Environment-friendly commercial concrete and preparation method thereof

Abstract

The invention provides environment-friendly commercial concrete and a preparation method thereof, and relates to the technical field of building materials, and the environment-friendly commercial concrete provided by the invention greatly improves various performance indexes of the concrete through an optimized raw material ratio and an advanced preparation method. For example, in the aspect of compressive strength, the compressive strength of 7 days, 28 days and 60 days is obviously higher than that of traditional concrete, which means that a building can have higher bearing capacity in the early stage, and the construction period is shortened. Meanwhile, the good anti-seepage performance effectively prevents water and harmful substances from permeating, the service life of a building is prolonged, and the repair and maintenance cost is reduced. Besides, the slump is optimized, so that the concrete is easier to pour and vibrate in the construction process, the construction efficiency and quality are improved, the uniformity and compactness of the concrete structure are ensured, the advantages of environmental protection and energy conservation are outstanding, and a large amount of industrial waste residues such as fly ash and slag powder are used for replacing part of cement in the aspect of raw material selection.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and more specifically, particularly relates to an environmentally friendly commercial concrete and a preparation method thereof. Background Art

[0002] In the field of modern construction engineering, commercial concrete is a widely used building material, and its performance and quality are directly related to the structural safety, durability and use function of the building. However, with the increasing demand for environmental protection and sustainable development in society, the problems exposed in the production and use of traditional commercial concrete have become increasingly prominent.

[0003] The production of traditional commercial concrete usually relies on a large amount of cement, and the manufacture of cement is a high-energy, high-emission process that not only consumes a large amount of natural resources, but also releases a large amount of greenhouse gases such as carbon dioxide, causing serious pollution to the environment. At the same time, traditional commercial concrete also has certain limitations in terms of performance, such as insufficient compressive strength, poor impermeability, and difficult to control slump, which may cause cracks and leakage in the building during use, affecting its service life and safety.

[0004] In addition, with the continuous expansion of the scale of construction projects and the increasing complexity, the performance requirements for commercial concrete are also getting higher and higher. For example, in projects such as high-rise buildings, large-span bridges, and underground projects, concrete is required to have higher strength, better durability, and better impermeability to meet the requirements of structural design and use environment. At the same time, during the construction process, the slump and workability of commercial concrete also directly affect the construction efficiency and quality, and it is required to have good operability and pouring performance.

[0005] In order to solve the above problems, researchers have been working hard to explore new commercial concrete and its preparation methods. In recent years, the application of environmentally friendly materials has gradually attracted attention. By adding fly ash, slag powder and other industrial waste residues into concrete, it can not only reduce the amount of cement and reduce production costs, but also improve the performance of concrete and realize resource recycling. At the same time, the research and development and application of new admixtures also provide possibilities for improving the performance of concrete. For example, high-performance water reducers can effectively improve the slump and fluidity of concrete, and reinforcing fibers can improve the tensile strength and crack resistance of concrete.

[0006] In terms of preparation methods, optimizing the mixing process, controlling the mixing time and speed, and adjusting the mixing temperature and humidity are also important for improving the uniformity and performance of concrete. In addition, by establishing a scientific mix design method, combining the characteristics of raw materials and engineering requirements, and accurately calculating the amount of each component, the maximum performance of concrete and the optimization of cost can be achieved.

[0007] However, the existing environmentally friendly commercial concrete and its preparation method still have some shortcomings. For example, the effects of some research results are not stable enough in practical applications, or although some performances have been improved, there is still room for improvement in comprehensive performance and cost-effectiveness. Therefore, the development of an environmentally friendly commercial concrete and its preparation method with superior performance, environmental protection and energy saving, reasonable cost and simple and reliable preparation process has become an important issue to be solved in the field of building materials. The present invention came into being in such a background, aiming to provide an effective solution to solve the above problems and promote the sustainable development of the construction industry. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides an environmentally friendly commercial concrete and a preparation method thereof to solve the above problems.

[0009] An environmentally friendly commercial concrete is made of the following raw materials in parts by weight: 220-280 parts of cement, 60-90 parts of fly ash, 60-90 parts of slag powder, 650-750 parts of sand, 1050-1150 parts of gravel, 160-190 parts of water, 6-9 parts of water reducing agent, and 6-9 parts of reinforcing fiber;

[0010] Among them, the reinforcing fiber is a mixture of basalt fiber and polypropylene fiber in a mass ratio of 1:1, and the compressive strength R of the concrete satisfies the following relationship with the cement content C, the fly ash content F, and the slag powder content K: R=0.15C+0.1F+0.12K+50, in MPa.

[0011] Preferably, the cement is ordinary Portland cement with a strength grade of 42.5 and a specific surface area of ​​300-400m

[0012] / kg.

[0013] Preferably, the fly ash is first-grade fly ash, the water requirement ratio of which is not greater than 95%, and the slag powder is S95-grade slag powder, the fluidity ratio of which is not less than 95%.

[0014] Preferably, the sand is medium sand with a fineness modulus of 2.7-2.9, a mud content of no more than 1.5%, and the fineness modulus M of the sand and the slump S of the concrete satisfy the formula: S=180-10M.

[0015] Preferably, the stone is a continuously graded crushed stone with a particle size of 5-25 mm, a crushing index of no more than 8%, and the crushing index Y of the stone and the concrete strength R satisfy the relationship: R=60-5Y.

[0016] A method for preparing environmentally friendly commercial concrete comprises the following steps:

[0017] S1: Put sand, gravel, fly ash and slag powder into a mixer and dry mix for 2.5 minutes at a speed of 35 rpm;

[0018] S2: Add cement and reinforcing fiber and continue stirring for 2.5 minutes at a mixer speed of 45 rpm;

[0019] S3: Add water and water reducing agent, stir for 4 minutes, and the speed of the mixer is 55 rpm to obtain environmentally friendly commercial concrete.

[0020] Preferably, in step S1, the temperature during dry mixing is controlled at 20-30°C.

[0021] Preferably, in step S2, the humidity during stirring is controlled at 50%-60%.

[0022] Preferably, in step S3, the ambient pressure during stirring is standard atmospheric pressure ±0.01 MPa.

[0023] Preferably, the water reducer is diluted with water before being added, the dilution ratio is 1:7, and the water temperature is controlled at 15-25°C during dilution.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. Significantly improve the performance of concrete. The environmentally friendly commercial concrete of the present invention has greatly improved various performance indicators of concrete through optimized raw material ratios and advanced preparation methods. For example, in terms of compressive strength, the compressive strength of 7 days, 28 days and 60 days is significantly higher than that of traditional concrete, which means that the building can have a higher bearing capacity in the early stage and shorten the construction period. At the same time, good impermeability effectively prevents the penetration of moisture and harmful substances, extends the service life of the building, and reduces repair and maintenance costs. In addition, the optimization of slump makes the concrete easier to pour and vibrate during the construction process, improves construction efficiency and quality, and ensures the uniformity and density of the concrete structure.

[0026] 2. The advantages of environmental protection and energy saving are outstanding. In terms of raw material selection, a large amount of industrial waste residues such as fly ash and slag powder are used to replace part of the cement, which not only reduces the energy consumption and carbon dioxide emissions in the cement production process, but also realizes the resource utilization of waste and reduces the pressure on the environment. At the same time, the low-energy mixing equipment and scientific mixing process in the preparation process further reduce energy consumption and meet the requirements of sustainable development. This environmental protection and energy-saving feature helps to promote the transformation of the construction industry towards a green and low-carbon direction and make a positive contribution to addressing global climate change.

[0027] 3. Significant cost-effectiveness. Although the cost of raw materials for some mixes may be slightly higher than that of traditional commercial concrete, the overall cost-effectiveness is significant when considering its excellent performance and reduced subsequent maintenance costs. High strength and high durability increase the reliability of buildings in long-term use and reduce the cost of repair and reconstruction due to structural damage. In addition, good construction performance reduces waste and rework during construction, improves construction efficiency, and indirectly reduces labor costs and time costs. From the perspective of the entire life cycle, the environmentally friendly commercial concrete of the present invention has a higher cost-effectiveness and brings greater economic value to construction projects.

[0028] 4. Innovative mix design. Through in-depth research on the characteristics and interactions of raw materials, the present invention proposes an innovative mix design. The precise proportions of cement, fly ash, slag powder, sand, gravel, water, water reducer and reinforcing fiber give full play to the advantages of each component and achieve a synergistic improvement in performance. This mix design is not a simple combination of materials, but an optimization result based on scientific principles and a large amount of experimental data. It not only provides new ideas and methods for the concrete industry, but also lays the foundation for the development of more high-performance concrete products.

[0029] 5. Enhance building safety and stability. High-performance concrete can provide more reliable structural support for buildings, enhance their resistance to natural disasters such as earthquakes and wind disasters, and protect the lives and property of people. Good impermeability can prevent the corrosion of steel bars inside the concrete and maintain the integrity and stability of the structure. In addition, the precise preparation method ensures the consistency and stability of concrete quality, reduces the safety hazards caused by quality fluctuations, and provides a strong guarantee for the high-quality development of the construction industry.

[0030] 6. Promote technological progress in the industry. The environmentally friendly commercial concrete and its preparation method of the present invention set a new benchmark for the concrete industry. Its innovative concept, advanced technology and remarkable effect will inspire peer companies to increase R&D investment and promote technological innovation and product upgrades. At the same time, relevant research results and practical experience will also promote the improvement of concrete industry standards and the updating of specifications, leading the industry to develop in a more scientific, environmentally friendly and efficient direction. This is of great significance to improving the technical level and competitiveness of the entire industry, and will help my country achieve greater breakthroughs and achievements in the field of building materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of concrete and its preparation method in the present invention. DETAILED DESCRIPTION

[0032] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0033] The present invention relates to an environmentally friendly commercial concrete and a preparation method thereof, aiming to provide a concrete product with superior performance, environmental protection and energy saving and scientific and reasonable preparation process, so as to meet the high quality requirements of modern construction projects for concrete materials.

[0034] Ordinary Portland cement with a strength grade of 42.5 and a specific surface area of ​​350m2 / kg is selected. To ensure that the stability of the cement is qualified, the initial setting time is not earlier than 45 minutes, and the final setting time is not later than 6.5 hours. First-grade fly ash is used, and its water requirement ratio is 90%. Fly ash should have good activity, and the loss on ignition is not more than 5%. S95 grade slag powder is selected, and the fluidity ratio is 98%. The specific surface area of ​​slag powder should be between 400-450m2 / kg. Medium sand with a fineness modulus of 2.8 and a mud content of 1.0% is selected. The particle grading of sand should meet the requirements of Zone II, and the solidity index is not more than 8%. Continuously graded crushed stone with a particle size of 5-25mm is used, and the crushing index is 6%. The needle-like particle content of the stone is not more than 10%, the mud content is not more than 0.5%, drinking water that meets national standards is used, and a high-performance polycarboxylate water-reducing agent is selected with a water reduction rate of not less than 25%. The reinforcing fiber is a mixture of basalt fiber and polypropylene fiber in a mass ratio of 1:1, and the fiber length is 6-12mm.

[0035] The design basis ratio is as follows (unit: kg / m3):

[0036]

[0037] In order to study the effect of different raw material amounts on concrete performance, the following adjusted mix ratios were designed:

[0038]

[0039] During preparation, a forced twin-shaft mixer with a capacity of 2m3 is used, sand, gravel, fly ash and slag powder are put into the mixer, dry mixed for 2.5 minutes, the mixer speed is 35 rpm, the temperature during dry mixing is controlled at 25°C, cement and reinforcing fiber are added, stirring is continued for 2.5 minutes, the mixer speed is 45 rpm, the humidity during stirring is controlled at 55%, water and water reducing agent are added, stirring for 4 minutes, the mixer speed is 55 rpm, and environmentally friendly commercial concrete is obtained. The ambient pressure during stirring is standard atmospheric pressure.

[0040] In order to verify the performance of the environmentally friendly commercial concrete of the present invention, the following experiments were carried out and compared with traditional commercial concrete. According to the "Standard for Test Methods for Mechanical Properties of Ordinary Concrete" (GB / T50081-2019), 150mm×150mm×150mm cubic specimens were made, and compressive strength tests were carried out after curing for 7 days, 28 days and 60 days, respectively. Three specimens were made for each mix ratio, and the average value was taken as the final result. The slump test was carried out in accordance with the "Standard for Test Methods for Performance of Ordinary Concrete Mixtures" (GB / T50080-2016), and each mix ratio was tested 3 times to take the average value. The water seepage height method was used to test the impermeability of the concrete in accordance with the "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete" (GB / T50082-2009). Six specimens were made for each mix ratio and the average value was taken.

[0041] Compressive strength results:

[0042]

[0043] From the above data, it can be seen that the compressive strength of the environmentally friendly commercial concrete of the present invention at 7 days, 28 days and 60 days is significantly higher than that of the traditional commercial concrete. Among them, the compressive strength of mix ratios 2 and 4 is relatively excellent.

[0044] Slump test results:

[0045]

[0046] It can be seen from the above data that the slump of the environmentally friendly commercial concrete of the present invention is generally greater than that of traditional commercial concrete, and has better construction performance.

[0047] Anti-seepage performance test results:

[0048]

[0049] The environmentally friendly commercial concrete of the present invention has significantly better anti-seepage performance than traditional commercial concrete, among which mix ratios 2 and 4 have the best anti-seepage effects.

[0050] Cost analysis of the environmentally friendly commercial concrete of the present invention and traditional commercial concrete was conducted, taking into account factors such as raw material cost, preparation cost and transportation cost:

[0051]

[0052] Although the cost of some of the mix proportions of the present invention is slightly higher than that of traditional commercial concrete, considering its excellent performance and environmental benefits, it has a higher cost-effectiveness.

[0053] The environmentally friendly commercial concrete and the preparation method thereof of the present invention have significant advantages. Through reasonable raw material selection and mix ratio design, combined with scientific preparation technology, it is possible to produce a concrete product with superior performance, environmental protection and energy saving. The verification experiment results show that the concrete of the present invention is superior to the traditional commercial concrete in terms of compressive strength, slump and impermeability, and has certain cost advantages and good application prospects.

[0054] Significantly improve the performance of concrete. The environmentally friendly commercial concrete of the present invention has greatly improved various performance indicators of concrete through optimized raw material ratios and advanced preparation methods. For example, in terms of compressive strength, the compressive strength of 7 days, 28 days and 60 days is significantly higher than that of traditional concrete, which means that the building can have a higher bearing capacity at an early stage and shorten the construction period. At the same time, good impermeability effectively prevents the penetration of moisture and harmful substances, extends the service life of the building, and reduces repair and maintenance costs. In addition, the optimization of slump makes the concrete easier to pour and vibrate during the construction process, improves construction efficiency and quality, and ensures the uniformity and density of the concrete structure;

[0055] The advantages of environmental protection and energy saving are outstanding. In terms of raw material selection, a large amount of industrial waste residues such as fly ash and slag powder are used to replace part of the cement, which not only reduces the energy consumption and carbon dioxide emissions in the cement production process, but also realizes the resource utilization of waste and reduces the pressure on the environment. At the same time, the low-energy mixing equipment and scientific mixing process in the preparation process further reduce energy consumption and meet the requirements of sustainable development. This environmental protection and energy-saving feature will help promote the transformation of the construction industry towards a green and low-carbon direction and make a positive contribution to addressing global climate change;

[0056] The cost-effectiveness is remarkable. Although the raw material cost of some mixes may be slightly higher than that of traditional commercial concrete, considering its excellent performance and reduced subsequent maintenance costs, the overall cost-effectiveness is remarkable. High strength and high durability increase the reliability of buildings in long-term use and reduce the cost of repair and reconstruction due to structural damage. In addition, good construction performance reduces waste and rework during construction, improves construction efficiency, and indirectly reduces labor costs and time costs. From the perspective of the entire life cycle, the environmentally friendly commercial concrete of the present invention has a higher cost-effectiveness and brings greater economic value to construction projects;

[0057] Innovative mix design. Through in-depth research on the characteristics and interactions of raw materials, the present invention proposes an innovative mix design. The precise proportions of cement, fly ash, slag powder, sand, gravel, water, water reducer and reinforcing fiber give full play to the advantages of each component and achieve a synergistic improvement in performance. This mix design is not a simple combination of materials, but an optimization result based on scientific principles and a large amount of experimental data. It not only provides new ideas and methods for the concrete industry, but also lays the foundation for the development of more high-performance concrete products;

[0058] Enhance building safety and stability. High-performance concrete can provide more reliable structural support for buildings, enhance their resistance to natural disasters such as earthquakes and wind disasters, and protect the lives and property of people. Good impermeability can prevent the corrosion of steel bars inside the concrete and maintain the integrity and stability of the structure. In addition, the precise preparation method ensures the consistency and stability of concrete quality, reduces the safety hazards caused by quality fluctuations, and provides a strong guarantee for the high-quality development of the construction industry.

[0059] The environmentally friendly commercial concrete and its preparation method of the present invention have set a new benchmark for the concrete industry by promoting technological progress in the industry. Its innovative concept, advanced technology and remarkable effects will inspire peer companies to increase their R&D investment and promote technological innovation and product upgrades. At the same time, relevant research results and practical experience will also promote the improvement of concrete industry standards and the updating of specifications, leading the industry to develop in a more scientific, environmentally friendly and efficient direction. This is of great significance for improving the technical level and competitiveness of the entire industry, and will help my country achieve greater breakthroughs and achievements in the field of building materials.

[0060] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. An environmentally friendly commercial concrete, characterized in that: Made of the following raw materials in parts by weight: 220-280 parts of cement, 60-90 parts of fly ash, 60-90 parts of slag powder, 650-750 parts of sand, 1050-1150 parts of gravel, 160-190 parts of water, 6-9 parts of water reducing agent, and 6-9 parts of reinforcing fiber; Among them, the reinforcing fiber is a mixture of basalt fiber and polypropylene fiber in a mass ratio of 1:1, and the compressive strength R of the concrete satisfies the following relationship with the cement content C, the fly ash content F, and the slag powder content K: R=0.15C+0.1F+0.12K+50, in MPa.

2. The environmentally friendly commercial concrete according to claim 1, characterized in that: The cement is ordinary Portland cement with a strength grade of 42.5 and a specific surface area of ​​300-400m2 / kg.

3. The environmentally friendly commercial concrete according to claim 1, characterized in that: The fly ash is first-grade fly ash, and its water demand ratio is not more than 95%. The slag powder is S95-grade slag powder, and its fluidity ratio is not less than 95%.

4. The environmentally friendly commercial concrete according to claim 1, characterized in that: The sand is medium sand with a fineness modulus of 2.7-2.9, the mud content does not exceed 1.5%, and the fineness modulus M of the sand and the slump S of the concrete satisfy the formula: S=180-10M.

5. The environmentally friendly commercial concrete according to claim 1, characterized in that: The gravel is continuously graded crushed stone with a particle size of 5-25 mm, and the crushing index is not more than 8%, and the crushing index Y of the gravel and the concrete strength R satisfy the relationship: R=60-5Y.

6. A method for preparing environmentally friendly commercial concrete, characterized in that: The following steps are involved: S1: Put sand, gravel, fly ash and slag powder into a mixer and dry mix for 2.5 minutes at a speed of 35 rpm; S2: Add cement and reinforcing fiber and continue stirring for 2.5 minutes at a mixer speed of 45 rpm; S3: Add water and water reducing agent, stir for 4 minutes, and the speed of the mixer is 55 rpm to obtain environmentally friendly commercial concrete.

7. The method for preparing the environmentally friendly commercial concrete according to claim 6, characterized in that: In step S1, the temperature during dry mixing is controlled at 20-30°C.

8. The method for preparing the environmentally friendly commercial concrete according to claim 6, characterized in that: In step S2, the humidity during stirring is controlled at 50%-60%.

9. The method for preparing the environmentally friendly commercial concrete according to claim 6, characterized in that: In step S3, the ambient pressure during stirring is standard atmospheric pressure ±0.01 MPa.

10. The method for preparing the environmentally friendly commercial concrete according to any one of claims 6 to 9, characterized in that: The water reducer should be diluted with water before adding, the dilution ratio is 1:7, and the water temperature should be controlled at 15-25℃ during dilution.

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