Fireproof sound-insulation heat-preservation type light-weight high-strength all-solid waste concrete and preparation method thereof

Abstract

The invention belongs to the technical field of solid waste concrete, and discloses fireproof sound-insulation heat-preservation light-weight high-strength all-solid waste concrete and a preparation method thereof.The fireproof sound-insulation heat-preservation light-weight high-strength all-solid waste concrete is prepared from an all-solid waste fireproof cementing material, all-solid waste light aggregate, water and a functional additive; the all-solid-waste fireproof cementing material comprises an alkaline activator component and an active powder component, the alkaline activator component comprises red mud and carbide slag in a mass ratio of (1.5-2.5): 1, and the active powder component comprises granulated blast furnace slag and low-temperature activated calcined coal gangue powder in a mass ratio of (1.0-1.8): 1; the all-solid-waste lightweight aggregate comprises coarse aggregate and fine aggregate in a mass ratio of (1-1.5): 1, wherein both the coarse aggregate and the fine aggregate comprise high-temperature expanded and roasted coal gangue lightweight aggregate; wherein the low-temperature activated and calcined coal gangue powder is obtained by performing gradient temperature control calcination on coal gangue at 650-800 DEG C and then grinding the coal gangue until the specific surface area is greater than or equal to 500m < 2 > / kg; the high-temperature expanded and roasted coal gangue lightweight aggregate is obtained by roasting and expanding coal gangue at 1100-1300 DEG C and then screening and grading.

Description

Technical Field

[0001] This invention belongs to the field of solid waste concrete technology, specifically relating to a fireproof, soundproof, heat-insulating, lightweight, high-strength all-solid waste concrete and its preparation method. Background Technology

[0002] Developing new building materials with high performance, multifunctionality, and low environmental impact has become an urgent need. The annual emissions of industrial solid waste (such as red mud, carbide slag, mine slag, and coal gangue) are enormous, and their accumulation not only occupies land but also poses environmental risks. Utilizing solid waste to prepare building materials is an effective resource recovery approach, but existing technologies face the following bottlenecks:

[0003] 1. Functional singularity and performance contradiction: Most studies focus on achieving a single function (such as load-bearing or heat insulation), making it difficult to achieve multiple properties such as lightweight, high strength, heat insulation, and sound insulation in a single material. In particular, it is difficult to endow the material with excellent active fire resistance without sacrificing mechanical properties.

[0004] 2. Fire resistance performance depends on external additives: Traditional methods usually improve fire resistance by adding organic flame retardants or increasing the thickness of the protective layer. The former may reduce durability or cause new environmental problems, while the latter increases cost and structural weight, and cannot achieve the intrinsic fire resistance of the material.

[0005] 3. Insufficient synergy in solid waste utilization: Existing technologies for solid waste utilization are mostly simple substitutions or single-system developments, failing to achieve deep synergy and performance enhancement of various solid wastes in terms of composition and function from the perspective of materials chemistry and microstructure design.

[0006] Therefore, there is an urgent need to develop an innovative material system that integrates lightweight, high strength, thermal insulation, sound insulation, and intrinsic fire resistance based on deep synergy with solid waste and microstructure design. Summary of the Invention

[0007] In view of this, to solve the problems mentioned in the background art, the purpose of this invention is to provide a fireproof, soundproof, and heat-insulating lightweight high-strength all-solid waste concrete and its preparation method. Specifically, the core lies in proposing a three-in-one technical solution of "solid waste synergy - chemical activation - microstructure design," achieving a breakthrough integration of material properties through innovation at the following four levels:

[0008] 1. Molecular-microscopic design of material components:

[0009] Based on the characteristics of red mud (rich in alkali and iron), carbide slag (high calcium), slag (high silicon and calcium), and coal gangue (high silicon and aluminum), a composite alkaline activator of "red mud-carbide slag" and a composite active powder of "slag-low temperature activated calcined coal gangue powder" were designed to achieve precise matching of alkalinity and active components.

[0010] By utilizing coal gangue through a dual-path approach—low-temperature activation calcination to produce powder and high-temperature expansion calcination to produce lightweight aggregates—the utilization value of coal gangue is maximized. Low-temperature activation calcination releases the activity of silicon and aluminum, while high-temperature expansion calcination forms a porous ceramic body.

[0011] 2. Intrinsic design of fire protection mechanism:

[0012] At room temperature: Alkali activation forms a composite cementitious phase mainly composed of heat-resistant ettringite (AFt), high-silica aluminate hydrated calcium silicate (C-(A)-SH) and geopolymer gel (N,CASH), which has high bound water content and stable structure.

[0013] High-temperature stage (fire conditions): The above-mentioned hydration products can undergo a "controlled dehydration-ceramization" transformation.

[0014] A stable ceramic network structure (such as calcium silicate and aluminosilicate crystalline phase) is gradually formed in the temperature range of 300 to 1000℃, avoiding the cracking and sudden drop in strength that are common in cement-based materials.

[0015] 3. Multi-scale structural construction:

[0016] Nanoscale: Controlling the type and morphology of hydration products to form a dense and interwoven matrix.

[0017] Mesoscale: Utilizing the closed pores (thermal insulation and sound insulation) and interconnected pores (stress buffering) inside expanded coal gangue lightweight aggregate, as well as the dense glaze layer on the surface (fireproof and waterproof), a multifunctional carrier is constructed.

[0018] Macro scale: Through optimized mix proportions and processes, ensure that the matrix and aggregates form a high-strength, low-defect interface transition zone.

[0019] 4. Integrated Functionality:

[0020] Lightweight and high strength: Low-density lightweight aggregates achieve lightweight properties, while high-strength cementitious matrix, high-strength aggregates, and optimized interfaces ensure mechanical properties.

[0021] Thermal insulation and sound insulation: The porous structure inside the lightweight aggregate and the pore structure of the matrix-aggregate composite system together provide thermal resistance and sound resistance.

[0022] Fire resistance and fire resistance: The inherently fire-resistant cementitious phase, non-combustible ceramic aggregates, and dense interface together form a thermal stability barrier.

[0023] To achieve the above objectives, the present invention provides the following technical solution:

[0024] A fireproof, soundproof, and heat-insulating lightweight, high-strength all-solid-waste concrete comprises the following components by weight:

[0025] Fire-resistant cementitious material made entirely from solid waste, 100 parts;

[0026] Lightweight aggregate from solid waste, 150-250 parts;

[0027] Water, 32-40 parts;

[0028] Functional admixture, 0.5 to 2 parts.

[0029] The solid waste fireproof cementitious material includes an alkaline activator component and an active powder component; the alkaline activator component includes red mud and carbide slag in a mass ratio of 1.5 to 2.5:1, and the active powder component includes granulated blast furnace slag and low-temperature activated calcined coal gangue powder in a mass ratio of 1.0 to 1.8:1.

[0030] The total solid waste lightweight aggregate includes coarse aggregate and fine aggregate with a mass ratio of 1 to 1.5:1, and both the coarse aggregate and the fine aggregate include high-temperature expanded roasted coal gangue lightweight aggregate.

[0031] in:

[0032] The low-temperature activated calcined coal gangue powder is obtained by calcining coal gangue at a gradient temperature of 650-800℃ and then grinding it to a specific surface area ≥500m². 2 / kg obtained;

[0033] The high-temperature expanded roasted coal gangue lightweight aggregate is obtained by roasting and expanding coal gangue at 1100-1300℃ and then screening and grading it.

[0034] Preferably, the components, based on their percentage of the total dry weight of the solid waste fireproof cementitious material, are: red mud 18%–22%, calcium carbide slag 9%–11%, granulated blast furnace slag 38%–42%, and low-temperature activated calcined coal gangue powder 28%–32%.

[0035] Preferably, the sodium oxide content in the red mud is 4-8 wt%.

[0036] Preferably, the calcium oxide content in the carbide slag is ≥65wt%.

[0037] Preferably, the granulated blast furnace slag has an alkalinity coefficient ≥1.2 and a 28-day activity index ≥95%.

[0038] Preferably, the low-temperature activated calcined coal gangue powder has an amorphous silicon-aluminum phase content of ≥70wt%, a total active SiO2 and Al2O3 content of ≥50wt%, and a loss on ignition of ≤5%.

[0039] Preferably, the coarse aggregate includes high-temperature expanded roasted coal gangue lightweight aggregate with a particle size of 5-15 mm; the fine aggregate includes high-temperature expanded roasted coal gangue lightweight aggregate with a particle size of 0-5 mm.

[0040] Preferably, the high-temperature expanded roasted coal gangue lightweight aggregate has a porous structure consisting of closed-cell and interconnected-cell composites, with a closed-cell rate ≥60%; and a continuous dense aluminosilicate ceramic glaze layer with a thickness of 50-200 μm is formed on the surface of the high-temperature expanded roasted coal gangue lightweight aggregate.

[0041] Preferably, the functional admixture is a compound system of one or more of the following components:

[0042] Plastic viscosity modifier, 0.2 to 1 part; optional: polycarboxylate-based high-performance water-reducing agent, lignin sulfonate;

[0043] Setting time regulator, 0.1-0.5 parts; optional include sodium gluconate, tartaric acid, and borax;

[0044] Air-entraining agent, 0.05–0.2 parts; optional: rosin thermal polymer, alkyl sulfonate;

[0045] Toughening fiber, 0.1 to 0.3 parts; can be basalt fiber or polypropylene fiber.

[0046] A method for preparing fire-resistant, sound-insulating, and heat-insulating lightweight, high-strength all-solid-waste concrete includes:

[0047] S1. Refined preparation of raw materials:

[0048] (1) Preparation of low-temperature activated calcined coal gangue powder: The coal gangue is crushed to ≤5mm, calcined in a rotary kiln at a gradient temperature of 650~800℃ for 1~3 hours, and then rapidly cooled and ground to a specific surface area ≥500m². 2 / kg;

[0049] (2) Preparation of lightweight aggregate from coal gangue after high-temperature puffing and roasting: Coal gangue is crushed, screened, and pelletized, and the particle size distribution of raw material pellets is controlled to be 0-15mm; it is roasted and puffed in a tunnel kiln at 1100-1300℃ for 15-30 minutes, and after slow cooling, it is screened and graded to obtain coarse aggregate and fine aggregate.

[0050] S2. Premixing of cementitious material components:

[0051] (1) Dry mix red mud and carbide slag in a forced mixer for 3-5 minutes until they are evenly mixed to obtain a homogeneous composite alkaline activator component;

[0052] (2) Granulated blast furnace slag and low-temperature activated calcined coal gangue powder are mixed evenly in a pneumatic homogenization chamber to obtain active powder components;

[0053] S3. Preparation of alkali-activated gelatinous paste:

[0054] Pre-dissolve water and functional additives, add alkaline activator components, stir for 1-2 minutes, then add active powder components, and stir in a planetary mixer at 120-150 r / min for 3-5 minutes to obtain a uniform slurry with an initial flowability of 180-220 mm.

[0055] S4. Concrete mixing:

[0056] Add fine aggregate and coarse aggregate sequentially to the uniform slurry obtained in step S3, stir until uniform, and control the outlet temperature at 10℃~35℃.

[0057] S5. Molding and Curing:

[0058] Pour the freshly mixed concrete from step S4 into the mold, compact it using low-frequency vibration at a frequency of 50-100Hz, and cover the surface with a film to retain moisture; then cure it in a stepped, humid heat manner until the specified age.

[0059] Preferably, in step S1: (2), the temperature is increased to 1100-1300℃ at a rate of 100-200℃ / h; and cooled slowly to below 600℃ at a rate of ≤5℃ / min.

[0060] Preferably, in step S5, the stepped damp heat curing is performed in a programmable curing chamber, and the specific curing control parameters are as follows:

[0061] Phase 1: 40-60℃, relative humidity ≥95%, curing time 3-6 hours;

[0062] Second stage: After raising the temperature to 70-85℃ at a rate of 10-15℃ / h, maintain the relative humidity ≥90% and keep the temperature constant for 8-16 hours;

[0063] Third stage: Allow the temperature to cool naturally to room temperature.

[0064] Compared with the prior art, the present invention has the following advantages:

[0065] 1. Superior performance and high integration: For the first time, "lightweight (≤1750kg / m³)" has been simultaneously achieved in a solid waste concrete. 3 It boasts six major performance indicators: high strength (≥35MPa), low thermal conductivity (≤0.30W / (m·K)), good sound insulation (Rw≥40dB), high fire resistance (≥2.0h), and A2-grade non-combustible, meeting the diverse needs of modern buildings for building envelope and structural materials.

[0066] 2. Intrinsically safe and long-lasting fire protection: The fire resistance performance comes from the material's own chemical composition and microstructure. It does not require any organic flame retardants, eliminates the risk of smoke toxicity, and its performance does not decrease over time, making it safe and reliable.

[0067] 3. Full utilization and deep synergy of solid waste: 100% resource utilization of four major solid wastes, namely red mud, carbide slag, slag and coal gangue, has been achieved. Through innovative component design, different solid wastes have synergistic effects in chemical activation, microstructure and macro function.

[0068] 4. Green, low-carbon, and environmentally friendly: It completely replaces cement and natural aggregates, significantly reducing production energy consumption and carbon dioxide emissions. The entire preparation process produces no secondary pollution, meeting the requirements of a circular economy and sustainable development.

[0069] 5. Controllable and scalable process: The provided preparation method uses readily available raw materials, has a clear process route and well-defined parameters, and is easy to modify existing concrete product production lines for large-scale production and application. Attached Figure Description

[0070] Figure 1 This is a flowchart illustrating the preparation method of the fireproof, soundproof, heat-insulating, lightweight, high-strength all-solid-waste concrete of the present invention. Detailed Implementation

[0071] To further understand the content of this invention, a detailed description of the invention is provided in conjunction with embodiments. The structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art, and are not intended to limit the implementation conditions of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effects and objectives of the invention, should still fall within the scope of the disclosed technical content. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention. It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein.

[0072] Example 1

[0073] (1) Raw materials and pretreatment

[0074] Red mud: Taken from an alumina plant, dried and ground to a specific surface area ≥ 450 m² 2 / kg, sodium oxide content is 6.2wt%, loss on ignition is 10.5%;

[0075] Calcium carbide slag: taken from an acetylene plant, dried at 105℃ and then ground to a specific surface area ≥500m².2 / kg, calcium oxide content ≥65wt%;

[0076] Granulated blast furnace slag: S95 grade, specific surface area 420 m² 2 / kg, alkalinity coefficient 1.25, 28d activity index ≥95%;

[0077] Low-temperature activated calcined coal gangue powder: Coal gangue (Al2O3 content ≥28wt%) is crushed to ≤5mm, calcined in a rotary kiln at 750℃ under controlled temperature gradient for 2.5 hours, and then rapidly cooled and ground to a specific surface area of ​​510m². 2 / kg, amorphous silicon-aluminum phase content 75wt%, total content of active SiO2 and Al2O3 ≥50wt%, loss on ignition ≤5%;

[0078] High-temperature expanded roasted coal gangue lightweight aggregate: Coal gangue is crushed, screened, and pelletized, with the raw material pellet size distribution controlled to be 0-15mm; it is then roasted and expanded in a tunnel kiln at 1250℃ (heating rate of 100-200℃ / h) for 25 minutes, and slowly cooled to below 600℃ at a rate of less than 5℃ / min. The high-temperature expanded roasted coal gangue lightweight aggregate has a porous structure with a combination of closed-cell and interconnected-cell structures, and a continuous and dense aluminosilicate ceramic glaze layer with a thickness of 50-200μm is formed on the surface. Bulk density: 700kg / m³ 3 The compressive strength of the cylinder is 6.5 MPa, the water absorption rate is 7.5% in 1 hour, and the closed-cell rate is 65%. After screening and classification, coarse aggregate with a particle size of 5-15 mm and fine aggregate with a particle size of 0-5 mm are obtained.

[0079] Functional additives: polycarboxylate superplasticizer (40% solid content), sodium gluconate, rosin thermal polymer.

[0080] (2) Proportion (parts by weight)

[0081] All-solid-waste fireproof cementitious material: 100 parts (20% red mud, 10% calcium carbide slag, 40% granulated blast furnace slag, 30% low-temperature activated calcined coal gangue powder);

[0082] Lightweight aggregate from solid waste: 200 parts (120 parts coarse aggregate and 80 parts fine aggregate);

[0083] Water: 38 parts;

[0084] Functional admixtures: 0.8 parts polycarboxylate superplasticizer (solid weight), 0.3 parts sodium gluconate, and 0.05 parts air-entraining agent.

[0085] (3) Preparation steps

[0086] S1. Refined preparation of raw materials;

[0087] S2. Premixing of cementitious material components:

[0088] 21) Dry mix red mud and carbide slag in a forced mixer for 3-5 minutes until uniformly mixed to obtain a homogeneous composite alkaline activator component; 21) Mix granulated blast furnace slag and low-temperature activated calcined coal gangue powder uniformly in a pneumatic homogenization chamber to obtain an active powder component.

[0089] S3. Preparation of alkali-activated gelatinous paste:

[0090] Pre-dissolve water and functional additives, add alkaline activator components, stir for 1-2 minutes, then add active powder components, and stir in a planetary mixer at 120-150 r / min for 3-5 minutes to obtain a uniform slurry with an initial flowability of 180-220 mm.

[0091] S4. Concrete mixing:

[0092] Add fine aggregate and coarse aggregate sequentially to the uniform slurry obtained in step S3, stir until uniform, and control the outlet temperature at 10℃~35℃.

[0093] S5. Molding and Curing:

[0094] Pour the freshly mixed concrete from step S4 into the mold, compact it by low-frequency vibration at a frequency of 50-100Hz, cover the surface with a film to keep it moist, and cure it in a stepped humid heat until the specified age.

[0095] The stepped damp heat curing is carried out in a programmable curing chamber, and the specific curing control parameters are as follows:

[0096] Phase 1: 50℃, relative humidity ≥95%, curing time 4 hours;

[0097] Second stage: After heating to 80℃ at a rate of 12℃ / h, maintain relative humidity ≥90% and keep the temperature constant for 12 hours;

[0098] Third stage: After naturally cooling to room temperature, demold and continue standard curing for 28 days.

[0099] (4) Performance testing

[0100] Dry apparent density: 1680 kg / m³ 3 ;

[0101] 28-day compressive strength: 42.8 MPa;

[0102] Thermal conductivity: 0.25 W / (m·K);

[0103] Weighted sound insulation (100mm panel): 42dB;

[0104] Fire resistance limit (100mm thick plate): 2.6 hours;

[0105] Its combustion performance meets the requirements for Class A2 non-combustible materials.

[0106] Example 2

[0107] (1) Raw materials and pretreatment: Same as in Example 1.

[0108] (2) Proportion (parts by weight)

[0109] All-solid-waste fireproof cementitious material: 100 parts (red mud 18%, calcium carbide slag 11%, granulated blast furnace slag 42%, low-temperature activated calcined coal gangue powder 29%).

[0110] Lightweight aggregate from solid waste: 170 parts (coarse aggregate: fine aggregate = 1:1);

[0111] Water: 35 parts;

[0112] Functional admixtures: 0.8 parts polycarboxylate superplasticizer (solid weight), 0.3 parts sodium gluconate, and 0.05 parts air-entraining agent.

[0113] (3) Preparation steps: Same as in Example 1.

[0114] (4) Performance testing

[0115] Dry apparent density: 1725 kg / m³ 3 ;

[0116] 28-day compressive strength: 48.5 MPa;

[0117] Thermal conductivity: 0.28 W / (m·K);

[0118] Weighted sound insulation (100mm panel): 40dB;

[0119] Fire resistance rating (100mm thick plate): 2.3 hours;

[0120] Its combustion performance meets the requirements for Class A2 non-combustible materials.

[0121] Example 3 (Optimized formula, focusing on lower density and better thermal insulation performance)

[0122] (1) Raw materials and pretreatment

[0123] Red mud: Same as in Example 1;

[0124] Calcium carbide slag: Same as in Example 1;

[0125] Granulated blast furnace slag: Same as Example 1;

[0126] Low-temperature activated calcined coal gangue powder: Coal gangue (Al2O3 content ≥28wt%) is crushed to ≤5mm, calcined in a rotary kiln at 750℃ under controlled temperature gradient for 2.5 hours, and then rapidly cooled and ground to a specific surface area of ​​550m².2 / kg, amorphous silicon-aluminum phase content 75wt%, total content of active SiO2 and Al2O3 ≥50wt%, loss on ignition ≤5%;

[0127] High-temperature expanded roasted coal gangue lightweight aggregate: Coal gangue is crushed, screened, and pelletized, with the raw material pellet size distribution controlled to be 0-15mm; it is then roasted and expanded in a tunnel kiln at 1250℃ (heating rate of 100-200℃ / h) for 25 minutes, and slowly cooled to below 600℃ at a rate of less than 5℃ / min. The high-temperature expanded roasted coal gangue lightweight aggregate has a porous structure with a combination of closed-cell and interconnected-cell structures, and a continuous and dense aluminosilicate ceramic glaze layer with a thickness of 50-200μm is formed on the surface. Bulk density: 650kg / m³ 3 The compressive strength of the cylinder is 4.8 MPa, the water absorption rate is 9.5% in 1 hour, and the closed-cell rate is 65%. After screening and classification, coarse aggregate with a particle size of 5-15 mm and fine aggregate with a particle size of 0-5 mm are obtained.

[0128] Functional additives: polycarboxylate superplasticizer (40% solid content), sodium gluconate, rosin thermal polymer.

[0129] (2) Proportion (parts by weight)

[0130] All-solid-waste fireproof cementitious material: 100 parts (red mud 22%, calcium carbide slag 10%, granulated blast furnace slag 38%, low-temperature activated calcined coal gangue powder 30%).

[0131] Lightweight aggregate from solid waste: 230 parts (coarse aggregate: fine aggregate = 1.5:1);

[0132] Water: 40 parts;

[0133] Functional admixtures: 0.75 parts polycarboxylate superplasticizer (solid weight), 0.3 parts sodium gluconate, and 0.08 parts air-entraining agent.

[0134] (3) Preparation steps

[0135] S1 to S4 are the same as in Example 1;

[0136] S5. Molding and Curing:

[0137] Pour the freshly mixed concrete from step S4 into the mold, compact it by low-frequency vibration at a frequency of 50-100Hz, cover the surface with a film to keep it moist, and cure it in a stepped humid heat until the specified age.

[0138] The stepped damp heat curing is carried out in a programmable curing chamber, and the specific curing control parameters are as follows:

[0139] Phase 1: 40℃, relative humidity ≥95%, curing time 6 hours;

[0140] Second stage: After heating to 80℃ at a rate of 10℃ / h, maintain relative humidity ≥90% and keep the temperature constant for 20 hours;

[0141] Third stage: After naturally cooling to room temperature, demold and continue standard curing for 28 days.

[0142] (4) Performance testing

[0143] Dry apparent density: 1580 kg / m³ 3 ;

[0144] 28-day compressive strength: 36.2 MPa;

[0145] Thermal conductivity: 0.22 W / (m·K);

[0146] Weighted sound insulation (100mm panel): 43dB;

[0147] Fire resistance rating (100mm thick plate): 2.4 hours;

[0148] Its combustion performance meets the requirements for Class A2 non-combustible materials.

[0149] Comparative Example 1

[0150] By using PO 42.5 cement to replace the all-solid-waste fire-retardant cementitious material in this invention, the irreplaceable nature of the all-solid-waste fire-retardant cementitious material in terms of fire resistance and performance synergy was verified by comparison.

[0151] (1) Raw materials and pretreatment

[0152] PO 42.5 cement;

[0153] High-temperature expanded roasted coal gangue lightweight aggregate: Same as Example 1.

[0154] Functional admixtures: Same as in Example 1.

[0155] (2) Proportion (parts by weight)

[0156] PO 42.5 cement: 100 parts;

[0157] Lightweight aggregate from solid waste: 200 parts (120 parts coarse aggregate and 80 parts fine aggregate);

[0158] Water: 38 parts;

[0159] Functional admixture: 0.7 parts of polycarboxylate superplasticizer (consolidated).

[0160] (3) Preparation steps

[0161] S1. Using conventional cement concrete mixing process: First, dry mix cement and high-temperature expanded roasted coal gangue lightweight aggregate evenly, then add water containing functional admixtures, and stir for 5 minutes until uniform.

[0162] S2. Molding and curing: Pour the fresh concrete from step S1 into the mold, and compact it by low-frequency vibration at a frequency of 50-100Hz. Cover the surface with a film to keep it moist. After standing at room temperature for 24 hours with the mold on, remove it from the mold and immediately place it in a standard curing room (20±2℃, humidity ≥95%) for curing for 28 days.

[0163] (4) Performance testing

[0164] Dry apparent density: 1750 kg / m³ 3 ;

[0165] 28-day compressive strength: 38.5 MPa;

[0166] Thermal conductivity: 0.31 W / (m·K);

[0167] Weighted sound insulation (100mm panel): 38dB;

[0168] Fire resistance rating (100mm thick plate): 1.2 hours;

[0169] Combustion test: Under high temperature, the cement stone cracked and peeled off severely, and the structure failed rapidly.

[0170] Comparative Example 2

[0171] Commercial expanded clay aggregates were used to replace the high-temperature expanded roasted coal gangue lightweight aggregate in this invention. The key role of the high-temperature expanded roasted coal gangue lightweight aggregate (with a dense glaze layer on the surface and chemical compatibility with alkali-activated slurry) in achieving high-strength interface, excellent fire resistance and thermal insulation and sound insulation synergy was verified by comparison.

[0172] (1) Raw materials and pretreatment

[0173] Red mud: Same as in Example 1;

[0174] Calcium carbide slag: Same as in Example 1;

[0175] Granulated blast furnace slag: Same as Example 1;

[0176] Low-temperature activated calcined coal gangue powder: Same as in Example 1;

[0177] High-temperature expanded roasted coal gangue lightweight aggregate: replaced with commercially available shale ceramsite with similar performance indicators (800-grade shale ceramsite, particle size 5-10mm, bulk density 800kg / m³). 3 (Cylinder compressive strength 6.0 MPa, water absorption rate 5.0% in 1 hour).

[0178] Functional admixtures: Same as in Example 1.

[0179] (2) Proportion (parts by weight)

[0180] All-solid-waste fire-resistant cementitious material: Same as Example 1;

[0181] Shale ceramsite: 200 parts;

[0182] Water: Same as in Example 1;

[0183] Functional admixtures: Same as in Example 1.

[0184] (3) Preparation steps

[0185] S1 to S3 are the same as in Example 1;

[0186] S4. Concrete mixing:

[0187] Add shale ceramsite to the homogeneous slurry obtained in step S3, stir until homogeneous, and control the outlet temperature at 10℃~35℃.

[0188] S5. Molding and curing: Same as in Example 1.

[0189] (4) Performance testing

[0190] Dry apparent density: 1760 kg / m³ 3 ;

[0191] 28-day compressive strength: 36.8 MPa;

[0192] Thermal conductivity: 0.29 W / (m·K);

[0193] Weighted sound insulation (100mm panel): 39dB;

[0194] Fire resistance rating (100mm thick plate): 1.8 hours;

[0195] Combustion test: Cross-sectional observation revealed obvious annular gaps between the ceramsite and the slurry, with thermal damage penetrating along the interface.

[0196] Comparative Example 3

[0197] The use of mechanically ground raw coal gangue powder without low-temperature activated calcination proves that "low-temperature activated calcination" is the key to activating the chemical activity of coal gangue powder and transforming it from an inert filler into an active cementing component.

[0198] (1) Raw materials and pretreatment

[0199] Red mud: Same as in Example 1;

[0200] Calcium carbide slag: Same as in Example 1;

[0201] Granulated blast furnace slag: Same as Example 1;

[0202] Raw coal gangue powder: crushed and ground to a specific surface area of ​​510 m² 2 / kg;

[0203] High-temperature expanded roasted coal gangue lightweight aggregate: Same as Example 1.

[0204] Functional admixtures: Same as in Example 1.

[0205] (2) Proportion (parts by weight)

[0206] All-solid-waste fire-resistant cementitious material: Same as Example 1;

[0207] Lightweight aggregate from solid waste: Same as in Example 1;

[0208] Water: 48 parts; the reason is that the raw coal gangue powder has low activity and a large water requirement;

[0209] Functional admixtures: Same as in Example 1.

[0210] (3) Preparation steps

[0211] Same as Example 1. However, after vibration molding, water seepage was observed on the surface of the specimen.

[0212] (4) Performance testing

[0213] Dry apparent density: 1745 kg / m³ 3 ;

[0214] 28-day compressive strength: 31.5 MPa;

[0215] Thermal conductivity: 0.28 W / (m·K);

[0216] Weighted sound insulation (100mm panel): 39dB;

[0217] Fire resistance limit (100mm thick plate): 1.9 hours;

[0218] Combustion test: Observations revealed that more microcracks appeared on the surface of the sample after combustion.

[0219] Comparative Example 4

[0220] The fact that high-temperature puffing and roasting of coal gangue lightweight aggregate was not used, but only medium-temperature sintering, proves that "high-temperature puffing and roasting" is an irreplaceable physical structural construction condition.

[0221] (1) Raw materials and pretreatment

[0222] Red mud: Same as in Example 1;

[0223] Calcium carbide slag: Same as in Example 1;

[0224] Granulated blast furnace slag: Same as Example 1;

[0225] Low-temperature activated calcined coal gangue powder: Same as in Example 1;

[0226] Medium-temperature roasted coal gangue lightweight aggregate: Coal gangue is crushed, screened, and pelletized, with the particle size distribution of raw material pellets controlled to be 0-15mm; the raw material pellets are placed in a box-type resistance furnace, heated to 850℃ at 5℃ / min, and kept at a constant temperature for 60 minutes, and then cooled with the furnace.

[0227] Functional admixtures: Same as in Example 1.

[0228] (2) Proportion (parts by weight)

[0229] All-solid-waste fire-resistant cementitious material: Same as Example 1;

[0230] Medium-temperature roasted coal gangue lightweight aggregate: 300 parts; to maintain an aggregate volume similar to that of Example 1;

[0231] Water: 45 parts; the reason is that medium-temperature roasted coal gangue lightweight aggregate requires a large amount of water;

[0232] Functional admixtures: Same as in Example 1.

[0233] (3) Preparation steps

[0234] Same as Example 1.

[0235] During the mixing process, the aggregates rapidly absorb water, causing a rapid loss of workability in the slurry and resulting in a "bottoming out" phenomenon. Therefore, the "pre-wetted aggregates" method is adopted to prepare the slurry.

[0236] (4) Performance testing

[0237] Dry apparent density: 1920 kg / m³ 3 ;

[0238] 28-day compressive strength: 34.8 MPa;

[0239] Thermal conductivity: 0.48 W / (m·K);

[0240] Weighted sound insulation (100mm panel): 36dB;

[0241] Fire resistance rating (100mm thick plate): 1.5 hours;

[0242] Combustion test: Observation and analysis revealed that moisture rapidly vaporized from the interior of the highly absorbent aggregate, causing stress concentration at the weak interface between the aggregate and the slurry, resulting in interface peeling and swelling and cracking of the surface slurry.

[0243] Comparative Example 5

[0244] By omitting the calcination and roasting steps and using raw coal gangue powder and aggregates, the necessity of the two core pretreatment processes of "low-temperature activation calcination" and "high-temperature expansion roasting" of coal gangue in this invention is demonstrated.

[0245] (1) Raw materials and pretreatment

[0246] Red mud: Same as in Example 1;

[0247] Calcium carbide slag: Same as in Example 1;

[0248] Granulated blast furnace slag: Same as Example 1;

[0249] Raw coal gangue powder: crushed and ground to a specific surface area of ​​510 m² 2 / kg;

[0250] Lightweight aggregate: Coal gangue is crushed and screened to obtain raw coal gangue crushed stone (bulk density 1450 kg / m³). 3 (Water absorption rate > 15%).

[0251] Functional admixtures: Same as in Example 1.

[0252] (2) Proportion (parts by weight)

[0253] All-solid-waste fire-resistant cementitious material: Same as Example 1;

[0254] Lightweight aggregate: 200 parts;

[0255] Water: 52 parts; the reason is that the raw coal gangue powder has low activity and a large water requirement;

[0256] Functional admixtures: Same as in Example 1.

[0257] (3) Preparation steps

[0258] Same as Example 1. However, after vibration molding, water seepage was observed on the surface of the specimen.

[0259] (4) Performance testing

[0260] Dry apparent density: 1950 kg / m³ 3 ;

[0261] 28-day compressive strength: 22.4 MPa;

[0262] Thermal conductivity: 0.52 W / (m·K);

[0263] Weighted sound insulation (100mm panel): 38dB;

[0264] When the specimen was heated to about 300°C in the refractory test furnace, a loud noise was heard inside, followed by bursting and failure.

[0265] In summary, the test performance of the embodiments and comparative examples in this invention is shown in the table below:

[0266]

[0267] The comprehensive comparative analysis in the table above shows that the fireproof, sound-insulating, and heat-insulating lightweight high-strength all-solid-waste concrete (example) described in this invention significantly and reasonably outperforms all comparative examples in core properties such as dry apparent density, compressive strength, thermal conductivity, and fire resistance limit. This fully demonstrates the innovation and necessity of the invention's "solid-waste synergistic activation - microstructure design - functional integration," resolving the fundamental contradiction of the difficulty in synergistic performance of traditional materials. The systematic failures of the comparative examples, from the opposite perspective, verify the indispensability and synergistic effect of the various technical features of this invention. A detailed analysis follows:

[0268] 1. Synergistic effect of lightweight and high strength: The dry apparent density of the embodiments of the present invention is between 1580 kg / m³. 3 ~1725kg / m 3 The 28-day compressive strength ranged from 36.2 MPa to 48.5 MPa; while the dry apparent density of comparative examples 1 to 5 ranged from 1750 kg / m³. 3 ~1950kg / m 3 The 28-day compressive strength of Comparative Examples 3 and 5 was far less than 35.0 MPa, indicating that unactivated coal gangue cannot achieve lightweight and high strength. This invention achieves a qualitative change in the properties of solid waste through "low-temperature activated calcined coal gangue powder" and "high-temperature expanded roasted coal gangue lightweight aggregate," thus resolving the traditional contradiction between lightweight and high strength.

[0269] 2. Intrinsic high fire resistance: The fire resistance limit of the embodiments of this invention is between 2.3h and 2.6h; while the fire resistance limit of Comparative Example 1 is only 1.2h, and the cement stone suffers severe cracking and spalling at high temperatures, and the structure fails rapidly. The solid waste alkali-activated cementitious system of this invention forms a heat-resistant gel phase, which undergoes "controllable dehydration-ceramization" upon contact with fire, achieving intrinsic fire resistance without the need for external flame retardants.

[0270] 3. Strong Interface and Thermal Barrier: The 28-day compressive strength of Example 1 is 42.8 MPa, and the fire resistance limit is 2.6 h; while the 28-day compressive strengths of Comparative Examples 2 and 4 are 36.8 MPa and 34.8 MPa, respectively, and the fire resistance limits are 1.8 h and 1.5 h, respectively, indicating that the interface of ordinary lightweight aggregates (ceramsite, medium-temperature sintered coal gangue aggregates) is relatively weak. The dense glaze layer of the lightweight aggregate of this invention enhances the chemical-mechanical interlocking with the alkali-activated slurry, forming a high-strength and dense interface, which, together with the matrix, constitutes an effective thermal barrier at high temperatures (fire).

[0271] 4. Multifunctional integration: Comparative analysis of Examples 1-5 and Examples 1-3 shows that they are severely lacking in different dimensions; however, the present invention is not a simple replacement, but a systematic design from the molecular, microscopic to macroscopic levels, which enables the components (activator, active powder, lightweight aggregate) to work together deeply in chemical and physical aspects, effectively achieving performance multiplication and multifunctional integration.

[0272] In the description of this invention, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0273] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A fireproof, soundproof, and heat-insulating lightweight high-strength full-solid-waste concrete, characterized in that: The full-solid waste fireproof cementing material, the full-solid waste lightweight aggregate, water, and functional additives are included. ​ The full-solid waste fireproof cementing material includes an alkaline activator component and an active powder component; the alkaline activator component includes red mud and carbide slag in a mass ratio of 1.5-2.5:1, and the active powder component includes granulated blast furnace slag and low-temperature activated calcined coal gangue powder in a mass ratio of 1.0-1.8:

1. The full-solid waste lightweight aggregate includes coarse aggregate and fine aggregate in a mass ratio of 1-1.5:1; the coarse aggregate and the fine aggregate both include high-temperature puffing calcined coal gangue lightweight aggregate. The high-temperature puffing calcined coal gangue lightweight aggregate is obtained by screening and grading coal gangue after puffing and calcination at 1100-1300℃. The low-temperature activated calcined coal gangue powder is obtained by grinding the coal gangue after gradient temperature calcination at 650-800 DEG C to specific surface area ≥500 m 2 / kg. The full-solid waste fireproof cementing material, the full-solid waste lightweight aggregate, water, and functional additives are included.

2. The fireproof, soundproof, and thermal insulation type lightweight high-strength full-solid waste concrete according to claim 1, characterized in that, The full-solid waste fireproof cementing material, the full-solid waste lightweight aggregate, water, and functional additives are included. The content of each component is 18%-22% of red mud, 9%-11% of carbide slag, 38%-42% of granulated blast furnace slag, and 28%-32% of low-temperature activated calcined coal gangue powder, based on the total dry basis mass percentage of the full-solid waste fireproof cementing material.

4. The fireproof soundproof and heat-insulating lightweight high-strength full-solid waste concrete according to claim 3, characterized in that: The content of sodium oxide in the red mud is 4-8wt%; The content of calcium oxide in the carbide slag is ≥65wt%; 3.The fireproof, soundproof, and thermal insulation type light-weight and high-strength full-solid-waste concrete according to claim 1 or 2, characterized in that: The alkalinity coefficient of the granulated blast furnace slag is ≥1.2, and the 28d activity index is ≥95%; The content of amorphous silicon aluminum phase in the low-temperature activated calcined coal gangue powder is ≥70wt%, the total content of active SiO2 and Al2O3 is ≥50wt%, and the loss on ignition is ≤5%. The coarse aggregate includes high-temperature puffing calcined coal gangue lightweight aggregate with a particle size of 5-15mm, and the fine aggregate includes high-temperature puffing calcined coal gangue lightweight aggregate with a particle size of 0-5mm. The high-temperature puffing calcined coal gangue lightweight aggregate has a closed-communicating hole composite porous structure inside, and the closed hole rate is ≥60%; a continuous dense silicate ceramic glaze layer with a thickness of 50-200μm is formed on the surface of the high-temperature puffing calcined coal gangue lightweight aggregate. The functional additives are a compounding system of one or more of the following components: Plastic viscosity modifier, 0.2-1 parts; 5. The fireproof, soundproof, thermal insulation, light weight, high strength, and full solid waste concrete according to claim 1 or 2, characterized in that: Setting time regulator, 0.1-0.5 parts; 6. The fireproof, soundproof, thermal insulation, light weight, high strength, and full solid waste concrete according to claim 5, characterized in that: Air entraining agent, 0.05-0.2 parts; 7. The fireproof, soundproof, thermal insulation type light weight high strength full solid waste concrete according to claim 2, characterized in that, Toughening fiber, 0.1-0.3 parts. The method includes the following steps: S1. Fine preparation of raw materials: (2) Preparation of high-temperature puffing calcined coal gangue lightweight aggregate: coal gangue is crushed, screened, and formed into balls, and the particle size distribution of the raw material balls is controlled to be 0-15mm; the balls are calcined and puffed in a tunnel kiln at 1100-1300℃ for 15-30 minutes, and then screened and graded after slow cooling to obtain coarse aggregate and fine aggregate; S2. Premixing of cementing material components:

8. A method for preparing the fireproof, soundproof, thermal insulation, light weight, high strength, and full solid waste concrete according to any one of claims 1-7, characterized in that, (1) Dry mixing red mud and carbide slag in a forced mixer for 3-5 minutes to obtain a homogeneous composite alkaline activator component; (2) mixing granulated blast furnace slag and low-temperature activated calcined coal gangue powder in a pneumatic homogenizing bin to obtain an active powder component; S3. Preparation of alkaline-activated cementing slurry: (1) Low-temperature activated calcined coal gangue powder preparation: coal gangue is crushed to ≤5 mm, calcined in a rotary kiln at 650-800°C for 1-3 hours with gradient temperature control, and then rapidly cooled and ground to a specific surface area ≥500 m 2 / kg; ​ ​ ​ ​ The water is pre-dissolved with functional admixture, the alkaline activator component is added, after stirring for 1-2 minutes, the active powder component is added, and stirring is carried out in a planetary mixer at 120-150 r / min for 3-5 minutes to obtain a uniform slurry with an initial fluidity of 180-220 mm; S4. Concrete mixing: The fine aggregate and the coarse aggregate are sequentially added to the uniform slurry prepared in step S3, and stirring is carried out until uniform, and the temperature of the out-machine is controlled at 10-35℃; S5. Molding and curing: The freshly mixed concrete in step S4 is poured into a mold, low-frequency vibration compaction is carried out at a frequency of 50-100 Hz, and a surface film is used for moisture retention; and ladder-type wet heat curing is carried out until a specified age.

9. The preparation method according to claim 8, characterized in that, In step S1: (2), the temperature is raised to 1100-1300℃ at a rate of 100-200℃ / h, and slow cooling is carried out to below 600℃ at a rate of ≤5℃ / min.

10. The preparation method according to claim 8, characterized in that, In step S5, the ladder-type wet heat curing is carried out in a programmable curing box, and the specific curing control parameters are as follows: First stage: 40-60℃, relative humidity ≥95%, and curing time is 3-6 hours; Second stage: after the temperature is raised to 70-85℃ at a rate of 10-15℃ / h, the relative humidity is kept at ≥90%, and the constant temperature curing time is 8-16 hours; Third stage: natural cooling to room temperature.

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