All-solid-waste-based geopolymer grouting material and preparation method thereof

Abstract

The invention relates to the technical field of solid waste resource utilization and geopolymer grouting material preparation, and discloses an all-solid-waste-based geopolymer grouting material and a preparation method thereof. The all-solid-waste-based geopolymer grouting material comprises the following components in parts by weight: 60-70 parts of slag, 20-30 parts of red mud, 10 parts of silica fume, 15.6-28 parts of an alkali activator, 0.8 part of a water reducing agent and 93.12-103.04 parts of water, wherein the total amount of the slag, the red mud and the silica fume is 100 parts. The all-solid-waste-based geopolymer grouting material provided by the invention has the characteristics of low price and easy acquisition of raw materials, simplicity and convenience in preparation, good working performance, high strength and the like. Solid waste resources are recycled, the use of cement is reduced, and good environment-friendly and economic benefits are achieved.

Description

Technical Field

[0001] This invention relates to the fields of solid waste resource utilization and geopolymer grouting material preparation technology, specifically to a solid waste-based geopolymer grouting material and its preparation method. Background Technology

[0002] Grouting is an important engineering measure in geotechnical engineering. It involves preparing a grout from raw materials in a specific ratio, then injecting the curable grout material into fissures in the strata, rocks, or sand using specialized equipment such as grouting pumps. This allows the grout to fill, diffuse, gel, or solidify, ultimately achieving seepage prevention, plugging, or ground reinforcement. With the increasing scale of underground engineering construction, hydrogeological conditions are becoming increasingly complex. In the construction of roadbeds, slopes, foundation pits, and tunnels, adverse geological conditions such as fractured rock masses and weak strata are frequently encountered, easily leading to engineering disasters such as foundation settlement, sudden water inrush, and sand inrush. If not addressed promptly, these can develop into more serious problems, endangering the safety of both underground and surface structures, and resulting in enormous repair difficulties and costs. Therefore, during the construction of underground engineering projects, it is necessary to select reasonable and effective measures to reinforce the strata, control surface deformation and groundwater level changes, and ensure the safety of the project.

[0003] Traditional grouting materials can be broadly categorized into cement-based grouting materials and chemical grouting materials. Cement-based grouting materials consume large amounts of cement, are costly, and their production process involves high energy consumption and pollution, significantly impacting the environment. While chemical grouting materials offer some advantages, their development faces challenges due to high costs, complex formulations, and shortcomings in environmental friendliness.

[0004] Geopolymer grouting materials are widely available, low in cost, simple in formulation, and pollution-free, and can reduce the environmental pressure caused by industrial waste dumping. Therefore, effectively utilizing industrial waste to replace cement in the preparation of green, high-performance new grouting materials is crucial. Existing research mostly uses red mud and silica fume as small amounts of admixtures in silicate cement or concrete binders. Research on the synergistic use of slag, red mud, and silica fume as novel materials to prepare geopolymer grouting materials is limited. The effects and mechanisms of the high alkalinity of red mud and the high silica content of silica fume on the performance of geopolymer materials are still unclear. This invention utilizes the synergistic reaction between industrial solid wastes such as slag, red mud, and silica fume, combined with the depolymerization and repolymerization effects of alkali activators, to further recombine and form a novel green and environmentally friendly polymer material that can be used for waterproofing, leak sealing, and foundation reinforcement.

[0005] Chinese patent document CN 110028256 B discloses a one-step polymer grouting material based on red mud and its preparation method. The method improves the strength of the grouting material through an alkali activator and enhances its workability through additives. However, this invention requires the uniform mixing of red mud, active aluminum-silicon source, and solid alkali activator, followed by high-temperature calcination and material crushing. The process is complex, quality is difficult to control, and the resulting material has low compressive strength. Summary of the Invention

[0006] To address the problems existing in the prior art, one objective of this invention is to provide a solid waste-based polymer grouting material. This grouting material is prepared using selected solid waste raw materials, ensuring that the grouting material meets strength requirements after solidification while reducing cement usage, lowering environmental pollution, and improving the comprehensive utilization rate of industrial solid waste. Furthermore, the material is readily available, inexpensive, and its preparation and application methods are simple. The solid waste-based polymer grouting material comprises, by weight, 60-70 parts slag, 20-30 parts red mud, 10 parts silica fume, 15.6-28 parts alkali activator, 0.8 parts water-reducing agent, and 93.12-103.04 parts water, wherein the total amount of slag, red mud, and silica fume is 100 parts.

[0007] Preferably, the apparent density of the slag is 3.10 g / cm³. 3 Specific surface area 430m² 2 / kg, the chemical composition and its mass percentage content are as follows: 27.04% SiO2, 14.39% Al2O3, 0.32% Fe2O3, 0.45% MnO, 44.62% CaO, 8.08% MgO, 0.44% K2O, 0.46% Na2O, 0.02% P2O5, 1.57% TiO2, 2.26% SO3, with the balance being impurities.

[0008] Preferably, the red mud is Bayer process red mud, with the following chemical composition and mass percentage content: 14.60% SiO2, 22.60% Al2O3, 44.70% Fe2O3, 0.09% MnO, 0.86% CaO, 0.13% MgO, 0.18% K2O, 10.10% Na2O, 0.22% P2O5, 5.37% TiO2, 0.68% SO3, and the balance being impurities.

[0009] Preferably, the specific surface area of ​​the silica fume is 19.1 m². 2 / g, the chemical composition and its mass percentage content are as follows: 95.86% SiO2, 0.54% Al2O3, 0.35% Fe2O3, 0.02% MnO, 0.58% CaO, 0.39% MgO, 1.30% K2O, 0.38% Na2O, 0.04% P2O5, 0.39% SO3, with the balance being impurities.

[0010] Preferably, the alkaline activator is sodium silicate.

[0011] Preferably, the water-reducing agent is a naphthalene-based high-efficiency water-reducing agent.

[0012] Naphthalene-based high-efficiency water-reducing agent is a non-air-entraining chemically synthesized high-efficiency water-reducing agent with naphthalene sulfonate formaldehyde condensate as the main component. It appears as a brownish-yellow powder or a brownish-brown viscous liquid.

[0013] Another object of the present invention is to provide a method for preparing a solid waste-based polymer grouting material, comprising the following steps: (1) Dissolve sodium silicate completely in water to obtain sodium silicate solution, and adjust the modulus of sodium silicate solution to 1.4~1.8 with NaOH.

[0014] (2) Mix the slag, red mud, silica fume and water-reducing agent thoroughly and evenly.

[0015] (3) Add the remaining water and the sodium silicate solution prepared in step (1), and stir evenly to obtain the solid waste base polymer grouting material.

[0016] The main products of slag-based grouting materials are C-(A)-SH gel and part of NASH gel. Their microstructure exhibits a uniform and dense structure, forming a continuous gel network, resulting in high compressive strength. Adding red mud improves the fluidity of the grout, significantly prolongs the setting time, and alleviates the flashing and low fluidity problems caused by slag, but it reduces compressive strength. Excessive red mud also affects the flexural strength of the material. The incorporation of silica fume increases the content of active silicon, promotes the formation of C-(A)-SH gel and NASH gel, and increases the Si / Al ratio of the system, which is beneficial for forming a denser, more polymerized geopolymer gel network structure. The denser microstructure is the reason for the improved strength of the grouting material. The addition of naphthalene-based water-reducing agents slightly increases the amount and crystallinity of the gel products.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) Studies have found that when the red mud content in slag-based grouting materials is too high, the compressive strength of the samples at all ages is significantly reduced. In this invention, slag is used as the main raw material to provide the main source of strength for grouting materials, red mud is used as an auxiliary material to adjust the working performance of grouting materials and provide an alkaline environment, and silica fume is used as an auxiliary material to adjust the performance and further improve the strength of the material. The advantages of each raw material are fully utilized. Compared with the geopolymer grouting materials prepared with red mud as the main raw material, the 3-day compressive strength and 28-day compressive strength are increased by about 3 times.

[0018] (2) For the slag base polymer grouting material described in this invention, compared with polycarboxylate superplasticizer, naphthalene superplasticizer has a more obvious effect on improving the fluidity of grout, has less impact on setting time, and can significantly improve the compressive strength of grouting material at all ages.

[0019] (3) The raw materials of this invention are industrial waste residues such as slag, red mud, and silica fume, which improves the utilization rate of industrial solid waste. The raw materials are inexpensive, the construction is simple and convenient, and both environmental protection and economic benefits are taken into account.

[0020] (4) Replacing cement with all-solid waste-based mixtures saves costs, reduces carbon emissions, and alleviates the pressure of solid waste accumulation and environmental pollution. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] Example 1 The grouting material prepared in this embodiment includes the following raw materials in parts by weight: 70 parts slag, 20 parts red mud, 10 parts silica fume, 15.6 parts alkali activator, 0.8 parts naphthalene-based high-efficiency water-reducing agent, and 93.12 parts water.

[0023] The specific preparation steps of the above-mentioned solid waste base polymer grouting material are as follows: (1) Dissolve sodium silicate in water to obtain sodium silicate solution. Use granular NaOH to adjust the modulus of sodium silicate solution to 1.6. Let it stand at room temperature for 24 hours before use.

[0024] (2) Put 70 parts of slag, 20 parts of red mud, 10 parts of silica fume and 0.8 parts of water-reducing agent into an NJ-160A cement paste mixer and stir for 3 minutes to make them fully mixed.

[0025] (3) Add the remaining water and the sodium silicate solution prepared in step (1), and stir for 5 minutes to obtain the solid waste base polymer grouting material.

[0026] The slurry prepared in this embodiment was used to test its fluidity and setting time. The slurry was poured into a triplet mold (40mm × 40mm × 160mm), cured for 24 hours, and then demolded. It was then cured under standard conditions (temperature 20±1℃, relative humidity ≥95%) for 3 days and 28 days respectively for strength testing. The slurry had a fluidity of 30.8 cm, an initial setting time of 136 min, a final setting time of 356 min, a 3-day compressive strength of 13.32 MPa, and a 28-day compressive strength of 22.91 MPa.

[0027] Example 2 The grouting material prepared in this embodiment includes the following raw materials in parts by weight: 60 parts slag, 30 parts red mud, 10 parts silica fume, 20.8 parts alkali activator, 0.8 parts naphthalene-based high-efficiency water-reducing agent, 97.28 parts water, and sodium silicate solution modulus of 1.6.

[0028] The preparation method and steps of the grouting material are the same as in Example 1. The grout prepared in this example is used to test the fluidity and setting time. The grout is poured into a triple mold of 40mm×40mm×160mm, cured for 24 hours, and then demolded. It is then cured under standard curing conditions (temperature 20±1℃, relative humidity ≥95%) for 3 days and 28 days respectively for strength testing. The fluidity of the grout is 31.3cm, the initial setting time is 88min, the final setting time is 285min, the 3-day compressive strength is 16.05MPa, and the 28-day compressive strength is 27.78MPa.

[0029] Example 3 The grouting material prepared in this embodiment includes the following raw materials in parts by weight: 60 parts slag, 30 parts red mud, 10 parts silica fume, 22.08 parts alkali activator, 0.8 parts water-reducing agent, 98.3 parts water, and sodium silicate solution modulus of 1.66.

[0030] The preparation method and steps of the grouting material are the same as in Example 1. The grout prepared in this example is used to test the fluidity and setting time. The grout is poured into a triple mold of 40mm×40mm×160mm, cured for 24 hours, and then demolded. It is then cured under standard conditions (temperature 20±1℃, relative humidity ≥95%) for 3 days and 28 days respectively for strength testing. The fluidity of the grout is 30.15cm, the initial setting time is 67min, the final setting time is 256min, the 3-day compressive strength is 16.27MPa, and the 28-day compressive strength is 26.11MPa.

[0031] Example 4 The grouting material prepared in this embodiment includes the following raw materials in parts by weight: 60 parts slag, 30 parts red mud, 10 parts silica fume, 28 parts alkali activator, 0.8 parts water-reducing agent, 103.04 parts water, and sodium silicate solution modulus of 1.8.

[0032] The preparation method and steps of the grouting material are the same as in Example 1. The grout prepared in this example is used to test the fluidity and setting time. The grout is poured into a triple mold of 40mm×40mm×160mm, cured for 24 hours, and then demolded. It is then cured under standard curing conditions (temperature 20±1℃, relative humidity ≥95%) for 3 days and 28 days respectively for strength testing. The fluidity of the grout is 30.9cm, the initial setting time is 31min, the final setting time is 91min, the 3-day compressive strength is 16.05MPa, and the 28-day compressive strength is 17.33MPa.

[0033] Comparative Example 1 In comparison, the difference between this comparative example and Example 1 is that the amount of red mud used is different from that in Example 1. The specific amounts of each substance are as follows: 50 parts of slag, 40 parts of red mud, 10 parts of silica fume, 15.6 parts of alkali activator, 0.8 parts of naphthalene-based high-efficiency water-reducing agent, and 93.12 parts of water.

[0034] The preparation method and steps of the grouting material are the same as in Example 1. The grout prepared in this example is used to test the fluidity and setting time. The grout is poured into a triple mold of 40mm×40mm×160mm, cured for 24 hours, and then demolded. It is then cured under standard curing conditions (temperature 20±1℃, relative humidity ≥95%) for 3 days and 28 days respectively for strength testing. The fluidity of the grout is 29.45cm, the initial setting time is 181min, the final setting time is 482min, the 3-day compressive strength is 4.75MPa, and the 28-day compressive strength is 6.03MPa.

[0035] Comparative Example 2 In comparison, this comparative example differs from Example 2 in that it uses a polycarboxylate superplasticizer, while the amounts of each substance are the same as in Example 2.

[0036] The preparation method and steps of the grouting material are the same as in Example 1. The grout prepared in this example is used to test its fluidity and setting time. The grout is poured into a triple mold of 40mm×40mm×160mm, cured for 24 hours, and then demolded. It is then cured under standard conditions (temperature 20±1℃, relative humidity ≥95%) for 3 days and 28 days respectively for strength testing. The fluidity of the grout is 30.4cm, the initial setting time is 116min, the final setting time is 334min, the 3-day compressive strength is 14.98MPa, and the 28-day compressive strength is 23.28MPa.

[0037] The above embodiments provide a detailed description of specific implementation schemes of the present invention. Within the scope of knowledge possessed by those skilled in the art, appropriate modifications can be made without departing from the present invention. Furthermore, the above embodiments are not intended to limit the scope of the present invention; any simple modifications or substitutions made to the present invention within the technical principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A polymer grouting material for all-solid waste bases, characterized in that: The solid waste-based polymer grouting material comprises, by weight, 60-70 parts slag, 20-30 parts red mud, 10 parts silica fume, 15.6-28 parts alkali activator, 0.8 parts water-reducing agent, and 93.12-103.04 parts water, of which the total amount of slag, red mud, and silica fume is 100 parts.

2. The all-solid waste base polymer grouting material according to claim 1, characterized in that: The alkaline activator is sodium silicate.

3. The all-solid waste base polymer grouting material according to claim 1, characterized in that: The water-reducing agent is a naphthalene-based high-efficiency water-reducing agent.

4. The preparation method of a solid waste-based polymer grouting material as described in claim 1, characterized in that: Includes the following steps: (1) Dissolve sodium silicate completely in water to obtain a sodium silicate solution, and adjust the modulus of the sodium silicate solution to 1.4~1.8 with NaOH; (2) Mix the slag, red mud, silica fume and water-reducing agent thoroughly and evenly; (3) Add the remaining water and the sodium silicate solution prepared in step (1), and stir evenly to obtain the solid waste base polymer grouting material.