Carbonized maintenance all-solid-waste cementitious material concrete prefabricated part and preparation method thereof

Abstract

The application relates to the technical field of building materials, and discloses a carbonization curing full-solid-waste cementitious material concrete prefabricated part and a preparation method thereof.A high-steel-slag full-solid-waste cementitious material comprises the following components in parts by weight: 40-60 parts of steel slag, 20-40 parts of mineral slag and 10-20 parts of desulfurization gypsum. The early strength of the concrete prefabricated part can be effectively improved by using 40-60 parts of steel slag, 20-40 parts of mineral slag and 10-20 parts of desulfurization gypsum, and the late strength performance is also improved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a precast concrete component made of carbonized curing solid waste cementitious material and its preparation method. Background Technology

[0002] With increasing global demands for environmental protection and sustainable resource utilization, the building materials sector is focusing on the development and utilization of environmentally friendly materials. Steel slag, mineral slag, and desulfurized gypsum, as industrial wastes, can not only reduce resource waste but also effectively mitigate environmental pollution when used in building materials. Traditional concrete preparation processes require high-temperature steam curing, which places high demands on energy consumption and production cycles. In recent years, with the increasing demand for autoclaved aerated concrete and low-carbon environmentally friendly concrete, autoclaved aerated carbonation curing technology has gradually become an effective curing method, especially in the precast concrete sector. Autoclaved aerated concrete technology optimizes the concrete curing process, reducing energy consumption associated with steam curing while also improving the production efficiency of concrete products.

[0003] However, existing methods for preparing autoclaved concrete typically rely on highly efficient cementitious binders, and there are still certain technical bottlenecks in the treatment of different types of waste (such as steel slag and blast furnace slag). Traditional methods for utilizing steel slag, blast furnace slag, and desulfurized gypsum often involve additional processing steps, which not only increases production costs but also limits the synergistic advantages of the three materials, resulting in limited improvement in the strength properties of concrete, especially its early strength properties, ultimately affecting the overall strength performance of the concrete. Summary of the Invention

[0004] This invention proposes a carbonization-cured precast concrete component made from solid waste cementitious materials and its preparation method, in order to solve or alleviate at least one of the above-mentioned problems.

[0005] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a high-strength steel slag solid waste cementitious material, comprising the following components in parts by weight: 40-60 parts steel slag, 20-40 parts blast furnace slag, and 10-20 parts desulfurized gypsum.

[0006] In one embodiment, the weight ratio of steel slag, ore slag, and desulfurized gypsum is 10~11:6~7:3.

[0007] In one embodiment, the preparation method of the high-strength steel slag solid waste cementitious material includes the following steps: The steel slag, ore slag, and desulfurized gypsum are blended and dried for the first time to obtain blend I; blend I is then ground for the first time to obtain blend II; blend II is dried and ground for the second time to obtain the high-steel slag all-solid waste cementitious material.

[0008] In one embodiment, the first drying process results in a moisture content of blend I of <0.1%; The second drying process involves drying at 40-60°C for 2-4 hours. The first grinding process involves adding water and grinding for 60-90 minutes, with the amount of water added being 1.2%-1.8% of the weight of the blend I. The second grinding process is a dry ball milling, grinding the high-steel slag solid waste cementitious material until the specific surface area is ≥530 m². 2 / kg, the mass percentage of high steel slag solid waste cementitious materials with a particle size >30μm is ≤1%.

[0009] Secondly, this invention provides a precast concrete component made from carbonized and cured solid waste cementitious material, the raw materials of which include the following components by weight: 1000-1200 parts coarse aggregate, 700-900 parts fine aggregate, 350-400 parts high-strength steel slag solid waste cementitious material, and 140-170 parts water; The high-strength steel slag solid waste cementitious material is the aforementioned high-strength steel slag solid waste cementitious material.

[0010] In one embodiment, the raw materials also include 4 to 6 parts of a water-reducing agent; The water-reducing agent includes polycarboxylate water-reducing agents.

[0011] In one embodiment, the coarse aggregate includes one or more of crushed stone and pebbles, and the particle size of the coarse aggregate is 10~31.5mm; The fine aggregate includes one or more of manufactured sand and river sand, and the particle size of the fine aggregate is 0.16~5mm.

[0012] Thirdly, the present invention provides a method for preparing precast concrete components made from carbonized and cured all-solid waste cementitious materials, comprising the following steps: The raw materials for the precast concrete are blended to obtain a mixture; the mixture is pre-cured, dried, and then carbonized to obtain the carbonized-cured precast concrete made of all-solid waste cementitious material.

[0013] In one embodiment, during the pre-curing process, the mixture is cured at 20°C for 24 hours; During the drying process, the temperature is 30~50℃ and the time is 2~4 hours; During the carbonization curing process, the humidity is 50%, the temperature is 20~25℃, the CO2 volume concentration is 50%~80%, and the time is 20~22h.

[0014] In one embodiment, the combined time for drying and carbonization curing is 24 hours.

[0015] To improve the early and later strength properties of precast concrete components, this invention introduces a high-steel slag all-solid waste cementitious material into the precast concrete components. Its components include 40-60 parts steel slag, 20-40 parts blast furnace slag, and 10-20 parts desulfurized gypsum. The combined use of specific amounts of steel slag, blast furnace slag, and desulfurized gypsum has the following beneficial effects: In the early stages of carbonation curing of precast concrete components made from all-solid-waste cementitious materials, steel slag continuously provides alkalinity and calcium ions, maintaining the concrete system in an alkaline environment. This effectively activates the slag, while the SO4 released by desulfurized gypsum... 2- This process promotes the formation of early-stage ettringite framework products. These framework products, together with the C-(A)-SH gel formed by slag hydration, effectively form the initial load-bearing network. In the subsequent carbonation stage, the calcium in the steel slag and early hydration products reacts rapidly under the action of CO2, transforming into carbonation products such as CaCO3 and precipitating out. This process fills pores, refines pore size, and makes the structure more compact, thereby significantly improving the early strength of precast concrete components. After carbonation is completed, the slag in the system continues to hydrate in a relatively stable alkaline environment, generating more C-(A)-SH gel, further optimizing the pore structure and laying the foundation for the continuous growth of the later-stage strength of precast concrete components.

[0016] Based on the above-mentioned working principle, using 40-60 parts steel slag, 20-40 parts blast furnace slag, and 10-20 parts desulfurized gypsum, and combining these components in specific proportions, can effectively improve the early strength of precast concrete components, while also enhancing their later strength performance. When the steel slag content decreases (<40 parts), the limited alkalinity and calcium sources during subsequent carbonation are rapidly consumed, leading to insufficient alkalinity after carbonation. This inhibits subsequent slag hydration, reduces gel formation capacity, and affects the improvement of early strength, resulting in a poorer improvement in later strength. Conversely, if the steel slag content is too high (>60 parts), the system tends to over-rely on the early strength provided by steel slag carbonation, while the proportion of blast furnace slag as the main later hydration substance is insufficient. The ability to continuously form the gel phase cannot keep up, making it difficult to continue reinforcing and stabilizing the load-bearing skeleton in the later stages, thus limiting the improvement of both early and later strength performance. Therefore, this invention controls the steel slag content to 40-60 parts, while retaining an effective proportion of 20-40 parts of slag, and combines it with 10-20 parts of desulfurized gypsum to regulate the aluminum phase reaction path and early skeleton formation. This ensures sufficient calcium source for rapid densification and early strength improvement during the carbonation stage, while also retaining sufficient slag for continuous hydration in the later stage, thereby stabilizing and improving the later strength, and ultimately improving the overall strength performance of the precast concrete components. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Steel slag, blast furnace slag, and desulfurized gypsum, as industrial wastes, can reduce resource waste and effectively mitigate environmental pollution when used in building materials. These materials are commonly used components in the preparation of concrete gel materials; however, traditional methods of utilizing them in concrete often rely on the proportions of a single material or require additional processing steps. This not only increases production costs but also negatively impacts concrete performance to some extent.

[0019] In recent years, the technology of preparing cementitious materials using a ternary system of steel slag-blast furnace slag-desulfurized gypsum for use in concrete has gradually increased. However, the steel slag content is generally less than 30%, while the few systems with higher steel slag content often have an excessively low water-cement ratio, resulting in a surge in the amount of water-reducing agent used in the prepared concrete, and a significant decrease in the early and later strength of the concrete, leading to great difficulties in industrial application. To solve the problem of relatively poor early and later strength of concrete, steel slag, blast furnace slag, and desulfurized gypsum are used in combination. By adjusting the content ratio of steel slag, blast furnace slag, and desulfurized gypsum, the steel slag content is controlled at 40-60 parts, while retaining an effective proportion of 20-40 parts of blast furnace slag, and combined with 10-20 parts of desulfurized gypsum. This ensures sufficient calcium source for rapid densification and improved early strength, while also retaining sufficient blast furnace slag for continuous hydration in the later stages, thereby stabilizing and improving later strength, and ultimately improving the overall strength performance of precast concrete components.

[0020] Specifically, in order to better understand the technical solution of the present invention, it is described in the following parts.

[0021] Part One This invention provides a high-strength steel slag solid waste cementitious material, comprising the following components in parts by weight: 40-60 parts steel slag, 20-40 parts blast furnace slag, and 10-20 parts desulfurized gypsum.

[0022] In this invention, when steel slag, blast furnace slag, and desulfurized gypsum are used to form a solid waste cementitious material, the steel slag content is 40-60 parts, for example, 40 parts, 45 parts, 50 parts, 55 parts, or 60 parts, preferably 50-55 parts. After water is added to the concrete system, the steel slag can rapidly increase the alkalinity of the system, and simultaneously, CSH gel and Ca are generated during the initial hydration of the steel slag. 2+ and OH - This invention provides a calcium ion basis for slag hydration. In this invention, the steel slag can be converter hot-quenched steel slag, converter hot-pouring steel slag, or converter drum steel slag, preferably converter hot-quenched steel slag. The steel slag content is 40-60 parts, preferably 50-55 parts. Within the range of 50-55 parts, the steel slag provides optimal alkalinity and calcium ion content. However, when the steel slag content is too high or too low, the improvement in early and later strength of the concrete is poor.

[0023] When steel slag, blast furnace slag, and desulfurized gypsum are used to form a solid waste cementitious material, the amount of steel slag is 40-60 parts and the amount of blast furnace slag is 20-40 parts. For example, the blast furnace slag content can be 20 parts, 25 parts, 30 parts, 35 parts, or 40 parts, preferably 30-35 parts. When the amount of steel slag is 40-60 parts and the amount of blast furnace slag is 20-40 parts, the blast furnace slag can be better activated by the alkaline environment provided by the steel slag. It can be used together with steel slag and desulfurized gypsum to jointly construct the initial load-bearing network structure. In the preparation of precast concrete components of the solid waste cementitious material under carbonization curing, during the later carbonization, a relatively sufficient amount of blast furnace slag can still continue to hydrate in the alkaline environment, generating more C-(A)-SH gel to optimize the pore structure and improve the later strength.

[0024] In this invention, when steel slag, ore slag, and desulfurized gypsum are used to form a solid waste cementitious material, the steel slag content is 40-60 parts, the ore slag content is 20-40 parts, and the desulfurized gypsum content is 10-20 parts. The desulfurized gypsum content can be, for example, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, or 20 parts, preferably 15-18 parts, and more preferably 15 parts.

[0025] In this invention, steel slag, mineral slag and desulfurized gypsum are used to form a solid waste cementitious material, and the dosage of the three is controlled. When this material is used in precast concrete components, the early strength of the precast concrete components can be effectively improved, and the later strength performance can also be improved.

[0026] In some embodiments of the present invention, the weight ratio of steel slag, mineral slag and desulfurized gypsum is 10~11:6~7:3.

[0027] In this invention, the content ratio of steel slag, blast furnace slag, and desulfurized gypsum is controlled, with a weight ratio of 10~11:6~7:3, for example, 10:7:3 or 11:6:3. In this invention, when the weight ratio of steel slag, blast furnace slag, and desulfurized gypsum is 10~11:6~7:3, the early and later strength of precast concrete components can be further improved.

[0028] In some embodiments of the present invention, the steel slag has an average particle size of <3mm, an iron content of ≤30%, an aging time of ≥1 month, and undergoes iron removal pretreatment before grinding.

[0029] In some embodiments of the present invention, the desulfurization gypsum is wet flue gas desulfurization gypsum from power plants.

[0030] In some embodiments of the present invention, the SO3 content of the desulfurized gypsum is ≥30%.

[0031] In some embodiments of the present invention, the slag is water-quenched alkaline ferroblast furnace slag.

[0032] In some embodiments of the present invention, the slag has an Al2O3 content ≥12%, an average particle size <2mm, and an aging time ≤6 months.

[0033] In some embodiments of the present invention, the preparation method of high-strength steel slag solid waste cementitious material includes the following steps: Steel slag, mineral slag, and desulfurized gypsum were blended and dried for the first time to obtain blend I. Blend I was then ground for the first time to obtain blend II. Blend II was dried and ground for the second time to obtain a high-steel slag solid waste cementitious material.

[0034] In the preparation method of high-strength steel slag solid waste cementitious material of this invention, a first drying process is performed to control the moisture content of the blend I formed by steel slag, slag, and desulfurized gypsum to <0.1%. This ensures the stability of the initial powder state of the steel slag, slag, and desulfurized gypsum, reduces the risk of agglomeration caused by excessive moisture content, and thus guarantees grinding efficiency. After the first drying, a first grinding is performed using 120kg all-steel segments as grinding media with a small amount of water added, ensuring that the three materials are fully and uniformly dispersed at the microscopic level, enhancing the overall performance. Interfacial contact shortens the ion migration path, which is beneficial to the diffusion of subsequent hydration reactions. Then, a second drying is carried out at 40~60℃ to remove the free water introduced during wet milling, prevent powder agglomeration, stabilize the powder flowability and grindability, and lay the foundation for subsequent milling. Then, a second milling is carried out using an SM-500 cement test mill to improve the specific surface area and sieving level, which significantly increases the reaction interface between steel slag and slag and improves the dissolution rate, providing a higher reaction kinetic basis for early hydration and subsequent carbonization.

[0035] In this invention, during the first grinding, the amount of water added is 1.2% to 1.8% of the weight of blend I, for example, it can be 1.2%, 1.5%, 1.6%, or 1.8%, preferably 1.5%; the grinding time is 60 to 90 minutes, for example, it can be any point value or a range between two points from 60 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85 minutes, or 90 minutes.

[0036] In this invention, the combination of a first drying, a first grinding, a second drying, and a second grinding process can further improve the early strength and later strength of precast concrete components.

[0037] In this invention, during the second grinding, the high-strength steel slag solid waste cementitious material is ground until the specific surface area is ≥530 m². 2 / kg, the mass percentage of high steel slag solid waste cementitious material with a particle size >30μm is ≤1%, and when the high steel slag solid waste cementitious material is ground a second time to a specific surface area ≥530m², the mass percentage of the high steel slag solid waste cementitious material is ≤1%. 2 / kg, and by controlling the screening residue, the reaction interface of the subsequent high steel slag solid waste cementitious materials can be effectively improved, which helps to further improve the early strength and later strength of concrete precast components.

[0038] Part Two This invention also provides a precast concrete component made from carbonized and cured solid waste cementitious material, the raw materials of which include the following components by weight: 1000-1200 parts coarse aggregate, 700-900 parts fine aggregate, 350-400 parts high-strength steel slag solid waste cementitious material, and 140-170 parts water; The high-strength steel slag solid waste cementitious material is the aforementioned high-strength steel slag solid waste cementitious material.

[0039] In this invention, the coarse aggregate in carbonized cured solid waste cementitious precast concrete components serves as the main skeletal component of the precast concrete, capable of bearing and transferring loads, reducing concrete deformation under stress, and improving the compressive strength and durability of the precast components. The coarse aggregate used in this invention is known in the art for use in precast concrete components, and this invention is not limited to the coarse aggregates listed below. For example, the coarse aggregate can be crushed stone or gravel. In this invention, the particle size of the coarse aggregate is 10~31.5mm, and the particle size can be any value from 10mm, 15mm, 20mm, 25mm, 30mm, 31.5mm, or a range between any two values.

[0040] In this invention, the fine aggregate in carbonized cured all-solid-waste cementitious precast concrete fills the voids between the coarse aggregate, making the particle size distribution of the concrete more reasonable and improving its density and workability. The fine aggregate used in this invention is known in the art for use in precast concrete, and this invention is not limited to the fine aggregates listed below. For example, the coarse aggregate can be manufactured sand or river sand. In this invention, the particle size of the fine aggregate is 0.16~5mm, and the particle size can be any value from 0.16mm, 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or any range between any two values.

[0041] In some embodiments of the present invention, the raw materials also include 4 to 6 parts of a water-reducing agent.

[0042] The water-reducing agent used in this invention is a water-reducing agent known in the art that can be used in precast concrete components, and this invention is not limited to the water-reducing agents listed below. As an example, the water-reducing agent may be a polycarboxylate water-reducing agent, a naphthalene-based water-reducing agent, or a lignin sulfonate water-reducing agent, preferably a polycarboxylate water-reducing agent.

[0043] Part Three This invention also provides a method for preparing precast concrete components made from carbonized and cured solid waste cementitious materials, comprising the following steps: The raw materials for precast concrete are blended to obtain a mixture; after pre-curing the mixture, it is dried and carbonized to obtain precast concrete made of carbonized solid waste cementitious material.

[0044] In some embodiments of the present invention, during pre-curing, the mixture is cured at 20°C for 24 hours; During drying, the temperature is 30~50℃ and the time is 2~4 hours; During carbonization curing, the humidity is 50%, the temperature is 20~25℃, the CO2 volume concentration is 50%~80%, and the time is 20~22h.

[0045] In this invention, carbonation curing technology is used for the curing and preparation of precast concrete components. Carbonation curing is mainly carried out in a CO2 atmosphere, which can promote the carbonation reaction of cement hydration products in concrete, thereby improving the strength and durability of concrete, while effectively reducing energy consumption.

[0046] This invention involves a 24-hour standard pre-curing process before carbonation curing of the mixture obtained from blending the raw materials of the precast concrete component. This pre-curing process allows the system to generate necessary early hydration products and strengthen the foundation skeleton, ensuring no cracking or loosening during demolding and subsequent carbonation. It also creates pore water and calcium sources, providing a medium and reactants for the carbonation reaction. After demolding, the pre-cured component is dried at 30-50°C for 2-4 hours, a short-term drying and humidification process that places the pores in a state more conducive to CO2 mass transfer, thereby improving the efficiency of subsequent carbonation curing. Finally, carbonation curing is performed, allowing carbonation products such as CaCO3 to fill the pores and refine the pore size, achieving rapid reinforcement and pore structure reconstruction. This results in precast concrete components with good early and later strength.

[0047] In this invention, the humidity is 50% during carbonization curing. Under this carbonization curing condition, the humidity requirements of the water film medium required for CO2 diffusion and carbonization reaction can be met simultaneously. The carbonization reaction depends on CO2 entering the pores and dissolving in the water film to form a carbonic acid system, which then reacts with the calcium source to precipitate CaCO3. Therefore, the pores cannot be "too wet" to avoid gas diffusion being blocked by water, nor can they be "too dry" to avoid insufficient carbonization power due to lack of reaction medium. Therefore, in the carbonization curing process of this invention, the humidity is controlled at 50%, and the internal moisture is adjusted to a suitable range through short-time drying. This is precisely to avoid the problem of incomplete carbonization reaction caused by excessively high or low humidity.

[0048] In this invention, the carbonization curing temperature is 20~25℃, preferably 20℃. The carbonization reaction is more stable within the 20~25℃ temperature range. Temperatures above 25℃ will increase the risk of water loss and shrinkage, leading to microcracks and deterioration of the pore structure.

[0049] In this invention, the CO2 volume concentration is 50%~80%, for example, it can be any value from 50%, 55%, 60%, 65%, 70%, 75%, 80% or any range between any two values. In this invention, a CO2 volume concentration of 50%~80% allows for the formation of sufficient carbonation products within a limited time, thereby achieving early strength improvement and densification. When the CO2 concentration is <50%, the carbonation efficiency is poor; when the CO2 volume concentration is >80%, the CO2 concentration is relatively too high, which can easily cause the surface of the precast concrete to densify too quickly, forming a "shell" that hinders carbonation and leads to uneven carbonation.

[0050] In some embodiments of the present invention, the drying and carbonization curing time is 24 hours.

[0051] In this invention, the drying time is 2-4 hours, the carbonation curing time is 20-22 hours, and the combined drying and carbonation curing time is 24 hours, which can further improve the early and later strength of precast concrete components. Specifically: The combined drying and carbonization curing time should be 24 hours. A time shorter than 24 hours results in insufficient CaCO3 formation, inadequate pore refinement, and decreased early strength, while also causing incomplete passivation of expansive components. A time longer than 24 hours will lead to a prolonged dry environment, which is detrimental to later strength improvement. Furthermore, assuming a combined drying and carbonization curing time of 24 hours, both excessively long and short drying times will disrupt the suitable moisture content within the specimen. Too short a drying time results in insufficient drainage of free water from the pores, hindered CO2 diffusion, incomplete carbonization, and insufficient CaCO3 formation, leading to limited early strength improvement. Too long a drying time leads to excessive moisture loss from the specimen, lack of a necessary water film medium for the carbonization reaction, and may induce drying shrinkage and microcracks, while also inhibiting subsequent hydration reactions, resulting in decreased later strength. Both excessively long and excessively short carbonation curing times will affect the formation of carbonation products and their uniform distribution within the specimen. When the carbonation time is too short, the reaction between CO2 and the Ca source in the system is insufficient, resulting in inadequate CaCO3 formation, limited pore filling and densification effects, and insignificant improvement in early strength and durability. When the carbonation time is too long, a dense carbonate layer is prone to form prematurely on the surface, hindering the continued diffusion of CO2 into the interior, causing uneven carbonation. It may also consume some alkaline components and inhibit subsequent slag hydration, which is detrimental to the later development of strength.

[0052] method The following methods are used to determine the performance defined in the examples and comparative examples.

[0053] The compressive strength performance was tested according to GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", including 3-day compressive strength, 7-day compressive strength and 28-day compressive strength tests.

[0054] Material Unless otherwise specified, all materials used in the embodiments and comparative examples of this invention can be purchased commercially. For example, the steel slag is specifically converter hot-quenched steel slag with an average particle size of 2.0 mm and an iron content of 18.5%; the slag is specifically water-quenched basic ironmaking furnace slag with an Al2O3 content of 14.8% and an average particle size of 1.8 mm; the desulfurization gypsum is specifically power plant wet flue gas desulfurization gypsum with an SO3 content of 33.5%; and the polycarboxylate superplasticizer has an effective component content of 30% and a water reduction rate of 24%.

[0055] The composition, some process parameters, specific surface area and particle size of the high-strength steel slag solid waste cementitious materials of Examples 1-8 and Comparative Examples 1-4 are shown in Table 1.

[0056] Table 1. Raw materials, process parameters, specific surface area, and particle size of high-strength steel slag solid waste cementitious materials.

[0057] The composition of precast concrete components made from carbonized curing all-solid waste cementitious materials in Examples 1-8 and Comparative Examples 1-4 is shown in Table 2.

[0058] Table 2. Components of precast concrete components made from carbonized solid waste cementitious materials

[0059] The drying and carbonation curing process parameters for precast concrete components made from solid waste cementitious materials are shown in Table 3.

[0060] Table 3. Process parameters for drying and carbonation curing of precast concrete components made from all-solid waste cementitious materials.

[0061] The preparation methods of high-strength steel slag solid waste cementitious materials in Examples 1-8 and Comparative Examples 1-4 all include the following steps: A1. Weigh out steel slag, blast furnace slag, and desulfurized gypsum according to the weight parts, mix them together, and dry them under the dark to obtain blend I with a water content of <0.1%; A2. After mixing and grinding blend I with water using a small experimental mill with 120kg all-steel grinding media, blend II was obtained. A3. After drying the blend II, grind it using an SM-500 cement test mill to obtain a high-strength steel slag solid waste cementitious material. The component content of steel slag, slag, and desulfurized gypsum, the amount of water added during mixing and grinding (based on the total mass of steel slag, slag, and desulfurized gypsum), the grinding time, the drying time of blend II, and the specific surface area and particle size of high steel slag solid waste cementitious material are all shown in Table 1. The precast concrete components made from carbonation-cured all-solid-waste cementitious materials in Examples 1-8 and Comparative Examples 1-4 all include the following steps: S1. After mixing the raw materials of the precast concrete in a mixer for 2 minutes, place them in a mold and vibrate for 60 seconds to obtain a mixture; S2. After placing the mixture in the mold in a standard curing room at 20°C for 24 hours, remove it, demold, dry, and carbonize to obtain carbonized solid waste cementitious precast concrete components. The drying and carbonation curing process parameters for precast concrete components made from carbonized solid waste cementitious materials are shown in Table 3.

[0062] The precast concrete components prepared by carbonization curing solid waste cementitious materials in Examples 1-8 and Comparative Examples 1-4 were subjected to 3-day, 7-day, and 28-day compressive strength tests. The test results are shown in Table 4.

[0063] Table 4. Compressive strength test results of Examples 1-8 and Comparative Examples 1-4

[0064] As shown in Table 4, compared with Comparative Examples 1-4, the 3-day compressive strength, 7-day compressive strength, and 28-day compressive strength of the precast concrete components prepared in Examples 1-8 were improved. This indicates that by using 40-60 parts of steel slag, 20-40 parts of blast furnace slag, and 10-20 parts of desulfurized gypsum, and by using a specific amount of steel slag, blast furnace slag, and desulfurized gypsum in combination, the early strength of the precast concrete components can be effectively improved, and the later strength performance is also improved.

[0065] Compared with Example 2, the 3-day compressive strength, 7-day compressive strength, and 28-day compressive strength of the precast concrete components prepared in Examples 6-8 were improved. This indicates that by adjusting the content ratio of steel slag, blast furnace slag, and desulfurized gypsum, when the weight ratio of steel slag, blast furnace slag, and desulfurized gypsum is 10-11:6-7:3, the early strength and later strength of the precast concrete components can be further improved.

[0066] Example 9 The preparation method of high-strength steel slag solid waste cementitious material includes the following steps: A1. Weigh out steel slag, blast furnace slag, and desulfurized gypsum according to the weight parts, mix them together, and dry them under the dark to obtain blend I with a water content of <0.1%; A2. Blend I was ground using a small experimental mill with 120kg all-steel section grinding media to obtain a high-strength steel slag solid waste cementitious material; the specific surface area of ​​the high-strength steel slag solid waste cementitious material was 531 m². 2 / kg, with a particle size >30μm accounting for 0.5% by mass; Everything else is the same as in Example 2.

[0067] Example 10 The preparation method of high-strength steel slag solid waste cementitious material includes the following steps: A1. Weigh out steel slag, blast furnace slag, and desulfurized gypsum according to the weight parts, mix them together, and dry them under the dark to obtain blend I with a water content of <0.1%; A2. Blend I was mixed and ground with 1.5% water using a small experimental mill with 120 kg of all-steel section grinding media to obtain a high-strength steel slag solid waste cementitious material; the specific surface area of ​​the high-strength steel slag solid waste cementitious material was 549 m². 2 / kg, with a particle size >30μm accounting for 0.5% by mass; Everything else is the same as in Example 2.

[0068] Example 11 The preparation method of high-strength steel slag solid waste cementitious material includes the following steps: A1. Weigh out steel slag, blast furnace slag, and desulfurized gypsum according to the weight parts, mix them together, and dry them under the dark to obtain blend I with a water content of <0.1%; A2. Blend I was mixed with 1.5% water and milled for 80 minutes using a small experimental mill with 120 kg of all-steel section grinding media to obtain a high-strength steel slag solid waste cementitious material; the specific surface area of ​​the high-strength steel slag solid waste cementitious material was 470 m². 2 / kg, the mass percentage of particles with a diameter >30μm is 3.4%; Everything else is the same as in Example 2.

[0069] The precast concrete components prepared by carbonization curing solid waste cementitious materials in Examples 2, 9-11 were subjected to 3-day, 7-day, and 28-day compressive strength tests. The test results are shown in Table 5.

[0070] Table 5 Performance test results of Examples 2 and 9-11

[0071] Compared with Examples 9-11, the 3-day, 7-day, and 28-day compressive strengths of the precast concrete obtained in Example 2 were improved. This indicates that in the preparation of high-strength steel slag solid waste cementitious material, the first drying process involves controlling the moisture content of the blend I formed by steel slag, blast furnace slag, and desulfurized gypsum to <0.1%. Then, with the addition of a small amount of water, the material is first ground using 120kg of all-steel segments as grinding media. A second drying process is then performed at 40-60℃, followed by final grinding using an SM-500 cement test mill. Through this combination of two drying and two grinding processes, a material with a specific surface area ≥530m² is obtained. 2 High-strength steel slag solid waste cementitious material per kilogram can be added to precast concrete components to further improve the early and later strength of the precast concrete components.

[0072] Example 12 Carbonation curing of precast concrete components made from all-solid-waste cementitious materials includes the following steps: S1. After mixing the raw materials of the precast concrete in a mixer for 2 minutes, place them in a mold and vibrate for 60 seconds to obtain a mixture; S2. After placing the mixture in the mold in a standard curing room at 20°C for 24 hours, remove it, demold it, dry it at 80°C for 4 hours, and then carbonize it for 20 hours under the conditions of 50% humidity, 20°C temperature and 50% CO2 volume concentration to obtain carbonized cured all-solid waste cementitious concrete precast parts. Everything else is the same as in Example 2.

[0073] Example 13 Carbonation curing of precast concrete components made from all-solid-waste cementitious materials includes the following steps: S1. After mixing the raw materials of the precast concrete in a mixer for 2 minutes, place them in a mold and vibrate for 60 seconds to obtain a mixture; S2. After placing the mixture in the mold in a standard curing room at 20°C for 24 hours, remove it, demold it, dry it at 20°C for 4 hours, and then carbonize it for 20 hours under the conditions of 50% humidity, 20°C temperature and 50% CO2 volume concentration to obtain carbonized and cured all-solid waste cementitious concrete precast parts. Everything else is the same as in Example 2.

[0074] Example 14 Carbonation curing of precast concrete components made from all-solid-waste cementitious materials includes the following steps: S1. After mixing the raw materials of the precast concrete in a mixer for 2 minutes, place them in a mold and vibrate for 60 seconds to obtain a mixture; S2. After placing the mixture in the mold in a standard curing room at 20°C for 24 hours, remove it, demold it, dry it at 30°C for 6 hours, and then carbonize it for 18 hours under the conditions of 50% humidity, 20°C temperature and 50% CO2 volume concentration to obtain carbonized and cured all-solid waste cementitious concrete precast parts. Everything else is the same as in Example 2.

[0075] Example 15 Carbonation curing of precast concrete components made from all-solid-waste cementitious materials includes the following steps: S1. After mixing the raw materials of the precast concrete in a mixer for 2 minutes, place them in a mold and vibrate for 60 seconds to obtain a mixture; S2. After placing the mixture in the mold in a standard curing room at 20°C for 24 hours, remove it, demold it, dry it at 30°C for 1 hour, and then carbonize it for 23 hours under the conditions of 50% humidity, 20°C temperature and 50% CO2 volume concentration to obtain carbonized and cured all-solid waste cementitious concrete precast parts. Everything else is the same as in Example 2.

[0076] Example 16 Carbonation curing of precast concrete components made from all-solid-waste cementitious materials includes the following steps: S1. After mixing the raw materials of the precast concrete in a mixer for 2 minutes, place them in a mold and vibrate for 60 seconds to obtain a mixture; S2. After placing the mixture in the mold in a standard curing room at 20°C for 24 hours, remove it, demold it, dry it at 30°C for 4 hours, and then carbonize it for 22 hours under the conditions of 50% humidity, 20°C temperature and 50% CO2 volume concentration to obtain carbonized and cured all-solid waste cementitious concrete precast parts. Everything else is the same as in Example 2.

[0077] Example 17 Carbonation curing of precast concrete components made from all-solid-waste cementitious materials includes the following steps: S1. After mixing the raw materials of the precast concrete in a mixer for 2 minutes, place them in a mold and vibrate for 60 seconds to obtain a mixture; S2. After placing the mixture in the mold in a standard curing room at 20°C for 2 days, the mold is removed to obtain precast concrete components made entirely of solid waste cementitious materials. Everything else is the same as in Example 2.

[0078] The precast concrete components prepared by carbonization curing solid waste cementitious materials in Examples 2, 12-17 were subjected to 3-day, 7-day, and 28-day compressive strength tests. The test results are shown in Table 6.

[0079] Table 6 Performance test results of Examples 2 and 12-17

[0080] Compared with Examples 12-17, the 3-day compressive strength, 7-day compressive strength, and 28-day compressive strength of the precast concrete obtained in Example 2 were improved. This indicates that carbonation curing of the precast concrete, followed by standard curing at 20°C for 24 hours, drying at 30-50°C for 2-4 hours, short-term drying and humidification, and then carbonization and oxidation at 50% humidity, 20-25°C, and 50%-80% CO2 concentration for 20-22 hours, with the total drying and carbonation curing time limited to 24 hours, can further improve the early and later strength of the precast concrete.

[0081] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-strength steel slag solid waste cementitious material, characterized in that, Includes the following components by weight: 40-60 parts steel slag, 20-40 parts blast furnace slag, and 10-20 parts desulfurized gypsum.

2. The high-strength steel slag solid waste cementitious material according to claim 1, characterized in that, The weight ratio of steel slag, mineral slag and desulfurized gypsum is 10~11:6~7:

3.

3. The high-strength steel slag solid waste cementitious material according to claim 1, characterized in that, The preparation method of the high-strength steel slag solid waste cementitious material includes the following steps: The steel slag, ore slag, and desulfurized gypsum are blended and dried for the first time to obtain blend I; blend I is then ground for the first time to obtain blend II; blend II is dried and ground for the second time to obtain the high-steel slag all-solid waste cementitious material.

4. The high-strength steel slag solid waste cementitious material according to claim 3, characterized in that, The first drying process resulted in a moisture content of blend I of <0.1%; The second drying process involves drying at 40-60°C for 2-4 hours. The first grinding process involves adding water and grinding for 60-90 minutes, with the amount of water added being 1.2%-1.8% of the weight of the blend I. The second grinding process is a dry ball milling, grinding the high-steel slag solid waste cementitious material until the specific surface area is ≥530 m². 2 / kg, the mass percentage of high steel slag solid waste cementitious materials with a particle size >30μm is ≤1%.

5. A precast concrete component made from carbonation-cured solid waste cementitious material, characterized in that, The raw materials include the following components by weight: 1000-1200 parts coarse aggregate, 700-900 parts fine aggregate, 350-400 parts high-strength steel slag solid waste cementitious material, and 140-170 parts water; The high-strength steel slag solid waste cementitious material is the high-strength steel slag solid waste cementitious material as described in any one of claims 1 to 4.

6. A precast concrete component made from carbonation-cured solid waste cementitious material according to claim 5, characterized in that, The raw materials also include 4-6 parts of a water-reducing agent; The water-reducing agent includes a polycarboxylate water-reducing agent.

7. A precast concrete component made from carbonation-cured solid waste cementitious material according to claim 5, characterized in that, The coarse aggregate includes one or more of crushed stone and pebbles, and the particle size of the coarse aggregate is 10~31.5mm; The fine aggregate includes one or more of manufactured sand and river sand, and the particle size of the fine aggregate is 0.16~5mm.

8. A method for preparing precast concrete components made from carbonation-cured all-solid-waste cementitious materials, used to prepare precast concrete components made from carbonation-cured all-solid-waste cementitious materials as described in any one of claims 5 to 7, characterized in that, Includes the following steps: The raw materials for the precast concrete are blended to obtain a mixture; the mixture is pre-cured, dried, and then carbonized to obtain the carbonized-cured precast concrete made of all-solid waste cementitious material.

9. The method for preparing precast concrete components using carbonation-cured all-solid waste cementitious materials according to claim 8, characterized in that, During the pre-curing process, the mixture is cured at 20°C for 24 hours. During the drying process, the temperature is 30~50℃ and the time is 2~4 hours; During the carbonization curing process, the humidity is 50%, the temperature is 20~25℃, the CO2 volume concentration is 50%~80%, and the time is 20~22h.

10. The method for preparing precast concrete components using carbonation-cured all-solid waste cementitious materials according to claim 9, characterized in that, The combined time for drying and carbonization curing is 24 hours.

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