Early-strength cement-based grouting material and preparation method thereof

Abstract

The invention belongs to the technical field of building materials, and provides an early-strength cement-based grouting material and a preparation method thereof.The early-strength cement-based grouting material is prepared from, by weight, 500-600 parts of sulphoaluminate cement, 200-300 parts of Portland cement, 40-100 parts of lithium slag, 1-3 parts of a coagulant, 0.5-1 part of an early strength agent, 5-8 parts of a water reducing agent, 0.5-2.5 parts of a thickening agent, 0.3-0.9 part of a defoaming agent and 260-310 parts of water; the coagulant is sodium metaaluminate and / or potassium metaaluminate; the early strength agent is selected from one or more than two of lithium carbonate, lithium sulfate, calcium formate, calcium acetate, calcium propionate, calcium butyrate and nano silicon dioxide. According to the technical scheme, the problems of poor dispersion resistance and low early strength of a cement-based grouting material in a flowing water environment in the prior art are solved.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology and relates to an early-strength cement-based grouting material and its preparation method. Background Technology

[0002] Grouting reinforcement technology is a key method in civil engineering for foundation treatment, crack sealing, structural reinforcement, and seepage prevention and water stoppage. Its core principle is to inject a cementing grout into the strata or structural cracks, which then solidifies to form a consolidated body, thereby achieving the purpose of reinforcement and water stoppage.

[0003] Currently, the grouting material commonly used in engineering is a two-liquid grout system composed of ordinary Portland cement as the main agent and water glass and other accelerators. This type of material has the advantages of wide availability, high strength and adjustable setting time, and performs well in conventional still water or low-permeability formations.

[0004] However, as projects such as tunnel and dam curtain grouting, and the treatment of water-rich fault fracture zones develop towards more complex geological conditions, the construction environment often faces severe challenges from water-rich, high-velocity flowing water conditions. In some areas, water pressure can be maintained at 1.5-2.0 MPa. Under such conditions, traditional cement-based grouting materials exhibit significant limitations: the grouting effect deteriorates, the grout is easily dispersed and diluted by water flow, leading to the loss of effective cementitious components and a significant reduction in grout retention and stone formation rates. Simultaneously, the early strength development of the grout solids is slow, making it difficult to quickly form an effective water-blocking body in flowing water environments. These defects seriously affect the reliability, durability, and ultimate water-stopping reinforcement effect of grouting projects. To address this, existing technologies introduce functional admixtures or improve components and processes in traditional cement-based materials to enhance anti-dispersion properties and control setting time; or composite organic polymer materials are used to block flowing water by utilizing their high permeability, rapid gelation, or expansion properties; for example, Chinese application CN 120923199 A discloses an anti-dispersion micro-expansion grouting material for flowing water environments and its preparation method. Component A of the grouting material is mainly composed of the following raw materials in parts by weight: 120-160 parts of volcanic ash gel material, 3-5 parts of retarder, 10-15 parts of magnesium oxide, 0.5-2 parts of citric acid, 5-8 parts of aluminum sulfate, 1-2 parts of sodium fluoride, 0.5-1 parts of gelatin, and 70-100 parts of water; Component B is mainly composed of the following raw materials in parts by weight: 4-8 parts of polyacrylamide, 5-10 parts of polyacrylic acid derivative salt, 1-2 parts of alcohol polysaccharide, 40-100 parts of water glass, and 30-50 parts of water; Magnesium oxide, aluminum sulfate, gelatin, and sodium fluoride in Component A are pre-prepared into core-shell anti-dispersibility particles. The core of this scheme is the prefabrication of core-shell anti-dispersion particles. The process is complicated and requires extremely high precision in the production process, which greatly increases the difficulty and cost of quality control in industrial production. Furthermore, a serious accident occurred due to the incorrect addition of citric acid, which caused the slurry to solidify prematurely and block the pipeline. This indicates that the method is fragile and has low fault tolerance. Most importantly, the performance of the underwater grouting material was not verified.

[0005] Therefore, developing a cement-based grouting material that combines excellent resistance to water flow dispersion with early strength has become an urgent need to solve engineering problems under complex hydrogeological conditions. Summary of the Invention

[0006] This invention proposes an early-strength cement-based grouting material and its preparation method, which solves the problems of poor anti-dispersion and low early strength of existing cement-based grouting materials in dynamic water environments.

[0007] The technical solution of this invention is implemented as follows:

[0008] A type of early-strength cement-based grouting material, characterized in that, by weight, it comprises: 500-600 parts of sulfoaluminate cement, 200-300 parts of silicate cement, 40-100 parts of lithium slag, 1-3 parts of accelerator, 0.5-1 part of early-strength agent, 5-8 parts of water-reducing agent, 0.5-2.5 parts of thickener, 0.3-0.9 parts of defoamer, and 260-310 parts of water; wherein the accelerator is sodium aluminate and / or potassium aluminate; and the early-strength agent is selected from one or more of lithium carbonate, lithium sulfate, calcium formate, calcium acetate, calcium propionate, calcium butyrate, and nano-silica.

[0009] Preferably, the thickener is 1.5 to 2.5 parts.

[0010] Preferably, the thickener is hydroxypropyl methylcellulose and / or bamboo oil thickener NC-1.

[0011] Preferably, the sulfoaluminate cement is a rapid-hardening sulfoaluminate cement with a strength grade of 42.5.

[0012] Preferably, the silicate cement is ordinary silicate cement with a strength grade of 42.5.

[0013] Preferably, the water-reducing agent is a polycarboxylate water-reducing agent.

[0014] Preferably, the defoamer is a silicone-based defoamer or a polyether-based defoamer.

[0015] Preferably, the coagulant is sodium aluminate.

[0016] Preferably, the early strength agent is lithium carbonate and calcium propionate in a mass ratio of 5:3-5.

[0017] Preferably, the early strength agent is lithium carbonate and calcium propionate in a mass ratio of 5:4.

[0018] Preferably, the nano-silica has a particle size of 10-20 nm and a specific surface area of ​​140-250 m² / g.

[0019] The present invention also provides a method for preparing the early-strength cement-based grouting material as described above, comprising the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and defoamer, then adding water and stirring to obtain the grouting material.

[0020] Preferably, the stirring step includes: first stirring at a speed of 140±5 r / min for 30-90 s, and then stirring at a speed of 285±10 r / min for 30-90 s.

[0021] The beneficial effects of the present invention using the above technical solution are as follows:

[0022] 1. This invention incorporates lithium slag, early strength agent, and accelerator into the grouting material, which greatly promotes the early strength development of the grouting material. The three work synergistically to accelerate the transformation of the grout from liquid to solid state, thereby indirectly improving the anti-dispersion and retention rate, shortening the grout setting time, and enabling the solidified body to obtain mechanical strength to resist water erosion more quickly.

[0023] 2. The accelerator in this invention can be used as both a cement accelerator and an alkali activator for lithium slag, effectively helping lithium slag and early strength agents to play their roles. The thickener used in the grouting material in this invention can effectively resist water erosion, ensuring that the early hydration reaction is efficient and complete, and working synergistically with the early strength system to achieve a high-strength early-stage stone body.

[0024] 3. The single-component cement-based grouting material prepared by this invention has a simple process, is easy to use, and effectively utilizes lithium slag, turning waste into treasure, which is more environmentally friendly and has both economic and environmental benefits. Detailed Implementation

[0025] 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.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. Unless otherwise specified, the experimental or testing methods involved in the embodiments of this invention are conventional methods in the prior art, and their names and / or abbreviations are conventional names in the art, clearly defined in their respective fields of application. Those skilled in the art can understand the conventional process steps based on these names and apply the corresponding equipment, implementing them under conventional conditions or conditions recommended by the manufacturer. The various instruments, equipment, raw materials, or reagents used in the embodiments of this invention are not subject to any special restrictions on their source; they are all conventional products that can be purchased through legitimate commercial channels and can be prepared according to conventional methods well known to those skilled in the art.

[0027] The lithium slag described in this invention conforms to the YB / T 4230 standard, referring to: the slag produced after lithium extraction from spodumene ore, which, after drying and grinding to a certain fineness, is a powder material mainly composed of amorphous silica and alumina, and the lithium slag meets the requirement of a specific surface area ≥ 400 m². 2 / kg, activity index ≥95% (28d), water requirement ≤115%, SO3 content ≤8%, density ≥2.4g / cm³ 3 ;

[0028] In the following examples and comparative examples, the polycarboxylate superplasticizer was purchased from Shanghai Sanrui Polymer Materials Co., Ltd. as SD-600P-E type;

[0029] The thickener was hydroxypropyl methylcellulose purchased from Hebei Yanxing Chemical Co., Ltd., specification HT-K100000S, with an apparent viscosity of 100000 mPa·s based on a 2% aqueous solution at 20℃. The thickener CHUPOL NC-1 was purchased from Nanjing Qinhai Trading Co., Ltd.

[0030] The silicone defoamer was purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-154; the polyether defoamer was purchased from Yantai Hengxin Chemical Technology Co., Ltd., model THIX-299.

[0031] The nano-silica has a particle size of 10-20 nm and a specific surface area of ​​140-250 m² / g;

[0032] The sulfoaluminate cement is a rapid-hardening sulfoaluminate cement with a strength grade of 42.5, purchased from Shanxi Yangquan Tianlong Engineering Materials Co., Ltd.; the silicate cement is an ordinary silicate cement with a strength grade of 42.5, purchased from Shijiazhuang Quzhai Cement Co., Ltd.

[0033] Example 1

[0034] An early-strength cement-based grouting material, by weight, comprises: 500 parts of sulfoaluminate cement, 300 parts of silicate cement, 40 parts of lithium slag, 3 parts of accelerator, 0.5 parts of early-strength agent, 8 parts of water-reducing agent, 1.5 parts of thickener, 0.9 parts of organosilicon defoamer, and 260 parts of water; wherein the accelerator is sodium aluminate; the early-strength agent is lithium sulfate; the water-reducing agent is polycarboxylate water-reducing agent; and the thickener is Zhuben oil thickener CHUPOL NC-1.

[0035] The preparation method of the above-mentioned early-strength cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 135 r / min for 90 s, and then stirring at a speed of 275 r / min for 90 s to obtain the grouting material.

[0036] Example 2

[0037] An early-strength cement-based grouting material, by weight, comprises: 600 parts of sulfoaluminate cement, 200 parts of silicate cement, 100 parts of lithium slag, 1 part of accelerator, 1 part of early-strength agent, 5 parts of water-reducing agent, 2.5 parts of thickener, 0.3 parts of organosilicon defoamer, and 310 parts of water; wherein the accelerator is potassium aluminate; the early-strength agent is calcium formate; the water-reducing agent is polycarboxylate superplasticizer; and the thickener is hydroxypropyl methylcellulose.

[0038] The preparation method of the above-mentioned early-strength cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 145 r / min for 30s, and then stirring at a speed of 295 r / min for 30s to obtain the grouting material.

[0039] Example 3

[0040] An early-strength cement-based grouting material, by weight, comprises: 570 parts of sulfoaluminate cement, 285 parts of silicate cement, 42 parts of lithium slag, 1.8 parts of accelerator, 0.9 parts of early-strength agent, 6.3 parts of water-reducing agent, 1.8 parts of thickener, 0.45 parts of organosilicon defoamer, and 270 parts of water; wherein the accelerator is sodium aluminate; the early-strength agent is lithium carbonate; the water-reducing agent is polycarboxylate superplasticizer; and the thickener is hydroxypropyl methylcellulose.

[0041] The preparation method of the above-mentioned early-strength cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0042] Example 4

[0043] An early-strength cement-based grouting material, by weight, comprises: 570 parts of sulfoaluminate cement, 285 parts of silicate cement, 42 parts of lithium slag, 1.8 parts of accelerator, 0.9 parts of early-strength agent, 6.3 parts of water-reducing agent, 1.8 parts of thickener, 0.45 parts of organosilicon defoamer, and 270 parts of water; wherein the accelerator is sodium aluminate; the early-strength agent is calcium propionate; the water-reducing agent is polycarboxylate superplasticizer; and the thickener is hydroxypropyl methylcellulose.

[0044] The preparation method of the above-mentioned early-strength cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0045] Example 5

[0046] An early-strength cement-based grouting material, by weight, comprises: 570 parts of sulfoaluminate cement, 285 parts of silicate cement, 42 parts of lithium slag, 1.8 parts of accelerator, 0.9 parts of early-strength agent, 6.3 parts of water-reducing agent, 1.8 parts of thickener, 0.45 parts of organosilicon defoamer, and 270 parts of water; wherein the accelerator is sodium aluminate; the early-strength agent is lithium carbonate and calcium propionate in a mass ratio of 5:4; the water-reducing agent is polycarboxylate superplasticizer; and the thickener is hydroxypropyl methylcellulose.

[0047] The preparation method of the above-mentioned early-strength cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0048] Example 6

[0049] An early-strength cement-based grouting material, by weight, comprises: 580 parts of sulfoaluminate cement, 290 parts of silicate cement, 60 parts of lithium slag, 1.8 parts of accelerator, 1.0 part of early-strength agent, 6.5 parts of water-reducing agent, 1.35 parts of thickener, 0.5 parts of organosilicon defoamer, and 280 parts of water; wherein the accelerator is sodium aluminate; the early-strength agent is calcium acetate and calcium butyrate in a 1:1 mass ratio; the water-reducing agent is a polycarboxylate water-reducing agent; and the thickener is Zhuben oil thickener CHUPOL NC-1.

[0050] The preparation method of the above-mentioned early-strength cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0051] Example 7

[0052] An early-strength cement-based grouting material, by weight, comprises: 590 parts of sulfoaluminate cement, 300 parts of silicate cement, 75 parts of lithium slag, 1.8 parts of accelerator, 0.9 parts of early-strength agent, 7.2 parts of water-reducing agent, 1.8 parts of thickener, 0.6 parts of organosilicon defoamer, and 290 parts of water; wherein the accelerator is potassium aluminate; the early-strength agent is lithium carbonate and nano-silica in a mass ratio of 2:1; the water-reducing agent is polycarboxylate water-reducing agent; and the thickener is hydroxypropyl methylcellulose.

[0053] The preparation method of the above-mentioned early-strength cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0054] Example 8

[0055] An early-strength cement-based grouting material, by weight, comprises: 540 parts of sulfoaluminate cement, 270 parts of silicate cement, 40 parts of lithium slag, 3 parts of accelerator, 0.5 parts of early-strength agent, 8 parts of water-reducing agent, 0.5 parts of thickener, 0.7 parts of polyether defoamer, and 260 parts of water; wherein the accelerator is sodium aluminate; the early-strength agent is lithium carbonate and calcium propionate in a mass ratio of 5:3; the water-reducing agent is a polycarboxylate water-reducing agent; and the thickener is Zhuben oil thickener CHUPOL NC-1.

[0056] The preparation method of the above-mentioned early-strength cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and polyether defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0057] Example 9

[0058] An early-strength cement-based grouting material, by weight, comprises: 550 parts sulfoaluminate cement, 250 parts silicate cement, 100 parts lithium slag, 1 part accelerator, 1 part early-strength agent, 5 parts water-reducing agent, 2.5 parts thickener, 0.5 parts polyether defoamer, and 310 parts water; wherein the accelerator is potassium aluminate; the early-strength agent is lithium carbonate and calcium propionate in a mass ratio of 5:5; the water-reducing agent is polycarboxylate water-reducing agent; and the thickener is Zhuben oil thickener CHUPOL NC-1.

[0059] The preparation method of the above-mentioned early-strength cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early-strength agent, water-reducing agent, thickener, and polyether defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0060] Comparative Example 1

[0061] Compared to Example 3, the only difference is that sodium aluminate was not added. Specifically:

[0062] A cement-based grouting material, by weight, comprises: 570 parts of sulfoaluminate cement, 285 parts of silicate cement, 42 parts of lithium slag, 0.9 parts of an early-strength agent, 6.3 parts of a water-reducing agent, 1.8 parts of a thickener, 0.45 parts of an organosilicon defoamer, and 270 parts of water; wherein the early-strength agent is lithium carbonate; the water-reducing agent is a polycarboxylate superplasticizer; and the thickener is hydroxypropyl methylcellulose.

[0063] The preparation method of the above-mentioned cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, early strength agent, water reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0064] Comparative Example 2

[0065] Compared to Example 5, the only difference is that hydroxypropyl methylcellulose is replaced with latex powder, specifically VAE redispersible latex powder, purchased from Hebei Aotai New Material Technology Co., Ltd., model JN-60. Details are as follows:

[0066] A cement-based grouting material, by weight, comprises: 570 parts of sulfoaluminate cement, 285 parts of silicate cement, 42 parts of lithium slag, 1.8 parts of accelerator, 0.9 parts of early-strength agent, 6.3 parts of water-reducing agent, 1.8 parts of thickener, 0.45 parts of organosilicon defoamer, and 270 parts of water; wherein the accelerator is sodium aluminate; the early-strength agent is lithium carbonate and calcium propionate in a mass ratio of 5:4; the water-reducing agent is a polycarboxylate water-reducing agent; and the thickener is latex powder.

[0067] The preparation method of the above-mentioned cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0068] Comparative Example 3

[0069] Compared to Example 5, the only difference is that hydroxypropyl methylcellulose is replaced with polyacrylamide from Sinopharm Chemical Reagent Co., Ltd. Specifically:

[0070] A cement-based grouting material, by weight, comprises: 570 parts of sulfoaluminate cement, 285 parts of silicate cement, 42 parts of lithium slag, 1.8 parts of accelerator, 0.9 parts of early-strength agent, 6.3 parts of water-reducing agent, 1.8 parts of thickener, 0.45 parts of organosilicon defoamer, and 270 parts of water; wherein the accelerator is sodium aluminate; the early-strength agent is lithium carbonate and calcium propionate in a mass ratio of 5:4; the water-reducing agent is polycarboxylate water-reducing agent; and the thickener is polyacrylamide.

[0071] The preparation method of the above-mentioned cement-based grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0072] Comparative Example 4

[0073] Compared to Example 5, the only difference is that hydroxypropyl methylcellulose was replaced with methyl hydroxyethyl cellulose, purchased from Hebei Guanxiang New Material Technology Co., Ltd., with a specification of 100,000 mPa·s. Details are as follows:

[0074] A cement-based grouting material, by weight, comprises: 570 parts of sulfoaluminate cement, 285 parts of silicate cement, 42 parts of lithium slag, 1.8 parts of accelerator, 0.9 parts of early-strength agent, 6.3 parts of water-reducing agent, 1.8 parts of thickener, 0.45 parts of organosilicon defoamer, and 270 parts of water; wherein the accelerator is sodium aluminate; the early-strength agent is lithium carbonate and calcium propionate in a mass ratio of 5:4; the water-reducing agent is a polycarboxylate water-reducing agent; and the thickener is methyl hydroxyethyl cellulose.

[0075] The preparation method of the above-mentioned grouting material includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early strength agent, water-reducing agent, thickener, and organosilicon defoamer, then adding water, first stirring at a speed of 140 r / min for 60 s, and then stirring at a speed of 285 r / min for 60 s to obtain the grouting material.

[0076] Test case

[0077] The material properties of each embodiment and comparative example were tested, and the test results are shown in Table 1.

[0078] To evaluate the performance of the aforementioned early-strength cement-based grouting material, the test consisted of two parts: First, its basic physical properties were determined according to national standards to ensure that the material met the basic requirements for grouting construction; second, specific performance tests for resistance to dynamic water were conducted to address the application challenges in dynamic water environments that this invention aims to solve, directly verifying its resistance to water flow dispersion and early underwater strength development. The specific methods are as follows:

[0079] 1. Basic performance testing

[0080] 1.1 Initial flowability was determined according to the method in GB / T 8077-2023. After mixing the grouting material with the standard water dosage, it was poured into a truncated cone mold, lifted vertically, and allowed to flow freely for 30 seconds. The diameters in two perpendicular directions were then measured. The average of the two measurements was taken.

[0081] 1.2 Setting time was determined according to the method in GB / T1346-2024 using a Vicat apparatus. The mixture was placed into a circular mold, and under standard curing conditions, the penetration resistance was tested at regular intervals using a test needle. Initial setting time: the time when the test needle is 4 mm ± 1 mm from the bottom plate. Final setting time: the time when the test needle penetrates the slurry to no more than 0.5 mm.

[0082] 1.3 The compressive strength under standard curing was determined according to the method of GB / T 17671-2021: 40mm×40mm×160mm specimens were molded and cured under standard conditions, i.e., temperature 20±1℃ and humidity ≥90%, for 2 hours at the specified age, and then tested using a compressive strength testing machine.

[0083] 2. Specific performance testing in dynamic water environments

[0084] 2.1 Dynamic water curing compressive strength test

[0085] After molding the 40mm×40mm×160mm specimen, immediately and smoothly transfer the entire mold into the water tank of the simulated dynamic water test device. Ensure the water flow direction is parallel to the long axis of the mold, adjust the water level to 1cm above the top surface of the mold, and control the flow velocity at 1.5m / s. After curing for the specified age of 2 hours, remove the specimen, wipe off any free water on the surface with a damp cloth, and immediately conduct a compressive strength test according to GB / T 17671-2021. Record the compressive strength after 2 hours of dynamic water curing.

[0086] 2.2 Anti-dispersion test in injected water

[0087] The same apparatus and flow rate conditions as in 2.1 were used. An empty 40mm×40mm×160mm mold was fixed in the water tank. The mixed slurry was continuously poured into the mold, with the water flow kept running throughout the pouring process. After pouring, flushing continued for the specified time of 2 hours.

[0088] Performance evaluation methods:

[0089] 2.2.1 Qualitative Observation

[0090] Record the slurry forming process and classify it according to the following standards:

[0091] No dispersion: The slurry surface is clear, the shape is complete, and the water is clear;

[0092] Slight dispersion: A small amount of flocculent material is present at the edge of the slurry, and the water is slightly turbid;

[0093] Severe dispersion: The slurry cannot be formed, resulting in large areas of turbidity or disintegration.

[0094] 2.2.2 Determination of slurry solids loss rate:

[0095] Preparation and testing of control group specimens:

[0096] The same batch of mixed slurry was poured into an identical 40mm×40mm×160mm mold. The mold was completely immersed in static water at 20±2℃ for 2 hours. After curing, the specimen was removed, the surface free water was gently wiped off with a damp cloth, and it was dried at 105±5℃ to constant weight. The solid mass was then measured. This mass is M, representing the solid mass formed by the slurry after 2 hours without being affected by dynamic water erosion.

[0097] Tests on test specimens:

[0098] According to Method 2.2 of this test standard, the slurry was injected into the mold in the moving water device and cured by flushing at a flow rate of 1.5 m / s for 2 hours. After curing, the molded body was removed from the mold, dried and weighed in the same way to obtain its solid mass m.

[0099] Calculation: Slurry solids retention rate = (m / M) × 100%;

[0100] Slurry solids loss rate = 100% - slurry solids retention rate.

[0101] Table 1. Performance test results of grouting materials in the examples and comparative examples.

[0102]

[0103] To further verify the applicability of the grouting material of the present invention under different flow velocities in dynamic water environments, the grout from Example 5 was selected. In the same apparatus, in addition to the 1.5 m / s flow velocity used in the basic test, tests were conducted on the anti-dispersion performance and grout solids loss rate in the injected water at flow velocities of 1.0 m / s and 3.0 m / s. The test methods were the same as described in section 2.2 above. The results show that the early-strength cement-based grouting material of the present invention not only performs excellently at a typical dynamic water flow velocity of 1.5 m / s, but also effectively maintains grout integrity and low loss rate within a flow velocity range of 1.0 m / s to 3.0 m / s, meeting the engineering application requirements under water-rich and high-flow-velocity geological conditions.

[0104] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-early-strength cement-based grouting material, characterized in that, The composition, by weight, includes: 500-600 parts of sulfoaluminate cement, 200-300 parts of silicate cement, 40-100 parts of lithium slag, 1-3 parts of accelerator, 0.5-1 part of early-strength agent, 5-8 parts of water-reducing agent, 0.5-2.5 parts of thickener, 0.3-0.9 parts of defoamer, and 260-310 parts of water; the accelerator is sodium aluminate and / or potassium aluminate; the early-strength agent is selected from one or more of lithium carbonate, lithium sulfate, calcium formate, calcium acetate, calcium propionate, calcium butyrate, and nano-silica.

2. The early-strength cement-based grouting material according to claim 1, characterized in that, The thickener is hydroxypropyl methylcellulose and / or bamboo oil thickener CHUPOL NC-1.

3. The early-strength cement-based grouting material according to claim 1, characterized in that, The sulfoaluminate cement is a rapid-hardening sulfoaluminate cement with a strength grade of 42.

5.

4. The early-strength cement-based grouting material according to claim 1, characterized in that, The silicate cement is ordinary silicate cement with a strength grade of 42.

5.

5. The early-strength cement-based grouting material according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent; the defoamer is an organosilicon defoamer or a polyether defoamer.

6. The early-strength cement-based grouting material according to claim 1, characterized in that, The coagulant is sodium aluminate.

7. The early-strength cement-based grouting material according to claim 1, characterized in that, The early strength agent is lithium carbonate and calcium propionate in a mass ratio of 5:3-5.

8. The early-strength cement-based grouting material according to claim 1, characterized in that, The nano-silica has a particle size of 10-20 nm and a specific surface area of ​​140-250 m² / g.

9. A method for preparing an early-strength cement-based grouting material as described in any one of claims 1-8, characterized in that, The process includes the following steps: mixing sulfoaluminate cement, silicate cement, lithium slag, accelerator, early strength agent, water-reducing agent, thickener, and defoamer, then adding water and stirring to obtain the final product.

10. The method for preparing an early-strength cement-based grouting material according to claim 9, characterized in that, The stirring steps include: first stirring at a speed of 140±5 r / min for 30-90 s, and then stirring at a speed of 285±10 r / min for 30-90 s.

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