Low-carbon low-shrinkage lightweight concrete prepared on basis of multi-source industrial solid wastes and preparation method of low-carbon low-shrinkage lightweight concrete

Abstract

The invention belongs to the technical field of building materials, and discloses low-carbon low-shrinkage lightweight concrete prepared on the basis of multi-source industrial solid wastes and a preparation method of the low-carbon low-shrinkage lightweight concrete. The low-carbon low-shrinkage lightweight concrete prepared on the basis of the multi-source industrial solid wastes is prepared from the following raw materials in parts by weight: 250 to 640 parts of cement, 150 to 250 parts of silica fume, 190 to 210 parts of fly ash microspheres, 260 to 650 parts of phosphorus slag, 1100 to 1300 parts of quartz sand, 10 to 15 parts of a de-foaming agent, 12 to 20 parts of a water reducing agent, 200 to 300 parts of water and 120 to 200 parts of fibers. According to the low-carbon low-shrinkage lightweight concrete prepared on the basis of the multi-source industrial solid waste, the synergistic utilization efficiency of the multi-source industrial solid waste can be remarkably improved, and high-value conversion of solid waste recycling is promoted; the comprehensive performance of low carbon, light weight and high strength can be considered, and the multiple performance requirements of modern structural materials are met.

Description

Low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste and its preparation method Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste and its preparation method. Background Technology

[0002] With the acceleration of global industrialization, the massive accumulation of industrial solid waste has placed severe pressure on the ecological environment. The traditional concrete industry, a typical high-energy-consuming and high-carbon-emission sector, consumes vast amounts of resources and releases huge amounts of CO2 during the production of its core raw material, cement. Meanwhile, traditional solid waste concrete generally suffers from insufficient strength, high brittleness, and susceptibility to shrinkage cracking, making it difficult to meet the stringent material performance requirements of modern engineering structures. Therefore, the construction industry's demand for high-performance, green, and low-carbon materials is increasingly urgent, especially in prefabricated buildings, large-span structures, and complex engineering scenarios. The contradiction between the lightweight requirements of prefabricated building components and the energy consumption of transportation and hoisting is prominent, necessitating concrete materials that combine lightweight, low-shrinkage deformation, and high strength. Against this backdrop, developing a new low-carbon, low-shrinkage concrete technology that uses multi-source industrial solid waste as the main raw material and significantly increases the solid waste content (to 50%–80%) can not only promote the large-scale disposal of solid waste and the development of the circular economy industry, but also respond to the national "dual-carbon" strategic goal, assist in the green transformation of the construction industry, and fill the market's technological gap for high-performance ecological building materials.

[0003] Currently, the preparation of lightweight solid waste-based concrete using low-carbon cementitious material systems composed of solid waste as composite aggregates faces challenges. These include limited solid waste utilization rates, immature multi-source solid waste co-utilization technologies, and low solid waste resource recovery efficiency. Furthermore, most low-carbon lightweight concretes have low strength, making it difficult to balance high compressive strength and low shrinkage, a significant challenge in the field. Related technologies focus on the mix design and development of low-carbon lightweight concrete. While some progress has been made in solid waste resource recovery and lightweighting, the utilization rate of the currently abundant lightweight solid waste materials remains low, limiting its application. Additionally, methods to reduce concrete weight, such as adding air-entraining agents and foam, create pores within the concrete to lower density. However, the uneven pore structure significantly reduces the mechanical properties of the concrete, failing to produce high-performance lightweight solid waste concrete. While incorporating ultrafine aggregates and fibers is an effective way to improve concrete performance, this solution increases concrete density, fundamentally conflicting with the lightweight requirements of prefabricated buildings.

[0004] Therefore, the main problem we face is how to comprehensively improve the utilization rate of solid waste in building materials, develop a low-carbon, low-shrinkage lightweight concrete by combining the intrinsic characteristics and limitations of various solid waste materials, and make the new concrete have excellent workability and mechanical properties, so as to provide a new generation of structural materials for prefabricated buildings that have both ecological benefits and engineering applicability. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to propose a low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste and its preparation method. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste provided by this invention can significantly improve the synergistic utilization efficiency of multi-source industrial solid waste, promote the high-value transformation of solid waste resources, and simultaneously achieve low-carbon, lightweight, and high-strength comprehensive performance, meeting the multiple performance requirements of modern structural materials.

[0006] In a first aspect, the present invention proposes a low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, wherein the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste comprises the following raw materials by weight: 250-640 parts cement, 150-250 parts silica fume, 190-210 parts fly ash microspheres, 260-650 parts phosphorus slag, 1100-1300 parts quartz sand, 10-15 parts defoamer, 12-20 parts water-reducing agent, 200-300 parts water, and 120-200 parts fiber.

[0007] According to the above embodiments of the present invention, the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, compared with the concrete systems of the prior art that only use a single or small amount of industrial solid waste, achieves the synergistic substitution of cement by multiple industrial solid wastes such as fly ash microspheres, silica fume, and phosphorus slag through optimized raw material ratios. The high admixture content significantly increases the application ratio of lightweight solid waste materials. This synergistic composite system fully leverages the reinforcing and synergistic properties of various solid wastes, achieving the formation of a cementitious system with balanced and complementary performance. This effectively solves the problems of low solid waste utilization and limited applicability in the prior art, significantly improving the resource utilization efficiency of industrial solid waste. Furthermore, by optimizing the mix design and process control, the present invention, without introducing a large number of porous structures, utilizes the synergistic reinforcement mechanism of ultrafine powder active components and steel fibers to prepare lightweight concrete materials with both C60 and above strength grades and low shrinkage performance, breaking through the technical bottleneck of "lightweight and strength cannot be simultaneously achieved" in the prior art. This low-carbon, low-shrinkage lightweight concrete, prepared from multi-source industrial solid waste, not only meets the requirements of lightweighting, but also possesses excellent crack resistance and deformation coordination due to the retarding effect of phosphorus slag on the materials in the cementitious system and the subsequent pozzolanic reaction. It is particularly suitable for the high-performance requirements of prefabricated building structural components and joint structures.

[0008] In addition, the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste according to the above embodiments of the present invention may also have the following additional technical features: In some embodiments of the present invention, the cement comprises P·O 52.5 grade silicate cement; and / or, based on the total mass of the cement, the mass percentage of CaO is 55%~57%; and / or, the specific surface area of ​​the cement is 410 m². 2 / kg~430m 2 / kg; and / or, based on the total mass of the raw materials for the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, the sum of the mass percentages of the fly ash microspheres, the silica fume, and the phosphorus slag is 50% to 80%. Therefore, the low-carbon, lightweight, and high-strength comprehensive properties of the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste can be considered.

[0009] In some embodiments of the present invention, the specific surface area of ​​the silica fume is ≥1.5×10⁻⁶. 4 m 2 / kg; and / or, based on the total mass of the silica fume, the mass percentage of SiO2 is ≥85%. Thus, the low-carbon, low-shrinkage, and high-strength comprehensive properties of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste can be achieved.

[0010] In some embodiments of the present invention, the specific surface area of ​​the fly ash microspheres is ≥1200 m². 2 / kg; and / or, the volume average particle size d50 of the fly ash microspheres is ≤3μm. Thus, the low-carbon, low-shrinkage, and high-strength comprehensive properties of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste can be achieved.

[0011] In some embodiments of the present invention, the particle size of the quartz sand is 20-40 mesh. This allows for a balance of low carbon content, lightweight properties, and high strength in low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0012] In some embodiments of the present invention, the specific surface area of ​​the phosphorus slag is ≥350 m². 2 / kg; and / or, the calcination vector of the phosphorus slag is ≤3.0%; and / or, based on the total mass of the phosphorus slag, the mass percentage of P2O3 is ≤3.5%; and / or, the 7-day activity index of the phosphorus slag is ≥60%. Thus, the low-carbon, low-shrinkage, lightweight concrete prepared from multi-source industrial solid waste can achieve a comprehensive performance of low carbon content, lightweight, and high strength.

[0013] In some embodiments of the present invention, the fiber comprises copper-plated steel fiber; and / or, the fiber is straight rod-shaped; and / or, the fiber length is 11.7 mm to 14.3 mm; and / or, the effective diameter of the fiber is 180 μm to 220 μm. Thus, the low-carbon, low-shrinkage, lightweight concrete prepared from multi-source industrial solid waste can achieve a combination of low carbon content, lightweight properties, and high strength.

[0014] In some embodiments of the present invention, the defoamer is a mixture of liquid hydrocarbons and polyglycerols with an inorganic carrier as the base; and / or, the water-reducing agent comprises modified polycarboxylic acid; and / or, the water-reducing agent has a density of 0.40 g / cm³. 3 ~0.55g / cm 3 Therefore, it is possible to take into account the comprehensive properties of low carbon, lightweight and high strength of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0015] In a second aspect of the invention, a method for preparing low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste as described in the first aspect is proposed, comprising: mixing cement, silica fume, fly ash microspheres, phosphorus slag and defoamer evenly; adding a pre-mixed water-reducing agent and water mixture; stirring to form a homogeneous slurry; adjusting the stirring speed to 275 r / min to 295 r / min; adding quartz sand to the homogeneous slurry; stirring to form a homogeneous mortar; reducing the stirring speed to 135 r / min to 145 r / min; and adding fiber evenly multiple times; stirring to form a fiber mixture; loading the fiber mixture into a mold whose inner wall has been coated with a thin layer of mineral oil; allowing it to stand for 20 h to 25 h; removing the mold; and curing to obtain low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste.

[0016] Therefore, the method for preparing low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste proposed in this invention, compared with some existing technologies that require complex chemical foaming and air entrainment processes to reduce concrete density, resulting in uneven pore structure and unstable product performance, adopts conventional mechanical mixing and step-by-step feeding processes, combined with multiple low-speed fiber dispersion methods, to ensure uniform material distribution and fiber dispersion effect. The process is simple and controllable, easy to standardize and promote, and is particularly suitable for the factory-based and large-scale production of precast components, significantly improving the engineering applicability and universality of the new material.

[0017] In some embodiments of the present invention, the settling temperature is 18°C ​​to 22°C; and / or, the relative humidity of the environment during settling is 50%RH to 70%RH; and / or, the curing temperature is 18°C ​​to 22°C; and / or, the relative humidity of the curing environment is ≥95%RH. Thus, the resulting concrete can balance both strength and ductility.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 shows a schematic flow diagram of a method for preparing low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste according to an embodiment of the present invention. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] In a first aspect, the present invention proposes a low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, wherein the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste comprises the following raw materials by weight: 250-640 parts cement, 150-250 parts silica fume, 190-210 parts fly ash microspheres, 260-650 parts phosphorus slag, 1100-1300 parts quartz sand, 10-15 parts defoamer, 12-20 parts water-reducing agent, 200-300 parts water, and 120-200 parts fiber.

[0022] For example, the weight percentages of cement can be 250 parts, 300 parts, 350 parts, 400 parts, 450 parts, 500 parts, 550 parts, 600 parts, 640 parts, etc.; the weight percentages of silica fume can be 150 parts, 175 parts, 200 parts, 225 parts, 250 parts, etc.; the weight percentages of fly ash microspheres can be 190 parts, 195 parts, 200 parts, 205 parts, 210 parts, etc.; and the weight percentages of phosphorus slag can be 260 parts, 300 parts, 350 parts, 400 parts, 450 parts, 500 parts, 550 parts, 600 parts, etc. The weight parts of the following materials can be as follows: 650 parts, etc.; the weight parts of the quartz sand can be 1100 parts, 1150 parts, 1200 parts, 1250 parts, 1300 parts, etc.; the weight parts of the defoamer can be 10 parts, 12 parts, 14 parts, 15 parts, etc.; the weight parts of the water-reducing agent can be 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, etc.; the weight parts of the water can be 200 parts, 220 parts, 240 parts, 260 parts, 280 parts, 300 parts, etc.; and the weight parts of the fiber can be 120 parts, 140 parts, 160 parts, 180 parts, 200 parts, etc.

[0023] According to the above embodiments of the present invention, the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, compared with the concrete systems of the prior art that only use a single or small amount of industrial solid waste, achieves the synergistic substitution of cement by multiple industrial solid wastes such as fly ash microspheres, silica fume, and phosphorus slag through optimized raw material ratios. The high admixture content significantly increases the application ratio of lightweight solid waste materials. This synergistic composite system fully leverages the reinforcing and synergistic properties of various solid wastes, achieving the formation of a cementitious system with balanced and complementary performance. This effectively solves the problems of low solid waste utilization and limited applicability in the prior art, significantly improving the resource utilization efficiency of industrial solid waste. Furthermore, by optimizing the mix design and process control, the present invention, without introducing a large number of porous structures, utilizes the synergistic reinforcement mechanism of ultrafine powder active components and steel fibers to prepare lightweight concrete materials with both C60 and above strength grades and low shrinkage performance, breaking through the technical bottleneck of "lightweight and strength cannot be simultaneously achieved" in the prior art. This low-carbon, low-shrinkage lightweight concrete, prepared from multi-source industrial solid waste, not only meets the requirements of lightweighting, but also possesses excellent crack resistance and deformation coordination due to the retarding effect of phosphorus slag on the materials in the cementitious system and the subsequent pozzolanic reaction. It is particularly suitable for the high-performance requirements of prefabricated building structural components and joint structures.

[0024] According to an embodiment of the present invention, the cement comprises P·O 52.5 grade Portland cement, wherein P·O represents "Portland Ordinary cement"; 52.5 indicates that the cement has a 28-day compressive strength of not less than 52.5 MPa under standard curing conditions. Therefore, by using the above-mentioned Portland cement, the strength and long-term stability of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste can be improved, resulting in high performance of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste.

[0025] According to an embodiment of the present invention, the mass percentage of CaO based on the total mass of the cement is 55% to 57%. For example, it can be 55%, 55.5%, 56%, 56.5%, 57%, etc. Thus, by controlling the calcium oxide content in the cement within the above range, the strength and safety of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste can be improved.

[0026] According to an embodiment of the present invention, the specific surface area of ​​the cement is 410 m². 2 / kg~430m 2 / kg. For example, it could be 410m 2 / kg, 415m 2 / kg, 420m 2 / kg, 425m 2 / kg, 430m 2 By controlling the specific surface area of ​​cement within the above range (e.g., / kg), the density of the paste is optimized and improved, effectively enhancing mechanical properties and shrinkage control capabilities. This constructs an internally self-compacting, highly filled cementitious system, achieving a significant reduction in self-shrinkage without the addition of shrinkage-reducing agents or expansion agents. This addresses the root cause of the problems of strong shrinkage dependence and poor long-term stability in traditional high-performance low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, thereby improving the material's strength, structural safety, and service life.

[0027] According to an embodiment of the present invention, based on the total mass of the raw materials for the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, the sum of the mass percentages of the fly ash microspheres, the silica fume, and the phosphorus slag is 50% to 80%. For example, it can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, etc. The fly ash microspheres, the silica fume, and the phosphorus slag are all industrial solid wastes. By controlling the content of the above-mentioned solid wastes in the raw materials for the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid wastes within the above range, the above-mentioned substances can synergistically replace cement, with high admixture content, significantly increasing the application ratio of lightweight solid waste materials, and having high environmental protection significance.

[0028] According to an embodiment of the present invention, the specific surface area of ​​the silica fume is ≥1.5×10⁻⁶.4 m 2 / kg, for example, could be 1.5 × 10 4 m 2 / kg, 1.6×10 4 m 2 / kg, 1.7×10 4 m 2 / kg, 1.8×10 4 m 2 / kg, 1.9×10 4 m 2 / kg, etc., control the specific surface area of ​​silica fume within the above range, improve the slurry density through particle size distribution optimization, effectively enhance mechanical properties and shrinkage control capabilities, and achieve a synergistic unity of low carbon and high performance.

[0029] According to an embodiment of the present invention, based on the total mass of the silica fume, the mass percentage of SiO2 is ≥85%, for example, it can be 85%, 87.5%, 90%, 92.5%, 95%, etc. By controlling the mass percentage of SiO2 in the silica fume within the above range, a high degree of compatibility between silica fume and water-reducing agent can be achieved, thereby realizing high strength and high durability of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste.

[0030] According to an embodiment of the present invention, the specific surface area of ​​the fly ash microspheres is ≥1200 m². 2 / kg, for example, could be 1200m 2 / kg, 1300m 2 / kg, 1400m 2 / kg, 1500m 2 / kg, 1600m 2 / kg, 1700m 2 / kg, 1800m 2 / kg, 1900m 2 / kg, 2000m 2 By controlling the specific surface area of ​​fly ash microspheres within the specified range (e.g., per kg), the particle size of the fly ash microspheres becomes smaller, which is beneficial for constructing an internally self-compacting, highly filled cementitious system. Furthermore, the fly ash microspheres are lightweight, enabling the production of low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste. This achieves the formation of a cementitious system from various raw materials, with balanced and complementary performance. It significantly reduces the self-shrinkage of low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste without adding shrinkage-reducing or expanding agents. This addresses the root cause of the strong shrinkage dependence and poor long-term stability issues inherent in traditional high-performance low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste, thereby improving the strength and low carbon content of the concrete.

[0031] According to an embodiment of the present invention, the volume average particle size d50 of the fly ash microspheres is ≤3μm. For example, it can be 0.1μm, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, etc. Controlling the volume average particle size d50 of the fly ash microspheres within the above range further facilitates the construction of an intrinsically self-compacting, highly filled cementitious system. This significantly reduces self-shrinkage without adding shrinkage-reducing agents or expansion agents, fundamentally solving the problems of strong shrinkage dependence and poor long-term stability of traditional high-performance low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste. This further improves the structural safety and service life of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0032] It is understood that volume average particle size is a well-known term in the field, also known as median particle size or average particle size d50, used to represent the average particle size of powder. Physically, it means that particles smaller than this size account for 50% of the total particle volume, and particles larger than this size also account for 50% of the total particle volume. Volume average particle size can be conveniently determined using a laser particle size analyzer, such as GB / T19077-2016 "Particle Size Distribution - Laser Diffraction Method", using the Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK.

[0033] According to an embodiment of the present invention, the particle size of the quartz sand is 20 mesh to 40 mesh, for example, it can be 20 mesh, 25 mesh, 30 mesh, 35 mesh, 40 mesh, etc. Controlling the particle size of the quartz sand within the above range is beneficial to the particle size matching with other components of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste, optimizes and improves the density of the paste, effectively enhances the mechanical properties and shrinkage control capability of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste, and achieves the synergistic unity of low carbon and high performance in low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste.

[0034] According to an embodiment of the present invention, the specific surface area of ​​the phosphorus slag is ≥350 m². 2 / kg, for example, could be 350m 2 / kg, 360m 2 / kg, 370m 2 / kg, 380m 2 / kg, 390m 2 / kg, by controlling the specific surface area of ​​phosphorus slag within the above range, its advantages in improving later strength and durability can be maximized. It can achieve low shrinkage of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste, while controlling the risks of retarded setting and early strength loss.

[0035] According to an embodiment of the present invention, the loss on ignition of the phosphorus slag is ≤3.0%; for example, it can be 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, etc. The loss on ignition of phosphorus slag refers to the percentage of mass lost by phosphorus slag after high-temperature ignition. Controlling the loss on ignition of phosphorus slag within the above range can reduce the collapse of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste during use, reduce the carbon content of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, and improve the strength, durability, and stability of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0036] According to an embodiment of the present invention, based on the total mass of the phosphorus slag, the mass percentage of P2O3 is ≤3.5%; for example, it can be 1.0%, 1.5%, 2.0%, 2.5%, or 3.0%. Controlling the P2O3 content in the phosphorus slag within the above range can improve the fluidity and setting time of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, and enhance the impermeability, durability, and stability of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0037] According to an embodiment of the present invention, the 7-day activity index of the phosphorus slag is ≥60%. For example, it can be 60%, 65%, 70%, 75%, or 80%. Referring to the GB / T 18736 standard, the 7-day activity index is calculated as follows: Activity Index = 7-day compressive strength of reference mortar / 7-day compressive strength of test mortar × 100%. Controlling the 7-day activity index of the phosphorus slag within the above range can further improve the fluidity and setting time of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, and enhance the impermeability, durability, and stability of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0038] According to an embodiment of the present invention, the steel fiber includes copper-plated steel fiber, which has good mechanical properties and interfacial anchoring effect. It has good dispersibility and stable interfacial bonding performance in low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste, and has high reinforcement efficiency. It can further improve the later-stage ductility and crack resistance of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste, and effectively solve the engineering problem of difficulty in achieving both strength and ductility.

[0039] According to an embodiment of the present invention, the steel fiber is in the shape of a straight rod. Straight rod steel fibers can enhance the strength of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0040] According to an embodiment of the present invention, the length of the steel fiber is 11.7mm to 14.3mm, for example, it can be 12mm, 12.5mm, 13mm, 13.5mm, 14mm, etc. Controlling the length of the steel fiber within the above range can further enhance its dispersibility and interfacial bonding performance in low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste, and further improve the later-stage ductility and crack resistance of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste.

[0041] According to an embodiment of the present invention, the effective diameter of the steel fiber is 180μm~220μm, for example, it can be 180μm, 190μm, 200μm, 210μm, 220μm, etc. Controlling the effective diameter of the steel fiber within the above range can further enhance its dispersibility and interfacial bonding performance in low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste, and further improve the later-stage ductility and crack resistance of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste.

[0042] It can be understood that the "effective diameter" (also known as the "equivalent diameter") is the calculated diameter obtained by converting a fiber of any cross-sectional shape into a circular cross-section according to the principle of equal cross-sectional area.

[0043] According to an embodiment of the present invention, the defoamer is a mixture of an inorganic carrier as a base, a liquid hydrocarbon and a polyglycerol. This composite defoamer is highly compatible with cement-based materials and can achieve instantaneous defoaming and continuous foam suppression. It can achieve multiple goals such as rapid defoaming, long-term foam suppression, convenient construction, cost optimization and green environmental protection while maintaining the mechanical properties and durability of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0044] It is understandable that inorganic carriers can include SiO2, Al2O3, bentonite, perlite, etc.; liquid hydrocarbons can include white oil, mineral oil, C12-C18 alkanes, etc.

[0045] According to an embodiment of the present invention, the water-reducing agent includes modified polycarboxylic acid. The water-reducing agent has a high compatibility with silica fume, which can further improve the strength and durability of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste.

[0046] According to an embodiment of the present invention, the density of the water-reducing agent is 0.40 g / cm³. 3 ~0.55g / cm 3 For example, it could be 0.40 g / cm³. 3 0.42 g / cm 3 0.45g / cm 3 0.47 g / cm 3 0.5g / cm3 0.52g / cm 3 0.54 g / cm 3 0.55g / cm 3 By controlling the density of the water-reducing agent within the above range, the strength stability of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste can be further improved.

[0047] In a second aspect of the present invention, the present invention proposes a method for preparing low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste as described in the first aspect. Please refer to Figure 1. The method includes: S1, mixing cement, silica fume, fly ash microspheres, phosphorus slag and defoamer evenly, adding a pre-mixed water-reducing agent and water mixture, stirring to form a homogeneous slurry, adjusting the stirring speed to 275 r / min~295 r / min, adding quartz sand to the homogeneous slurry, stirring to form a uniform mortar, reducing the stirring speed to 135 r / min~145 r / min, and adding fiber evenly multiple times while stirring, stirring evenly to form a fiber mixture.

[0048] In this step, multiple low-speed fiber dispersion methods are used to ensure the uniformity of material distribution and fiber dispersion effect, further enabling the low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste to take into account both high compressive strength and high ductility.

[0049] S2. The fiber mixture is loaded into a mold whose inner wall has been coated with a thin layer of mineral oil, left to stand for 20-25 hours, then demolded and cured to obtain low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste.

[0050] For example, the settling time can be 20h, 21h, 22h, 23h, 24h, 25h, etc.

[0051] According to some embodiments of the present invention, the settling temperature is 18°C ​​to 22°C. For example, it can be 18°C, 19°C, 20°C, 21°C, 22°C, etc., which facilitates the uniform curing of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, ensuring uniformity, and taking into account both the strength and ductility of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0052] According to some embodiments of the present invention, the relative humidity of the environment during the static setting is 50%RH to 70%RH. For example, it can be 50%RH, 55%RH, 60%RH, 65%RH, 70%RH, etc., which facilitates the uniform curing of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, ensuring uniformity, and taking into account both the strength and ductility of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0053] According to some embodiments of the present invention, the curing temperature is 18℃~22℃, for example, it can be 18℃, 19℃, 20℃, 21℃, 22℃, etc., thereby facilitating the uniform curing of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste, ensuring uniformity, and taking into account both the strength and ductility of low-carbon, low-shrinkage lightweight concrete prepared based on multi-source industrial solid waste.

[0054] According to some embodiments of the present invention, the relative humidity of the curing environment is ≥95%RH. For example, it can be 95%RH, 96%RH, 97%RH, 98%RH, 99%RH, 100%RH, etc., thereby further balancing the strength and ductility of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste.

[0055] In summary, the method for preparing low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste proposed in this invention addresses the problems of uneven pore structure and unstable product performance caused by some existing technologies that require complex chemical foaming and air entrainment processes to reduce the density of low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste. This invention adopts conventional mechanical stirring and step-by-step feeding processes, combined with multiple low-speed fiber dispersion methods, to ensure uniform material distribution and fiber dispersion effect. The process is simple and controllable, easy to standardize and promote, and is particularly suitable for the factory-based and large-scale production of precast components, significantly improving the engineering applicability and universality of the new material.

[0056] The present disclosure will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the disclosure. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0057] Example 1 This example discloses a low-carbon, low-shrinkage, lightweight concrete based on multi-source industrial solid waste and its preparation method. The specific mass parts are: cement 640, silica fume 200, fly ash microspheres 200, phosphorus slag 260, quartz sand 1200, defoamer 13, water-reducing agent 13, water 208, and fiber 156.

[0058] Example 2 This example discloses a low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste and its preparation method. The specific mass parts are: cement 510, silica fume 200, fly ash microspheres 200, phosphorus slag 390, quartz sand 1200, defoamer 13, water-reducing agent 13, water 208, and fiber 156.

[0059] Example 3 This example discloses a low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste and its preparation method. The specific mass parts are: cement 380, silica fume 200, fly ash microspheres 200, phosphorus slag 520, quartz sand 1200, defoamer 13, water-reducing agent 13, water 208, and fiber 156.

[0060] Example 4 This example discloses a low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste and its preparation method. The specific mass parts are: cement 250, silica fume 200, fly ash microspheres 200, phosphorus slag 650, quartz sand 1200, defoamer 13, water-reducing agent 13, water 208, and fiber 156.

[0061] In Examples 1-4 above, the cement was P·O 52.5 grade Portland cement with a CaO content of 55.95% and a specific surface area of ​​420 m². 2 / kg; Specific surface area of ​​silica fume 1.81×10 4 m 2 / kg, SiO2 content 93.77%; fly ash microspheres specific surface area ≥1200m² 2 / kg, fineness (d50) is 1.62μm; specific surface area of ​​phosphorus slag is 385m². 2 / kg, calcination vector is 1.2%, based on the total mass of phosphorus slag, the mass ratio of P2O3 is 1.25%, and the 7-day activity index of phosphorus slag is 70%; the particle size of quartz sand is 20~40 mesh; the steel fiber is copper-plated steel fiber, straight rod shape, length 12.97mm, effective diameter 200μm; the defoamer is a mixture of liquid hydrocarbons and polyglycerol with inorganic carrier as base; the main component of the water-reducing agent is modified polycarboxylic acid, Sika ViscoCrete-540P powder water-reducing agent, density 0.40~0.55g / cm³. 3 .

[0062] The low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste in Examples 1-4 above was prepared by the following steps: (1) Cement, silica fume, fly ash microspheres, phosphorus slag and defoamer were mixed evenly, and a mixed solution of water-reducing agent and water that had been mixed evenly in advance was added and stirred into a homogeneous slurry. The stirring speed was adjusted to 285±10r / min, and quartz sand was added to the homogeneous slurry. After stirring for a period of time to form a homogeneous mortar, the stirring speed was reduced to 140±5r / min. , and add the fiber evenly multiple times and stir until it is evenly mixed to make a fiber mixture; (2) Put the mixture from step (1) into a mold whose inner wall is already covered with a thin layer of mineral oil, use a spatula to tamp along the mold wall and scrape off the excess mixture at the top of the mold; (3) After the mold containing the mixture from step (2) is left to stand for 24 hours at room temperature of 20℃±2℃ and relative humidity of 60±10%RH, remove the mold and place it in a curing room of 20℃±2℃ and relative humidity of 95%RH or higher for 28 days.

[0063] Comparative Example 1 cites "Example 2" from the patent "A Low-Shrinkage, Environmentally Friendly, Economical, and High-Ductility Cement-Based Composite Material and Its Preparation Method" (Application No. 202410774241.5), specifically including the following raw materials by weight: 307 parts cement, 816 parts fly ash, 319 parts water, 375 parts recycled fine aggregate, 26.8 parts polyvinyl alcohol fiber, and 3.8 parts water-reducing agent. In Comparative Example 1, the cement is P·O 52.5 ordinary Portland cement; the recycled fine aggregate has a particle size of less than 1.18 mm; the fly ash is Grade I fly ash; the polyvinyl alcohol fiber has a length of 9 mm, an elongation of 7%, a diameter of 15.3 μm, a tensile strength of 1830 MPa, and an elastic modulus of 40 GPa; the water-reducing agent is a polycarboxylate water-reducing agent.

[0064] Comparative Example 2 cites "Example 2" from the patent "A Low-Shrinkage, High-Elongation Green Cement-Based Composite Material" (Application No. 201910368899.5), specifically including the following raw materials by weight: 50 parts cement, 30 parts fly ash, 15 parts granulated blast furnace slag, 15 parts metakaolin, 0.2 parts polycarboxylate superplasticizer, 9 parts calcium sulfoaluminate expansive agent, 0.3 parts dispersible latex powder, 0.3 parts defoamer, 45 parts sand, and 32 parts water, wherein hydrophilic polyvinyl alcohol fiber accounts for 0.9% of the total weight. In Comparative Example 2, the cement is P·O 52.5 ordinary Portland cement; the fly ash is Class F Grade 1 fly ash; the granulated blast furnace slag is S105 grade; the metakaolin has a mesh size of 200 mesh; and the sand is manufactured sand with a particle size of less than 0.6 mm.

[0065] Comparative Example 3 used concrete made entirely of P·O 52.5 ordinary Portland cement as the cementing material, specifically comprising the following raw materials by weight: cement 1300, quartz sand 1200, defoamer 13, water-reducing agent 13, water 208, and steel fiber 156. The raw materials in Comparative Example 3 are consistent with those in the method of this invention.

[0066] The compressive strength of the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste in the examples and comparative examples was tested according to GB / T 17671-2021 "Test Method for Compressive Strength of Cement Mortar (ISO Method)". The tensile strength of the concrete in the examples and comparative examples was tested according to JC / T 2461-2018 "Test Method for Mechanical Properties of High-Ductility Fiber-Reinforced Cement-Based Composite Materials". The autogenous shrinkage test was conducted according to GB / T 50082-2024 "Standard for Test Methods of Long-Term Performance and Durability of Concrete". The test results are shown in Table 1.

[0067] Table 1

[0068] Mechanical property tests were conducted on the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste in Examples 1-4 obtained by the above steps. The results showed that its performance met the requirements of GB / T 51231-2016 "Technical Standard for Prefabricated Concrete Buildings" and JGJ 1-2014 "Technical Specification for Prefabricated Concrete Structures". The density of the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste in Example 1 was 2405 kg / m³. 3 The average autogenous shrinkage over 7 days was -671 με, and the average compressive strength over 28 days was 110.8 MPa. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste in Example 2 had a density of 2397 kg / m³. 3 The average autogenous shrinkage over 7 days was -574 με, and the average compressive strength over 28 days was 101.0 MPa. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste in Example 3 had a density of 2392 kg / m³. 3 The average autogenous shrinkage over 7 days was -420 με, and the average compressive strength over 28 days was 88.9 MPa. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste in Example 4 had a density of 2383 kg / m³. 3 The average autogenous shrinkage over 7 days is -358 με, and the average compressive strength over 28 days is 77.0 MPa.

[0069] Compared with Comparative Examples 1-3, the low-carbon, low-shrinkage lightweight concrete prepared by Examples 1-4 based on multi-source industrial solid waste according to the method of the present invention exhibits a maximum autogenous shrinkage of 671 με after 7 days, which is 4.0% to 28.2% lower than that of Comparative Examples 1-3. The minimum compressive strength of the low-carbon, low-shrinkage lightweight concrete prepared by Examples 1-4 based on multi-source industrial solid waste is 77.0 MPa, which is at least 116 MPa higher than that of Comparative Examples 1 and 2. 3% and 65.2%; The minimum flexural strength of the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste in Examples 1-4 was 18.5 MPa, which was at least 293.6% higher than that of Comparative Example 1; The minimum tensile strength of the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste in Examples 1-4 was 3.9 MPa, which was at least 34.5% and 69.6% higher than that of Comparative Examples 1 and 3, respectively; The maximum density of the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste in Examples 1-4 was 2405 kg / m³. 3 Compared to Comparative Example 3, the mass of low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste can be reduced by at least 131 kg per cubic meter; the carbon emissions of Examples 1-4 are reduced by 36.9-55.2% compared to Comparative Example 3.

[0070] Based on the test results of the above embodiments and the comparison results with the comparative examples, Examples 1-4 constructed a composite technology system for low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste. This system is based on "multi-element solid waste synergistic cementation," controlled shrinkage through "low heat of hydration and internal curing," and supplemented by "fiber toughening." Through the physical and chemical interactions of each component, this system optimizes the pore structure and interfacial properties at the microscale, simultaneously achieving multiple objectives of high strength, low shrinkage, lightweight, and low carbonization at the macroscale. The 28-day compressive strength reaches the C60 standard, significantly higher than other low-carbon, low-shrinkage concretes, and the maximum autogenous shrinkage is 671 με, exhibiting excellent mechanical and workability properties. The low-carbon, low-shrinkage lightweight concrete utilizes industrial solid waste materials to replace cement at a rate of up to 80%, significantly reducing cement usage. The mass of each cubic meter of concrete can be reduced by up to 131 kg, and carbon emissions and autogenous shrinkage can be reduced by up to 50.0%, providing a reliable technical path for the high-value utilization of industrial solid waste and the green transformation of the construction industry.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," "some implementations," 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 present 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0072] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, characterized in that, The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste comprises the following raw materials by weight: 250-640 parts cement, 150-250 parts silica fume, 190-210 parts fly ash microspheres, 260-650 parts phosphorus slag, 1100-1300 parts quartz sand, 10-15 parts defoamer, 12-20 parts water-reducing agent, 200-300 parts water, and 120-200 parts fiber.

2. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste according to claim 1, characterized in that, The cement comprises P·O 52.5 grade Portland cement; and / or, based on the total mass of the cement, the mass percentage of CaO is 55%~57%; and / or, the specific surface area of ​​the cement is 410 m². 2 / kg~430m 2 / kg; and / or, based on the total mass of the raw materials for the low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste, the sum of the mass percentages of the fly ash microspheres, the silica fume, and the phosphorus slag is 50% to 80%.

3. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste according to claim 1 or 2, characterized in that, The specific surface area of ​​the silica fume is ≥1.5×10⁻⁶. 4 m 2 / kg; and / or, based on the total mass of the silica fume, the mass percentage of SiO2 is ≥85%.

4. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste according to claim 1 or 2, characterized in that, The specific surface area of ​​the fly ash microspheres is ≥1200 m². 2 / kg; and / or, the volume average particle size d50 of the fly ash microspheres is ≤3μm.

5. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste according to claim 1 or 2, characterized in that, The specific surface area of ​​the phosphorus slag is ≥350m². 2 / kg; and / or, the calcination vector of the phosphorus slag is ≤3.0%; and / or, based on the total mass of the phosphorus slag, the mass percentage of P2O3 is ≤3.5%; and / or, the 7-day activity index of the phosphorus slag is ≥60%.

6. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste according to claim 1 or 2, characterized in that, The particle size of the quartz sand is 20 mesh to 40 mesh.

7. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste according to claim 1 or 2, characterized in that, The fiber includes copper-plated steel fiber; and / or, the fiber is straight rod-shaped; and / or, the fiber length is 11.7 mm to 14.3 mm; and / or, the fiber effective diameter is 180 μm to 220 μm.

8. The low-carbon, low-shrinkage lightweight concrete prepared from multi-source industrial solid waste according to claim 7, characterized in that, The defoamer is a mixture of liquid hydrocarbons and polyglycerols with an inorganic carrier as the base; and / or, the water-reducing agent comprises modified polycarboxylic acid; and / or, the water-reducing agent has a density of 0.40 g / cm³. 3 ~0.55g / cm 3 .

9. A method for preparing low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste as described in any one of claims 1 to 8, characterized in that, include: Cement, silica fume, fly ash microspheres, phosphorus slag, and defoamer are mixed evenly. A pre-mixed solution of water-reducing agent and water is added and stirred to form a homogeneous slurry. The stirring speed is adjusted to 275 r / min to 295 r / min, and quartz sand is added to the homogeneous slurry. After stirring to form a homogeneous mortar, the stirring speed is reduced to 135 r / min to 145 r / min, and fibers are added evenly multiple times and stirred until a fiber mixture is formed. The fiber mixture is then placed into a mold whose inner wall has been coated with a thin layer of mineral oil and left to stand for 20 h to 25 h. After demolding, the mixture is cured to obtain low-carbon, low-shrinkage lightweight concrete based on multi-source industrial solid waste.

10. The method according to claim 9, characterized in that, The settling temperature is 18℃~22℃; and / or the relative humidity of the environment during settling is 50%RH~70%RH; and / or the curing temperature is 18℃~22℃; and / or the relative humidity of the curing environment is ≥95%RH.

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