene, adjust the pH to 7, generate 8-aniline-1-naphthalenesulfonic acid sodium, rotary evaporation to remove water, then pass nitrogen into the device, add allyl chloride and triethylamine, warm to 75 ℃, keep the reaction for 5h, the reaction is complete, after the temperature in the reaction bottle drops to 30 ℃, filter, rotary evaporation, column chromatography purification, rotary evaporation, vacuum drying to obtain an intermediate; S3. Mix the pre-modified nano-scale silica with N,N-dimethylformamide, start magnetic stirring, stir for 15 minutes to make the pre-modified nano-scale silica evenly dispersed, add azobisisobutyronitrile and the intermediate, keep warm at 60°C for 8 hours, and after the reaction is completed, wash, freeze-dry, and grind to obtain modified nano-scale silica.

4. The method for preparing a crack-resistant and wear-resistant cement-based self-leveling mortar for flooring according to claim 3, characterized in that: In step S1, the ratio of the amount of nano-silica, ethanol aqueous solution, hydrochloric acid solution, and silane coupling agent KH-580 is 1 g: 100 mL: 10 mL: 3.7 g.

5. The method for preparing a crack-resistant and wear-resistant cement-based self-leveling mortar for flooring according to claim 3, characterized in that: In step S2, the ratio of 8-aniline-1-naphthalenesulfonic acid, toluene, allyl chloride and triethylamine is 29.9 g:100 mL:7.6 g:15 mL.

6. The method for preparing a crack-resistant and wear-resistant cement-based self-leveling mortar for flooring according to claim 3, characterized in that: In step S3, the ratio of the amount of pre-modified nano-silica, N,N-dimethylformamide, azobisisobutyronitrile, and the intermediate is 1.0 g: 100 mL: 0.1 g: 7.3 g.

7. The method for preparing a crack-resistant and wear-resistant cement-based self-leveling mortar for flooring according to claim 1, characterized in that: The pre-processing comprises the following steps: The cement and quartz sand are sieved separately to remove impurities and ensure that their particle sizes meet the requirements; the modified nano-scale silica is dried at 100°C for 2 hours; the high-hardness fine ceramic particles are washed with clean water and then dried at 100°C for 2 hours; the anti-cracking fiber is cut to the required length to obtain pretreated cement, quartz sand, modified nano-scale silica, high-hardness fine ceramic particles and anti-cracking fiber.

8. The method for preparing a crack-resistant and wear-resistant cement-based self-leveling mortar for flooring according to claim 1, characterized in that: The dry mixing comprises the following steps: In a clean mixer, add pretreated cement and quartz sand, stir at low speed for 3 minutes to ensure uniform mixing; then add pretreated modified nano-scale silica and high-hardness fine ceramic particles, continue to stir at low speed for 4 minutes to evenly disperse these fine particles; then add pretreated anti-cracking fiber and plasticizer, stir at low speed for 3 minutes to ensure uniform distribution of the fiber and sufficient mixing of the plasticizer to obtain a dry mixed mixture.

9. The method for preparing a crack-resistant and wear-resistant cement-based self-leveling mortar for flooring according to claim 1, characterized in that: The wet mixing comprises the following steps: The bio-based water reducer and acrylic emulsion are pre-mixed evenly to form a liquid additive; the liquid additive is slowly added to the dry-mixed mixture, and water is gradually added at the same time, and stirred at high speed for 4-5 minutes until the mortar reaches the required fluidity and flatness, thereby obtaining a cement-based self-leveling mortar for crack-resistant and wear-resistant floors.

10. A cement-based self-leveling mortar for crack-resistant and wear-resistant floors, characterized in that: Prepared according to the method according to any one of claims 1 to 9.

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