Lightweight high-strength geopolymer concrete suitable for fabricated building and preparation method thereof

Abstract

The application provides a kind of lightweight high-strength geopolymer concrete suitable for fabricated building, comprising the following components and weight fractions: waste ceramic powder 90-180 parts, fly ash 45-135 parts, slag 225-315 parts, alkali activator 158-256 parts, fine aggregate 626-765 parts, light coarse aggregate 504-576 parts, mixed fiber 4.5-13.5 parts, and composite admixture solution 1-36 parts. The application uses lightweight high-strength shale ceramic as light coarse aggregate to reduce the self-weight of concrete; through alkali activator to stimulate the potential activity of solid waste such as waste ceramic powder, fly ash and slag, to generate geopolymer, to improve the strength of lightweight aggregate concrete and maintain the lightweight feature; by adding mixed fiber and composite admixture, the performance of lightweight aggregate concrete is further improved. Therefore, the application realizes the balance of lightweight and high strength, and can be applied to various fabricated buildings such as bridges, high-rise buildings, tunnel segments, etc.

Description

Technical Field

[0001] This invention belongs to the field of lightweight concrete technology, and particularly relates to a lightweight, high-strength polymer concrete suitable for prefabricated buildings and its preparation method. Background Technology

[0002] Prefabricated buildings have gradually become a hot topic in the construction industry due to their advantages such as fast construction speed, stable quality, energy saving, and environmental protection. However, during construction, prefabricated buildings face significant challenges in the transportation and lifting of components. Lightweight concrete, as a concrete material with low self-weight and high specific strength, has been widely used in projects such as roads, long-span bridges, high-rise buildings, and tunnel segments. The density of ordinary concrete is approximately 2350 kg / m³. 3 The density of lightweight concrete typically does not exceed 1950 kg / m³. 3 This can effectively reduce the weight of prefabricated building components, thereby reducing the difficulty of transportation and lifting.

[0003] There are two main design approaches for lightweight concrete: one is to introduce gas or foam to form a porous structure; the other is to use lightweight aggregates to partially or completely replace traditional aggregates, the latter having higher strength and being more suitable for structural applications. For example, Chinese patent document CN115974482A discloses a lightweight, high-durability concrete and its preparation method. This material, by adding basalt fibers and polyacrylonitrile fibers, not only improves strength but also inhibits crack propagation, achieving a maximum 28-day compressive strength of 42.6 MPa. However, although this concrete is lightweight, its strength cannot fully meet the requirements of prefabricated buildings such as bridges, high-rise buildings, and tunnel segments. Moreover, the cement used in this technology itself has problems such as high energy consumption and high pollution during production, which does not meet the requirements of contemporary sustainable development.

[0004] Geopolymers are hydraulic cementitious materials produced by reacting amorphous aluminosilicate materials with alkaline activators. In recent years, geopolymers have gained increasing attention due to their rapid setting, high strength, good durability, low energy consumption, low pollution, and ability to treat solid waste, and are considered one of the effective alternatives to traditional cement. Chinese patent document CN113264719A discloses a geopolymer-based foamed concrete for roads and its preparation method. This material has advantages such as lightweight, heat resistance, good stability, and good fluidity, and its strength is far higher than the standard requirement of 0.6 MPa. However, because this material reduces weight by introducing foam, its strength is difficult to match that of concrete that reduces weight by using lightweight aggregates, making it unsuitable for structural applications and limiting the application range of geopolymers to some extent.

[0005] In summary, under the premise of ensuring low energy consumption and low pollution, how to expand the application scope of geopolymers and use them in conjunction with lightweight aggregates in the field of lightweight concrete, while solving the technical problem that existing concrete cannot achieve both lightweight and strength, has gradually become a research hotspot in this field. Summary of the Invention

[0006] To address the aforementioned technical challenges, this invention provides a lightweight, high-strength polymer concrete suitable for prefabricated buildings, achieving a balance between lightweight and high strength. Moreover, the raw materials used in this invention are all solid wastes, resulting in low costs and a simple preparation process that meets the requirements of environmental protection and sustainable development. The final product can be applied to prefabricated buildings such as bridges, high-rise buildings, and tunnel segments.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A lightweight, high-strength polymer concrete suitable for prefabricated buildings comprises the following components and their weight percentages: 90-180 parts waste ceramic powder, 45-135 parts fly ash, 225-315 parts slag, 158-256 parts alkali activator, 626-765 parts fine aggregate, 504-576 parts lightweight coarse aggregate, 4.5-13.5 parts mixed fiber; and 1-36 parts composite admixture solution; wherein the alkali activator is a 1-2M sodium silicate solution.

[0009] The mixed fiber is composed of polyvinyl alcohol fiber and basalt fiber mixed in a mass ratio of 1:1.5 to 3;

[0010] The composite admixture solution is prepared from organic water-reducing agent, inorganic retarder and water in a mass ratio of 1-3:1:6-12;

[0011] The total water content in the alkali activator and the composite additive solution is 40 wt% of the total amount of waste ceramic powder, fly ash, and slag.

[0012] This invention utilizes an alkali activator to activate the potential activity of solid wastes such as waste ceramic powder, fly ash, and slag, generating geopolymers to replace traditional ordinary cement as a binder. This improves the strength of lightweight aggregate concrete while maintaining its lightweight characteristics. The performance of lightweight aggregate concrete is further enhanced by adding mixed fibers and composite admixtures.

[0013] The composite admixture solution in this invention is composed of two or more additives and water. The organic water-reducing agent is used to improve dispersibility and enhance fluidity; the inorganic retarder is used to delay the gel formation time and prevent the setting time from being too fast, so as to facilitate subsequent operations; the total water content in the alkali activator and composite admixture solution is limited to ensure fluidity without being too thin and affecting the strength after hardening.

[0014] Preferably, the lightweight high-strength polymer concrete comprises the following components and their weight proportions: 90 parts waste ceramic powder, 45 parts fly ash, 315 parts slag, 207 parts alkali activator, 695 parts fine aggregate, 540 parts lightweight coarse aggregate, 9 parts mixed fiber; and 18 parts composite admixture solution; wherein the alkali activator is a 1.5M sodium silicate solution.

[0015] The mixed fiber is composed of polyvinyl alcohol fiber and basalt fiber mixed in a mass ratio of 1:3;

[0016] The composite admixture solution is prepared from organic water-reducing agent, inorganic retarder and water in a mass ratio of 1:1:6;

[0017] The total water content in the alkali activator and the composite additive solution is 40 wt% of the total amount of waste ceramic powder, fly ash, and slag.

[0018] Preferably, the waste ceramic powder is prepared from ceramic waste such as wall tiles, floor tiles, and daily-use ceramics through crushing, water washing and selection, and ball milling, with a particle size of 325-800 mesh.

[0019] Preferably, the fly ash is Grade I or Grade II, and the total content of SiO2 and Al2O3 is not less than 80 wt%; the slag is S95 grade granulated blast furnace slag powder.

[0020] The waste ceramic powder in this invention is a powder made from ceramic waste such as wall tiles, floor tiles, and daily-use ceramics through crushing, washing and selection, and grinding in a ball mill. Its main components are silicon dioxide and alumina. Fly ash is a fine powdery substance collected from flue gas by a dust removal device during the coal-fired power generation process in power plants. It is mainly composed of minerals and unburned carbon. Grade I or II fly ash has higher effective components such as SiO2 and Al2O3, and the fineness requirements are also higher. Slag is a molten material mainly composed of silicates and aluminosilicates formed by the reaction of impurities such as silicon dioxide and alumina with lime after metal extraction from iron ore during metal smelting. It is formed by quenching and granulation. This invention applies ceramic waste and industrial waste generated in the daily production process of industries such as steel and power to the preparation of lightweight concrete required for prefabricated buildings, realizing the recycling of waste, reducing the preparation cost of concrete, and meeting the requirements of environmental protection and sustainable development.

[0021] Preferably, the alkaline activator is prepared as follows: using 2.3-3.4M industrial water glass as raw material, sodium hydroxide and water are added in proportion to adjust the modulus M.

[0022] The modulus refers to the molar ratio of SiO2 to Na2O in a sodium silicate solution. Adding sodium hydroxide (NaOH) increases the Na2O ratio in the solution, thereby reducing the modulus, while water acts as a diluent. Industrial water glass with a modulus of 2.3 to 3.4 is relatively easy to obtain. In actual preparation, it can also be prepared by mixing sodium silicate solutions with other moduli. The mixing process is a conventional technique known to those skilled in the art.

[0023] Preferably, the fine aggregate is medium sand; the light coarse aggregate is shale ceramsite with a particle size of 5–20 mm and a bulk density of 700–900 kg / m³. 3 .

[0024] This invention selects shale ceramsite (also known as expanded shale) as lightweight coarse aggregate. Shale ceramsite is a lightweight porous artificial aggregate made from high-quality shale through high-temperature calcination. It can significantly reduce the self-weight of concrete by replacing traditional crushed stone coarse aggregate.

[0025] Preferably, in the mixed fibers, the polyvinyl alcohol fibers have a length of 2-4 mm and a diameter of 14-16 μm; the basalt fibers have a length of 5-7 mm and a diameter of 16-18 μm.

[0026] The hybrid fiber in this invention is composed of polyvinyl alcohol fiber and basalt fiber, wherein the polyvinyl alcohol fiber is used to suppress microcracks and the basalt fiber is used to control the propagation of macrocracks; the two fibers work synergistically to form a crack control system from micro to macro.

[0027] Preferably, in the composite admixture solution, the organic water-reducing agent is a polycarboxylate-based water-reducing agent; and the inorganic retarder is zinc sulfate.

[0028] The organic water-reducing agent and inorganic retarder in this invention must be suitable for geopolymer systems, such as polycarboxylate superplasticizers and zinc sulfate. Polycarboxylate superplasticizers are a new type of green and environmentally friendly organic water-reducing agent suitable for geopolymer systems, possessing advantages such as high water reduction rate, low slump loss, and high dispersibility. Even at low content, they can maintain high fluidity in the slurry. Zinc sulfate can maintain the plasticity of the geopolymer slurry for a longer period, thereby regulating the slurry's setting time. Besides zinc sulfate, inorganic retarder can also be barium chloride, borax, etc.

[0029] The present invention also provides a method for preparing the aforementioned lightweight high-strength polymer concrete, comprising the following steps:

[0030] S1. Mix water glass, sodium hydroxide and water in a certain proportion to prepare an alkaline activator with the required modulus, and set aside for later use;

[0031] S2. Soak the light and coarse aggregates in water for 1-2 hours, then spread them out to air dry naturally until they are saturated and surface dry, to obtain pre-soaked light and coarse aggregates.

[0032] S3. Dilute and mix the organic water-reducing agent, inorganic retarder and water in a certain proportion to obtain a composite admixture solution;

[0033] S4. Weigh waste ceramic powder, fly ash, slag and fine aggregate by weight, mix them evenly, and then add them to the pre-soaked light coarse aggregate obtained in step S2. Mix them evenly again to obtain mixed system I.

[0034] S5. Add the alkali activator prepared in step S1 and the composite additive solution obtained in step S3 to the mixed system I obtained in step S4 in sequence. After stirring evenly, add the mixed fiber and continue stirring so that the slurry fully coats the fine aggregate, light coarse aggregate and fiber to obtain the final product.

[0035] Preferably, the mixing in step S4 is performed at a speed of 30-60 rpm for 1-3 minutes; the mixing again is performed at a speed of 30-60 rpm for 1-3 minutes; the mixing in step S5 is performed at a speed of 30-60 rpm for 1-3 minutes; and the continued mixing is performed at a speed of 30-60 rpm for 1-3 minutes.

[0036] This invention uses lightweight, high-strength shale ceramsite as lightweight coarse aggregate, replacing traditional crushed stone coarse aggregate, significantly reducing the self-weight of concrete. By activating the potential activity of solid waste such as waste ceramic powder, fly ash, and slag with an alkali activator, geopolymers are generated to replace traditional ordinary cement as a binder, thereby improving the strength of lightweight aggregate concrete while maintaining its lightweight characteristics. The performance of lightweight aggregate concrete is further enhanced by adding mixed fibers and composite admixtures.

[0037] Therefore, compared with the prior art, the lightweight high-strength polymer concrete prepared by the present invention has the following advantages:

[0038] (1) The lightweight high-strength polymer concrete prepared by this invention can achieve a compressive strength of more than 50MPa after 28 days, which meets the strength requirements of prefabricated buildings such as bridges, high-rise buildings, and tunnel segments.

[0039] (2) The lightweight and high-strength polymer concrete prepared by this invention can take into account both lightweight and high strength. The raw materials used are all solid waste, realizing the recycling of waste and reducing the preparation cost of concrete.

[0040] (3) The production process of this invention does not require calcination to produce cement, resulting in less environmental pollution. The preparation process is simple, energy consumption is low, and it meets the requirements of environmental protection and sustainable development. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. Unless otherwise specified, the raw materials, equipment, etc. used in the following embodiments can be obtained through conventional means.

[0042] Example 1: A lightweight, high-strength polymer concrete suitable for prefabricated buildings

[0043] The lightweight, high-strength polymer concrete comprises the following components and their weight proportions: 90 parts waste ceramic powder, 90 parts Class I fly ash, 270 parts slag, 198 parts 1M sodium silicate solution, 695 parts medium sand, 540 parts shale ceramsite, 4.5 parts mixed fiber, and 9 parts composite admixture solution; wherein the mixed fiber is composed of polyvinyl alcohol fiber and basalt fiber mixed in a mass ratio of 1:2; the composite admixture solution is made from Subote -Ⅰ Polycarboxylate superplasticizer, zinc sulfate and water are prepared in a mass ratio of 1:1:6.

[0044] The method for preparing the lightweight, high-strength polymer concrete includes the following steps:

[0045] S1. Add sodium hydroxide and water to water glass with a raw material modulus of 2.39 in proportion 24 hours in advance to prepare a 1M sodium silicate solution to obtain an alkaline activator for later use.

[0046] S2. Soak shale ceramsite in water for 2 hours, then spread it out to air dry naturally until it reaches a saturated surface-dry state to obtain pre-soaked light coarse aggregate;

[0047] S3, Subote -Ⅰ Polycarboxylate superplasticizer, zinc sulfate and water are diluted and mixed in a ratio of 1:1:6 to obtain a composite admixture solution;

[0048] S4. Weigh waste ceramic powder, Class I fly ash, slag, and medium sand by weight, and stir at 48 rpm for 2 minutes until uniform. Then add it to the pre-soaked light coarse aggregate obtained in step S2, and stir again at 48 rpm for 2 minutes until uniform to obtain mixed system I. During the preparation process, ensure that the total water content in the alkali activator and composite additive solution is 40 wt% of the total amount of waste ceramic powder, fly ash, and slag.

[0049] S5. Add the alkali activator prepared in step S1 and the composite additive solution obtained in step S3 to the mixed system I obtained in step S4 in sequence. Stir at 48 rpm for 2 minutes until the mixture is uniform. Then add the mixed fiber and continue stirring at 48 rpm for 2 minutes to make the slurry fully coat the fine aggregate, light coarse aggregate and fiber.

[0050] The prepared lightweight, high-strength polymer concrete suitable for prefabricated buildings was injected into a mold, placed in a curing box for curing, and its compressive strength and density grade were measured after 28 days.

[0051] Example 2: A lightweight, high-strength polymer concrete suitable for prefabricated buildings

[0052] The lightweight, high-strength polymer concrete comprises the following components and their weight proportions: 180 parts waste ceramic powder, 45 parts Class I fly ash, 225 parts slag, 207 parts 2M sodium silicate solution, 695 parts medium sand, 540 parts shale ceramsite, 13.5 parts mixed fiber, and 27 parts composite admixture solution; wherein the mixed fiber is composed of polyvinyl alcohol fiber and basalt fiber mixed in a mass ratio of 1:3; the composite admixture solution is made from Subote -Ⅰ Polycarboxylate superplasticizer, zinc sulfate and water are prepared in a mass ratio of 2:1:9;

[0053] The method for preparing the lightweight, high-strength polymer concrete includes the following steps:

[0054] S1. Add sodium hydroxide and water to water glass with a raw material modulus of 2.39 in proportion 24 hours in advance to prepare a 2M sodium silicate solution to obtain an alkaline activator for later use.

[0055] S2. Soak shale ceramsite in water for 1.5 hours, then spread it out to air dry naturally until it reaches a saturated surface-dry state to obtain pre-soaked light coarse aggregate;

[0056] S3, Subote -Ⅰ Polycarboxylate superplasticizer, zinc sulfate and water are diluted and mixed in a ratio of 2:1:9 to obtain a composite admixture solution;

[0057] S4. Weigh waste ceramic powder, Class I fly ash, slag, and medium sand by weight, and stir at 48 rpm for 2 minutes until uniform. Then add it to the pre-soaked light coarse aggregate obtained in step S2, and stir again at 48 rpm for 2 minutes until uniform to obtain mixed system I. During the preparation process, ensure that the total water content in the alkali activator and composite additive solution is 40 wt% of the total amount of waste ceramic powder, fly ash, and slag.

[0058] S5. Add the alkali activator prepared in step S1 and the composite additive solution obtained in step S3 to the mixed system I obtained in step S4 in sequence. Stir at 48 rpm for 2 minutes until the mixture is uniform. Then add the mixed fiber and continue stirring at 48 rpm for 2 minutes to make the slurry fully coat the fine aggregate, light coarse aggregate and fiber.

[0059] The prepared lightweight, high-strength polymer concrete suitable for prefabricated buildings was injected into a mold, placed in a curing box for curing, and its compressive strength and density grade were measured after 28 days.

[0060] Example 3: A lightweight, high-strength polymer concrete suitable for prefabricated buildings

[0061] The lightweight, high-strength polymer comprises the following components and their weight proportions: 90 parts waste ceramic powder, 45 parts fly ash, 315 parts slag, 207 parts 1.5M sodium silicate solution, 695 parts medium sand, 540 parts shale ceramsite, 9 parts mixed fibers, and 18 parts composite additive solution; wherein the mixed fibers are composed of polyvinyl alcohol fibers and basalt fibers mixed in a mass ratio of 1:3; the composite additive solution is composed of... -Ⅰ Polycarboxylate superplasticizer, zinc sulfate and water are prepared in a mass ratio of 1:1:6;

[0062] The method for preparing the lightweight, high-strength polymer concrete includes the following steps:

[0063] S1. Add sodium hydroxide and water to water glass with a raw material modulus of 2.39 in proportion 24 hours in advance to prepare a 1.5M sodium silicate solution to obtain an alkaline activator for later use.

[0064] S2. Soak shale ceramsite in water for 1 hour, then spread it out to air dry naturally until it reaches a saturated surface dry state to obtain pre-soaked light coarse aggregate;

[0065] S3, Subote -Ⅰ Polycarboxylate superplasticizer, zinc sulfate and water are diluted and mixed in a ratio of 1:1:6 to obtain a composite admixture solution;

[0066] S4. Weigh waste ceramic powder, Class I fly ash, slag, and medium sand by weight, and stir at 48 rpm for 2 minutes until uniform. Then add it to the pre-soaked light coarse aggregate obtained in step S2, and stir again at 48 rpm for 2 minutes until uniform to obtain mixed system I. During the preparation process, ensure that the total water content in the alkali activator and composite additive solution is 40 wt% of the total amount of waste ceramic powder, fly ash, and slag.

[0067] S5. Add the alkali activator prepared in step S1 and the composite additive solution obtained in step S3 to the mixed system I obtained in step S4 in sequence. Stir at 48 rpm for 2 minutes until the mixture is uniform. Then add the mixed fiber and continue stirring at 48 rpm for 2 minutes to make the slurry fully coat the fine aggregate, light coarse aggregate and fiber.

[0068] The prepared lightweight, high-strength polymer concrete suitable for prefabricated buildings was injected into a mold, placed in a curing box for curing, and its compressive strength and density grade were measured after 28 days.

[0069] Example 4: A lightweight, high-strength polymer concrete suitable for prefabricated buildings

[0070] The lightweight, high-strength polymer comprises the following components and their weight proportions: 90 parts waste ceramic powder, 45 parts Class I fly ash, 315 parts slag, 207 parts 1.5M sodium silicate solution, 643 parts medium sand, 567 parts shale ceramsite, 9 parts mixed fibers, and 18 parts composite additive solution; wherein the mixed fibers are composed of polyvinyl alcohol fibers and basalt fibers mixed in a mass ratio of 1:3; the composite additive solution is composed of... -Ⅰ Polycarboxylate superplasticizer, zinc sulfate and water are prepared in a mass ratio of 1:1:6;

[0071] The preparation method of the lightweight high-strength polymer concrete is similar to that in Example 3.

[0072] The prepared lightweight, high-strength polymer concrete suitable for prefabricated buildings was injected into a mold, placed in a curing box for curing, and its compressive strength and density grade were measured after 28 days.

[0073] Comparative Example 1: A cement-based lightweight aggregate concrete

[0074] Except that the aluminosilicate materials and activator are replaced with 450 parts of ordinary silicate cement and 180 parts of water, the composition and preparation method of the cement-based lightweight aggregate concrete are similar to those in Example 3.

[0075] The difference from Example 3 is that Comparative Example 1 uses the reaction of ordinary silicate cement and water instead of the reaction of aluminosilicate material and alkali activator to generate gel in this invention.

[0076] Comparative Example 2: A lightweight, high-strength polymer concrete

[0077] The composition and preparation method of the lightweight high-strength polymer concrete are similar to those in Example 3;

[0078] The difference from Example 3 is that Comparative Example 2 does not include mixed fibers and composite additive solution.

[0079] Comparative Example 3: A Lightweight High-Strength Polymer Concrete

[0080] The composition and preparation method of the lightweight high-strength polymer concrete are similar to those in Example 3;

[0081] The difference from Example 3 is that in Comparative Example 3, the composite fiber was replaced with pure polyvinyl alcohol fiber.

[0082] Comparative Example 4: A lightweight, high-strength polymer concrete

[0083] The composition and preparation method of the lightweight high-strength polymer concrete are similar to those in Example 3;

[0084] The difference from Example 3 is that in Comparative Example 4, the composite fiber was replaced with pure basalt fiber.

[0085] Comparative Example 5: A Lightweight High-Strength Polymer Concrete

[0086] The composition and preparation method of the lightweight high-strength polymer concrete are similar to those in Example 3;

[0087] The difference from Example 3 is that Comparative Example 5 uses subophthalic acid in the composite additive solution. -Ⅰ Replace the polycarboxylate high-performance water-reducing agent with Subote. -A Naphthalene-based high-efficiency water-reducing agent.

[0088] Comparative Example 6: A Lightweight High-Strength Polymer Concrete

[0089] The composition and preparation method of the lightweight high-strength polymer concrete are similar to those in Example 3;

[0090] The difference from Example 3 is that in Comparative Example 6, zinc sulfate in the composite additive solution was replaced with citric acid.

[0091] Test Case Performance Testing

[0092] 1. Test samples: Lightweight high-strength polymer concrete and cement-based lightweight aggregate concrete prepared in Examples 1-4 and Comparative Examples 1-6;

[0093] 2. Test methods: The dry apparent density of the above samples was determined in accordance with the industry standard "Technical Standard for Application of Lightweight Aggregate Concrete" (JGJ / T12-2019) to classify the density grades, and the compressive strength of the above samples was determined in accordance with the national standard "Standard for Test Methods of Physical and Mechanical Properties of Concrete" GB / T 50081-2019.

[0094] 3. Experimental results: The specific experimental results are shown in Table 1.

[0095] Table 1. Results of compressive strength and density grade determination for different test samples.

[0096]

[0097]

[0098] As shown in Table 1 above, the 28-day compressive strength of the lightweight high-strength geopolymer concretes prepared in Examples 1-3 of this invention is all above 55 MPa. This indicates that, while maintaining the basic concrete mix proportions such as total aluminosilicate material, fine aggregate, lightweight coarse aggregate content, and total water content, appropriately adjusting factors such as the aluminosilicate material ratio, alkali activator modulus M, mixed fiber content, composite admixture content, and pre-soaking time of lightweight coarse aggregate will not significantly affect the compressive strength. Example 4, prepared with reference to the best example 3, reduces the concrete density grade to 1800 kg / m³ by increasing the proportion of lightweight coarse aggregate in the total aggregate. 3 Meanwhile, the compressive strength remains above 50MPa after 28 days.

[0099] Compared to the preferred embodiment 3, in Comparative Example 1, ordinary cement was used to generate gel, resulting in a 18 MPa decrease in the compressive strength of the concrete. In Comparative Example 2, the concrete performance also decreased significantly due to the absence of mixed fibers and composite admixture solution. In Comparative Examples 3 and 4, the two fibers were used alone, failing to form a crack control system from micro to macro levels, and their compressive strength improvement effect was less than that of the mixed fibers. In Comparative Examples 5 and 6, the composite admixture solution's effect on improving compressive strength was weakened due to the use of water-reducing agents and retarders that are not suitable for geopolymer systems.

[0100] Therefore, compared with traditional cement-based lightweight aggregate concrete, the lightweight high-strength polymer concrete of this invention has higher compressive strength and can be applied to prefabricated buildings such as bridges, high-rise buildings, and tunnel segments. Furthermore, the raw materials used in this invention are all solid waste, resulting in lower costs and a simpler preparation process, meeting the requirements of environmental protection and sustainable development.

[0101] Finally, it should be noted that the above embodiments are merely illustrative of the principles, performance, and effects of the present invention, and are not intended to limit the present invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A lightweight, high-strength polymer concrete suitable for prefabricated buildings, characterized in that, It includes the following components and their weight percentages: 90-180 parts waste ceramic powder, 45-135 parts fly ash, 225-315 parts slag, 158-256 parts alkali activator, 626-765 parts fine aggregate, 504-576 parts light coarse aggregate, and 4.5-13.5 parts mixed fiber. 1-36 parts of compound admixture solution; The alkaline activator is a 1-2M sodium silicate solution; The mixed fiber is composed of polyvinyl alcohol fiber and basalt fiber mixed in a mass ratio of 1:1.5~3; The composite admixture solution is prepared from organic water-reducing agent, inorganic retarder and water in a mass ratio of 1~3:1:6~12; The total water content in the alkali activator and the composite admixture solution is 40 wt% of the total amount of waste ceramic powder, fly ash, and slag; in the composite admixture solution, the organic water-reducing agent is a polycarboxylate-based water-reducing agent; and the inorganic retarder is zinc sulfate.

2. The lightweight, high-strength polymer concrete as described in claim 1, characterized in that, It includes the following components and their weight proportions: 90 parts waste ceramic powder, 45 parts fly ash, 315 parts slag, 207 parts alkali activator, 695 parts fine aggregate, 540 parts light coarse aggregate, 9 parts mixed fiber; and 18 parts composite admixture solution. The alkaline activator is a 1.5M sodium silicate solution; The mixed fiber is composed of polyvinyl alcohol fiber and basalt fiber mixed in a mass ratio of 1:3; The composite admixture solution is prepared from organic water-reducing agent, inorganic retarder and water in a mass ratio of 1:1:

6.

3. The lightweight high-strength polymer concrete as described in claim 1 or 2, characterized in that, The waste ceramic powder is prepared from ceramic waste such as wall tiles, floor tiles, and daily-use ceramics through crushing, water washing and selection, and ball milling, with a particle size of 325-800 mesh.

4. The lightweight high-strength polymer concrete as described in claim 1 or 2, characterized in that, The fly ash is Grade I or Grade II, with a total SiO2 and Al2O3 content of not less than 80wt%; the slag is S95 grade granulated blast furnace slag powder.

5. The lightweight high-strength polymer concrete as described in claim 1 or 2, characterized in that, The preparation process of the alkali activator is as follows: using 2.3~3.4M industrial water glass as raw material, sodium hydroxide and water are added to adjust the modulus M.

6. The lightweight high-strength polymer concrete as described in claim 1 or 2, characterized in that, The fine aggregate is medium sand; the light coarse aggregate is shale ceramsite with a particle size of 5–20 mm and a bulk density of 700–900 kg / m³. 3 .

7. The lightweight high-strength polymer concrete as described in claim 1 or 2, characterized in that, In the mixed fibers, the polyvinyl alcohol fibers have a length of 2-4 mm and a diameter of 14-16 μm; the basalt fibers have a length of 5-7 mm and a diameter of 16-18 μm.

8. A method for preparing lightweight high-strength polymer concrete as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Mix water glass, sodium hydroxide and water to prepare an alkaline activator with the required modulus, and set aside for later use; S2. Soak the light and coarse aggregates in water for 1-2 hours, then spread them out to air dry naturally until they are saturated and surface dry, to obtain pre-soaked light and coarse aggregates. S3. Dilute and mix the organic water-reducing agent, inorganic retarder and water in a certain proportion to obtain a composite admixture solution; S4. Weigh waste ceramic powder, fly ash, slag and fine aggregate by weight, mix them evenly, and then add them to the pre-soaked light coarse aggregate obtained in step S2. Mix them evenly again to obtain mixed system I. S5. Add the alkali activator prepared in step S1 and the composite additive solution obtained in step S3 to the mixed system I obtained in step S4 in sequence. After stirring evenly, add the mixed fiber and continue stirring so that the slurry fully coats the fine aggregate, light coarse aggregate and fiber to obtain the final product.

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