Preparation method of high-flow-state self-compacting grouting dry-mixed mortar

Abstract

The invention relates to the technical field of building materials, in particular to a preparation method of high-flow-state self-compacting grouting dry-mixed mortar. The preparation method of the high-flow-state self-compacting grouting dry-mixed mortar comprises the following steps: adding 40-60 parts by weight of cement, 60-100 parts by weight of graded sand, 15-25 parts by weight of fly ash, 30-40 parts by weight of silica fume, 2-4 parts by weight of rubber powder, 0.3-0.6 part by weight of cellulose ether, 0.2-0.5 part by weight of a water reducing agent, 5-8 parts by weight of a fiber reinforcing agent, 3-5 parts by weight of a functional auxiliary agent, 0.6-1.2 parts by weight of an expanding agent and 0.3-0.6 part by weight of a thickening agent into a mixing device; and uniformly mixing and stirring to obtain mixed slurry, namely the high-flow-state self-compacting grouting dry-mixed mortar. The graded sand comprises 40-50% of gravel with the particle size of 1.6-2.0 mm, 10-15% of sand with the particle size of 0.015-0.075 mm, and the balance of sand with the particle size of 4.0-5.0 mm; the grouting dry-mixed mortar prepared by the invention not only has high flowing property, self-compacting property and ultrahigh strength, but also has excellent micro-expansion low-shrinkage property and high durability, and the quality of the grouting dry-mixed mortar is effectively ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mortar, in particular to a preparation method of high-flow self-compacting grouting dry-mixed mortar. BACKGROUND

[0002] As a key filling and reinforcing material in modern construction engineering, grouting dry-mixed mortar is widely used in equipment foundation anchoring, prefabricated component connection, structure crack repair and grouting construction in complex reinforcement areas. With the development of building structures towards high-rise, large-span and complex, more stringent requirements are put forward for the performance of grouting materials. The ideal grouting material not only needs to have ultra-high strength to ensure the safety of the structure, but also must have excellent high-flow and self-compacting performance, so as to completely fill the narrow, tortuous or densely reinforced space without applying vibration, avoid forming voids or defects, and ensure the uniformity and integrity of the grouting body. In addition, in order to ensure the long-term durability and dimensional stability of the structure, the grouting material should also have good micro-expansion and low shrinkage properties to compensate for the inherent hardening shrinkage of cement-based materials, prevent shrinkage cracking, and resist the erosion of external environmental factors.

[0003] However, traditional high-strength grouting materials often achieve high strength by reducing the water-binder ratio and increasing the cement content, but this usually leads to poor flowability and high viscosity of the mixture, which requires strong vibration during construction and is difficult to ensure grouting compactness in complex conditions. Although the application of high-efficiency water-reducing agents such as polycarboxylic acid has significantly improved the flowability, in low water-binder ratio systems, the paste has high viscosity, fast loss of flowability, easy segregation and water bleeding, etc., which still highlight the problems, and it is difficult to meet the simultaneous requirements of "high flow", "self-compacting" and "ultra-high strength". On the other hand, ordinary expansion agents such as calcium sulphoaluminate can provide early expansion, but the late expansion effect is limited, and may affect the volume stability and durability due to the incoordination of expansion and strength development or poor compatibility with water-reducing components. The existing technical solutions mainly focus on the optimization of single performance, such as only increasing the strength or only improving the flowability, and there are still obvious deficiencies in how to simultaneously improve the construction performance, mechanical properties and long-term performance of grouting materials through innovative design and synergistic effect of material components.

[0004] Based on the above, the present application provides a preparation method of high-flow self-compacting grouting dry-mixed mortar to solve the above technical problems. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of high-flow self-compacting grouting dry-mixed mortar, which not only has high flow performance, self-compacting performance and ultra-high strength, but also has excellent micro-expansion and low shrinkage performance and high durability, effectively ensuring its quality.

[0006] To achieve the above object, the present application provides the following technical solutions. A preparation method of high-flow self-compacting grouting dry-mixed mortar, comprising the following steps: adding 40-60 parts of cement, 60-100 parts of graded sand, 15-25 parts of fly ash, 30-40 parts of micro-silica powder, 2-4 parts of glue powder, 0.3-0.6 parts of cellulose ether, 0.2-0.5 parts of water reducing agent, 5-8 parts of fiber reinforcing agent, 3-5 parts of functional additives, 0.6-1.2 parts of expanding agent and 0.3-0.6 parts of thickening agent into a mixing device, and uniformly mixing and stirring to obtain a mixed slurry, which is the high-flow self-compacting grouting dry-mixed mortar.

[0007] Further, the functional additives are prepared by the following method: mixing and stirring isoprenyl alcohol polyoxyethylene ether with a molecular weight of 2500-4500, methacrylic acid, butyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid in a molar ratio of 1:(2.5-4):(0.1-0.25):(0.15-0.3), raising the temperature of the obtained mixed components to 65-80℃ under nitrogen protection, then adding 0.6-1.8wt% of ammonium persulfate and 0.1-0.2wt% of mercaptopropionic acid into the mixed components respectively, uniformly mixing, and then keeping the temperature at 65-80℃ for 3-5h of reaction; after the reaction is completed, adjusting the pH of the product components to 6.5-7.2 with 30-40wt% sodium hydroxide aqueous solution; and then performing spray drying treatment to obtain the functional additives; wherein, during the spray drying, the spray drying inlet temperature is 170-190℃, the outlet temperature is 90-95℃, the atomizer rotation speed is 18000-25000r / min, and the feeding flow rate is 30-50L / h.

[0008] Further, the thickening agent is compounded by sodium bentonite, polyvinyl alcohol and carboxymethyl starch ether in a mass ratio of 1:5-8:3-5.

[0009] Further, the water reducing agent is selected from any one of polycarboxylic acid water reducing agent and naphthalene series water reducing agent.

[0010] Further, the expanding agent is compounded by calcium sulphoaluminate, calcium oxide and magnesium oxide in a mass ratio of 1:0.5-0.8:0.3-0.6.

[0011] Further, in the graded sand, the sand and gravel with a particle size of 1.6-2.0mm accounts for 40-50%, the sand with a particle size of 0.015-0.075mm accounts for 10-15%, and the rest is sand with a particle size of 4.0-5.0mm.

[0012] Further, the fineness of the fly ash is 500-800 meshes, the fineness of the micro-silica powder is 600-800 meshes, and the cement is any one of P.O42.5R portland cement and P.O52.5R portland cement.

[0013] Further, the cellulose ether is any one of methyl cellulose ether, hydroxypropyl methyl cellulose ether, hydroxyethyl methyl cellulose ether, and the viscosity value of the cellulose ether is 40000-100000 MPa·s.

[0014] Further, the fiber reinforcing agent is any one of polypropylene fiber, polyvinyl alcohol fiber, and steel fiber, and the length is 5-8 mm.

[0015] Further, the rubber powder is any one of vinyl acetate-ethylene copolymer rubber powder, ethylene-polyvinyl chloride-lauric acid ethylene terpolymer rubber powder, vinyl acetate-ethylene-high fatty acid ethylene terpolymer rubber powder, vinyl acetate-high fatty acid copolymer rubber powder, acrylate-styrene copolymer rubber powder, vinyl acetate-acrylate-high fatty acid terpolymer rubber powder, vinyl acetate homopolymer rubber powder, and styrene-butadiene copolymer rubber powder.

[0016] Compared with the prior art, the present application has the following beneficial effects: The present application combines the steric hindrance skeleton of isopentenyl alcohol polyoxyethylene ether with the functional groups of methacrylic acid, butyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid, forms a polymer with a comb structure under the regulation of an initiator and a chain transfer agent. The polymer molecule provides a double anion effect through sulfonic acid groups and carboxyl groups, and the polyoxyethylene side chain forms a stereoscopic barrier to establish an "electrostatic-space" synergistic stabilization mechanism in the cement hydration system. The prepared functional additive can significantly improve the dispersibility and fluidity of the mortar system, so that the low water-binder ratio mixture obtains excellent self-compacting performance, and the ion resistance of the sulfonic acid group maintains the persistent stability of the fluidity. Furthermore, it can optimize the micro arrangement of the hydration product in the hardening stage, improve the interface transition zone structure, thereby enhancing the matrix densification and mechanical strength. In addition, it can form a synergistic effect with the expansion component and fiber material, effectively improve the volume stability and anti-cracking ability of the mortar, and finally make the prepared dry-mixed grouting mortar have high flow state construction performance and long-term durability.

[0017] The present application realizes complete self-compaction filling under non-vibration conditions by the skeleton supporting effect of the functional additive combined with the graded sand, and the mortar still maintains excellent high flow characteristics under very low water-binder ratio conditions, and is particularly suitable for grouting construction in complex structures and densely reinforced areas. Meanwhile, through the three-stage synergistic expansion effect of calcium sulphoaluminate, calcium oxide and magnesium oxide in the composite expansion system, combined with the micro-reinforced structure formed by the fiber reinforced network, a multi-scale volume stability guarantee system from early to long-term is formed, and the shrinkage cracking phenomenon is significantly inhibited. In addition, the use of micro-silica powder and fly ash not only optimizes the particle size distribution and bulk density, but also improves the micro-densification of the matrix through the pozzolanic effect, thereby significantly enhancing the compressive strength, flexural strength and long-term durability. The synergistic water retention effect of the thickening agent and the interface enhancement function of the glue powder further ensure the material stability during construction and the structural integrity after hardening. In addition, the prepared grouting dry-mixed mortar not only has high flow performance and high stability, but also has excellent construction performance and long-term durability. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0019] Embodiment 1: A preparation method of a high flow self-compacting grouting dry-mixed mortar, comprising the following steps: adding 40 parts of cement, 60 parts of graded sand, 15 parts of fly ash, 30 parts of micro-silica powder, 2 parts of vinyl acetate-ethylene copolymer glue powder, 0.3 parts of cellulose ether, 0.2 parts of Concrete Power W20 polycarboxylic acid water reducer, 5 parts of fiber reinforcing agent, 3 parts of functional additive, 0.6 parts of expansion agent and 0.3 parts of thickening agent into a mixing device, and uniformly mixing and stirring to obtain a mixed slurry, which is the high flow self-compacting grouting dry-mixed mortar.

[0020] The functional aid is prepared by the following method: isopentenyl alcohol polyoxyethylene ether with a molecular weight of 2500, methacrylic acid, butyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid are mixed in a molar ratio of 1:2.5:0.1:0.15 and stirred uniformly, the temperature of the obtained mixed components is raised to 65°C under nitrogen protection, then 0.6wt% ammonium persulfate and 0.1wt% mercaptopropionic acid of the mixed components are added respectively, after uniform mixing, the reaction is carried out at 65°C for 5h; after the reaction is completed, the pH of the product components is adjusted to 6.5 with 30wt% sodium hydroxide aqueous solution; after spray drying treatment, the functional aid is obtained; wherein, during spray drying, the spray drying inlet temperature is 170°C, the outlet temperature is 90°C, the atomizer rotating speed is 18000r / min, and the feeding flow rate is 30L / h.

[0021] The thickening agent is compounded by sodium bentonite, polyvinyl alcohol and carboxymethyl starch ether in a mass ratio of 1:5:3.

[0022] The expanding agent is compounded by calcium sulphoaluminate, calcium oxide and magnesium oxide in a mass ratio of 1:0.5:0.3.

[0023] In the graded sand, 40% is sand with a particle size of 1.6mm, 10% is sand with a particle size of 0.015mm, and the rest is sand with a particle size of 4.0mm.

[0024] The fineness of the fly ash is 500 meshes, the fineness of the microsilica is 600 meshes, and the P.O42.5R portland cement.

[0025] The cellulose ether is a methyl cellulose ether, and the viscosity value thereof is 40000MPa·s.

[0026] The fiber reinforcing agent is polypropylene fiber, and the length thereof is 5mm.

[0027] Example 2: A preparation method of a high-fluidity self-compacting grouting dry-mixed mortar, comprising the following steps: 50 parts of cement, 80 parts of graded sand, 20 parts of fly ash, 35 parts of microsilica, 3 parts of ethylene-polyvinyl chloride-lauric acid ethylene terpolymer powder, 0.5 parts of cellulose ether, 0.3 parts of Concrete Power W20 polycarboxylic acid water reducer, 6 parts of fiber reinforcing agent, 4 parts of functional aid, 1 part of expanding agent and 0.5 parts of thickening agent are added into a mixing device, and the obtained mixed slurry after uniform mixing is the high-fluidity self-compacting grouting dry-mixed mortar.

[0028] The functional aid is prepared by the following method: isopentenyl alcohol polyoxyethylene ether with a molecular weight of 3500, methacrylic acid, butyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid are mixed in a molar ratio of 1:3:0.2:0.2 and stirred uniformly, the temperature of the obtained mixed components is raised to 70 DEG C under nitrogen protection, then 1wt% ammonium persulfate and 0.1.5wt% mercaptopropionic acid of the mixed components are added respectively, after uniform mixing, the reaction is carried out at 70 DEG C for 4h; after the reaction is completed, the pH of the product components is adjusted to 7.0 by using 35wt% sodium hydroxide aqueous solution; after spray drying treatment, the functional aid is obtained; wherein, during spray drying, the spray drying inlet temperature is 180 DEG C, the outlet temperature is 90 DEG C, the atomizer rotating speed is 20000r / min, and the feeding flow rate is 40L / h.

[0029] The thickening agent is prepared by compounding sodium bentonite, polyvinyl alcohol and carboxymethyl starch ether in a mass ratio of 1:6:4.

[0030] The expanding agent is prepared by compounding calcium sulphoaluminate, calcium oxide and magnesium oxide in a mass ratio of 1:0.6:0.5.

[0031] The graded sand contains 45% sand with a particle size of 1.8mm, 15% sand with a particle size of 0.05mm, and the rest is sand with a particle size of 4.5mm.

[0032] The fineness of the fly ash is 600 meshes, the fineness of the microsilica is 700 meshes, and the P.O42.5R portland cement.

[0033] The cellulose ether is hydroxypropyl methyl cellulose ether, and the viscosity value thereof is 80000MPa·s.

[0034] The fiber reinforcing agent is polypropylene fiber, and the length thereof is 6mm. Example 3: A preparation method of a high-fluidity self-compacting grouting dry-mixed mortar, comprising the following steps: 60 parts of cement, 100 parts of graded sand, 25 parts of fly ash, 40 parts of microsilica, 4 parts of acetic acid ethyl ester-vinyl-higher fatty acid vinyl ester terpolymer powder, 0.6 parts of cellulose ether, 0.5 parts of Concrete Power W20 polycarboxylic acid water reducer, 8 parts of fiber reinforcing agent, 5 parts of functional aid, 1.2 parts of expanding agent and 0.6 parts of thickening agent are added into a mixing device, and the obtained mixed slurry after uniform mixing is the high-fluidity self-compacting grouting dry-mixed mortar.

[0035] The functional adjuvant is prepared by the following method: isopentenyl alcohol polyoxyethylene ether with a molecular weight of 4500, methacrylic acid, butyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid are mixed in a molar ratio of 1:4:0.25:0.3 and stirred uniformly, the temperature of the obtained mixed components is raised to 80°C under nitrogen protection, then 1.8wt% ammonium persulfate and 0.2wt% mercaptopropionic acid of the mixed components are added respectively, after uniform mixing, the reaction is carried out at 80°C for 3h; after the reaction is completed, the pH of the product components is adjusted to 7.2 with 40wt% sodium hydroxide aqueous solution; after spray drying treatment, the functional adjuvant is obtained; wherein, during spray drying, the spray drying inlet temperature is 190°C, the outlet temperature is 95°C, the atomizer rotating speed is 25000r / min, and the feeding flow rate is 50L / h.

[0036] The thickening agent is compounded by sodium bentonite, polyvinyl alcohol and carboxymethyl starch ether in a mass ratio of 1:8:5.

[0037] The expanding agent is compounded by calcium sulfoaluminate, calcium oxide and magnesium oxide in a mass ratio of 1:0.8:0.6.

[0038] In the graded sand, 45% of the sand and gravel has a particle size of 2.0mm, 15% of the sand has a particle size of 0.075mm, and the rest is sand with a particle size of 5.0mm.

[0039] The fineness of the fly ash is 800 meshes, the fineness of the microsilica is 800 meshes, and the P.O42.5R portland cement.

[0040] The cellulose ether is hydroxyethyl methyl cellulose ether, and the viscosity value thereof is 100000MPa·s.

[0041] The fiber reinforcing agent is polypropylene fiber, and the length thereof is 8mm.

[0042] The comparative example is different from example 1 in that no functional adjuvant is used in the comparative example. Performance test: the related performances of the grouting dry-mixed mortar samples prepared in examples 1-3 and the comparative example are tested, and the obtained test results are recorded in the following table: Note: In the table, the flexural strength and compressive strength tests are mortar forming test pieces: the test piece size is 70.7mm×70.7mm×70.7mm, demolding after 24h, and placing in a standard constant temperature and humidity curing box for curing to the corresponding age (curing for 7 days and 28 days, respectively).

[0043] Through comparison and analysis of the data in the table, it can be known that the prepared grouting dry-mixed mortar has high fluidity, self-compacting performance and super high strength, and also has excellent micro-expansion low-shrinkage performance and high durability, which effectively ensures the quality thereof, thereby indicating that the provided preparation method of the high-fluidity self-compacting grouting dry-mixed mortar has a broader market prospect and is more suitable for promotion.

[0044] In the description of the present specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do 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.

[0045] The preferred embodiments of the application disclosed above are only used to help explain the application. The preferred embodiments do not describe all the details and limit the application to the specific embodiments. Obviously, according to the content of the present specification, many modifications and changes can be made. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the application, so that those skilled in the art can well understand and utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. A method for the preparation of a high fluidity self-compacting dry mortars grout, characterized in that, The method comprises the following steps: The following ingredients are added into a mixing device by weight parts: 40-60 parts of cement, 60-100 parts of graded sand, 15-25 parts of fly ash, 30-40 parts of micro-silica powder, 2-4 parts of glue powder, 0.3-0.6 parts of cellulose ether, 0.2-0.5 parts of water reducing agent, 5-8 parts of fiber reinforcing agent, 3-5 parts of functional additive, 0.6-1.2 parts of expanding agent and 0.3-0.6 parts of thickening agent; the obtained mixed slurry after uniform mixing and stirring is high-fluidity self-compacting grouting dry-mixed mortar.

2. A process for the preparation of a high fluidity self compacting dry mortar grout as claimed in claim 1, wherein, The functional additive is prepared by the following method: isopentenyl alcohol polyoxyethylene ether with a molecular weight of 2500-4500, methacrylic acid, butyl methacrylate and 2-acrylamide-2-methylpropanesulfonic acid are uniformly mixed at a molar ratio of 1:(2.5-4):(0.1-0.25):(0.15-0.3); the temperature of the obtained mixed components is raised to 65-80°C under nitrogen protection; then 0.6-1.8wt% of ammonium persulfate and 0.1-0.2wt% of mercaptopropionic acid are added into the mixed components respectively; after uniform mixing, the reaction is carried out at 65-80°C for 3-5h; after the reaction is completed, the pH of the product components is adjusted to 6.5-7.2 by using 30-40wt% sodium hydroxide aqueous solution; after spray drying, the functional additive is obtained; during spray drying, the inlet temperature is 170-190°C, the outlet temperature is 90-95°C, the atomizer rotating speed is 18000-25000r / min and the feeding flow rate is 30-50L / h.

3. A process for the preparation of a high fluidity self compacting dry mortar grout as claimed in claim 1, wherein: The thickening agent is prepared by compounding sodium bentonite, polyvinyl alcohol and carboxymethyl starch ether at a mass ratio of 1:5-8:3-5.

4. A process for the preparation of a high fluidity self compacting dry mortar grout as claimed in claim 1, wherein: The water reducing agent is any one of polycarboxylic acid water reducing agent and naphthalene series water reducing agent.

5. A process for the preparation of a high fluidity self compacting dry mortar grout as claimed in claim 1, wherein: The expanding agent is prepared by compounding calcium sulphoaluminate, calcium oxide and magnesium oxide at a mass ratio of 1:0.5-0.8:0.3-0.

6.

6. A process for the preparation of a high fluidity self compacting grout dry mortar mix as claimed in claim 1, wherein: In the graded sand, 40-50% of sand and gravel with a particle size of 1.6-2.0mm, 10-15% of sand with a particle size of 0.015-0.075mm and the rest of sand with a particle size of 4.0-5.0mm.

7. A process for the preparation of a high fluidity self compacting dry mortar grout as claimed in claim 1, wherein: The fineness of the fly ash is 500-800 meshes and the fineness of the micro-silica powder is 600-800 meshes; the cement is any one of P.O42.5R Portland cement and P.O52.5R Portland cement.

8. A process for the preparation of a high fluidity self compacting dry mortar grout as claimed in claim 1, wherein: The cellulose ether is any one of methyl cellulose ether, hydroxypropyl methyl cellulose ether and hydroxyethyl methyl cellulose ether, and the viscosity value of the cellulose ether is 40000-100000MPa·s.

9. A process for the preparation of a high fluidity self compacting dry mortar grout as claimed in claim 1, wherein: The fiber reinforcing agent is any one of polypropylene fiber, polyvinyl alcohol fiber and steel fiber, and the length thereof is 5-8mm.

10. A process for the preparation of a high fluidity self compacting grout dry mortar mix as claimed in claim 1, wherein: The glue powder is any one of vinyl acetate-ethylene copolymer glue powder, ethylene-polyvinyl chloride-lauric acid ethylene terpolymer glue powder, vinyl acetate-ethylene-higher fatty acid ethylene terpolymer glue powder, vinyl acetate-higher fatty acid copolymer glue powder, acrylate-styrene copolymer glue powder, vinyl acetate-acrylate-higher fatty acid terpolymer glue powder, vinyl acetate homopolymer glue powder, and styrene-butadiene copolymer glue powder.

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