A fast-drying cement-based repair mortar and a method for preparing the same

Abstract

The application relates to the technical field of building materials, in particular to a fast-drying cement-based repair mortar and a preparation method thereof, which comprises the following raw materials in parts by weight: base material 45-55 parts, aggregate 25-35 parts, additive liquid 5-10 parts, additive 3-5 parts, water reducing agent 1-1.5 parts, defoaming agent 0.5-1 part and retarder 0.5-1 part. The base material is rich in high-activity anhydrous minerals such as tricalcium silicate which is sensitive to moisture, and provides a fast-hydration skeleton basis for the mortar; the powder removes the obstacle for the base material to exert high activity without interference in the fast-drying stage; calcium nitrate can accelerate the hydration-precipitation reaction chain of key mineral phases, significantly shortens the setting time, and the cellulose and silk form a hydrophilic fiber network to lock water and solidify the mortar in the plastic stage of the mortar, so that the whole mortar system can form good early strength in a short time, and the disadvantage that the repair area is easily damaged by pedestrians and non-motor vehicles in the early stage is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a fast-drying cement-based repair mortar and a preparation method thereof. BACKGROUND

[0002] The cement-based repair mortar is a new type of repair material made of cement as a cementitious material, sand, mineral admixtures and additives, which has good adhesion, compressive strength and durability, can quickly repair cracks and peeling defects of concrete structures, is convenient to construct, can be used after being stirred with water, and is suitable for repairing and reinforcing concrete components such as walls, floors and bridges of buildings.

[0003] In the prior art, the repair mortar product often has the problem of insufficient early strength, and the setting time is too long, which is easily affected by impurities during the fast-drying stage and affects the activity, and the water loss is too fast due to the weak water locking and solidifying ability in the plastic stage, which leads to the problem that the repaired area is easily damaged by pedestrians and non-motor vehicles in the early stage and is difficult to be quickly put into use. Based on this, the present application provides a fast-drying cement-based repair mortar and a preparation method thereof. SUMMARY

[0004] The purpose of the present application is to provide a fast-drying cement-based repair mortar and a preparation method thereof, which not only solves the problem that the repaired area is easily damaged by pedestrians and non-motor vehicles in the early stage, but also solves the problem that the traditional repair mortar is prone to cracking due to the imbalance between strength and toughness during long-term use.

[0005] To achieve the above purpose, the present application provides the following technical scheme: a fast-drying cement-based repair mortar, comprising the following raw materials by weight: base material 45-55 parts, aggregate 25-35 parts, additive liquid 5-10 parts, additive 3-5 parts, water reducing agent 1-1.5 parts, defoaming agent 0.5-1 part, and retarder 0.5-1 part.

[0006] The raw materials of the base material include powder, steel slag, desulfurization gypsum, fly ash and bauxite.

[0007] The raw materials of the powder include phosphogypsum, S95 grade slag and carbide slag.

[0008] The preparation method of the base material comprises the following steps:

[0009] Step 1: add steel slag, desulfurization gypsum, fly ash and bauxite into a ball mill, set the rotation speed to 30-45 rpm, and process for 45-60 min to obtain a first coarse material, and sieve to obtain a first fine material with a particle size of 65-75 μm;

[0010] Step 2: the first fine material and powder material are premixed and then added into a calcining furnace, heated to 900-950℃ for 60-80min, then heated to 1250-1350℃ at a heating rate of 8-10℃ / min for 25-35min, and the obtained material is air-cooled to 20-30℃ to obtain a to-be-processed material;

[0011] Step 3: the to-be-processed material is ground and then sieved through a 75μm mesh screen to obtain the base material.

[0012] Preferably, the mass ratio of the powder material, the steel slag, the desulfurized gypsum, the fly ash and the bauxite is (45-55):(9-12):(10-15):(10-18):(10-18), and the mass ratio of the phosphogypsum, the S95 grade slag and the carbide slag is (28-32):(52-60):(10-15).

[0013] Preferably, the aggregate is selected from any one of calcium carbonate and dolomite, and the particle size is 0.1-0.5mm; and the water reducing agent is selected from any one of polycarboxylic acid type water reducing agent, naphthalene type water reducing agent and melamine type water reducing agent.

[0014] Preferably, the defoaming agent is selected from any one of silicone defoaming agent, polyether defoaming agent and fatty acid ester defoaming agent; and the retarder is selected from any one of sodium citrate, sodium tartrate and sodium gluconate.

[0015] Preferably, the additive is selected from any one of ethylene-vinyl acetate copolymer emulsion, vinyl acetate-acrylic ester copolymer emulsion and butadiene-styrene copolymer emulsion.

[0016] Preferably, the preparation method of the powder material comprises the following steps: phosphogypsum is added into an ammonia water solution with a mass fraction of 1%, stirred at a stirring speed of 50-80rpm for 10-15min, and then left to stand for 15-20min; the obtained product is added into an oven, and dried to constant weight at a setting temperature of 40-50℃; the obtained product is added into a stirrer, and S95 grade blast furnace slag and carbide slag are added, and dry-mixed at 80-100rpm for 5-10min to obtain a mixed material; water is further added into the stirrer to continue stirring for 5-10min to obtain a wet mixed material; and the wet mixed material is transferred into an oven and dried to constant weight at a temperature of 35-45℃ to obtain the powder material.

[0017] Preferably, the mass ratio of the phosphogypsum and the ammonia water solution is 1:(2-3), and the mass ratio of the dry mixed material and water is 1:(3-4).

[0018] Preferably, the preparation method of the additive solution comprises the following steps:

[0019] Step 1: cellulose, silk fibroin, water are added into a stirring kettle, the stirring speed is set to 80-120 rpm, and the obtained product is treated for 15-25 min, then the obtained product is transferred into a vacuum drying oven, and vacuum drying treatment is carried out at 75-85 DEG C until the weight is constant, thereby obtaining a second coarse material;

[0020] Step 2: the mulberry silk is cut into 1-3 mm to obtain a silk material, and the obtained product is immersed in a sodium carbonate solution with a mass concentration of 1-2%, then the obtained product is added into a water bath kettle, heated at 85-95 DEG C for 15-25 min, and the obtained product is centrifuged and washed with deionized water until neutral, thereby obtaining a second fine material;

[0021] Step 3: the second coarse material and the second fine material are added into a calcium nitrate solution with a mass concentration of 10-12% according to a mass ratio of 1:(1-2), and the obtained product is treated at 75-80 DEG C and 100-150 rpm for 50-80 min, thereby obtaining an additive solution.

[0022] Preferably, the mass ratio of cellulose, silk fibroin and water is (7-8):(2-4):(80-90), the mass ratio of the silk material and the sodium carbonate solution is 1:(85-90), and the total mass of the second coarse material and the second fine material is 30-45% of the mass of the calcium nitrate solution.

[0023] Preferably, a preparation method of the fast-drying cement-based repair mortar comprises the following steps:

[0024] S1: the base material, aggregate, additive, water reducing agent, defoaming agent and retarder are added into a double-shaft mixer, the rotating speed is set to 80-100 rpm, and the obtained product is treated for 15-20 min, thereby obtaining a blank;

[0025] S2: the additive solution is added into a spray dryer, the inlet air temperature is set to 120-150 DEG C, the outlet air temperature is set to 80-90 DEG C, and the obtained product is treated until the water content is less than or equal to 1%, then the obtained product is added into the double-shaft mixer of S1, the rotating speed is adjusted to 120-150 rpm, and the obtained product is treated for 20-30 min, thereby obtaining a treated material;

[0026] S3: the treated material is sieved through a 100-150 mesh vibrating screen, and then sealed and packaged, thereby obtaining the fast-drying cement-based repair mortar.

[0027] Compared with the prior art, the fast-drying cement-based repair mortar has the following beneficial effects:

[0028] 1. In the repair mortar, the calcined and activated base material is rich in highly active anhydrous minerals such as tricalcium silicate, which are sensitive to moisture. This provides a framework for rapid hydration of the mortar. The ammonia-treated powder removes harmful impurities, eliminating obstacles to the base material's high activity during the rapid drying stage. In the additive liquid obtained after treatment, calcium nitrate accelerates the hydration-precipitation reaction chain of key mineral phases, significantly shortening the setting time. Cellulose and silk form a hydrophilic fiber network, which locks in water and solidifies the mortar during the plastic stage. With the addition of water-reducing agents and other additives, the entire mortar system can form good early strength in a short time, solving the problem that the repaired area is susceptible to damage from pedestrians and non-motorized vehicles in the early stage.

[0029] 2. In the present invention, during the use of repair mortar, the cellulose in the additive liquid forms a three-dimensional water-retaining network through molecular chain entanglement, providing a continuous water environment for the pozzolanic reaction of fly ash and bauxite in the base material, causing it to slowly release active silicon and aluminum ions, continuously generating hydrated calcium silicate gel to fill microscopic pores. The modified silk fibroin and the organic molecules formed by the hydrolysis products of silkworm silk can form covalent bonds with the inorganic calcium salt generated by the reaction of calcium nitrate, constructing a flexible transition layer at the interface of hydration products to alleviate stress concentration. At the same time, the potential activity of slag in the base material is gradually activated with age, and together with the continuously generated hydration products, it strengthens the overall structure, improving both the density required for compressive strength and the toughness required for flexural strength, thus solving the problem of cracking caused by the imbalance of strength and toughness in traditional repair mortar during long-term use. Attached Figure Description

[0030] Figure 1 A flowchart is provided for the invention of a fast-drying cement-based repair mortar and its preparation method.

[0031] Figure 2 A flowchart of the base material preparation process for a fast-drying cement-based repair mortar and its preparation method is provided for the invention.

[0032] Figure 3 This invention proposes a quick-drying cement-based repair mortar and a method for preparing the additive liquid, which is shown in the flowchart. Detailed Implementation

[0033] 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.

[0034] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0035] Embodiment 1:

[0036] A fast-drying cement-based repair mortar, comprising the following raw materials by weight: base material 45 parts, aggregate 25 parts, additive liquid 5 parts, additive 3 parts, water reducing agent 1 part, defoaming agent 0.5 part, retarder 0.5 part;

[0037] The raw materials of the base material include powder, steel slag, desulfurization gypsum, fly ash, bauxite;

[0038] The raw materials of the powder include phosphogypsum, S95 grade slag, carbide slag;

[0039] The preparation method of the base material comprises the following steps:

[0040] Step 1: add steel slag, desulfurization gypsum, fly ash, and bauxite into a ball mill, set the rotation speed to 30 rpm, and process for 45 min to obtain a first coarse material, and sieve to obtain a first fine material with a particle size of 65 μm;

[0041] Step 2: mix the first fine material and the powder, and then add them into a calcining furnace, heat to 900℃ and keep for 60 min, then heat to 1250℃ at a rate of 8℃ / min and keep for 25 min, and then air cool to 20℃ to obtain a material to be processed;

[0042] Step 3: crush and grind the material to be processed, and then sieve through a 75 μm aperture sieve to obtain the base material.

[0043] The mass ratio of the powder, steel slag, desulfurization gypsum, fly ash, and bauxite is 45:9:10:10:10, and the mass ratio of the phosphogypsum, S95 grade slag, and carbide slag is 28:52:10.

[0044] The aggregate is selected from calcium carbonate with a particle size of 0.1 mm, and the water reducing agent is selected from a polycarboxylic acid type water reducing agent.

[0045] The defoaming agent is selected from an organic silicon defoaming agent, and the retarder is selected from sodium citrate.

[0046] The additive is selected from an ethylene-vinyl acetate copolymer emulsion, which is purchased from Changsha Jingbin New Material Technology Co., Ltd.

[0047] The preparation method of the powder comprises the following steps: add phosphogypsum into a 1% ammonia water solution, stir at a stirring speed of 50 rpm for 10 min, and then stand for 15 min, then put the obtained product into an oven, set the temperature to 40℃, and dry to constant weight, then put the obtained product into a blender, add S95 grade blast furnace slag and carbide slag, and dry mix at 80 rpm for 5 min to obtain a mixed material, then add water into the blender and continue to stir for 5 min to obtain a wet mixed material, and then put the wet mixed material into an oven and dry to constant weight at 35℃ to obtain the powder.

[0048] The mass ratio of the phosphogypsum and the ammonia water solution is 1:2, and the mass ratio of the dry mixture and water is 1:3.

[0049] The preparation method of the additive solution comprises the following steps:

[0050] Step 1: cellulose, silk fibroin and water are added into a stirring kettle, a stirring speed of 80 rpm is set, and treatment is performed for 15 min; the obtained product is transferred into a vacuum drying oven, vacuum drying treatment is performed at 75 DEG C until a constant weight is obtained, and a second coarse material is obtained;

[0051] Step 2: the mulberry silk is cut into 1 mm to obtain a silk material, the silk material is immersed into a sodium carbonate solution with a mass concentration of 1%, the obtained product is added into a water bath kettle, heating is performed at 85 DEG C for 15 min, the obtained product is centrifuged and filtered, and then washed with deionized water until neutral, and a second fine material is obtained;

[0052] Step 3: the second coarse material and the second fine material are added into a calcium nitrate solution with a mass concentration of 10% according to a mass ratio of 1:1, treatment is performed at 75 DEG C and 100 rpm for 50 min, and an additive solution is prepared.

[0053] The mass ratio of the cellulose, the silk fibroin and water is 7:2:80, the mass ratio of the silk material and the sodium carbonate solution is 1:85, and the total mass of the second coarse material and the second fine material is 30% of the mass of the calcium nitrate solution.

[0054] A preparation method of a fast-drying cement-based repair mortar comprises the following steps:

[0055] S1: a base material, an aggregate, an additive, a water reducing agent, a defoaming agent and a retarder are added into a double-shaft mixer, a rotating speed of 80 rpm is set, and treatment is performed for 15 min, so that a blank is obtained;

[0056] S2: an additive solution is added into a spray dryer, an inlet air temperature of 120 DEG C and an outlet air temperature of 80 DEG C are set, and treatment is performed until the water content is less than or equal to 1%; the obtained product is added into the double-shaft mixer of S1, the rotating speed is adjusted to 120 rpm, and treatment is performed for 20 min, so that a treated material is obtained;

[0057] S3: the treated material is screened through a 100-mesh vibrating screen, and then sealed and packaged, so that the fast-drying cement-based repair mortar is prepared.

[0058] Example 2:

[0059] A fast-drying cement-based repair mortar comprises the following raw materials in parts by weight: a base material 50 parts, an aggregate 30 parts, an additive solution 8 parts, an additive 4 parts, a water reducing agent 1.2 parts, a defoaming agent 0.8 parts, and a retarder 0.8 parts.

[0060] The raw materials of the base material include a powder, a steel slag, a desulfurization gypsum, a fly ash and an aluminum bauxite.

[0061] The raw materials of the powder include phosphogypsum, S95 grade slag, carbide slag;

[0062] The preparation method of the base material includes the following steps:

[0063] Step 1: add steel slag, desulfurization gypsum, fly ash and bauxite into a ball mill, set the rotation speed to 38 rpm and process for 52 min to obtain a first coarse material, and sieve to obtain a first fine material with a particle size of 70 μm;

[0064] Step 2: premix the first fine material and the powder, then add them into a calcining furnace, heat to 925 ℃ and keep for 70 min, then heat to 1300 ℃ at a heating rate of 9 ℃ / min and keep for 30 min, air cool the obtained material to 25 ℃ to obtain a material to be processed;

[0065] Step 3: sieve the material to be processed after crushing and grinding through a sieve with a pore size of 75 μm to obtain the base material.

[0066] The mass ratio of the powder, steel slag, desulfurization gypsum, fly ash and bauxite is 50:11:13:15:14, and the mass ratio of the phosphogypsum, S95 grade slag and carbide slag is 30:55:12.

[0067] The aggregate is selected from calcium carbonate with a particle size of 0.3 mm, and the water reducing agent is selected from a naphthalene series water reducing agent.

[0068] The defoaming agent is selected from a polyether defoaming agent, and the retarder is selected from sodium tartrate.

[0069] The additive is selected from a vinyl acetate-acrylate copolymer emulsion, which is purchased from Wuhan Ruizhuang Chemical Co., Ltd.

[0070] The preparation method of the powder includes the following steps: add phosphogypsum into an ammonia water solution with a mass fraction of 1%, stir at a stirring speed of 65 rpm for 12 min, then stand for 18 min, add the obtained product into an oven, set the drying temperature to 45 ℃ and dry to constant weight, add the obtained product into a stirrer, then add S95 grade blast furnace slag and carbide slag, dry mix for 8 min under the condition of 90 rpm, add water into the stirrer and continue to stir for 8 min to obtain a wet mixed material, and transfer the wet mixed material into an oven, dry at 40 ℃ to constant weight to obtain the powder.

[0071] The mass ratio of the phosphogypsum and the ammonia water solution is 1:2.5, and the mass ratio of the dry mixed material and water is 1:3.5.

[0072] The preparation method of the additive solution includes the following steps:

[0073] Step 1: cellulose, silk fibroin, water are added to a stirring kettle, set the stirring speed to 100 rpm, and process for 20 min; the resulting product is transferred to a vacuum drying oven and dried at 80℃ until the weight is constant; a second coarse material is obtained;

[0074] Step 2: cut the mulberry silk to 2mm to obtain silk material, immerse it in a 1.5% sodium carbonate solution, add the resulting product to a water bath, heat at 90℃ for 20 min, centrifuge and filter the resulting product, then wash it with deionized water until it is neutral; a second fine material is obtained;

[0075] Step 3: add the second coarse material and the second fine material to a 11% calcium nitrate solution at a mass ratio of 1:1.5, process at 78℃ and 125 rpm for 65 min to obtain an additive solution.

[0076] The mass ratio of cellulose, silk fibroin, and water is 7.5:3:85, the mass ratio of silk material and sodium carbonate solution is 1:88, and the total mass of the second coarse material and the second fine material is 38% of the mass of the calcium nitrate solution.

[0077] A preparation method of a fast-drying cement-based repair mortar, comprising the following steps:

[0078] S1: add base material, aggregate, additive, water reducing agent, defoaming agent, and retarder to a double-shaft mixer, set the rotation speed to 90 rpm, and process for 18 min to obtain a blank;

[0079] S2: add the additive solution to a spray dryer, set the inlet air temperature to 135℃ and the outlet air temperature to 85℃, and process until the water content is ≤1%; add the resulting product to the double-shaft mixer of S1, adjust the rotation speed to 135 rpm, and process for 25 min to obtain a treated material;

[0080] S3: screen the treated material through a 125-mesh vibrating screen and seal and package it to obtain a fast-drying cement-based repair mortar.

[0081] Example 3:

[0082] A fast-drying cement-based repair mortar, comprising the following raw materials by weight: base material 55 parts, aggregate 35 parts, additive solution 10 parts, additive 5 parts, water reducing agent 1.5 parts, defoaming agent 1 part, and retarder 1 part;

[0083] The raw materials of the base material include powder, steel slag, desulfurization gypsum, fly ash, and bauxite;

[0084] The raw materials of the powder include phosphogypsum, S95-grade slag, and carbide slag;

[0085] The preparation method of the base material comprises the following steps:

[0086] Step 1: Steel slag, desulfurization gypsum, fly ash, bauxite are added into a ball mill, and a rotation speed of 45 rpm is set for 60 min to obtain a first coarse material, and a first fine material with a particle size of 75 μm is obtained after sieving;

[0087] Step 2: The first fine material and the powder are premixed and then added into a calcining furnace, and the temperature is increased to 950 ℃ for 80 min, and then the temperature is increased to 1350 ℃ at a rate of 10 ℃ / min for 35 min, and the obtained material is air-cooled to 30 ℃ to obtain a material to be processed;

[0088] Step 3: The material to be processed is crushed and ground, and then sieved through a 75 μm aperture screen to obtain a base material.

[0089] The mass ratio of the powder, steel slag, desulfurization gypsum, fly ash, and bauxite is 55:12:15:18:18, and the mass ratio of the phosphogypsum, S95 grade slag, and carbide slag is 32:60:15.

[0090] The aggregate is selected from dolomite, and the particle size is 0.5 mm, and the water reducing agent is selected from a poly-melamine-based water reducing agent.

[0091] The defoaming agent is selected from a fatty acid ester defoaming agent, and the retarder is selected from sodium gluconate.

[0092] The additive is selected from a butadiene-styrene copolymer emulsion, which is purchased from Liyang Ruipu New Material Co., Ltd.

[0093] The preparation method of the powder comprises the following steps: phosphogypsum is added into an ammonia water solution with a mass fraction of 1%, stirred at a stirring speed of 80 rpm for 15 min, and then left to stand for 20 min, the obtained product is added into an oven, and dried at 50 ℃ until the weight is constant, the obtained product is added into a stirrer, S95 grade blast furnace slag and carbide slag are further added, and dry-mixed at 100 rpm for 10 min to obtain a mixed material, water is further added into the stirrer and stirred for 10 min to obtain a wet mixed material, and the wet mixed material is transferred into an oven and dried at 45 ℃ until the weight is constant to obtain the powder.

[0094] The mass ratio of the phosphogypsum and the ammonia water solution is 1:3, and the mass ratio of the dry-mixed material and water is 1:4.

[0095] The preparation method of the additive solution comprises the following steps:

[0096] Step 1: cellulose, silk fibroin, and water are added into a stirring kettle, and a stirring speed of 120 rpm is set for 25 min, the obtained product is transferred into a vacuum drying oven and vacuum-dried at 85 ℃ until the weight is constant to obtain a second coarse material;

[0097] Step 2: Cut the mulberry silk into 3mm to obtain the silk material, immerse it in a 2% sodium carbonate solution by mass concentration, add the obtained product to a water bath, heat at 95℃ for 25min, centrifugal filter the obtained product, and wash it with deionized water until it is neutral to obtain the second fine material;

[0098] Step 3: Add the second coarse material and the second fine material in a mass ratio of 1:2 to a 12% calcium nitrate solution by mass concentration, and treat at 80℃ and 150rpm for 80min to obtain the additive solution.

[0099] The mass ratio of cellulose, silk fibroin and water is 8:4:90, the mass ratio of the silk material and the sodium carbonate solution is 1:90, and the total mass of the second coarse material and the second fine material is 45% of the mass of the calcium nitrate solution.

[0100] A preparation method of a fast-drying cement-based repair mortar, comprising the following steps:

[0101] S1: Add the base material, aggregate, additive, water reducing agent, defoaming agent and retarder to a double-shaft mixer, set the rotation speed to 100rpm, and treat for 20min to obtain a blank;

[0102] S2: Add the additive solution to a spray dryer, set the inlet air temperature to 150℃ and the outlet air temperature to 90℃, and treat until the water content is ≤1%, then add the obtained product to the double-shaft mixer of S1, adjust the rotation speed to 150rpm, and treat for 30min to obtain a treated material;

[0103] S3: Screen the treated material through a 150-mesh vibrating screen, seal and package, and obtain the fast-drying cement-based repair mortar.

[0104] Comparative Example 1: The difference between this comparative example and Example 1 is that in this comparative example, the base material is replaced by an equal amount of Haisi P.O 42.5 ordinary portland cement.

[0105] Comparative Example 2: The difference between this comparative example and Example 1 is that in this comparative example, the additive solution is not included.

[0106] Comparative Example 3: The difference between this comparative example and Example 1 is that in the preparation of the base material in this comparative example, no powder is added.

[0107] Comparative Example 4: The difference between this comparative example and Example 1 is that in this comparative example, no powder and additive solution are included.

[0108] Performance test: 25 kg of fast-drying cement-based repair mortar prepared according to Examples 1-3 and Comparative Examples 1-4 was prepared, and 6 kg of water was prepared. The water was added to the stirring barrel and stirred, and the mortar was poured and stirred to form a lump-free flowing slurry. The slurry was uniformly spread to a thickness of 3 mm at a temperature of 20°C and a humidity of 50% using a notched plate, and after standing for 1 d and 28 d, 40 mm x 40 mm x 160 mm samples were prepared according to the JC / T985-2017 standard. The 1 d compressive strength, 28 d compressive strength, and 28 d flexural strength of the samples were recorded in the following table:

[0109] Table 1:

[0110] Group 1 d compressive strength (MPa) 28 d compressive strength (MPa) 28 d flexural strength (MPa) Example 1 8.3 38 8.5 Example 2 8.1 36 8.3 Example 3 8.5 40 8.1 Comparative Example 1 3.8 21 6.9 Comparative Example 2 5.5 28 5.1 Comparative Example 3 4.9 23 6.7 Comparative Example 4 1.9 17 3.9

[0111] As can be seen from the data in the table, the 1 d compressive strength, 28 d compressive strength, and 28 d flexural strength of the fast-drying cement-based repair mortar prepared according to Example 1-3 are all superior to those of the fast-drying cement-based repair mortar prepared according to Comparative Example 1-4.

[0112] This shows that: during the use of the repair mortar, the base material treated by calcination and activation is rich in water-sensitive tricalcium silicate and other high-activity anhydrous minerals, which provides a rapid hydration framework for the mortar. The powder treated with ammonia removes harmful impurities, allowing the base material to exhibit high activity without interference during the fast-drying stage. The addition of calcium nitrate in the treated additive solution accelerates the hydration-precipitation reaction chain of key mineral phases, significantly shortening the setting time. The cellulose and silk form a hydrophilic fiber network that locks water and solidifies the mortar during the plastic stage, supplemented by water reducing agents and other additives, allowing the entire mortar system to form good early strength in a short period of time, solving the problem of early damage to the repair area by pedestrians and non-motor vehicles.

[0113] During the use of the repair mortar, the cellulose in the additive solution forms a three-dimensional water retention network through molecular chain entanglement, providing a sustained water environment for the pozzolanic reaction of fly ash and bauxite, allowing them to slowly release active silicon and aluminum ions and continuously generate hydrated calcium silicate gel to fill micro-pores. The modified silk fibroin and silk hydrolysate form organic molecules that can form covalent bonds with the inorganic calcium salts generated by the reaction of calcium nitrate, forming a flexible transition layer at the interface of the hydration products, relieving stress concentration. At the same time, the latent activity of the slag in the base material is gradually activated with age, and the continuously generated hydration products together strengthen the overall structure, improving the density required for compressive strength and the toughness required for flexural strength, solving the problem of cracking caused by the imbalance between strength and toughness in the long-term use of traditional repair mortar.

[0114] Through comparison and analysis of the related data in the table, it can be known that the fast-drying cement-based repair mortar prepared by the application not only solves the problem that the repair area is easily damaged by pedestrians and non-motor vehicles in the early stage, but also solves the problem that the traditional repair mortar is easily cracked due to imbalance between strength and toughness in long-term use.

[0115] 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.

[0116] 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 described. Obviously, many modifications and variations can be made according to the content of the present specification. 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 quick-drying cement-based repair mortar, characterized in that, The raw materials include the following parts by weight: 45-55 parts base material, 25-35 parts aggregate, 5-10 parts additive liquid, 3-5 parts additive, 1-1.5 parts water-reducing agent, 0.5-1 part defoamer, and 0.5-1 part retarder; The raw materials for the base material include powder, steel slag, desulfurized gypsum, fly ash, and bauxite; The raw materials for the powder include phosphogypsum, S95 grade slag, and carbide slag; The preparation method of the base material includes the following steps: Step 1: Add steel slag, desulfurized gypsum, fly ash and bauxite to a ball mill, set the speed to 30-45 rpm and process for 45-60 minutes to obtain the first coarse material. After sieving, the first fine material with a particle size of 65-75 μm is obtained. Step 2: After premixing the first fine material and powder, add them to the calcining furnace, heat to 900-950℃ and hold for 60-80 minutes, then heat to 1250-1350℃ at a heating rate of 8-10℃ / min and hold for 25-35 minutes. The resulting material is then air-cooled to 20-30℃ to obtain the material to be processed. Step 3: The material to be processed is crushed and ground, then passed through a 75μm mesh screen to obtain the base material; The preparation method of the powder includes the following steps: adding phosphogypsum to a 1% ammonia solution, stirring at 50-80 rpm for 10-15 min, letting stand for 15-20 min, adding the obtained product to an oven, drying at 40-50℃ to constant weight, adding the obtained product to a mixer, adding S95 grade blast furnace slag and carbide slag, dry mixing at 80-100 rpm for 5-10 min to obtain a mixture, adding water to the mixer and continuing to stir for 5-10 min to obtain a wet mixture, transferring the wet mixture to an oven, drying at 35-45℃ to constant weight to obtain the powder; The preparation method of the additive solution includes the following steps: Step 1: Add cellulose, silk fibroin and water to a mixing tank, set the stirring speed to 80-120 rpm and process for 15-25 min. Transfer the obtained product to a vacuum drying oven and vacuum dry at 75-85℃ until constant weight to obtain the second coarse material. Step 2: Cut the mulberry silk into 1-3 mm pieces to obtain silk material, soak it in a 1-2% sodium carbonate solution, add the product to a water bath, heat it at 85-95℃ for 15-25 min, centrifuge and filter the product, wash it with deionized water until neutral, and obtain the second fine material. Step 3: Add the second coarse material and the second fine material to a calcium nitrate solution with a mass concentration of 10-12% at a mass ratio of 1:(1-2), and treat at 75-80℃ and 100-150rpm for 50-80 minutes to obtain the additive solution.

2. The quick-drying cement-based repair mortar according to claim 1, characterized in that, The mass ratio of the powder, steel slag, desulfurized gypsum, fly ash, and bauxite is (45-55): (9-12): (10-15): (10-18): (10-18), and the mass ratio of the phosphogypsum, S95 grade slag, and carbide slag is (28-32): (52-60): (10-15).

3. The quick-drying cement-based repair mortar according to claim 1, characterized in that, The aggregate is selected from calcium carbonate and dolomite, with a particle size of 0.1-0.5 mm. The water-reducing agent is selected from polycarboxylate-based water-reducing agents, naphthalene-based water-reducing agents, and melamine-based water-reducing agents.

4. The quick-drying cement-based repair mortar according to claim 1, characterized in that, The defoamer is selected from any one of silicone defoamers, polyether defoamers, and fatty acid ester defoamers, and the retarder is selected from any one of sodium citrate, sodium tartrate, and sodium gluconate.

5. The quick-drying cement-based repair mortar according to claim 1, characterized in that, The additive is selected from any one of ethylene-vinyl acetate copolymer emulsion, vinyl acetate-acrylate copolymer emulsion, and butadiene-styrene copolymer emulsion.

6. The quick-drying cement-based repair mortar according to claim 1, characterized in that, The mass ratio of phosphogypsum to ammonia solution is 1:(2-3), and the mass ratio of dry mixture to water is 1:(3-4).

7. The quick-drying cement-based repair mortar according to claim 1, characterized in that, The mass ratio of cellulose, silk fibroin, and water is (7-8):(2-4):(80-90), the mass ratio of silk material to sodium carbonate solution is 1:(85-90), and the total mass of the second coarse material and the second fine material is 30-45% of the mass of calcium nitrate solution.

8. A method for preparing a quick-drying cement-based repair mortar, characterized in that, The quick-drying cement-based repair mortar according to any one of claims 1 to 7 is used, comprising the following steps: S1: Add the base material, aggregate, additives, water-reducing agent, defoamer, and retarder to the twin-shaft mixer, set the speed to 80-100 rpm, and process for 15-20 minutes to obtain the billet; S2: Add the additive liquid to the spray dryer, set the inlet air temperature to 120-150℃ and the outlet air temperature to 80-90℃ and treat until the moisture content is ≤1%. Add the resulting product to the twin-shaft mixer of S1, adjust the speed to 120-150 rpm, and treat for 20-30 minutes to obtain the treated material. S3: After screening the processed material through a 100-150 mesh vibrating screen, seal and package it to obtain a quick-drying cement-based repair mortar.

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