High-performance environment-friendly geopolymer and preparation method thereof

Abstract

The invention relates to the field of building materials, provides a high-performance and environment-friendly geopolymer which comprises an aluminosilicate-based raw material extracted from industrial waste residues, an alkaline activator, an additive and water, and further provides a preparation method of the high-performance and environment-friendly geopolymer. The preparation method comprises the following steps: weighing the aluminosilicate-based raw material, the alkaline exciting agent, the additive and the water according to the proportion, mixing the aluminosilicate-based raw material, the alkaline exciting agent and the water, adding the additive, and mixing and stirring to form homogeneous slurry; the slurry is poured into a mold, curing is conducted in the environment with the temperature being 20-90 DEG C and the humidity being 60%-90%, the curing time is not shorter than 28 days, and the constant condition is kept in the first 7 days. The geopolymer disclosed by the invention is a novel geopolymer material with high strength, low shrinkage, good bending resistance and environmental friendliness, and the material has the characteristics of high performance, high weather resistance and environmental friendliness.

Description

Technical Field

[0001] The invention relates to the field of building materials, and in particular to a high-performance, environment-friendly geopolymer and a preparation method thereof. Background Art

[0002] The global annual emission of industrial solid waste is as high as billions of tons, which not only causes serious damage to the ecological environment, but also leads to the waste of precious resources. Effective use of these solid wastes for environmental governance has become an effective way to achieve its high added value recycling. Geopolymer, as a new type of green cementitious material, is composed of silicon-oxygen tetrahedrons and aluminum-oxygen tetrahedrons alternately connected by bridging oxygen to form a zeolite-like three-dimensional network structure. Due to its composition variability and potential for combination with other reinforcing materials, it shows great application prospects. Compared with traditional cement, the preparation of geopolymer can use industrial solid waste as raw material, eliminating the high energy consumption process of "two grindings and one burning", reducing energy consumption by about 60%, and reducing greenhouse gas emissions. According to research, each ton of geopolymer produced can reduce carbon dioxide emissions by up to 80%. At present, the research and application of geopolymers in the field of building materials have made significant progress.

[0003] As environmental awareness continues to increase, the public has higher and higher requirements for the environmental impact of building materials. However, traditional geopolymers may use environmentally harmful raw materials or produce harmful by-products during the preparation process, which runs counter to the current green environmental protection concept.

[0004] Geopolymer materials often face the problem of greater brittleness in practical applications, which limits their reliability as components that bear bending forces. Studies have shown that the compressive and flexural strength of traditional geopolymers synthesized using fly ash and kaolin as raw materials at room temperature is generally lower than that of traditional cement-based materials.

[0005] In addition, the high shrinkage rate of geopolymers leads to cracks easily during the hardening process, which has always been a difficult problem that needs to be solved urgently in the engineering field. The control of shrinkage rate is considered to be a key factor in increasing the application range of geopolymers.

[0006] In view of the above challenges, there is an urgent need to develop a new type of geopolymer material that is not only environmentally friendly, high-strength, low-shrinkage, but also has good flexural resistance. This material will combine high performance, high weather resistance and green environmental protection to meet the needs of the modern construction industry for sustainable building materials and is expected to be widely used in multiple engineering fields. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a high-performance, environmentally friendly geopolymer and a preparation method thereof. The geopolymer material has significantly improved fluidity, stable initial fluidity, excellent flexural strength, and a 28-day flexural strength of more than 5MPa. It also has a lower shrinkage rate, and a 28-day shrinkage rate is less than 0.02%. The 1-day, 3-day, and 28-day compressive strengths are more than 20MPa, 30MPa, and 50MPa, respectively. The structural safety of building materials is significantly improved, and the risk of cracks caused by shrinkage is greatly reduced. The geopolymer material can replace cement materials. Using industrial waste slag as the main raw material not only reduces environmental pollution, but also converts waste into treasure, and has a significant environmental protection effect.

[0008] The object of the present invention is to provide a high-performance, environmentally friendly geopolymer, which comprises an aluminosilicate-based raw material extracted from industrial waste, an alkaline activator, an additive and water.

[0009] The aluminosilicate-based raw material consists of the following components in weight percentage,

[0010]

[0011] The alkaline activator is composed of a mixed solution of industrial grade NaOH and Na2SiO3, the dry matter weight ratio of NaOH to Na2SiO3 is 1:0.3-3, the dry matter amount of NaOH is 5-30% of the weight of the aluminosilicate-based raw material, and the dry matter amount of Na2SiO3 is 5-30% of the weight of the aluminosilicate-based raw material;

[0012] The additives include fiber reinforcement materials, high molecular polymers, water reducing agents, and bio-based materials. The amount of fiber reinforcement materials is 0.01-1% of the weight of the aluminosilicate-based raw materials, the amount of high molecular polymers is 0-3% of the weight of the aluminosilicate-based raw materials, the amount of water reducing agents is 0-5% of the weight of the aluminosilicate-based raw materials, and the amount of bio-based materials is 0-10% of the weight of the aluminosilicate-based raw materials.

[0013] The amount of water used is 20-30% by weight of the aluminosilicate-based raw material.

[0014] Furthermore, in the above-mentioned geopolymer, the fiber reinforcement material includes at least one of polypropylene fiber and carbon fiber, the polymer includes at least one of polyester and polyether polymers, the water reducer includes at least one of polycarboxylic acid water reducer and naphthalene water reducer; and the bio-based material includes at least one of rice husk ash, cassava flour and coffee grounds.

[0015] Furthermore, in the above-mentioned geopolymer, the additives also include stone powder, nano-SiO2, and high-activity kaolin. The amount of the above-mentioned stone powder is 0-5% of the weight of the aluminosilicate-based raw material, the amount of the above-mentioned nano-SiO2 is 0-5% of the weight of the aluminosilicate-based raw material, and the amount of the above-mentioned high-activity kaolin is 0-5% of the weight of the aluminosilicate-based raw material.

[0016] The high-activity metakaolin and nano-SiO2 used in the present invention enhance the microstructure and mechanical properties of the geopolymer; according to the characteristics of different waste residues, stone powder and silica fume are added as micro-fillers to improve the fluidity and compactness of the slurry; the fiber-reinforced material can improve the crack resistance and toughness of the geopolymer; the polycarboxylic acid water-reducing agent or the naphthalene-based water-reducing agent adsorbs on the surface of the geopolymer particles to reduce the aggregation between the particles, improve the fluidity of the material, slow down the rate of the hydration reaction of the geopolymer, and extend the operable time of the geopolymer particles. In some cases, the polycarboxylic acid water-reducing agent can also introduce tiny bubbles to further increase the fluidity of the material and improve the strength. By reducing the amount of cementitious materials and improving the compactness, the water-reducing agent can improve the early and final strength of the geopolymer material, and at the same time improve the durability, reduce the porosity and improve the compactness, which is helpful to improve the impermeability, frost resistance and chemical corrosion resistance of the geopolymer material.

[0017] The geopolymer of the present invention has high early strength, can quickly reach service strength within a short curing time, shortens the construction period, reduces construction costs, and has a one-day compressive strength of more than 20 MPa, a three-day compressive strength of more than 30 MPa, and a 28-day compressive strength of more than 50 MPa; has a low shrinkage rate, which greatly reduces the internal stress generated during the hardening process, effectively preventing the generation of cracks, and a 28-day shrinkage rate of less than 0.02%; has excellent flexural strength, and a 28-day flexural strength of more than 5 MPa, and can replace cement materials as a material for reliable components that withstand bending forces.

[0018] Furthermore, in the above-mentioned geopolymer, the fly ash is high-calcium fly ash, the weight ratio of the above-mentioned high-calcium fly ash to slag is 1:1, and industrial brine is added to the above-mentioned alkaline activator, and the above-mentioned industrial brine is a sodium chloride aqueous solution with a concentration of 3wt% to 5wt%, and its amount is 1% to 5% of the total weight of the dry matter of the aluminosilicate-based raw material and the alkaline activator.

[0019] The ratio of high calcium fly ash to slag in the raw material mixture is 1:1 to achieve the best reactivity. Industrial salt water is added to the activator to promote the reaction between the raw materials and the growth of the polymer chain.

[0020] According to the aluminum-silicon ratio of the above-mentioned aluminosilicate-based raw materials, the dosage of Na2SiO3 and NaOH is adjusted. When the aluminum-silicon ratio of the aluminosilicate-based raw materials decreases, the dosage of Na2SiO3 is increased. When the aluminum-silicon ratio of the aluminosilicate-based raw materials increases, the dosage of NaOH is increased.

[0021] Fly ash has a lower aluminum-silicon ratio, and smelting slag has a higher aluminum-silicon ratio. When increasing the amount of fly ash, adjust the amount of Na2SiO3 added according to the aluminum-silicon ratio to ensure a suitable network structure. When increasing the amount of slag, increase the amount of NaOH to promote the dissolution and polymerization reaction of silicon and aluminum.

[0022] The present invention also aims to provide a method for preparing a high-performance, environmentally friendly geopolymer, comprising the following steps:

[0023] (1) weighing an aluminosilicate-based raw material, an alkaline activator, an additive, and water according to a ratio, mixing the aluminosilicate-based raw material, the alkaline activator, and the water, adding the additive, and mixing and stirring to form a homogeneous slurry;

[0024] (2) Pour the slurry into a mold and cure it in an environment with a temperature of 20-90° C. and a humidity of 60%-90% for no less than 28 days, and keep constant conditions in the first 7 days. Specifically, the constant condition curing temperature is controlled at 25-75° C. and the humidity is controlled at 70%-85%.

[0025] Furthermore, in the above preparation method, the mixing method in step (1) is low-frequency oscillation mixing, and the oscillation frequency is 10-50 Hz. The low-frequency oscillation mixing technology is used to promote the uniform distribution of the additive and the base material.

[0026] The curing time is extended to 50-60 days, specifically 56 days. Microwave drying is performed from the 28th day to the 32nd day, the microwave power is 100-1000W, and the microwave drying time is 1-4 hours.

[0027] By adopting the above preparation method, a geopolymer with extremely high compressive strength and durability can be obtained, ensuring that the performance of the geopolymer is optimal.

[0028] Compared with the prior art, the geopolymer of the present invention has the following advantages:

[0029] (1) The geopolymer of the present invention has high early strength and can quickly reach service strength within a short curing time, thus shortening the construction period, greatly reducing the production and construction costs, and improving production efficiency. The compressive strength reaches more than 30 MPa in 3 days and more than 50 MPa in 28 days;

[0030] (2) It has a low shrinkage rate. The low shrinkage rate greatly reduces the internal stress generated during the hardening process, effectively preventing the generation of cracks. The shrinkage rate after 28 days is less than 0.02%;

[0031] (3) Excellent flexural strength, with a 28-day flexural strength exceeding 5MPa;

[0032] (4) Anti-sulfate corrosion, able to resist corrosion by 3% sodium sulfate solution;

[0033] (5) Waste can be recycled and reused. By using industrial waste as raw materials, the environmental impact of building materials production is reduced, which meets the requirements of green buildings and reduces environmental impact;

[0034] (6) The geopolymer of the present invention is suitable for various engineering fields such as construction, roads, bridges, etc., and can still maintain high performance requirements under extreme environments such as high temperature, high humidity, chemical erosion, etc.

[0035] In summary, the geopolymer exhibits high early strength, low shrinkage, excellent flexural strength, resistance to sulfate erosion, and recyclability of waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The 28-day XRD pattern and semi-quantitative analysis diagram of the geopolymer prepared in Example 1;

[0037] Figure 2 This is the SEM analysis picture of the geopolymer prepared in Example 3 after 7 days. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The raw materials in the following examples are all commercially available products.

[0040] Example 1

[0041] This example describes a method for preparing a high-performance, environmentally friendly geopolymer, and the specific steps are as follows:

[0042] First, aluminosilicates are extracted from industrial waste as basic raw materials. Fly ash and slag are used as aluminosilicate sources, and the appropriate particle size distribution is screened by physical methods. Specifically, a 100-200 mesh sieve is used for screening to ensure the fineness and activity of the raw materials.

[0043] The aluminosilicate-based raw material of this embodiment is composed of 70% by weight of fly ash, 15% by weight of slag, 10% by weight of highly active ultrafine metakaolin, and 5% by weight of silica fume.

[0044] In order to improve the initial and final solidification strength of the geopolymer, an alkaline activator is selected. A weight ratio of 3-20 g is added for every 100 g of the aluminosilicate-based raw material. The activator used in this embodiment is a mixed solution of industrial-grade NaOH and Na2SiO3, and the mixing ratio of NaOH and Na2SiO3 dry matter weight is about 1:1, and the dry matter weight of NaOH and Na2SiO3 is 12% of the total weight of the aluminosilicate-based raw material.

[0045] The fiber reinforcement material of this embodiment is polypropylene fiber, and the amount of polypropylene fiber used is 0.2% of the total weight of the aluminosilicate-based raw material.

[0046] The high molecular polymer used in this embodiment is a polyester high molecular polymer, and its usage is 0.3% of the total weight of the aluminosilicate-based raw material.

[0047] In this embodiment, a polycarboxylate water reducer is also added, and the amount used is 1.5% of the total weight of the aluminosilicate-based raw material.

[0048] The aluminosilicate-based raw material, activator and water are uniformly mixed in the above proportions, with the amount of water being 27% of the weight of the aluminosilicate-based raw material. Subsequently, additives are introduced into the mixed system in the above proportions, and then fully stirred in a high-speed mixer to form a homogeneous material slurry.

[0049] Finally, the mixed slurry is poured into the pre-prepared mold for preliminary curing. Generally, demoulding can be carried out after 24 hours, followed by standard curing to obtain the final geopolymer product.

[0050] By optimizing the curing conditions and cycles, the performance of the geopolymer is ensured to be optimal. Generally speaking, the curing conditions include temperature control at 20-60°C, humidity control at 60%-80%, and curing time of not less than 28 days. The 28-day XRD spectrum and semi-quantitative analysis of the geopolymer prepared in this example are shown in Figure 1. Figure 1As shown in Figure 2, two main mineral phases were identified by X-ray diffraction (XRD) analysis of geopolymer samples: quartz (SiO2) and mullite (3Al2O3·2SiO2). The XRD spectrum shows that mullite is significantly present at a relative content of about 72.77%, while quartz appears at a relative content of about 27.23%. The characteristic diffraction peaks of mullite are sharp and intense, indicating its high crystallinity, while the diffraction peaks of quartz are relatively weak, reflecting the dominance of the mullite phase in the geopolymer. The high content of mullite suggests that the geopolymer material may have excellent mechanical properties and chemical corrosion resistance, which is because mullite, as a mineral phase with good thermal and chemical stability, is usually associated with these properties. At the same time, the presence of quartz may contribute to the wear resistance of the material.

[0051] Example 2

[0052] Based on Example 1, this example further illustrates in detail the influence of different raw material sources on the performance of geopolymers.

[0053] In this embodiment, two industrial waste residues from different sources are selected, one is fly ash and the other is smelting slag. The aluminum-silicon ratio of the two industrial waste residues is tested respectively, and the addition amount of the activator and the additive is adjusted according to the different aluminum-silicon ratios.

[0054] The fly ash used in this embodiment has a lower aluminum-silicon ratio, and the smelting slag has a higher aluminum-silicon ratio, which is adjusted according to the aluminum-silicon ratio and chemical composition.

[0055] The aluminosilicate-based raw material of this embodiment is composed of 60% by weight of fly ash, 25% by weight of slag, 10% by weight of high-activity ultrafine kaolin, 3% by weight of silica fume and 2% by weight of stone powder.

[0056] Taking into account the characteristics of different waste residues, stone powder and silica fume are added as micro-fillers to improve the fluidity and compactness of the slurry.

[0057] The activator used in this embodiment is a mixed solution of industrial-grade NaOH and Na2SiO3, the dry matter weight of NaOH is 15% of the total weight of the aluminosilicate-based raw materials, and the dry matter weight of Na2SiO3 is 10% of the total weight of the aluminosilicate-based raw materials.

[0058] When fly ash is used as raw material, the aluminum-silicon ratio is usually low, and a certain amount of Na2SiO3 needs to be added to improve the network structure of the geopolymer. In contrast, when smelting slag is used, the aluminum-silicon ratio is high, and the amount of NaOH in the activator will be increased to provide sufficient alkalinity to promote the dissolution and polymerization of silicon and aluminum.

[0059] In the preparation of geopolymer materials, the aluminum-silicon ratio (Al / Si ratio) of aluminosilicate-based raw materials is a key factor, which affects the network structure and final properties of the material. The adjustment of the Al / Si ratio is usually achieved by changing the amount of Na2SiO3 (water glass) and NaOH (sodium hydroxide).

[0060] Principles for adjusting dosage: When the aluminum-silicon ratio of aluminosilicate-based raw materials decreases, it means that the silicon content is relatively high. At this time, it is necessary to increase the dosage of Na2SiO3 to supplement the silicon deficiency in order to maintain or enhance the network structure of the geopolymer. When the aluminum-silicon ratio of aluminosilicate-based raw materials increases, the aluminum content is relatively high. At this time, it is necessary to increase the dosage of NaOH to increase the pH value of the solution and promote the dissolution and polymerization reaction of aluminosilicate.

[0061] Methods for adjusting dosage: The dosage adjustment is usually based on a predetermined stoichiometric ratio and experimental optimization. First, the aluminum-silicon ratio is determined based on the chemical analysis results of the raw materials. Then, the required amount of Na2SiO3 and NaOH is calculated based on the stoichiometric relationship between the aluminum-silicon ratio and the geopolymer formation reaction. This usually involves a series of laboratory-scale tests to determine the optimal dosage ratio.

[0062] The relationship between the aluminum-silicon ratio and the dosage: The relationship between the aluminum-silicon ratio and the dosage is not linear, but is determined by the chemical kinetics and thermodynamic characteristics of the geopolymer formation reaction. Usually, this needs to be optimized through experiments. For example, if a geopolymer formula requires an aluminum-silicon ratio of 1:3, and the aluminum-silicon ratio of the raw material is 1:4, then the dosage of Na2SiO3 may need to be increased to adjust to the required ratio.

[0063] Experimental optimization: In the experiment, the optimal dosage can be determined by changing the dosage of Na2SiO3 and NaOH and observing the performance indicators such as setting time, strength development, shrinkage rate, etc. of the geopolymer. Response surface methodology (RSM) or other statistical methods can be used to design experiments and optimize the formulation.

[0064] Technical implementation: A person skilled in the art can determine the specific dosage adjustment scheme through laboratory-scale tests based on the chemical analysis results of the raw materials and the performance requirements of the geopolymer. It is necessary to consider not only the aluminum-silicon ratio, but also the activity of the raw materials, reaction conditions (such as temperature, time), and the required geopolymer properties.

[0065] The fiber reinforcement material of this embodiment uses carbon fiber, and its usage is 0.3% of the total weight of the aluminosilicate-based raw material. The high molecular polymer used is a polyether high molecular polymer, and its usage is 0.4% of the total weight of the aluminosilicate-based raw material.

[0066] The amount of water used is 30% by weight of the aluminosilicate-based raw material.

[0067] A geopolymer product was prepared according to the preparation method described in Example 1.

[0068] During the preparation process, the viscosity and fluidity of the slurry, as well as the early strength development, are monitored in real time to ensure the quality stability and performance consistency of the geopolymer.

[0069] Example 3

[0070] This embodiment uses a mixture of high-calcium fly ash and slag as raw materials, with a weight ratio of 1:1. This raw material mixture can provide higher reaction activity and better polymer formation conditions.

[0071] The aluminosilicate-based raw material of this embodiment is composed of 50% by weight of high-calcium fly ash and 50% by weight of slag.

[0072] The activator used in this embodiment is a mixed solution of industrial-grade NaOH and Na2SiO3, the dry matter weight of NaOH is 10% of the total weight of the aluminosilicate-based raw materials, and the dry matter weight of Na2SiO3 is 8% of the total weight of the aluminosilicate-based raw materials.

[0073] Add an appropriate amount of industrial brine to the activator to promote the reaction between the raw materials and the growth of the polymer chain. The industrial brine is a sodium chloride (NaCl) aqueous solution with a concentration of 3wt% to 5wt% (weight ratio), and the amount is 1% to 5% (weight ratio) of the total mixture (aluminosilicate-based raw materials + alkaline activator dry matter).

[0074] This embodiment introduces nano SiO2 and high-activity metakaolin as additives, which not only enhance the microstructure of the geopolymer but also improve its mechanical properties and durability through their microscopic filling effect in the material. The amount of nano SiO2 is 0.5% of the weight of the aluminosilicate-based raw material, and the amount of high-activity metakaolin is 1% of the weight of the aluminosilicate-based raw material.

[0075] This embodiment also introduces bio-based material rice husk ash as an additive, which can improve the microstructure of the geopolymer material, reduce shrinkage, improve mechanical properties, and increase the environmental friendliness of the material. The dosage is 3% of the weight of the above-mentioned aluminosilicate-based raw material.

[0076] The fiber reinforcement material of this embodiment adopts polypropylene fiber, and its usage is 0.5% of the weight of the aluminosilicate-based raw material. This embodiment also adds polycarboxylic acid water-reducing agent, and its usage is 0.5-1% of the weight of the aluminosilicate-based raw material.

[0077] The amount of water used was 29% by weight of the aluminosilicate-based raw material.

[0078] Mixing is done using a low-frequency oscillation method to promote uniform distribution of additives and base materials, and compaction is done by mould vibration to ensure that the geopolymer is dense and free of pores.

[0079] Finally, according to the optimized curing process, the curing time was extended to 56 days, and microwave drying was performed on the 29th day, with a microwave power of 600W and a time control of 2 hours. Thus, a geopolymer with extremely high compressive strength and durability was obtained. The 7-day SEM analysis of the prepared geopolymer is shown in the figure below. Figure 2 As shown, the prepared geopolymer forms a dense and relatively uniform structure at the microscopic level, and has higher mechanical properties at the macroscopic level.

[0080] Comparative Example 1

[0081] Comparative Example The aluminosilicate-based raw material is composed of 75% by weight of fly ash and 25% by weight of slag. The activator is a mixed solution of industrial-grade NaOH and Na2SiO3, the dry weight of NaOH is 12% of the total weight of the aluminosilicate-based raw material, and the dry weight of Na2SiO3 is 12% of the total weight of the aluminosilicate-based raw material. A geopolymer product is prepared according to the preparation method of Example 1.

[0082] Examples, Comparative Examples Mechanical Properties and Working Performance Tests

[0083] Test method:

[0084] 1. Refer to DG / TJ 08-2240-2017 "Technical Specifications for Road Grouting Reinforcement", GB / T 1346-2011 "Test Methods for Water Consumption, Setting Time and Stability of Cement Standard Consistency", GB / T 17671-1999 "Test Methods for Strength of Cement Mortar (ISO Method)" and other standards to test the fluidity, setting time, flexural strength, compressive strength and shrinkage of fly ash-mineral powder geopolymer materials respectively.

[0085] 2. Bruker D8 Da Vinci X-ray diffractometer uses CuKa as the anode material, and the scanning angle 2θ is from 5° to 90°, maintaining a scanning speed of 2° / min. After sampling, in order to prevent the polymerization reaction from continuing, the sample needs to be placed in ethanol for grinding, and then dried for XRD analysis.

[0086] 3. In the SEM analysis, the operating voltage of the TESCAN MI RA3 equipment is 20KeV, and the EDS energy spectrum is used to analyze the composition points at different positions on the sample surface. The sample needs to be sampled by the DYNAVAC sputtering coater for Perkum plating.

[0087] The results of the mechanical properties and working performance tests are shown in the following table

[0088]

[0089]

[0090] It can be seen from the test data in the table that, through a comprehensive analysis of the test data, the geopolymer material of the present invention shows significant advantages over traditional cement-based materials in multiple key performance indicators. Specifically, the shrinkage rate of the geopolymer of the present invention is controlled to be 0% at 28 days, which is much lower than 3.5% of Comparative Example 1. This characteristic significantly reduces the internal stress during the hardening process and effectively prevents the formation of cracks. In addition, the fluidity of the material of the present invention is significantly improved, the initial fluidity is stable, and the setting time is short. These characteristics not only improve the convenience of construction, but also significantly improve the construction efficiency. In terms of mechanical properties, the flexural strength and compressive strength of the geopolymer of the present invention are significantly improved. The compressive strength of 3 days can reach more than 30MPa, and it exceeds 50MPa at 28 days, far exceeding the 19.8MPa of Comparative Example 1. In particular, in Example 3, the compressive strength of 28 days reached 90.8MPa, which is far beyond the strength of traditional cement-based materials, demonstrating its excellent early strength and long-term stability.

[0091] The innovation of the geopolymer material of the present invention lies in that it innovatively utilizes industrial waste residue as raw materials, combined with specific alkaline activators and selected additives, not only achieving environmental friendliness and resource recycling, but also being superior to traditional cement-based materials in terms of early strength, compressive strength and working performance. The combination of these characteristics enables the geopolymer material of the present invention to show a wide range of application potential in various engineering fields such as construction, roads, bridges, etc. In addition, the practicality of the geopolymer material of the present invention is outstanding, especially in shortening the engineering cycle and reducing production and construction costs. Through the optimized maintenance process, the material of the present invention can reach the use strength in just 3 days, which is of great significance for improving production efficiency. At the same time, the low shrinkage rate of the geopolymer material of the present invention is crucial to improving the structural safety of buildings, helping to reduce maintenance costs and extend the service life of buildings.

[0092] In summary, the geopolymer material of the present invention not only shows significant superiority in performance, but also has great development potential in environmental protection and economic benefits. This material uses industrial waste as raw materials, reduces the exploitation of natural resources, reduces energy consumption and greenhouse gas emissions in the production process, and provides a low-carbon and environmentally friendly development path for the construction industry. With the continuous advancement of technology, the gradual improvement of market recognition, and the guidance and support of relevant policies, the geopolymer material of the present invention is expected to become a new direction in the future construction field, leading the industry to transform towards a greener and more sustainable development direction.

[0093] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A high-performance, environmentally friendly geopolymer, characterized in that: The geopolymer comprises an aluminosilicate-based raw material extracted from industrial waste, an alkaline activator, an additive and water. The aluminosilicate-based raw material is composed of the following components in weight percentage: Fly ash 35-90% Slag 10-65% Highly active ultrafine kaolin 0-15% Silica fume 0-10%; The alkaline activator is composed of a mixed solution of industrial-grade NaOH and Na2SiO3, the dry matter weight ratio of NaOH to Na2SiO3 is 1:0.3-3, the dry matter amount of NaOH is 5-30% of the weight of the aluminosilicate-based raw material, and the dry matter amount of Na2SiO3 is 5-30% of the weight of the aluminosilicate-based raw material; The additives include fiber reinforcement materials, high molecular polymers, water reducing agents, and bio-based materials. The fiber reinforcement materials are used in an amount of 0.01-1% by weight of the aluminosilicate-based raw materials, the high molecular polymers are used in an amount of 0-3% by weight of the aluminosilicate-based raw materials, the water reducing agents are used in an amount of 0-5% by weight of the aluminosilicate-based raw materials, and the bio-based materials are used in an amount of 0-10% by weight of the aluminosilicate-based raw materials. The amount of water used is 20-30% by weight of the aluminosilicate-based raw material.

2. A high-performance, environmentally friendly geopolymer according to claim 1, characterized in that: The fiber-reinforced material includes at least one of polypropylene fiber and carbon fiber, the high molecular polymer includes at least one of polyester and polyether high molecular polymers, the water reducer includes at least one of polycarboxylic acid water reducer and naphthalene water reducer; the bio-based material includes at least one of rice husk ash, cassava flour and coffee grounds.

3. A high-performance, environmentally friendly geopolymer according to claim 2, characterized in that: The additives also include stone powder, nano-SiO2, and high-activity kaolin. The amount of the stone powder is 0-5% of the weight of the aluminosilicate-based raw material, the amount of the nano-SiO2 is 0-5% of the weight of the aluminosilicate-based raw material, and the amount of the high-activity kaolin is 0-5% of the weight of the aluminosilicate-based raw material.

4. A high-performance, environmentally friendly geopolymer according to claim 3, characterized in that: The fly ash is high-calcium fly ash, and the weight ratio of the high-calcium fly ash to slag is 1:

1. Industrial brine is added to the alkaline activator, and the industrial brine is a sodium chloride aqueous solution with a concentration of 3wt% to 5wt%, and its dosage is 1% to 5% of the total dry matter weight of the aluminosilicate-based raw material and the alkaline activator.

5. A method for preparing a high-performance, environmentally friendly geopolymer according to any one of claims 1 to 4, characterized in that: The following steps are included: (1) weighing an aluminosilicate-based raw material, an alkaline activator, an additive, and water according to a ratio, mixing the aluminosilicate-based raw material, the alkaline activator, and the water, adding the additive, and mixing and stirring to form a homogeneous slurry; (2) Pour the slurry into a mold and cure it in an environment with a temperature of 20-90° C. and a humidity of 60%-90% for no less than 28 days, and keep constant conditions in the first 7 days, wherein the constant condition curing temperature is controlled at 25-75° C. and the humidity is controlled at 70%-85%.

6. The method for preparing a high-performance, environmentally friendly geopolymer according to claim 5, characterized in that: The mixing method in step (1) is low-frequency oscillation mixing, and the oscillation frequency is 10-50 Hz.

7. The method for preparing a high-performance, environmentally friendly geopolymer according to claim 5, characterized in that: The curing time is 50-60 days, and microwave drying treatment is carried out from the 28th day to the 32nd day, the microwave power is 100-1000W, and the microwave drying treatment time is 1-4 hours.

Images