Production process of concrete and concrete

Abstract

The invention discloses a concrete production process and concrete, belongs to the field of concrete preparation, and aims at solving the problems that in the prior art, a fixed formula is mostly designed for single performance, the performance cannot be flexibly adjusted according to different engineering scenes, the applicability is limited, and special intermediates are lacked for component integration and pre-dispersion. The method for preparing the concrete comprises the following steps: preparing an intermediate, pretreating basic raw materials, weighing the pretreated cement, the solid waste low-carbon material and the aggregate according to the proportion, putting into a stirrer, stirring to obtain a basic mixture, mixing the prepared intermediate with mixing water, and uniformly stirring to obtain the concrete. And adding the intermediate slurry and the residual mixing water into the basic mixture to obtain the concrete mixture. By adjusting the mixing amount of the intermediate and synergistically proportioning the basic materials, the customized regulation and control of the concrete performance are realized, and the defects of single performance regulation and control and limited applicability in the prior art are effectively overcome.

Description

Technical Field

[0001] This invention relates to the field of artificial concrete preparation, and more particularly to a concrete production process and concrete. Background Technology

[0002] In the field of concrete preparation, in response to the demands for low-carbon environmental protection and solid waste resource utilization, existing technologies have widely explored the introduction of industrial solid waste as admixtures into concrete systems. For example, granulated blast furnace slag powder, fly ash, and steel slag powder are used to replace a portion of cement, reducing carbon emissions during cement production. Simultaneously, to address issues such as early cracking and insufficient strength in concrete caused by solid waste admixtures, related technologies enhance the crack resistance and mechanical properties of concrete by adding anti-cracking components (such as polyurethane resin microcapsules, superabsorbent resins, and nano-silica) or optimizing mix proportions (such as adjusting the water-cement ratio and aggregate-bond ratio). Furthermore, existing processes have standardized operations for raw material pretreatment (such as aggregate screening, solid waste drying, and water-reducing agent compounding), mixing (such as a combination of dry and wet mixing), and curing (such as standard temperature and humidity curing and steam curing), forming a concrete preparation technology system centered on "solid waste admixture + performance optimization."

[0003] However, existing concrete still has the following defects: 1. Existing technologies are mostly designed with fixed formulas for single performance (such as crack resistance and low carbon). For example, crack-resistant concrete improves crack resistance by using a fixed proportion of crack-resistant mixture, and environmentally friendly admixture concrete achieves low carbon targets by using a fixed amount of solid waste. They cannot flexibly adjust performance according to different engineering scenarios (such as cold region projects with high frost resistance requirements or precast component projects with early high strength requirements), thus limiting their applicability. 2. Existing technologies directly add anti-cracking components and solid waste admixtures to concrete base materials in the form of solid powders. There is a lack of specialized intermediates for component integration and pre-dispersion. This can easily lead to uneven distribution of functional components in concrete due to powder agglomeration, which in turn causes performance fluctuations, such as insufficient local crack resistance and large differences in strength. 3. Existing technologies mostly adopt uniform curing methods (such as standard natural curing or fixed parameter steam curing) without dynamically adjusting curing parameters according to the characteristics of functional components in concrete (such as crack-resistant components and solid waste admixtures). This results in the functional components not being able to fully play their role. For example, concrete with high solid waste content needs enhanced curing due to slow early hydration, but this has not been addressed specifically, affecting the final performance. 4. In existing technologies, solid waste admixtures are often simply mixed with functional components such as crack-resistant and high-strength materials. They are not designed to achieve synergistic effects. For example, the filling effect of solid waste and the water retention effect of crack-resistant components are not complementary, making it difficult to ensure the strength, crack resistance and durability of concrete at high solid waste content. Summary of the Invention

[0004] To overcome the above problems, this invention aims to propose a concrete production process and concrete, which addresses the current issues of fixed formulas designed for single properties (such as crack resistance and low carbon content), which cannot flexibly adjust performance according to different engineering scenarios, have limited applicability, lack specialized intermediates for component integration and pre-dispersion, and are prone to uneven distribution of functional components in concrete due to powder agglomeration, thus causing performance fluctuations.

[0005] Therefore, the specific technical solution adopted by the present invention is as follows: According to one aspect of the present invention, a concrete production process is provided, comprising the following steps: S1. Preparation of intermediates: S11. Select a solid waste matrix, a functional regulator, a performance compensator, and a compatibility stabilizer. The solid waste matrix is ​​a mixture of granulated blast furnace slag powder and steel slag micro powder. The functional regulator is a mixture of nano-silica and modified starch ether. The performance compensator is a mixture of ultrafine calcium carbonate and potassium aluminum sulfate. The compatibility stabilizer is polyethylene glycol 4000. S12. Add the solid waste matrix to a twin-screw mixer, introduce hot air at 80-100℃ and dry mix for 3-5 minutes. Simultaneously add a silane coupling agent for surface modification. After cooling to 40-50℃, add a functional regulator and perform low-speed shearing combined with ultrasonic dispersion for 8-10 minutes. Then add a performance compensator and a compatibility stabilizer, and stir at high speed for 2-3 minutes. S13. The above mixture is processed by a spray granulation device to control the particle size to 0.1-0.3 mm, thereby obtaining a granular intermediate. S2. Basic raw material pretreatment: S21. Separate the coarse and fine aggregates through a sieve of specified specifications to remove impurities, and place them in a dry environment for later use. The coarse aggregate is crushed stone with a particle size of 5-25mm and a crushing value of no more than 10%. The fine aggregate is river sand with a fineness modulus of 2.3-3.0 and a mud content of no more than 3%. S22. The industrial solid waste is dried until the moisture content is less than 1%, and then classified and screened using an air classifier or vibrating screen to remove lumps and foreign matter. The industrial solid waste is selected from at least one of steel slag, nickel slag, mineral slag, phosphorus slag, and fly ash. S23. Randomly inspect the type, strength grade, soundness, and setting time of cement. If slight caking occurs, break it up and store it in a dry, moisture-proof condition. Dilute the polycarboxylate superplasticizer mother liquor with water in a predetermined ratio, determine the solid content, and then use it for later use. S3. Weigh the pretreated cement, low-carbon solid waste materials, and aggregates according to the proportions, and put them into a mixer to dry mix at 180-220 r / min for 1-2 minutes to obtain the basic mixture. S4. Take the intermediate prepared in step S1, mix it with 10% by weight of mixing water, and disperse it at a high speed of 1500 r / min for 2-3 min to prepare an intermediate slurry. The amount of the intermediate is 8-18% of the total mass of the cementitious material, and the cementitious material is a mixture of cement and low-carbon solid waste materials. S5. Add intermediate slurry and remaining mixing water to the base mixture, stir at 200 r / min for 2-3 min, then add the pretreated water-reducing agent, and continue stirring for 1-2 min to obtain the concrete mixture. The total amount of mixing water should meet the water-cement ratio requirement of 0.32-0.50. S6. Pour the concrete mixture into a mold preheated to 30-40℃ and cure it for 28 days according to the corresponding curing method based on the amount of intermediate admixture to obtain the finished concrete product.

[0006] Optionally, in step S11, the mass ratio of granulated blast furnace slag powder to steel slag powder in the solid waste matrix is ​​7:3, the mass ratio of nano silica to modified starch ether in the functional regulator is 1:1, the mass ratio of ultrafine calcium carbonate to potassium aluminum sulfate in the performance compensator is 2:1, and the amount of silane coupling agent added is 1% of the total mass of the solid waste matrix.

[0007] Optionally, in step S12, the rotation speed of the low-speed shearing is 300 r / min, the frequency of the ultrasonic dispersion is 20 kHz, and the rotation speed of the high-speed stirring is 800 r / min.

[0008] Optionally, in step S4, when the target performance is high crack resistance, the amount of the intermediate is 12-15% of the total mass of the cementitious material, and the amount of fine aggregate is increased by 5% compared with the basic mix ratio, and the water-cement ratio is controlled at 0.32-0.35. When the target performance is early high strength, the amount of the intermediate is 10-12% of the total mass of the cementitious material, and the amount of cement is increased by 10% compared with the basic mix ratio, and the amount of coarse aggregate is increased by 3% compared with the basic mix ratio.

[0009] Optionally, in step S4, when the target performance is high frost resistance, the intermediate content is 15-18% of the total mass of the cementitious material, and the water-reducing agent content is increased by 0.2% compared to the basic mix ratio, while the total amount of mixing water is reduced by 5% compared to the basic mix ratio. When the target performance is low-carbon economy, the intermediate content is 8-10% of the total mass of the cementitious material, and the amount of solid waste low-carbon material is increased by 10% compared to the basic mix ratio, while the amount of cement is reduced by 15% compared to the basic mix ratio.

[0010] Optionally, in step S6, the dynamic curing method is as follows: if the intermediate content is ≥15%, the first 3 days are "40℃ steam curing + 2h / day 25kHz ultrasonic curing", with a relative humidity of 95% for steam curing environment, and the following 25 days are natural curing with a relative humidity of ≥90%; if the intermediate content is ≤10%, the first 7 days are natural curing with a relative humidity of ≥90%, with a 5% concentration of intermediate dilution sprayed once a day, and the following 21 days are conventional natural curing with a relative humidity of ≥90%.

[0011] Optionally, in step S22, when the industrial solid waste contains nickel slag, the pretreatment of the nickel slag further includes: crushing the nickel slag to a particle size of no more than 3 mm, calcining it at 800-900℃ for 1-2 hours, cooling it, and then grinding it to a specific surface area of ​​350-450 m² / kg. During the calcination process, valuable metals such as nickel and cobalt are recovered, with a recovery efficiency of no less than 85%. When the industrial solid waste contains phosphorus slag, the pretreatment of the phosphorus slag further includes: mixing the phosphorus slag with an activator at a mass ratio of 100:3-5, wherein the activator is a mixture of silica fume and sodium hydroxide, with a mass ratio of silica fume to sodium hydroxide of 2:1, and modifying it at 60-70℃ for 30-60 minutes.

[0012] Optionally, in step S5, the dosage of the water-reducing agent is 0.8-1.5% of the total mass of the cementitious materials. During the mixing process, the workability of the concrete mixture is monitored in real time, and the slump of the mixture is controlled at 160-220mm by finely adjusting the amount of mixing water.

[0013] Optionally, in step S1, the particle size of the nano-silica is 20 nm, the particle size of the ultrafine calcium carbonate is 1500 mesh, the particle size of the granulated blast furnace slag powder is 800 mesh, and the particle size of the steel slag powder is 1200 mesh.

[0014] A type of concrete, prepared using the above-mentioned production process, wherein the concrete has a 28-day compressive strength of not less than 30 MPa, a freeze-thaw cycle resistance of not less than 300 cycles, and a permeability grade of not less than P8. Compared with traditional cement concrete, each ton of the concrete used reduces carbon dioxide emissions by more than 0.8 tons.

[0015] Compared with the prior art, this application has the following beneficial effects: This invention addresses the shortcomings of existing technologies by designing a dedicated intermediate, optimizing the production process, and implementing a dynamic control scheme, achieving the following well-founded and beneficial effects: This invention achieves customized control of concrete performance by adjusting the dosage of intermediates and coordinating them with the base material. For example, when high crack resistance is required, increasing the dosage of intermediates to 12-15% and reducing the water-cement ratio to 0.32-0.35 can increase the crack reduction rate by 15-20% compared to existing crack-resistant concrete. When low carbon economy is required, controlling the dosage of intermediates to 8-10% and increasing the dosage of solid waste by 10% can further reduce the unit carbon emission by 8-10% compared to existing environmentally friendly admixture concrete, effectively solving the defects of existing technologies in terms of single performance control and limited applicability.

[0016] The intermediate designed in this invention integrates multiple components such as solid waste matrix and functional regulator into granules through a segmented activation, mixing and spray granulation process. After pre-dispersion, it is made into a slurry and added to the base material. Compared with the existing technology of directly adding solid powder, it can improve the dispersion uniformity of functional components by more than 30% and reduce the performance fluctuation range of concrete by 10-15%, completely solving the performance instability defect caused by agglomeration.

[0017] This invention dynamically adjusts the curing method based on the amount of intermediates. For example, when the amount of intermediates is ≥15%, steam curing combined with ultrasonic curing is used to promote the combination of functional components and cement hydration products, which can increase the number of freeze-thaw cycles of concrete by 50-80 times compared with the existing technology. When the amount of intermediates is ≤10%, curing is supplemented by spraying intermediate dilution liquid, which can increase the 28-day compressive strength compliance rate of low-carbon economic concrete to 100%, solving the defect of low matching degree between curing and material properties in the existing technology.

[0018] The intermediate of this invention forms a synergistic system through the filling effect of the solid waste matrix (slag powder + steel slag powder), the compaction and water retention effect of the functional regulator (nano silica + starch ether), and the strength compensation effect of the performance compensator (ultrafine calcium carbonate + potassium aluminum sulfate). For example, even with a 10% increase in solid waste content, the compressive strength of concrete can still be maintained above 30 MPa after 28 days, which is 8-12% higher than the strength of existing high solid waste content concrete, thus solving the defect of weak synergistic effect between solid waste and functional components in existing technologies. Attached Figure Description

[0019] The above-mentioned features, characteristics, and advantages of the present invention, as well as their implementation methods, will become clearer and more readily understood in conjunction with the following description of the embodiments, which are illustrated in detail with reference to the accompanying drawings. Schematic diagrams are shown here: Figure 1 This is a concrete production process and a flowchart of concrete according to an embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0021] Example 1 According to an embodiment of the present invention, a concrete production process and concrete are provided.

[0022] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 1 As shown, according to an embodiment of the present invention, a concrete production process is provided, comprising the following steps: S1. Preparation of intermediates: S11. Select a solid waste matrix, a functional regulator, a performance compensator, and a compatibility stabilizer. The solid waste matrix is ​​a mixture of granulated blast furnace slag powder and steel slag micro powder. The functional regulator is a mixture of nano-silica and modified starch ether. The performance compensator is a mixture of ultrafine calcium carbonate and potassium aluminum sulfate. The compatibility stabilizer is polyethylene glycol 4000. S12. Add the solid waste matrix to a twin-screw mixer, introduce hot air at 80-100℃ and dry mix for 3-5 minutes. Simultaneously add a silane coupling agent for surface modification. After cooling to 40-50℃, add a functional regulator and perform low-speed shearing combined with ultrasonic dispersion for 8-10 minutes. Then add a performance compensator and a compatibility stabilizer, and stir at high speed for 2-3 minutes. S13. The above mixture is processed by a spray granulation device to control the particle size to 0.1-0.3 mm, thereby obtaining a granular intermediate. S2. Basic raw material pretreatment: S21. Separate the coarse and fine aggregates through a sieve of specified specifications to remove impurities, and place them in a dry environment for later use. The coarse aggregate is crushed stone with a particle size of 5-25mm and a crushing value of no more than 10%. The fine aggregate is river sand with a fineness modulus of 2.3-3.0 and a mud content of no more than 3%. S22. The industrial solid waste is dried until the moisture content is less than 1%, and then classified and screened using an air classifier or vibrating screen to remove lumps and foreign matter. The industrial solid waste is selected from at least one of steel slag, nickel slag, mineral slag, phosphorus slag, and fly ash. S23. Randomly inspect the type, strength grade, soundness, and setting time of cement. If slight caking occurs, break it up and store it in a dry, moisture-proof condition. Dilute the polycarboxylate superplasticizer mother liquor with water in a predetermined ratio, determine the solid content, and then use it for later use. S3. Weigh the pretreated cement, low-carbon solid waste materials, and aggregates according to the proportions, and put them into a mixer to dry mix at 180-220 r / min for 1-2 minutes to obtain the basic mixture. S4. Take the intermediate prepared in step S1, mix it with 10% by weight of mixing water, and disperse it at a high speed of 1500 r / min for 2-3 min to prepare an intermediate slurry. The amount of the intermediate is 8-18% of the total mass of the cementitious material, and the cementitious material is a mixture of cement and low-carbon solid waste materials. S5. Add intermediate slurry and remaining mixing water to the base mixture, stir at 200 r / min for 2-3 min, then add the pretreated water-reducing agent, and continue stirring for 1-2 min to obtain the concrete mixture. The total amount of mixing water should meet the water-cement ratio requirement of 0.32-0.50. S6. Pour the concrete mixture into a mold preheated to 30-40℃ and cure it for 28 days according to the corresponding curing method based on the amount of intermediate admixture to obtain the finished concrete product.

[0023] In step S11, the mass ratio of granulated blast furnace slag powder to steel slag powder in the solid waste matrix is ​​7:3, the mass ratio of nano silica to modified starch ether in the functional regulator is 1:1, the mass ratio of ultrafine calcium carbonate to potassium aluminum sulfate in the performance compensator is 2:1, and the amount of silane coupling agent added is 1% of the total mass of the solid waste matrix.

[0024] In step S12, the rotation speed of the low-speed shearing is 300 r / min, the frequency of the ultrasonic dispersion is 20 kHz, and the rotation speed of the high-speed stirring is 800 r / min.

[0025] In step S4, when the target performance is high crack resistance, the amount of the intermediate is 12-15% of the total mass of the cementitious material, and the amount of fine aggregate is increased by 5% compared with the basic mix ratio, and the water-cement ratio is controlled at 0.32-0.35. When the target performance is early high strength, the amount of the intermediate is 10-12% of the total mass of the cementitious material, and the amount of cement is increased by 10% compared with the basic mix ratio, and the amount of coarse aggregate is increased by 3% compared with the basic mix ratio.

[0026] In step S4, when the target performance is high frost resistance, the intermediate content is 15-18% of the total mass of cementitious materials, and the water-reducing agent content is increased by 0.2% compared to the basic mix ratio, while the total amount of mixing water is reduced by 5% compared to the basic mix ratio. When the target performance is low carbon economy, the intermediate content is 8-10% of the total mass of cementitious materials, and the amount of solid waste low carbon materials is increased by 10% compared to the basic mix ratio, while the amount of cement is reduced by 15% compared to the basic mix ratio.

[0027] In step S6, the dynamic curing method is as follows: if the intermediate content is ≥15%, the first 3 days are "40℃ steam curing + 2h / day 25kHz ultrasonic curing", with a relative humidity of 95% for steam curing environment, and the following 25 days are natural curing with a relative humidity of ≥90%. If the intermediate content is ≤10%, the first 7 days are natural curing with a relative humidity of ≥90%, with a 5% concentration of intermediate dilution sprayed once a day, and the following 21 days are conventional natural curing with a relative humidity of ≥90%.

[0028] In step S22, when the industrial solid waste contains nickel slag, the pretreatment of the nickel slag further includes: crushing the nickel slag to a particle size of no more than 3 mm, calcining it at 800-900℃ for 1-2 hours, cooling it, and grinding it to a specific surface area of ​​350-450 m² / kg. During the calcination process, valuable metals such as nickel and cobalt are recovered with a recovery efficiency of no less than 85%. When the industrial solid waste contains phosphorus slag, the pretreatment of the phosphorus slag further includes: mixing the phosphorus slag with an activator at a mass ratio of 100:3-5, wherein the activator is a mixture of silica fume and sodium hydroxide, with a mass ratio of silica fume to sodium hydroxide of 2:1, and modifying it at 60-70℃ for 30-60 minutes.

[0029] In step S5, the dosage of the water-reducing agent is 0.8-1.5% of the total mass of the cementitious materials. During the mixing process, the workability of the concrete mixture is monitored in real time, and the slump of the mixture is controlled at 160-220mm by finely adjusting the amount of mixing water.

[0030] In step S1, the particle size of the nano-silica is 20 nm, the particle size of the ultrafine calcium carbonate is 1500 mesh, the particle size of the granulated blast furnace slag powder is 800 mesh, and the particle size of the steel slag powder is 1200 mesh.

[0031] A type of concrete, prepared using the above-mentioned production process, wherein the concrete has a 28-day compressive strength of not less than 30 MPa, a freeze-thaw cycle resistance of not less than 300 cycles, and a permeability grade of not less than P8. Compared with traditional cement concrete, each ton of the concrete used reduces carbon dioxide emissions by more than 0.8 tons.

[0032] Example 2 This embodiment details the production process of high crack-resistant concrete, as follows: S1. Preparation of intermediates: S11. A solid waste matrix is ​​composed of 800-mesh granulated blast furnace slag powder and 1200-mesh steel slag powder at a mass ratio of 7:3; a functional regulator is composed of 20nm nano-silica and modified starch ether at a mass ratio of 1:1; a performance compensator is composed of 1500-mesh ultrafine calcium carbonate and potassium aluminum sulfate at a mass ratio of 2:1; and polyethylene glycol 4000 is used as a compatibility stabilizer. S12. Put the solid waste matrix into a twin-screw mixer, dry mix with 90℃ hot air for 4 min, and simultaneously add 1% of the total mass of the solid waste matrix as silane coupling agent (KH-550); after cooling to 45℃, add the functional regulator, and disperse at a low speed of 300 r / min with 20 kHz ultrasonication for 9 min; then add the performance compensator and compatibility stabilizer, and stir at a high speed of 800 r / min for 2.5 min. S13. After being processed by a spray granulation device, the particle size is controlled to be 0.2 mm to obtain an intermediate. S2. Basic raw material pretreatment: S21. Take crushed stone with a particle size of 5-25mm and a crushing value of 8% as coarse aggregate, and take river sand with a fineness modulus of 2.5 and a mud content of 2% as fine aggregate. After screening to remove impurities, dry them for later use. S22. Take fly ash, dry it to a moisture content of 0.8%, and use a vibrating screen to classify and screen to remove lumps; S23. Select P.O42.5 cement, and after sampling and confirming that the strength grade, stability and setting time are qualified, dry and store it; dilute the polycarboxylate superplasticizer mother liquor with water at a ratio of 1:5 and mix it with water, and determine that the solid content is 20% for later use. S3. Weigh out 80 parts cement, 30 parts fly ash, 320 parts coarse aggregate, and 265 parts fine aggregate by weight (5% more than the basic mix proportion), put them into a mixer and dry mix at 200 r / min for 1.5 min to obtain the basic mixture; S4. Take 18 parts of the intermediate (accounting for 15% of the total mass of the cementitious material, which is cement + fly ash), mix it with 10 parts of mixing water, and disperse it at a high speed of 1500 r / min for 2.5 min to prepare the intermediate slurry; S5. Add intermediate slurry and remaining mixing water (total water content 38 parts, water-cement ratio 0.34) to the base mixture, stir at 200 r / min for 2.5 min, then add 1.2 parts water-reducing agent, continue stirring for 1.5 min, control the slump to 170 mm, and obtain concrete mixture; S6. Pour the concrete mixture into a mold preheated to 35°C. For the first 3 days, use steam curing at 40°C and 95% relative humidity, combined with 2 hours of 25kHz ultrasonic curing daily. For the next 25 days, use natural curing at 92% relative humidity. After 28 days of curing, a high crack-resistant concrete product is obtained.

[0033] Tests showed that the finished product has a 28-day compressive strength of 42 MPa, a crack reduction rate of 100%, and a permeability grade of P10, meeting the requirements of high crack resistance in engineering scenarios such as basements and tunnels.

[0034] Example 3 This embodiment details the production process of low-carbon, economical concrete, as follows: S1. Preparation of intermediates: Same as in Example 2, except that the amount of modified starch ether in the functional regulator is adjusted to 40% of the total mass of the functional regulator; S2. Basic raw material pretreatment: S21. Take crushed stone with a particle size of 5-25mm and a crushing value of 9% as coarse aggregate, and take river sand with a fineness modulus of 2.8 and a mud content of 2.5% as fine aggregate. After screening to remove impurities, dry it for later use. S22. Take steel slag, crush it to a particle size ≤ 5mm, dry it to a moisture content of 0.9%, and screen it using an air classifier; S23. Cement and water-reducing agent treatment: Same as in Example 2; S3. Weigh out 68 parts of cement (15% less than the basic mix proportion), 40 parts of steel slag (10% more than the basic mix proportion), 330 parts of coarse aggregate, and 250 parts of fine aggregate by weight, and put them into a mixer to dry mix at 190 r / min for 1.2 min to obtain the basic mixture. S4. Take 9 parts of the intermediate (accounting for 8% of the total mass of the cementitious material), mix with 9 parts of mixing water, and disperse at a high speed of 1500 r / min for 2 min to prepare the intermediate slurry; S5. Add intermediate slurry and remaining mixing water (total water content 36 parts, water-cement ratio 0.45) to the base mixture, stir at 200 r / min for 2 min, then add 1.0 part of water-reducing agent, continue stirring for 1 min, control the slump to 200 mm, and obtain concrete mixture; S6. Pour the concrete mixture into a mold preheated to 32°C. For the first 7 days, use natural curing with a relative humidity of 90% and spray with a 5% concentration of intermediate diluent once a day. For the next 21 days, use conventional natural curing with a relative humidity of 90%. After 28 days of curing, you will get a low-carbon and economical concrete product.

[0035] Experimental Example 1 To verify the performance advantages of the concrete of this invention, two groups of known prior art control groups and the experimental group of this invention were set up for comparative testing. The control groups adopted industry-standard crack-resistant concrete, environmentally friendly admixture concrete formulas and processes. The test methods and results are as follows: 1. Test sample Control group 1 (common crack-resistant concrete): The industry-standard crack-resistant concrete formula was adopted, with P.O42.5 cement as the cementitious material, 0.3% cellulose ether (water-retaining and crack-preventing component) and 0.5% nano silica (dense crack-resistant component) added. The aggregate consisted of 5-25mm crushed stone and river sand with a fineness modulus of 2.5. The water-cement ratio was 0.38. The conventional mixing process of "dry mixing for 2 minutes + wet mixing for 3 minutes" was adopted, and standard natural curing (humidity 90%, temperature 20℃) was carried out for 28 days.

[0036] Control group 2 (commonly known environmentally friendly admixture concrete): The industry-standard low-carbon and environmentally friendly concrete formula was adopted, with P.O42.5 cement + 30% fly ash (industrial solid waste admixture) as cementing material, 5-25mm crushed stone and river sand with a fineness modulus of 2.8 as aggregate, water-cement ratio of 0.45, polycarboxylate superplasticizer dosage of 1.0%, conventional mixing process, steam curing (40℃, humidity 95%) for 3 days and then natural curing for 28 days.

[0037] Experimental Group 1: High crack-resistant concrete prepared according to Example 2 of the present invention; Experimental Group 2: Low-carbon and economical concrete prepared according to Example 3 of the present invention.

[0038] 2. Test Methods 28-day compressive strength: determined according to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete"; Crack reduction rate: According to the plate specimen method in GB / T50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete", the number, width and total area of ​​cracks were observed within 28 days of curing, and the crack reduction rate was calculated (crack reduction rate = (total area of ​​cracks in the control group - total area of ​​cracks in the experimental group) / total area of ​​cracks in the control group × 100%). Freeze-thaw cycle resistance: determined according to the rapid freezing method in GB / T50082-2009, with a mass loss rate of ≤5% and a relative dynamic modulus of elasticity of ≥60% as the failure criteria; Permeability grade: determined according to GB / T50082-2009 stepwise pressure method; Carbon emissions per unit: calculated according to GB / T38584-2020 "Calculation Method for Carbon Emissions of Cement-based Materials"; Dispersion uniformity of functional components: Concrete cross-sections were taken and observed using scanning electron microscopy (SEM). The standard deviation of particle distribution of functional components was statistically analyzed (the smaller the standard deviation, the higher the uniformity). Performance fluctuation range: 10 parallel specimens were prepared for each group, and the compressive strength was measured after 28 days. The coefficient of variation was calculated (coefficient of variation = standard deviation / mean × 100%, the smaller the coefficient of variation, the smaller the fluctuation range).

[0039] 3. Test Results 4. Experimental Conclusions Compared with control group 1 (known crack-resistant concrete), experimental group 1 showed a 7.5% increase in crack reduction rate, a 32.1% increase in freeze-thaw cycle resistance, a decrease in the standard deviation of functional component dispersion from 3.5 to 1.2 (significantly improved uniformity), and a decrease in the coefficient of variation of compressive strength from 6.8% to 3.2% (significantly reduced performance fluctuation range), demonstrating the technical advantages of this invention in crack resistance, component dispersion, and performance stability. Compared with control group 2 (commonly known environmentally friendly admixture concrete), experimental group 2 showed a 10.4% reduction in unit carbon emissions, a stable 28-day compressive strength of over 30 MPa, met the freeze-thaw cycle resistance standard (≥300 times), and maintained a permeability grade of P8. This achieved a balance between low carbonization and mechanical properties, solving the problem of insufficient strength in existing environmentally friendly concrete with high solid waste content. All experimental groups met the explicit performance requirements of "the concrete has a 28-day compressive strength of not less than 30 MPa, a freeze-thaw cycle resistance of not less than 300 times, a permeability grade of not less than P8, and a reduction of more than 0.8 tons of carbon dioxide emissions per ton of concrete used compared to traditional cement concrete". The test data were obtained through standardized testing methods and have sufficient reliability and repeatability.

[0040] Although the present invention has been disclosed above with reference to preferred embodiments, the embodiments are merely examples for illustrative purposes and are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. The scope of protection claimed by the present invention should be determined by the claims.

Claims

1. A concrete production process, characterized in that, Includes the following steps: S1. Preparation of intermediates: S11. Select a solid waste matrix, a functional regulator, a performance compensator, and a compatibility stabilizer. The solid waste matrix is ​​a mixture of granulated blast furnace slag powder and steel slag micro powder. The functional regulator is a mixture of nano-silica and modified starch ether. The performance compensator is a mixture of ultrafine calcium carbonate and potassium aluminum sulfate. The compatibility stabilizer is polyethylene glycol 4000. S12. Add the solid waste matrix to a twin-screw mixer, introduce hot air at 80-100℃ and dry mix for 3-5 minutes. Simultaneously add a silane coupling agent for surface modification. After cooling to 40-50℃, add a functional regulator and perform low-speed shearing combined with ultrasonic dispersion for 8-10 minutes. Then add a performance compensator and a compatibility stabilizer, and stir at high speed for 2-3 minutes. S13. The above mixture is processed by a spray granulation device to control the particle size to 0.1-0.3 mm, thereby obtaining a granular intermediate. S2. Basic raw material pretreatment: S21. Separate the coarse and fine aggregates through a sieve of specified specifications to remove impurities, and place them in a dry environment for later use. The coarse aggregate is crushed stone with a particle size of 5-25mm and a crushing value of no more than 10%. The fine aggregate is river sand with a fineness modulus of 2.3-3.0 and a mud content of no more than 3%. S22. The industrial solid waste is dried until the moisture content is less than 1%, and then classified and screened using an air classifier or vibrating screen to remove lumps and foreign matter. The industrial solid waste is selected from at least one of steel slag, nickel slag, mineral slag, phosphorus slag, and fly ash. S23. Randomly inspect the type, strength grade, soundness, and setting time of cement. If slight caking occurs, break it up and store it in a dry, moisture-proof condition. Dilute the polycarboxylate superplasticizer mother liquor with water in a predetermined ratio, determine the solid content, and then use it for later use. S3. Weigh the pretreated cement, low-carbon solid waste materials, and aggregates according to the proportions, and put them into a mixer to dry mix at 180-220 r / min for 1-2 minutes to obtain the basic mixture. S4. Take the intermediate prepared in step S1, mix it with 10% by weight of mixing water, and disperse it at a high speed of 1500 r / min for 2-3 min to prepare an intermediate slurry. The amount of the intermediate is 8-18% of the total mass of the cementitious material, and the cementitious material is a mixture of cement and low-carbon solid waste materials. S5. Add intermediate slurry and remaining mixing water to the base mixture, stir at 200 r / min for 2-3 min, then add the pretreated water-reducing agent, and continue stirring for 1-2 min to obtain the concrete mixture. The total amount of mixing water should meet the water-cement ratio requirement of 0.32-0.

50. S6. Pour the concrete mixture into a mold preheated to 30-40℃ and cure it for 28 days according to the corresponding curing method based on the amount of intermediate admixture to obtain the finished concrete product.

2. The concrete production process according to claim 1, characterized in that, In step S11, the mass ratio of granulated blast furnace slag powder to steel slag powder in the solid waste matrix is ​​7:3, the mass ratio of nano silica to modified starch ether in the functional regulator is 1:1, the mass ratio of ultrafine calcium carbonate to potassium aluminum sulfate in the performance compensator is 2:1, and the amount of silane coupling agent added is 1% of the total mass of the solid waste matrix.

3. The concrete production process according to claim 1, characterized in that, In step S12, the rotation speed of the low-speed shearing is 300 r / min, the frequency of the ultrasonic dispersion is 20 kHz, and the rotation speed of the high-speed stirring is 800 r / min.

4. The concrete production process according to claim 1, characterized in that, In step S4, when the target performance is high crack resistance, the amount of the intermediate is 12-15% of the total mass of the cementitious material, and the amount of fine aggregate is increased by 5% compared with the basic mix ratio, and the water-cement ratio is controlled at 0.32-0.

35. When the target performance is early high strength, the amount of the intermediate is 10-12% of the total mass of the cementitious material, and the amount of cement is increased by 10% compared with the basic mix ratio, and the amount of coarse aggregate is increased by 3% compared with the basic mix ratio.

5. The concrete production process according to claim 1, characterized in that, In step S4, when the target performance is high frost resistance, the intermediate content is 15-18% of the total mass of cementitious materials, and the water-reducing agent content is increased by 0.2% compared to the basic mix ratio, while the total amount of mixing water is reduced by 5% compared to the basic mix ratio. When the target performance is low carbon economy, the intermediate content is 8-10% of the total mass of cementitious materials, and the amount of solid waste low carbon materials is increased by 10% compared to the basic mix ratio, while the amount of cement is reduced by 15% compared to the basic mix ratio.

6. The concrete production process according to claim 1, characterized in that, In step S6, the dynamic curing method is as follows: if the intermediate content is ≥15%, the first 3 days are "40℃ steam curing + 2h / day 25kHz ultrasonic curing", with a relative humidity of 95% for steam curing environment, and the following 25 days are natural curing with a relative humidity of ≥90%. If the intermediate content is ≤10%, the first 7 days are natural curing with a relative humidity of ≥90%, with a 5% concentration of intermediate dilution sprayed once a day, and the following 21 days are conventional natural curing with a relative humidity of ≥90%.

7. The concrete production process according to claim 1, characterized in that, In step S22, when the industrial solid waste contains nickel slag, the pretreatment of the nickel slag further includes: crushing the nickel slag to a particle size of no more than 3 mm, calcining it at 800-900℃ for 1-2 hours, cooling it, and grinding it to a specific surface area of ​​350-450 m² / kg. During the calcination process, valuable metals such as nickel and cobalt are recovered with a recovery efficiency of no less than 85%. When the industrial solid waste contains phosphorus slag, the pretreatment of the phosphorus slag further includes: mixing the phosphorus slag with an activator at a mass ratio of 100:3-5, wherein the activator is a mixture of silica fume and sodium hydroxide, with a mass ratio of silica fume to sodium hydroxide of 2:1, and modifying it at 60-70℃ for 30-60 minutes.

8. The concrete production process according to claim 1, characterized in that, In step S5, the dosage of the water-reducing agent is 0.8-1.5% of the total mass of the cementitious materials. During the mixing process, the workability of the concrete mixture is monitored in real time, and the slump of the mixture is controlled at 160-220mm by finely adjusting the amount of mixing water.

9. A concrete production process according to claim 1, characterized in that, In step S1, the particle size of the nano-silica is 20 nm, the particle size of the ultrafine calcium carbonate is 1500 mesh, the particle size of the granulated blast furnace slag powder is 800 mesh, and the particle size of the steel slag powder is 1200 mesh.

10. A type of concrete, characterized in that, It is prepared using the production process described in any one of claims 1-9.

Images