Quick-hardening early-strength admixture, preparation method thereof and application of quick-hardening early-strength admixture in preparation of cement-based structural material

Abstract

The invention provides a quick-hardening early-strength admixture, a preparation method thereof and application of the quick-hardening early-strength admixture in preparation of a cement-based structural material.The quick-hardening early-strength admixture is prepared from, by weight, 30-35 parts of superfine calcium hydroxide powder, 14-18 parts of monopotassium phosphate, 8-10 parts of silicon dioxide sol, 1.0-1.5 parts of a dispersing agent, 30-35 parts of aluminoferrite cement, 0.5-1.5 parts of a surface modifier and 4-6 parts of an active activator. And 2-4 parts of ultrafine calcium carbonate powder. By adding the quick-hardening early-strength admixture, excellent wear resistance, adhesive property and sulfate corrosion resistance can be obtained, the material setting time can be controlled to be greater than or equal to 15 minutes, the compressive strength can be greater than or equal to 20 MPa in 3 hours and greater than or equal to 30 MPa in 6 hours, and the later strength of a matrix is not reduced; the prepared repairing material is compact in matrix and very small in porosity, forms super-strong bonding with an old concrete base surface, and can stably serve in water or in a humid environment for a long time; meanwhile, the structure repairing material is produced by adopting the quick-hardening early-strength mixed material, so that the dust raising condition can be obviously reduced, the operation is simple, and the environment is protected.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fast-hardening and early-strength admixtures, and particularly relates to a fast-hardening and early-strength admixture, a preparation method thereof and application of the fast-hardening and early-strength admixture in preparation of cement-based structural materials. BACKGROUND

[0002] In the field of road and bridge engineering, especially in the scenes of emergency repair, winter construction and old bridge reconstruction, fast-hardening and early-strength structural repair materials become key core materials because they can quickly form strength and shorten the traffic interruption time. However, the existing fast-hardening and early-strength repair materials still have many performance defects in the application of road and bridge concrete, which seriously restricts the engineering quality and structural durability. The specific problems are as follows:

[0003] Traditional early-strength materials such as single sulfate and chloride salt early-strength agents have slow early strength growth due to the limitation of hydration mechanism, which is difficult to meet the time efficiency demand of road and bridge emergency repair. Even if the portland cement system is used and the early strength is improved by fine particles, the 3d compressive strength still has limited improvement, which is difficult to match the rapid bearing requirement of heavy-load road and bridge. At the same time, the existing fast-hardening and early-strength cementitious materials generally have the problem of stagnation or even reversal of later strength growth, which is directly related to the abnormal development of the hydration process. This strength decay directly reduces the long-term bearing capacity of road and bridge, which brings safety hazards to heavy-load traffic. The surface layer concrete of road and bridge needs to bear the continuous vehicle friction, and the wear resistance of the existing fast-hardening and early-strength materials is generally insufficient. Traditional materials often lead to uneven distribution of hydration products and high internal porosity in order to pursue early strength, which leads to diseases such as sanding and bone exposure on the road surface in a short period of time, significantly shortening the maintenance cycle. In bridge repair, pavement overlay and other engineering, the adhesion performance of the interface between the fast-hardening and early-strength cementitious material and the old concrete directly determines the repair effect. The existing materials have large differences in hydration degree and shrinkage deformation with the old interface, and the loose layer is easily formed in the interface transition zone. This weakly bonded interface is easy to become a weak link of water and stress concentration, leading to peeling and crack propagation of the repair layer, which shortens the repair life to 1-2 years. The existing fast-hardening and early-strength materials have insufficient resistance to the erosion factors such as chloride ions, sulfate and freeze-thaw cycles in the service environment of road and bridge, which puts forward strict requirements for the durability of cementitious materials. Sulfate early-strength agents can increase the alkalinity of the paste and induce active aggregate reaction, which produces expansion cracks in the sulfate environment; chloride salt materials directly reduce the impermeability, which increases the chloride ion permeability coefficient by more than 30%, accelerates the corrosion of steel bars, and is difficult to meet the long-term service demand of road and bridge in coastal and saline-alkali areas.

[0004] The above defects make it difficult for the existing fast-hardening and early-strength cementitious materials to balance the timeliness and durability in road and bridge engineering, so it is a technical problem to be solved in the field to develop cementitious materials with high early strength, stable later performance, excellent wear resistance, strong interface adhesion and erosion resistance. SUMMARY

[0005] The application aims to provide a fast-hardening and early-strength admixture, a preparation method thereof and an application of the fast-hardening and early-strength admixture in preparing a cement-based structural material.

[0006] Technical scheme: In order to achieve the above-mentioned application purposes, the application adopts the following technical scheme:

[0007] In the first aspect, the application provides a fast-hardening and early-strength admixture, which comprises the following components in parts by weight:

[0008] 30-35 parts of superfine calcium hydroxide powder, 14-18 parts of potassium dihydrogen phosphate, 8-10 parts of silica sol, 1.0-1.5 parts of dispersant, 30-35 parts of ferric aluminate cement, 0.5-1.5 parts of surface modifier, 4-6 parts of active activator and 2-4 parts of superfine calcium carbonate powder.

[0009] Preferably, the fast-hardening and early-strength admixture comprises the following components in parts by weight:

[0010] 32 parts of superfine calcium hydroxide powder, 17 parts of potassium dihydrogen phosphate, 9.3 parts of silica sol, 1.2 parts of dispersant, 32 parts of ferric aluminate cement, 0.5 parts of surface modifier, 5 parts of active activator and 3 parts of superfine calcium carbonate powder.

[0011] As a specific embodiment:

[0012] The Ca(OH)2 content in the superfine calcium hydroxide powder is ≥95%, the particle size is 700-900 mesh and the dry loss is ≤1.0%;

[0013] The CaCO3 content in the superfine calcium carbonate powder is ≥98%, the particle size is 2500-3500 mesh and the water content is ≤1.0%.

[0014] As a specific embodiment:

[0015] The KH2PO4 content in the potassium dihydrogen phosphate is ≥98%, the particle size is 70-90 mesh and the water content is ≤0.1%;

[0016] The silica sol is acidic SiO2 sol, the solid content is 30±1%, the particle size is 10-15 nm and the PH is 2-4;

[0017] The ferric aluminate cement is 525 fast-hardening and erosion-resistant ferric aluminate cement, the specific surface area is ≥350 m 2≤180min, 1d compressive strength ≥35MPa, 28d compressive strength ≥52.5MPa, 28d sulfate attack resistance coefficient ≥1.05.

[0018] As a specific embodiment:

[0019] The dispersant is composed of sodium stearate and water-soluble silicone oil, and the mass ratio of the two is 2: (1-5); preferably the mass ratio is 2:3;

[0020] The surface modifier is a mixture of triethanolamine and diethylisopropanolamine, and the mass ratio of the two is 1: (0.2-2.0); preferably the mass ratio is 1:1.

[0021] The active activator is a mixture of calcium fluoride and cryolite powder in a mass ratio of 1: (0.2-2.0), preferably the mass ratio is 1:1, the average particle size of the mixture is 70-90μm, and the water content is ≤1.0%.

[0022] In a second aspect, the application provides a preparation method of the fast-hardening and early-strength admixture, comprising the following steps:

[0023] S1, mix the silica sol and the dispersant, heat and stir, then slowly add the superfine calcium hydroxide powder, and stir and disperse again;

[0024] S2, mix the mixture prepared in step S1 with potassium dihydrogen phosphate, heat and stir, and react;

[0025] S3, dry the substance obtained by the reaction in step S2, grind and sieve;

[0026] S4, calcine the sieved powder in step S3, rapidly cool after the calcination is completed, and grind the cooled material until the superfine powder with a particle size of 10-30μm is obtained;

[0027] S5, mix the superfine powder prepared in step S4 with the ferrite cement, the surface modifier, the active activator, and the superfine calcium carbonate powder, modify under the condition of heating and stirring, and obtain the fast-hardening and early-strength admixture.

[0028] As a specific embodiment:

[0029] In step S1, the heating and stirring condition is heating to 60-65℃ and stirring at a rate of 300-500r / min for 5-10min; the stirring and dispersing condition is stirring and dispersing at a rate of 500-700r / min for 30-40min;

[0030] In step S2, the heating, stirring and reaction are performed by heating in a water bath to 70-80 DEG C, stirring at a rate of 200-400 r / min for 6-7 h;

[0031] In step S3, the drying is performed at 80-90 DEG C for 30-40 min, the powder grinding is performed for 10-15 min, and the sieving is performed through an 80-mesh sieve;

[0032] In step S4, the calcining is performed at 800-1000 DEG C for 5-7 h, and the powder grinding is performed for 30-40 min;

[0033] In step S5, the heating and stirring are performed at 80-90 DEG C at a stirring rate of 1500-2500 r / min.

[0034] In a third aspect, the application provides application of the fast-hardening and early-strength admixture in preparation of a cement-based structural material for rapid repair.

[0035] In a fourth aspect, the application provides a cement-based structural material for rapid repair, which comprises the fast-hardening and early-strength admixture.

[0036] As an embodiment, the cement-based structural material for rapid repair comprises the following components in parts by weight:

[0037] cement 35-45 parts, fast-hardening and early-strength admixture 8-12 parts, fine sand 44-51 parts, silica fume 1.5-2.5 parts, and additive 0.3-0.5 parts.

[0038] As a further embodiment:

[0039] The cement is PII525 or PO525 Portland cement;

[0040] The fine sand is a mixture of sand of 40-80 mesh and sand of 80-120 mesh in a mass ratio of 6:(3-5);

[0041] The additive is a water reducing agent, a stabilizer, an antifoaming agent and a setting regulator, and the mass ratio is 0.15-0.2:0.01-0.02:0.05-0.08:0.1-0.2.

[0042] Advantages: Compared with the prior art, the application has the following advantages:

[0043] The application provides a fast-hardening and early-strength mixing material, which is mainly prepared from superfine calcium hydroxide powder, potassium dihydrogen phosphate and silica sol through a specific process, chemical reaction, calcination and powder grinding, and then mixed with ferric aluminate cement to form a hydraulic cementing material; the dispersant helps to disperse the superfine calcium hydroxide powder, improve the agglomeration phenomenon between superfine powders and promote the chemical synthesis reaction; the active activator can further promote the hydration reaction activity of the fast-hardening and early-strength mixing material, improve the hydration reaction rate and obtain higher early strength; the surface modifier can be fully mixed with the hydraulic cementing material powder, adsorbed on the surface of the powder and significantly reduce the dust emission of the powder during production and use, thereby improving the construction operation environment and promoting the hydration of cement particles to a certain extent; the superfine calcium carbonate powder can control the hydration reaction rate of the hydraulic cementing material to match the performance requirements of the material and the construction progress.

[0044] The fast-hardening and early-strength mixing material has very high hydration reaction activity, and the main minerals are anhydrous calcium sulphoaluminate, iron phase, hydroxyapatite, beta-C2S and beta-C3P, etc. The cementing material has high early and late strength, and the flexural strength and bonding strength are very high. The cementing material can be used in combination with Portland cement, and the hydration reaction rate of the cement can be greatly improved by replacing part of the Portland cement, thereby greatly improving the early strength of the cement matrix.

[0045] The application provides a bridge and road rapid repair cement-based structural material prepared by using the fast-hardening and early-strength mixing material as a raw material. The fast-hardening and early-strength mixing material can obtain excellent wear resistance, bonding performance and sulfate corrosion resistance. The setting time of the material can be controlled to be greater than or equal to 15 min, the compressive strength can be greater than or equal to 20 MPa at 3 h, greater than or equal to 30 MPa at 6 h, and the late strength of the matrix does not decrease. The prepared repair material matrix is dense, has very small porosity, forms super strong bonding with the old concrete surface, and can be used in water or humid environment for a long time. At the same time, the fast-hardening and early-strength mixing material can significantly reduce the dust emission during the production of the structural repair material. During use, only water needs to be added for stirring, and the operation is simple and green. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described below in connection with the embodiments of the application. Obviously, the described embodiments are some but not all of the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0047] In the following examples and comparative examples, unless otherwise specified, the fast hardening and early strength admixture and the cement-based structural material for rapid repair of bridges and roads are prepared according to the following preparation methods and raw materials.

[0048] The preparation method of the fast hardening and early strength admixture comprises the following steps:

[0049] S1, mix the silica sol and the dispersant, heat to 65°C and stir at a speed of 400 r / min for 8 min, then slowly add the superfine calcium hydroxide powder, and stir and disperse at a speed of 600 r / min for 35 min, and reserve;

[0050] S2, mix the mixture prepared in step S1 with potassium dihydrogen phosphate, heat in a water bath to 75°C, and stir at a speed of 300 r / min for 7 h;

[0051] S3, dry the substance obtained in step S2 at 85°C for 40 min, grind for 15 min, and then pass through an 80-mesh sieve;

[0052] S4, calcine the sieved powder in step S3 at 900°C for 6 h, rapidly cool after calcination, and grind the cooled material for 30-40 min until the superfine powder with a particle size of 20±2 μm is obtained;

[0053] S5, mix the superfine powder prepared in step S4 with the ferrite aluminate cement, the surface modifier, the active activator, and the superfine calcium carbonate powder, modify while stirring at 85°C, and the stirring speed is 2000 r / min.

[0054] In the raw materials of the fast hardening and early strength admixture, the Ca(OH)2 content of the superfine calcium hydroxide powder used is ≥95%, the particle size is 800 mesh, and the dry loss is ≤1.0%; the KH2PO4 content of the potassium dihydrogen phosphate is ≥98%, the particle size is 80 mesh, and the water content is ≤0.1%; the silica sol used is an acidic SiO2 sol with a solid content of 30±1%, a particle size of 10-15 nm, and a PH of 2-4; the dispersant is a mixture of sodium stearate and water-soluble silicone oil with a mass ratio of 2:3; the ferrite aluminate cement is 525 fast hardening and erosion-resistant ferrite aluminate cement with a specific surface area of ≥350 m 2 / kg, an initial setting time of ≥25 min, a final setting time of ≤180 min, a 1d compressive strength of ≥35 MPa, a 28d compressive strength of ≥52.5 MPa, and a 28d sulfate erosion resistance coefficient of ≥1.05; the surface modifier is a mixture of triethanolamine and diisopropyl ethanolamine with a mass ratio of 1:1; the active activator is a mixture of calcium fluoride and cryolite powder with a mass ratio of 1:1, the average particle size of the mixture is 80 μm, and the water content is ≤1.0%; the superfine calcium carbonate powder has a CaCO3 content of ≥98%, a particle size of 3000 mesh, and a water content of ≤1.0%.

[0055] The preparation method of the cement-based structural material for rapid repair of bridges and roads is as follows: each component of the cement-based structural material is put into a compulsory mixer for mixing and stirring until uniform, and then mixed with water directly, and the stirring time is 3-5 min; generally, the water-material ratio is controlled to be 0.11-0.12.

[0056] The cement used in the cement-based structural material for rapid repair of bridges and roads is PII525 Portland cement; the fine sand is quartz sand of 40-80 mesh and quartz sand of 80-120 mesh mixed in a ratio of 6:4; the water reducing agent is a polycarboxylic acid high-performance water reducing agent, and the water reducing rate is ≥30%; the stabilizer is Stabilizer-420 high-performance viscosity modifier produced by Sika; the defoaming agent is German Mingling Chemical P803 powder defoaming agent; the setting adjusting agent is tartaric acid; and the mass ratio of the water reducing agent, the stabilizer, the defoaming agent and the setting adjusting agent in the additive is 0.18:0.015:0.06:0.15.

[0057] Example 1

[0058] The fast-hardening and early-strength mixed material provided in this example contains, by mass percentage, 30% of superfine calcium hydroxide powder, 18% of potassium dihydrogen phosphate, 8.2% of silica sol, 1.1% of dispersant, 34% of ferric aluminate cement, 1.2% of surface modifier, 5% of active activator and 2.5% of superfine calcium carbonate powder.

[0059] The cement-based structural material for rapid repair of bridges and roads prepared by using the fast-hardening and early-strength mixed material as raw material contains, by mass percentage, 37.5% of cement, 10% of fast-hardening and early-strength mixed material, 50% of fine sand, 2.0% of silica fume and 0.5% of additive.

[0060] Example 2

[0061] The fast-hardening and early-strength mixed material provided in this example contains, by mass percentage, 35% of superfine calcium hydroxide powder, 14.8% of potassium dihydrogen phosphate, 10% of silica sol, 1.5% of dispersant, 30% of ferric aluminate cement, 0.7% of surface modifier, 4% of active activator and 4% of superfine calcium carbonate powder.

[0062] The fast-hardening and early-strength mixed material of this example is applied to the cement-based structural material for rapid repair of bridges and roads, and the raw materials of the repair material are the same as those of Example 1.

[0063] Example 3

[0064] The fast hardening and early strength mixing material provided by the embodiment contains, by mass percentage, 33% of superfine calcium hydroxide powder, 14% of potassium dihydrogen phosphate, 8% of silica sol, 1.0% of dispersant, 35% of ferrite aluminate cement, 1.0% of surface modifier, 6% of active activator, and 2% of superfine calcium carbonate powder.

[0065] The fast hardening and early strength mixing material of the embodiment is applied to the cement-based structural material for bridge and road rapid repair, and the raw materials of the repair material are the same as those of Example 1.

[0066] Example 4

[0067] The fast hardening and early strength mixing material provided by the embodiment contains, by mass percentage, 33% of superfine calcium hydroxide powder, 14% of potassium dihydrogen phosphate, 8% of silica sol, 1.0% of dispersant, 35% of ferrite aluminate cement, 1.0% of surface modifier, 6% of active activator, and 2% of superfine calcium carbonate powder.

[0068] The fast hardening and early strength mixing material of the embodiment is applied to the cement-based structural material for bridge and road rapid repair, and the raw materials of the repair material are the same as those of Example 1.

[0069] Example 5

[0070] The fast hardening and early strength mixing material provided by the embodiment contains, by mass percentage, 33% of superfine calcium hydroxide powder, 14% of potassium dihydrogen phosphate, 8% of silica sol, 1.0% of dispersant, 35% of ferrite aluminate cement, 1.0% of surface modifier, 6% of active activator, and 2% of superfine calcium carbonate powder.

[0071] The fast hardening and early strength mixing material of the embodiment is applied to the cement-based structural material for bridge and road rapid repair, and the raw materials of the repair material are the same as those of Example 1.

[0072] Example 6

[0073] The fast hardening and early strength mixing material provided by the embodiment contains, by mass percentage, 33% of superfine calcium hydroxide powder, 14% of potassium dihydrogen phosphate, 8% of silica sol, 1.0% of dispersant, 35% of ferrite aluminate cement, 1.0% of surface modifier, 6% of active activator, and 2% of superfine calcium carbonate powder.

[0074] Example 7

[0075] The fast hardening and early strength mixing material provided by the embodiment contains, by mass percentage, 33% of superfine calcium hydroxide powder, 14% of potassium dihydrogen phosphate, 8% of silica sol, 1.0% of dispersant, 35% of ferrite aluminate cement, 1.0% of surface modifier, 6% of active activator, and 2% of superfine calcium carbonate powder.

[0076] Comparative Example 1

[0077] The difference between the fast hardening and early strength admixture prepared in this comparative example and Example 4 is that the raw materials are, by mass percentage, superfine calcium hydroxide powder 32%, potassium dihydrogen phosphate 17%, silica sol 9.3%, ferrite cement 33.5%, surface modifier 0.5%, active activator 5%, and superfine calcium carbonate powder 3%, i.e., no dispersant is added, and the missing part is replaced with ferrite cement.

[0078] Comparative Example 2

[0079] The difference between the fast hardening and early strength admixture prepared in this comparative example and Example 4 is that the raw materials are, by mass percentage, superfine calcium hydroxide powder 32%, potassium dihydrogen phosphate 17%, silica sol 9.3%, dispersant 1.2%, ferrite cement 37%, surface modifier 0.5%, and superfine calcium carbonate powder 3%, i.e., no active activator is added, and the missing part is replaced with ferrite cement.

[0080] Comparative Example 3

[0081] The difference between the fast hardening and early strength admixture prepared in this comparative example and Example 4 is that the raw materials are, by mass percentage, superfine calcium hydroxide powder 32%, potassium dihydrogen phosphate 17%, silica sol 9.3%, dispersant 1.2%, ferrite cement 32.5%, active activator 5%, and superfine calcium carbonate powder 3%, i.e., no surface modifier is added, and the missing part is replaced with ferrite cement.

[0082] Comparative Example 4

[0083] The difference between the fast hardening and early strength admixture prepared in this comparative example and Example 4 is that the raw materials are, by mass percentage, superfine calcium hydroxide powder 32%, potassium dihydrogen phosphate 17%, silica sol 9.3%, dispersant 1.2%, ferrite cement 35%, surface modifier 0.5%, and active activator 5%, i.e., no superfine calcium carbonate powder is added, and the missing part is replaced with ferrite cement.

[0084] Comparative Example 5

[0085] In this comparative example, no fast hardening and early strength admixture is added in the cement-based structural material for rapid repair of bridges and roads, but instead, sulfur aluminum cement is used to replace it. The sulfur aluminum cement is North Pole Bear 525 fast hardening sulfur aluminum cement. The cement is 37.5%, sulfur aluminum cement is 10%, fine sand is 50%, silica fume is 2.0%, and admixture is 0.5%.

[0086] In Examples 1-7 and Comparative Examples 1-5, the mixed cement-based structural repair material was poured into the mold, filled to the brim at once, and then placed on a concrete vibrating table for 2 minutes. The surface was then smoothed, covered with a film for 24 hours of curing, and the mold was removed. The molds were then cured in a standard curing environment (temperature 20±2℃, humidity ≥95%) until the age to be tested, and performance tests were carried out.

[0087] The cement-based structural repair materials of Examples 1-7 and Comparative Examples 1-5 were tested for setting time, 3-hour compressive strength, 6-hour compressive strength, 28-day compressive strength, 28-day flexural strength, abrasion per unit area, bond strength, and 28-day erosion resistance coefficient, respectively. The setting time test method was based on GB / T 50080-2016 "Standard for Test Methods of Performance of Ordinary Concrete Mixtures", and the compressive strength, flexural strength, abrasion per unit area, and bond strength test methods were based on GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Ordinary Concrete". The 28-day erosion resistance coefficient test method was based on GB / T 45920-2025 "Aluminoferrite Cement". The dust generation during the mixing process of the structural repair was determined by visual inspection.

[0088] The performance test results of the cement-based structural repair materials are shown in Table 1.

[0089] Table 1 Test results of cement-based structural repair materials

[0090]

[0091] As shown in Table 1, the data from Examples 1-7 demonstrate that the rapid-hardening, early-strength composite material provided by this invention exhibits extremely high hydration reactivity. Cement-based structural materials for rapid bridge and road repair prepared using this rapid-hardening, early-strength composite material as a raw material possess high early and later-stage strength, extremely high flexural and bond strength, and no shrinkage in the later-stage strength of the matrix. This material also exhibits excellent wear resistance and sulfate resistance. Furthermore, using this rapid-hardening, early-strength composite material to produce structural repair materials significantly reduces dust generation and is convenient, environmentally friendly, and easy to operate. These components interact with each other rather than existing independently, which will help solve the problems currently existing in the application of rapid-hardening, early-strength repair materials.

[0092] Comparing the test data of Comparative Examples 1-5 in Table 1 with the data of Example 4, it can be seen that, in Comparative Example 1, the lack of dispersant will affect the dispersion of the superfine calcium hydroxide powder, and further affect the chemical synthesis and sintering process of the cementitious material, the setting time of the repair material is significantly prolonged, the strength at each age is reduced, and other performances are reduced to different degrees; in Comparative Example 2, the lack of active activator reduces the setting time and early strength of the structural repair material, but has little effect on the later strength; in Comparative Example 3, the lack of surface modifier has a greater impact, which is that the structural repair material has a large amount of dust during use, and the early strength is slightly reduced; in Comparative Example 4, the lack of superfine calcium carbonate powder significantly shortens the setting time, but reduces the early strength, and has no obvious effect on the 28d strength; in Comparative Example 5, the ordinary sulphoaluminate cement is used to replace the fast-hardening and early-strength admixture, and the performances of the repair material are significantly reduced.

[0093] The above describes the embodiments of the present application in detail in combination with specific examples, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the present application.

Claims

1. A quick-hardening early-strength admixture, characterized by comprising: Components comprising the following weight parts: Superfine calcium hydroxide powder 30~35 parts, potassium dihydrogen phosphate 14~18 parts, silica sol 8~10 parts, dispersant 1.0~1.5 parts, ferrite cement 30~35 parts, surface modifier 0.5~1.5 parts, active activator 4~6 parts, super fine calcium carbonate powder 2~4 parts.

2. The fast hardening early strength admixture according to claim 1, characterized in that: Ca(OH)2 in the superfine calcium hydroxide powder is ≥95%, the particle size is 700-900 mesh, and the dry loss is ≤1.0%; CaCO3 in the superfine calcium carbonate powder is ≥98%, the particle size is 2500-3500 mesh, and the water content is ≤1.0%.

3. The fast hardening early strength admixture according to claim 1, characterized in that: KH2PO4 content in the potassium dihydrogen phosphate is ≥98%, the particle size is 70-90 mesh, and the water content is ≤0.1%; The silica sol is an acidic SiO2 sol, with a solid content of 30±1%, a particle size of 10~15 nm, and a PH value of 2~4; The ferrite aluminate cement is 525 fast-hardening erosion-resistant ferrite aluminate cement, with specific surface area ≥ 350 m 2 / kg, initial setting time ≥ 25 min, final setting time ≤ 180 min, 1d compressive strength ≥ 35 MPa, 28d compressive strength ≥ 52.5 MPa, and 28d sulfate erosion resistance coefficient ≥ 1.

05.

4. The fast hardening early strength admixture according to claim 1, characterized in that: The dispersant is composed of sodium stearate and water-soluble silicone oil, with a mass ratio of 2: (1-5); preferably, the mass ratio is 2:3; The surface modifier is a mixture of triethanolamine and diethyl isopropyl amine, with a mass ratio of 1: (0.2-2.0); preferably, the mass ratio is 1:1; The active activator is a mixture of calcium fluoride and cryolite powder, with a mass ratio of 1: (0.2-2.0); preferably, the mass ratio is 1:1, the average particle size of the mixture is 70-90 μm, and the water content is ≤1.0%.

5. The method of producing a high early-strength admixture according to any one of claims 1 to 4, characterized by, Comprising the following steps: S1, mix the silica sol and the dispersant, heat and stir, then slowly add the superfine calcium hydroxide powder, stir and disperse, and reserve; S2, mix the mixture prepared in step S1 with the potassium dihydrogen phosphate, heat and stir, and react; S3, dry the substance obtained in step S2, grind and sieve; S4, calcine the sieved powder in step S3, rapidly cool after calcination, grind the cooled material, and obtain the superfine powder with a particle size of 10~30 μm; S5, mix the superfine powder prepared in step S4 with the ferrite cement, the surface modifier, the active activator, and the super fine calcium carbonate powder, modify under the condition of heating and stirring, and obtain the fast hardening early strength admixture.

6. The preparation method of the fast hardening early strength admixture according to claim 5, characterized in that: In step S1, the heating and stirring conditions are: heating to 60~65℃, and stirring at a rate of 300-500 r / min for 5~10 min; the stirring and dispersing conditions are: stirring and dispersing at a rate of 500-700 r / min for 30~40 min; In step S2, the process of heating, stirring and reacting is: heating the water bath to 70~80℃, and stirring at a rate of 200-400 r / min for 6~7 h; In step S3, the drying is performed at 80-90℃ for 30-40min; the grinding time is 10-15min; and the sieving is performed through an 80-mesh sieve; In step S4, the calcination is performed at 800-1000℃ for 5-7h; and the grinding time is 30-40min; In step S5, the heating and stirring conditions are as follows: the stirring speed is 1500-2500r / min at 80-90℃.

7. Use of the fast-hardening and early-strength admixture according to any one of claims 1-4 in the preparation of a cement-based structural material for rapid repair.

8. A cement-based structural material for rapid repair, characterized by, The cement-based structural material for rapid repair comprises the fast-hardening and early-strength admixture according to any one of claims 1-4.

9. The rapid repair cementitious material according to claim 8, wherein The cement-based structural material for rapid repair comprises the following components by weight: cement 35-45 parts, fast-hardening and early-strength admixture 8-12 parts, fine sand 44-51 parts, silica fume 1.5-2.5 parts, and additive 0.3-0.5 parts.

10. The cement-based structural material for rapid repair according to claim 9, wherein: the cement is PII525 or PO525 Portland cement; the fine sand is a mixture of 40-80-mesh sand and 80-120-mesh sand in a mass ratio of 6:(3-5); the additive is a water-reducing agent, a stabilizer, a defoaming agent, and a setting regulator, and the mass ratio is 0.15-0.2:0.01-0.02:0.05-0.08:0.1-0.2.

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