Geopolymer for road grouting reinforcement and preparation method and application thereof

Abstract

The application discloses a geopolymer for road grouting and reinforcement, and a preparation method and application thereof. The geopolymer is prepared from slag, fly ash, metakaolin and an alkaline activator as raw materials, and is suitable for roadbed reinforcement. The fly ash is activated at high temperature in alkaline condition, and is mixed with a filler and a dispersing agent to obtain the geopolymer with high compressive strength, high temperature resistance, chemical corrosion resistance, excellent impermeability and low shrinkage, which is used for grouting and repairing damaged roads, reduces material consumption and is environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of geopolymers, specifically relating to a geopolymer for road grouting reinforcement, its preparation method, and its application. Background Technology

[0002] The rapid development of Chinese cities and the surge in the number of vehicles have made traffic congestion one of the most persistent problems plaguing urban construction and development. Once a road surface is damaged, it inevitably becomes impassable, exacerbating already congested traffic and severely impacting people's travel. Therefore, for current urban construction, effectively addressing road surface damage and quickly repairing road surfaces is of paramount importance.

[0003] Currently, cement grouting materials are commonly used for road grouting treatment, with advantages including mature technology and wide application. However, they also have drawbacks such as high water separation rate and long setting time. Many projects have begun to use geopolymer grouting materials to replace traditional cement. These geopolymer grouting materials are characterized by low energy consumption and high performance during production, and have broad application prospects. Actively applying geopolymer grouting technology in road maintenance projects can effectively repair damaged roads and further improve the comfort and safety of road surfaces.

[0004] Studies have shown that the modulus of the activator and the alkali-to-solid ratio can alter the compressive strength of the solidified soil within a certain range, and the compressive strength of the geopolymer-solidified soil samples all exhibit a trend of first increasing and then decreasing. The compressive strength of fly ash geopolymer-solidified soil is only slightly affected by the modulus of the alkali activator and the alkali-to-solid ratio; the compressive strength of fly ash geopolymer-solidified soil remains consistently low, making it difficult to meet the needs of practical engineering. The high-alumina fly ash used has a mineral composition consisting of crystalline minerals such as mullite and corundum, as well as amorphous aluminosilicate minerals. Its pozzolanic activity is poor, making it difficult to prepare geopolymers through depolymerization-condensation under low alkali or sulfate activation. This invention addresses these problems by using a mixed alkali for high-temperature activation.

[0005] The condensation reaction and free water evaporation of geopolymers cause shrinkage deformation in structural components, making them highly susceptible to cracking under constrained conditions. This limits the widespread application of geopolymers. Geopolymer cracking primarily occurs during the drying shrinkage stage. Therefore, slowing down the rate of water loss through evaporation in dry environments and improving the material's shrinkage resistance are crucial ways to address drying shrinkage cracking in concrete components. Studies have shown that silicon-containing substances can fill pores during the carbonation process of geopolymer-recycled concrete, effectively reducing the porosity of both harmful and rare pores.

[0006] When pouring large volumes of concrete, the exposed concrete surface often experiences significant temperature differences. If the temperature changes drastically, or if the concrete is exposed to cold air for an extended period, the surface temperature drops rapidly. This causes the concrete surface shrinkage to be constrained by internal forces, namely the tensile strength of the material itself. When this resistance cannot withstand the concrete shrinkage, cracks will form. Dispersion liquids can significantly improve the dispersion stability of solid particles in liquid media. Polymer dispersants increase the surface charge of particles by forming an adsorption layer on the particle surface, thereby enhancing the reaction force between particles and preventing particle aggregation and sedimentation. The focus of this invention is on how to formulate dispersion liquids to reduce uneven settlement and cracking problems in polymer concrete. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the specific preparation method and application of the present invention are as follows:

[0008] A method for preparing a geopolymer for road grouting reinforcement:

[0009] Add 18-25% mixed alkaline solution to fly ash, stir at 500 RPM for 20-30 min, place it in a muffle furnace, heat to 600-700℃ at 15℃ / min for 80-90 min to activate, cool to room temperature, and then grind to a specific surface area of ​​280-320 m². 2 / kg yields alkaline-thermal activated fly ash;

[0010] Mix alkali-heat activated fly ash, slag powder and metakaolin in a ratio of 5:3:2, add 2-5% silane and stir evenly, then add dispersion liquid at a material-to-liquid ratio of 6:4, stir slowly at 10-50 RPM for 1 minute, then stir rapidly at 100-200 RPM for 4 minutes to obtain high-performance geopolymer.

[0011] The mixed alkaline solution is a solution of tetra-n-butylammonium difluorotriphenylsilicate and sodium hydroxide mixed in a 1:3 ratio with a mass fraction of 8-20%.

[0012] The silane substance is benzyltriethoxysilane.

[0013] The dispersion is prepared by mixing 0.1-0.5 parts of cellulose ether, 2-5 parts of FDN-C type naphthalene water-reducing agent, 0.5-0.8 parts of polyethylene glycol and 600 parts of water, then adding 2-5 parts of surfactant and dispersing evenly. The mixture is stirred at 300 RPM, heated at 80℃ for 40-60 min, and then ultrasonically dispersed in an ultrasonic cleaner for 30 min, and then left at room temperature for 2-3 h.

[0014] The surfactant is sodium cocooxyethyl sulfonate.

[0015] A geopolymer for road grouting reinforcement, its preparation method, and its application, characterized in that its application includes:

[0016] (1) Divide the construction area according to the disease detection results and design. In the construction area, lay out the grouting drilling hole layout diagram on site, determine the drilling hole position and mark the position with self-spraying paint, and mark the drilling depth.

[0017] (2) Use a 20mm diameter drill bit to drill holes. Drill holes according to the hole layout. Keep the drill perpendicular to the road surface during drilling and avoid swaying left and right. After the drill rod reaches the designed depth, pull the drill rod up and down to remove the powder in the hole. Move to the next hole and repeat the step.

[0018] (3) After drilling is completed, check the hole depth. If the depth is not deep enough, deepen it again to reach the designed hole depth. During the drilling process, use a cleaning tool to clean the powder around the hole. Use a special container to hold the powder and dispose of it in a centralized manner after the construction is completed.

[0019] (4) The prepared geopolymer grouting material is injected with a grouting pressure of 0.6 MPa, a grouting hole spacing of 150 cm, a grouting volume of 70-120 kg / m2, and a grouting depth of 0.8-1.2 m;

[0020] (5) After grouting is completed, quickly seal the grouting hole with a plug, wash away the grout that has spilled onto the road surface, and clean the road surface.

[0021] (6) Grouting should be cured for 6 hours after completion before subsequent paving construction can begin.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. This invention discloses a method for preparing and applying a geopolymer for road grouting reinforcement. Using slag, fly ash, metakaolin, and alkaline activators as raw materials, this invention develops a geopolymer grouting material suitable for roadbed reinforcement. Through alkaline high-temperature activation of fly ash, combined with fillers and dispersants, a geopolymer with high compressive strength, high temperature resistance, chemical corrosion resistance, excellent impermeability, and low shrinkage is obtained for grouting repair of damaged roads, reducing material consumption and making the process environmentally friendly.

[0024] 2. Traditional road repair requires 14 steps, resulting in high overall costs, long repair times, and significant traffic disruption. In contrast, the grouting technology of this invention requires only 6 steps, saving costs and significantly shortening the construction cycle. Furthermore, grouting can address various road surface problems such as cracks, voids, and subsidence. By injecting geopolymer grouting material through drilling into cracked or semi-rigid pavement base layers, the technology reinforces the subgrade or base layer and allows for the reuse of industrial waste. Compared to open-cut repairs, grouting reinforcement technology offers advantages such as shorter construction cycles, reduced machinery and labor costs, less impact on traffic and the environment, and less public pressure and social impact. The geopolymer grout exhibits good fluidity, excellent water retention and volume stability under pressure, high early strength after setting, and no shrinkage or micro-expansion. Therefore, this invention uses tetra-n-butylammonium difluorotriphenylsilicate and sodium hydroxide as active activators to improve the reactivity of high-alumina fly ash through alkaline thermal activation. Under alkaline thermal activation conditions, the activator can effectively improve the reactivity of high-alumina fly ash, causing the mullite and corundum phases in the fly ash to basically disappear, and promoting the transformation of amorphous phases into sodium aluminosilicate and sodium silicate with higher crystallinity.

[0025] 3. The ionic groups in tetrabutylammonium difluorotriphenylsilicate reconstruct the layered bimetallic hydroxide main plate structure of fly ash with OH-. At the same time, the tetrabutylammonium ions and fluorine ions in tetrabutylammonium difluorotriphenylsilicate enter the interlayer and reconstruct with Na+ and Ca2+ in fly ash to form compounds with higher crystallinity. By providing a variety of abundant ionic groups, tetrabutylammonium difluorotriphenylsilicate promotes the formation of a large number of (N,C)-ASH and CSH in fly ash-slag geopolymer solidified soil, which fills the gaps between particles, resulting in good soil structure integrity, high compressive strength of solidified soil, and increased strength, compressive and flexural properties of geopolymer materials.

[0026] 4. This invention optimizes the formulation of geopolymers using benzyltriethoxysilane, improving the shrinkage and cracking phenomenon of geopolymer materials. Benzyltriethoxysilane helps form a protective film in the slurry, slowing down moisture evaporation and thus reducing the risk of drying shrinkage. The internal curing function of benzyltriethoxysilane compensates for moisture loss from the sample under dry conditions, reducing polymer setting time. Even in dry environments, it optimizes the internal water retention of the geopolymer material, minimizing the rate of water loss through evaporation, and significantly delaying the problem of drying shrinkage and cracking in geopolymer materials.

[0027] 5. Adding benzyltriethoxysilane as a filler enhances the formation of new calcium silicate and hydrated calcium aluminosilicate gels. The various gels formed intertwine and connect to form a gel structure. As the amount of gel generated gradually increases, the free water in the mixture is gradually converted into bound water, and the slurry gradually hardens. Therefore, the addition of benzyltriethoxysilane accelerates this reaction process, shortens the setting time of the geopolymer slurry, and ensures the construction quality.

[0028] 6. This invention selects sodium cocoyl oxyethyl sulfonate as a surfactant to enhance the water-reducing, flow-enhancing, and setting-reducing effects in the dispersion. By adding additives with retarding and water-reducing functions, the release of heat of hydration can be delayed, reducing heat generation and minimizing temperature cracking in concrete.

[0029] 7. Sodium cocoyl oxyethyl sulfonate molecules possess both hydrophilic and hydrophobic components. This amphiphilic structure allows it to reduce surface tension in dispersions, subsequently improving the flowability of geopolymers and thus achieving a flow enhancement effect. The hydroxyl and sulfonic acid groups in sodium cocoyl oxyethyl sulfonate can form more hydrogen bonds with components in the dispersion, thereby enhancing the adhesion of subsequent geopolymer materials. By adsorbing onto the surface of geopolymer particles, it reduces friction between particles, increasing both flowability and slurry viscosity. This effectively minimizes temperature variations in the geopolymer, reducing shrinkage and stress concentration caused by temperature differences, improving freeze-thaw resistance, and significantly reducing the possibility of cracking.

[0030] 8. Sodium cocoyl oxyethyl sulfonate effectively controls the distribution of moisture in the mixture, reducing evaporation and loss. This helps maintain the slurry's moisture level and prevents shrinkage caused by rapid drying. Silanes promote cross-linking reactions in the geopolymer, making the material's structure more stable. This stability reduces internal stress caused by uneven shrinkage during temperature changes. The synergistic effect of sodium cocoyl oxyethyl sulfonate molecules and benzyltriethoxysilane in the geopolymer effectively controls slurry temperature changes, reduces shrinkage stress caused by temperature differences, thereby improving freeze-thaw resistance and reducing the risk of cracking. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the embodiments.

[0032] The fly ash used in this invention is Class II fly ash, which meets the requirements of the national standard GB / T1596-2017 "Fly Ash for Cement and Concrete". The slag powder used in this paper is S95 grade granulated blast furnace slag powder produced by Tengyan Minerals in Lingshou County, Hebei Province, which meets the requirements of the national standard GB / T18046-2017 "Granulated Blast Furnace Slag Powder for Cement and Concrete". The metakaolin is produced by Shuangshi Mineral Products Processing Plant in Lingshou County, Hebei Province, and meets the requirements of the national standard GB / T18046-2017 "Granulated Blast Furnace Slag Powder for Cement and Concrete". Unless otherwise specified, all raw materials or chemical reagents were obtained through conventional commercial channels.

[0033] Example 1

[0034] Add 22% mixed alkaline solution to fly ash. The mixed alkaline solution is a 18% (w / w) solution of tetrabutylammonium difluorotriphenylsilicate and sodium hydroxide in a 1:3 ratio. Stir at 500 RPM for 25 min, then place it in a muffle furnace and heat to 650℃ at a rate of 15℃ / min for 80-90 min to activate it. After cooling to room temperature, grind it to a specific surface area of ​​300 m². 2 / kg yields alkaline-thermal activated fly ash;

[0035] Alkali-heat activated fly ash, slag powder, and metakaolin were mixed in a ratio of 5:3:2. 4% benzyltriethoxysilane was added and stirred until homogeneous. Then, 0.3 parts cellulose ether, 3.5 parts FDN-C type naphthalene water-reducing agent, 0.6 parts polyethylene glycol, and 600 parts water were mixed. Finally, 3.5 parts sodium cocoyl oxyethyl sulfonate were added and dispersed evenly. The mixture was stirred at 300 RPM for 80°C for 50 minutes. The mixture was then ultrasonically dispersed in an ultrasonic cleaner for 30 minutes and allowed to stand at room temperature for 2.5 hours to obtain a dispersion. The dispersion was then added at a material-to-liquid ratio of 6:4, and stirred slowly at 30 RPM for 1 minute, followed by rapid stirring at 150 RPM for 4 minutes to obtain the high-performance geopolymer.

[0036] Example 2

[0037] Add 18% mixed alkaline solution to fly ash. The mixed alkaline solution is a 20% (w / w) solution of tetra-n-butylammonium difluorotriphenylsilicate and sodium hydroxide in a 1:3 ratio. Stir at 500 RPM for 20 min, then place it in a muffle furnace and heat to 700℃ at a rate of 15℃ / min for 80 min to activate it. After cooling to room temperature, grind it to a specific surface area of ​​320 m². 2 / kg yields alkaline-thermal activated fly ash;

[0038] Alkali-heat activated fly ash, slag powder, and metakaolin were mixed in a ratio of 5:3:2. 2% benzyltriethoxysilane was added and stirred until homogeneous. Then, 0.5 parts cellulose ether, 2 parts FDN-C type naphthalene water-reducing agent, 0.8 parts polyethylene glycol, and 600 parts water were mixed. Finally, 2 parts sodium cocoyl oxyethyl sulfonate were added and dispersed evenly. The mixture was stirred at 300 RPM at 80℃ for 60 minutes. The mixture was then ultrasonically dispersed in an ultrasonic cleaner for 30 minutes and allowed to stand at room temperature for 2 hours to obtain a dispersion. The dispersion was then added at a material-to-liquid ratio of 6:4, and stirred slowly at 50 RPM for 1 minute, followed by rapid stirring at 100 RPM for 4 minutes to obtain the high-performance geopolymer.

[0039] Example 3

[0040] Add 25% mixed alkaline solution to fly ash. The mixed alkaline solution is a 1:3 mixture of tetrabutylammonium difluorotriphenylsilicate and sodium hydroxide at a mass fraction of 8%. Stir at 500 RPM for 30 min, then place it in a muffle furnace and heat to 600℃ at a rate of 15℃ / min for 90 min to activate it. After cooling to room temperature, grind it to a specific surface area of ​​280 m². 2 / kg yields alkaline-thermal activated fly ash;

[0041] Alkali-heat activated fly ash, slag powder, and metakaolin were mixed in a ratio of 5:3:2. 5% benzyltriethoxysilane was added and stirred until homogeneous. Then, 0.1 parts cellulose ether, 5 parts FDN-C type naphthalene water-reducing agent, 0.5 parts polyethylene glycol, and 600 parts water were mixed. Finally, 5 parts sodium cocoyl oxyethyl sulfonate were added and dispersed evenly. The mixture was heated at 80°C for 40 minutes at a speed of 300 RPM. The mixture was then ultrasonically dispersed in an ultrasonic cleaner for 30 minutes and allowed to stand at room temperature for 3 hours to obtain a dispersion. The dispersion was then added at a material-to-liquid ratio of 6:4, and stirred slowly at 10 RPM for 1 minute, followed by rapid stirring at 200 RPM for 4 minutes to obtain the high-performance geopolymer.

[0042] Comparative Example 1

[0043] In this comparative example, alkali activation was carried out at room temperature. The specific process is as follows: 22% mixed alkali solution was added to fly ash. The mixed alkali solution was a solution of tetrabutylammonium difluorotriphenyl silicate and sodium hydroxide mixed in a 1:3 ratio with a mass fraction of 18%. The mixture was first stirred slowly at 30 RPM for 2 min, and then stirred rapidly at 150 RPM for 2 min.

[0044] Alkali-activated fly ash slag powder and metakaolin were mixed in a ratio of 5:3:2. 4% benzyltriethoxysilane was added and stirred until homogeneous. Then, 0.3 parts cellulose ether, 3.5 parts FDN-C type naphthalene water-reducing agent, 0.6 parts polyethylene glycol, and 600 parts water were mixed. Finally, 3.5 parts sodium cocoyl oxyethyl sulfonate were added and dispersed evenly. The mixture was stirred at 300 RPM for 80℃ for 50 minutes. The mixture was then ultrasonically dispersed in an ultrasonic cleaner for 30 minutes and allowed to stand at room temperature for 2.5 hours to obtain a dispersion. The dispersion was then added at a material-to-liquid ratio of 6:4, and stirred slowly at 30 RPM for 1 minute, followed by rapid stirring at 150 RPM for 4 minutes to obtain the high-performance geopolymer.

[0045] Comparative Example 2

[0046] In this comparative example, tetrabutylammonium difluorotriphenylsilicate is water glass, and the rest is the same as in Example 1.

[0047] Comparative Example 3

[0048] In this comparative example, the amount of tetra-n-butylammonium difluorotriphenylsilicate used differs. Specifically, 22% of a mixed alkaline solution is added to the fly ash. This mixed alkaline solution is a 18% mass fraction solution of tetra-n-butylammonium difluorotriphenylsilicate and sodium hydroxide mixed in a 1:1 ratio. The mixture is stirred at 500 RPM for 25 min, then placed in a muffle furnace and heated to 650℃ at a rate of 15℃ / min for 80-90 min to activate it. After cooling to room temperature, it is ground to a specific surface area of ​​300 m². 2 / kg; the rest is the same as in Example 1.

[0049] Comparative Example 4

[0050] In this comparative example, the amount of tetra-n-butylammonium difluorotriphenylsilicate used differs. Specifically, 22% of a mixed alkaline solution is added to the fly ash. This mixed alkaline solution is a 18% mass fraction solution of tetra-n-butylammonium difluorotriphenylsilicate and sodium hydroxide mixed in a 1:5 ratio. The mixture is stirred at 500 RPM for 25 min, then placed in a muffle furnace and heated to 650℃ at a rate of 15℃ / min for 80-90 min to activate it. After cooling to room temperature, it is ground to a specific surface area of ​​300 m². 2 / kg; the rest is the same as in Example 1.

[0051] Comparative Example 5

[0052] In this comparative example, benzyltriethoxysilane was not added; otherwise, it was the same as in Example 1.

[0053] Comparative Example 6

[0054] In this comparative example, benzyltriethoxysilane is methylsilane, and the other implementation methods are the same as in Example 1.

[0055] Comparative Example 7

[0056] In this comparative example, the amount of benzyltriethoxysilane added was different. Specifically, alkali-heat activated fly ash, slag powder, and metakaolin were mixed in a ratio of 5:3:2. 8% benzyltriethoxysilane was added and stirred evenly. Then, 0.3 parts cellulose ether, 3.5 parts FDN-C type naphthalene water-reducing agent, 0.6 parts polyethylene glycol, and 600 parts water were mixed. Finally, 3.5 parts sodium cocoyl oxyethyl sulfonate were added and dispersed evenly. The stirring speed was 300 RPM, the heating temperature was 80℃, and the time was 50 min. The mixture was then ultrasonically dispersed in an ultrasonic cleaner for 30 min and left at room temperature for 2.5 h to obtain a dispersion. The dispersion was added at a material-to-liquid ratio of 6:4, and stirred slowly at 30 RPM for 1 min, followed by rapid stirring at 150 RPM for 4 min to obtain the high-performance geopolymer. The remaining implementation methods were the same as in Example 1.

[0057] Comparative Example 8

[0058] The amount of benzyltriethoxysilane added in this comparative example is different. Specifically, the alkaline-heat activated fly ash, slag powder and metakaolin are mixed in a ratio of 5:3:2. 1% benzyltriethoxysilane is added and stirred evenly. Then, 0.3 parts cellulose ether, 3.5 parts FDN-C type naphthalene water-reducing agent, 0.6 parts polyethylene glycol and 600 parts water are mixed. Then, 3.5 parts sodium cocoyl oxyethyl sulfonate are added and dispersed evenly. The stirring speed is 300 RPM, the heating temperature is 80℃ and the time is 50 min. Then, it is placed in an ultrasonic cleaner for ultrasonic dispersion for 30 min and then placed at room temperature for 2.5 h to obtain a dispersion. The dispersion is added at a material-to-liquid ratio of 6:4. It is first stirred slowly at 30 RPM for 1 min and then stirred rapidly at 150 RPM for 4 min to obtain the high-performance geopolymer. The rest of the implementation method is the same as in Example 1.

[0059] Comparative Example 9

[0060] Sodium cocoyl oxyethyl sulfonate was not added in this comparative example; the rest of the implementation methods are the same as in Example 1.

[0061] Comparative Example 10

[0062] In this comparative example, sodium cocoyl oxyethyl sulfonate is hexadecyltrimethylammonium bromide; the rest of the implementation methods are the same as in Example 1.

[0063] Comparative Example 11

[0064] The amount of sodium cocoyl oxyethyl sulfonate added in this comparative example is different. Specifically, the alkaline-heat activated fly ash, slag powder and metakaolin are mixed in a ratio of 5:3:2. 4% benzyltriethoxysilane is added and stirred evenly. Then, 0.3 parts cellulose ether, 3.5 parts FDN-C type naphthalene water-reducing agent, 0.6 parts polyethylene glycol and 600 parts water are mixed, and then 8 parts sodium cocoyl oxyethyl sulfonate are added and dispersed evenly. The stirring speed is 300 RPM, the heating temperature is 80℃ and the time is 50 min. Then, it is placed in an ultrasonic cleaner for ultrasonic dispersion for 30 min, and then placed at room temperature for 2.5 h to obtain a dispersion. The dispersion is added at a material-to-liquid ratio of 6:4. It is first stirred slowly at 30 RPM for 1 min, and then stirred rapidly at 150 RPM for 4 min to obtain the high-performance geopolymer. The rest is the same as in Example 1.

[0065] Comparative Example 12

[0066] The amount of sodium cocoyl oxyethyl sulfonate added in this comparative example is different. Specifically, the alkaline-heat activated fly ash, slag powder and metakaolin are mixed in a ratio of 5:3:2. 4% benzyltriethoxysilane is added and stirred evenly. Then, 0.3 parts cellulose ether, 3.5 parts FDN-C type naphthalene water-reducing agent, 0.6 parts polyethylene glycol and 600 parts water are mixed, and then 1 part sodium cocoyl oxyethyl sulfonate is added and dispersed evenly. The stirring speed is 300 RPM, the heating temperature is 80℃ and the time is 50 min. Then, it is placed in an ultrasonic cleaner for ultrasonic dispersion for 30 min, and then placed at room temperature for 2.5 h to obtain a dispersion. The dispersion is added at a material-to-liquid ratio of 6:4. It is first stirred slowly at 30 RPM for 1 min, and then stirred rapidly at 150 RPM for 4 min to obtain the high-performance geopolymer. The rest is the same as in Example 1.

[0067] Experiment 1:

[0068] The conductive ultra-high performance geopolymer was prepared into test blocks with dimensions of 40*40*160m. After being coated and cured in the laboratory for 24 hours, the blocks were demolded and standard cured for 28 days before their flexural strength and compressive strength were tested. The test results are shown in Table 1.

[0069] Table 1 Strength Measurement

[0070] Group Flexural strength (MPa) Flexural strength (MPa) Example 1 153.4 31.3 Example 2 152.5 30.8 Example 3 153.2 30.6 Comparative Example 1 142.8 20.3 Comparative Example 2 143.9 21.6 Comparative Example 3 150.7 28.5 Comparative Example 4 146.5 25.9 Comparative Example 5 151.3 27.8 Comparative Example 6 152.2 27.5 Comparative Example 7 151.6 28.2 Comparative Example 8 150.9 28.3 Comparative Example 9 147.2 28.0 Comparative Example 10 146.5 27.9 Comparative Example 11 150.4 28.5 Comparative Example 12 148.3 28.4

[0071] Experiment 2: Determination of Coagulation Properties, Viscosity, and Flowability

[0072] The initial setting time and final setting time of the high-performance geopolymers in Examples 1-3 and Comparative Examples 1-12 were tested.

[0073] Marsh funnel viscosity test:

[0074] The Marsh funnel viscometer, also known as a cone Marsh funnel, consists of a six-hole (16-mesh) sieve and a 1000mL measuring cup. The upper diameter of the cone is 152mm, the lower diameter of the cone and the diameter of the guide tube are 4.76mm, the length of the cone is 305mm, the total length of the funnel is 356mm, and the volume of the funnel below the sieve bottom is 1500mL.

[0075] Measurement Method: Before measuring viscosity, clean the flow cone with water. Stir the geopolymer slurry from Examples 1-3 and Comparative Examples 1-12 until homogeneous. Then, inject 1725 mL ± 5 mL of slurry (3 mm wall thickness) into the flow cone using a measuring cup. Seal the cone opening (13 mm inner diameter) with a rubber stopper to prevent slurry outflow. During measurement, place the measuring cup under the outlet, remove the rubber stopper, and start a stopwatch. After the slurry has completely flowed out, stop the stopwatch again and record the time it takes for the slurry to flow out. This is the viscosity of the slurry, expressed in seconds. Under specified conditions, the time required for a certain volume of slurry to flow out is defined as the viscosity of the grouting material, measured in seconds (s).

[0076] Flowability: Flowability was determined according to the relevant provisions of GB / T8077-2012 Test Method for Homogeneity of Concrete Admixtures. In Examples 1-3 and Comparative Examples 1-12, after the geopolymer slurry was prepared, it was poured into a truncated cone mold flowability tester (36mm top opening, 60mm bottom opening, and 60mm height) placed on a square glass plate (the surface of which had been moistened) with a diameter of L=600mm. The plate was then lifted vertically and timing began. After 30 seconds, the diffusion degree of the slurry was measured using a ruler. Each group of slurries was measured three times, and the average of the three measurements was taken as the flowability. The results are shown in Table 2.

[0077] Table 2 Results of Measurement

[0078] Group Initial setting time (min) Final setting time (min) Viscosity (s) Flowability (mm) Example 1 42 48 45 298 Example 2 45 52 43 295 Example 3 45 53 44 296 Comparative Example 1 54 66 38 287 Comparative Example 2 56 63 36 289 Comparative Example 3 52 62 40 290 Comparative Example 4 54 58 39 285 Comparative Example 5 72 86 32 242 Comparative Example 6 69 85 34 247 Comparative Example 7 56 68 39 292 Comparative Example 8 60 73 37 282 Comparative Example 9 71 85 33 255 Comparative Example 10 65 78 34 262 Comparative Example 11 54 64 40 291 Comparative Example 12 58 69 38 284

[0079] Experiment 3: Freeze-thaw resistance test

[0080] The polymers from Examples 1-3 and Comparative Examples 1-12 were injected into molds (70.7mm*70.7mm*70.7mm cubic molds), with 10 molds per group. After curing for 24 hours, the molds were removed, and the demolded samples were labeled and cured in a standard curing room for 28 days. Two days before the freeze-thaw test, the test blocks were removed from the curing room and placed in water at room temperature for two days of complete immersion. After removing them, the surface moisture was wiped dry with a brush, and the samples were weighed and subjected to a pressure test. The weighing data and compressive strength data were recorded. The freeze-thaw test specimens were then placed in a freeze-thaw machine for the freeze-thaw test. The freeze-thaw temperature range was set to -15℃ to 15℃, the number of freeze-thaw cycles was set to 100, and the thawing and freezing times were both 4 hours. After the number of freeze-thaw cycles was reached, the specimens were removed, weighed, and subjected to a pressure test. The mass loss rate was calculated. The results are shown in Table 3 below.

[0081] Mass loss rate after 100 freeze-thaw cycles = (average mass after 100 freeze-thaw cycles - average initial mass) / average initial mass

[0082] Table 3 Freeze-thaw resistance test

[0083] Sample group Initial average mass (g) Average mass (g) after 100 freeze-thaw cycles Weight loss rate (%) after 100 freeze-thaw cycles Example 1 692 685 1.01 Example 2 703 695 1.14 Example 3 701 692 1.28 Comparative Example 1 689 674 2.18 Comparative Example 2 692 675 2.46 Comparative Example 3 695 681 2.01 Comparative Example 4 700 685 2.14 Comparative Example 5 698 668 4.29 Comparative Example 6 695 674 3.02 Comparative Example 7 688 676 1.74 Comparative Example 8 689 672 2.47 Comparative Example 9 694 668 3.75 Comparative Example 10 695 670 3.60 Comparative Example 11 699 683 2.43 Comparative Example 12 703 682 2.99

Claims

1. A method for preparing a geopolymer for road grouting reinforcement, characterized in that: Add 18-25% mixed alkaline solution to fly ash, stir at 500 RPM for 20-30 min, place it in a muffle furnace, heat to 600-700℃ at 15℃ / min for 80-90 min to activate, cool to room temperature, and then grind to a specific surface area of ​​280-320 m². 2 / kg yields alkaline-thermal activated fly ash; Mix alkali-heat activated fly ash, slag powder and metakaolin in a ratio of 5:3:2, add 2-5% silane and stir evenly, then add dispersion liquid at a material-to-liquid ratio of 6:4, stir slowly at 10-50 RPM for 1 minute, then stir rapidly at 100-200 RPM for 4 minutes to obtain high-performance geopolymer. The mixed alkaline solution is a solution of tetra-n-butylammonium difluorotriphenylsilicate and sodium hydroxide mixed in a 1:3 ratio with a mass fraction of 8-20%. The silane substance is benzyltriethoxysilane; The dispersion is prepared by mixing 0.1-0.5 parts of cellulose ether, 2-5 parts of FDN-C type naphthalene water-reducing agent, 0.5-0.8 parts of polyethylene glycol and 600 parts of water, then adding 2-5 parts of surfactant and dispersing evenly. The mixing process is carried out at a speed of 300 RPM, a heating temperature of 80℃, and a time of 40-60 min. The mixture is then ultrasonically dispersed in an ultrasonic cleaner for 30 min and left at room temperature for 2-3 h. The surfactant is sodium cocooxyethyl sulfonate.

2. The application of a geopolymer for road grouting reinforcement obtained by the preparation method of claim 1, characterized in that, application include: (1) Divide the construction area according to the disease detection results and design. In the construction area, lay out the grouting hole layout diagram on site, determine the hole position and mark the position with self-spray paint, and mark the drilling depth. (2) Use a 20mm diameter drill bit to drill holes according to the hole layout. When drilling, keep the drill perpendicular to the road surface and avoid swaying left and right. After the drill rod reaches the designed depth, pull the drill rod up and down to remove the powder in the hole and move to the next hole position to repeat the step. (3) After drilling is completed, check the hole depth. If the depth is not deep enough, deepen it again to reach the designed hole depth. During the drilling process, use a cleaning tool to clean the powder around the hole. Use a special container to hold the powder and dispose of it in a centralized manner after the construction is completed. (4) The prepared geopolymer grouting material is injected with a grouting pressure of 0.6 MPa, a grouting hole spacing of 150 cm, a grouting volume of 70-120 kg / m2, and a grouting depth of 0.8-1.2 m; (5) After grouting is completed, quickly seal the grouting hole with a plug, wash away the grout that has spilled onto the road surface, and clean the road surface. (6) Grouting should be cured for 6 hours before subsequent paving can be carried out.