High-performance geopolymer self-compacting concrete and preparation method thereof

Abstract

The invention discloses high-performance geopolymer self-compacting concrete and a preparation method thereof, and the concrete is prepared from the following raw materials in parts by mass: 300-400 parts of geopolymer cement, 100-180 parts of fly ash, 10-30 parts of silica fume, 800-900 parts of medium sand, 780-950 parts of gravel, 5-10 parts of a water reducing agent, 2.5-15 parts of polymer latex powder, 0-15 parts of a corrosion inhibitor, 0.25-1 part of a defoaming agent, 2.5-10 parts of an early strength agent and 140-190 parts of water. By utilizing the characteristics of low energy consumption, low carbon emission and high solid waste utilization rate of the geopolymer cement, the energy consumption and environmental pollution in the production process are obviously reduced; by adding the polymer latex powder, a polymer film is formed in the concrete, so that the impermeability and durability of the concrete are effectively improved, and the carbonization resistance is enhanced; the early strength agent sodium sulfate and hot water are added for mixing, so that the early strength of the geopolymer self-compacting concrete is improved; by adding the phosphate corrosion inhibitor, the corrosion resistance of the reinforced concrete in medium and high corrosion environments is effectively improved, and the service safety of a geopolymer reinforced concrete structure is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete preparation, and more specifically, relates to a high-performance geopolymer self-compacting concrete and a preparation method thereof. Background Art

[0002] Self-compacting concrete (SCC) is a high-performance concrete that flows and compacts under its own gravity, completely filling molds even in the presence of dense rebar. Its outstanding fluidity and lack of segregation have led to its widespread use in high-rise buildings and large-scale water conservancy and hydropower projects.

[0003] Existing self-compacting concrete still has many problems, such as: the high amount of cementitious materials used, the high heat of hydration, which causes thermal cracks and reduces concrete quality; and the high risk of shrinkage and cracking. The high use of Portland cement is not in line with the concept of sustainable environmental development.

[0004] Geopolymer cement is a cementitious material primarily composed of aluminosilicate industrial solid waste or natural pozzolanic raw materials, reacted with appropriate amounts of one or more activators, such as alkali activators, sulfate activators, and industrial alkali slag. Its production process produces low carbon dioxide emissions and utilizes industrial waste, aligning with environmental principles. It can address the environmental concerns associated with the high use of cementitious materials in traditional self-compacting concrete. However, the low early strength and poor carbonation resistance of ettringite-based geopolymer cement have limited its application in infrastructure projects.

[0005] Therefore, there is an urgent need to develop a high-performance geopolymer self-compacting concrete that can improve the early strength and carbonation resistance of geopolymer cement while giving full play to the environmental advantages of geopolymer cement so that it can meet the needs of actual engineering applications. Summary of the Invention

[0006] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a high-performance geopolymer self-compacting concrete and a preparation method thereof. Based on the advantages and disadvantages of geopolymer self-compacting concrete, the formula and preparation process of geopolymer self-compacting concrete are improved, its carbonation resistance is enhanced, and the preparation of high-performance geopolymer concrete is achieved, thereby solving the problems of existing self-compacting concrete such as high hydration heat, easy shrinkage and cracking, and environmental pollution, so that the prepared concrete can better adapt to various complex engineering environments and long-term use requirements.

[0007] To achieve the above-mentioned object, one aspect of the present invention provides a high-performance geopolymer self-compacting concrete, which comprises the following components, calculated by weight, of geopolymer cement 300-400 parts, fly ash 100-180 parts, silica fume 10-30 parts, medium sand 800-900 parts, gravel 780-950 parts, water reducer 5-10 parts, polymer latex powder 2.5-15 parts, rust inhibitor 0-15 parts, defoamer 0.25-1 part, early strength agent 2.5-10 parts, and water 140-190 parts.

[0008] Furthermore, the strength grade of the geopolymer cement in step S1 is 42.5 or 52.5, and the type belongs to ettringite-type geopolymer cement;

[0009] The fly ash is Class I fly ash, with a sieve residue of ≤12%; a water requirement ratio of ≤95%; and a loss on ignition of ≤5%;

[0010] The silica fume has a silicon dioxide content of ≥92%, a loss on ignition of ≤3.0%, a sieve residue of ≤5.0%, and a water requirement of ≤125%.

[0011] Furthermore, the fineness modulus of the medium sand particle size is 2.4-2.8;

[0012] The particle size of the crushed stone is 5-15 mm.

[0013] Furthermore, the water reducer is a liquid polycarboxylic acid high-efficiency water reducer.

[0014] Furthermore, the polymer latex powder is styrene-butadiene rubber powder or styrene-acrylate powder.

[0015] Furthermore, the rust inhibitor is phosphate rust inhibitor powder.

[0016] Furthermore, the early strength agent is powdered sodium sulfate.

[0017] Furthermore, the defoaming agent is organic silicon, and has the appearance of a milky white viscous liquid, a pH value of 6-8, and a solid content of 25%-30%.

[0018] A second aspect of the present invention provides a method for preparing high-performance geopolymer self-compacting concrete, which is used to prepare the high-performance geopolymer self-compacting concrete, comprising the following steps:

[0019] S1: Heat tap water to 30-60°C for later use;

[0020] S2: 300-400 parts of geopolymer cement, 100-180 parts of fly ash, 10-30 parts of silica fume, 800-900 parts of medium sand, 780-950 parts of crushed stone, 2.5-15 parts of polymer latex powder, 0-15 parts of rust inhibitor, and 2.5-10 parts of early strength agent were mixed and stirred for 3-5 minutes to obtain mixture A;

[0021] S3: Add 5-10 parts of a water reducer and 0.25-1 part of a defoamer to 140-190 parts of water and stir evenly to obtain a mixture B;

[0022] S4: Adding mixture B to the mixture A mixed evenly in step S2, stirring for 5-10 minutes, and then stirring evenly to obtain the self-compacting concrete.

[0023] The third aspect of the present invention provides an application of the high-performance geopolymer self-compacting concrete in infrastructure construction projects.

[0024] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0025] (1) The present invention discloses a high-performance geopolymer self-compacting concrete and a preparation method thereof. The geopolymer cement is used as a core cementitious component. The geopolymer cement has micro-expansion, low hydration heat and good sulfate erosion resistance. By utilizing its low energy consumption, low carbon emission and high solid waste utilization rate, the energy consumption and environmental pollution in the production process can be significantly reduced, and the efficient utilization of industrial solid waste can be achieved. Compared with traditional silicate cement, the energy consumption and carbon emission can be greatly reduced, and the high solid waste utilization rate reduces costs, bringing significant economic and environmental benefits. By adding polymer latex powder, a polymer film is formed inside the concrete, filling micropores and cracks, preventing crack expansion, reducing the penetration of moisture and harmful substances, and improving the concrete's impermeability, shrinkage resistance and durability. At the same time, it can also improve the crystal shape of calcium aluminate and enhance its carbonization resistance. The present invention, through the synergistic effect of geopolymer cement and polymer latex powder, can not only solve the problems of temperature cracks and shrinkage cracking caused by high hydration heat of conventional self-compacting concrete, but also solve the problem of its poor resistance to sulfuric acid erosion.

[0026] (2) The high-performance geopolymer self-compacting concrete and its preparation method of the present invention improve the early strength of the geopolymer self-compacting concrete by adding the early strength agent sodium sulfate and using hot water mixing, thereby solving the problem of low early strength of the geopolymer self-compacting concrete; at the same time, the "ball-rolling" effect of silica fume and fly ash improves the fluidity of the self-compacting concrete, and the silica fume also enhances the collapse resistance of the concrete, reduces the porosity, and improves the durability.

[0027] (3) The high-performance geopolymer self-compacting concrete and its preparation method of the present invention effectively improve the corrosion resistance of reinforced concrete in medium and high corrosion environments by adding phosphate rust inhibitors. When the geopolymer self-compacting concrete is applied to steel structures in medium and high corrosion environments, the service safety of the geopolymer reinforced concrete structure can be ensured.

[0028] (4) The high-performance geopolymer self-compacting concrete and its preparation method of the present invention are simple and easy to use. By rationally matching various raw materials, a geopolymer self-compacting concrete with high fluidity, self-compacting performance, good mechanical properties and durability is prepared, which meets the requirements of engineering applications for strength, durability, workability, etc., and conforms to the concepts of environmental protection and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic flow chart of a method for preparing high-performance geopolymer self-compacting concrete according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of an electron microscope microscopic test of a polymer film formed in concrete when the polymer latex powder is styrene-acrylate powder in a method for preparing high-performance geopolymer self-compacting concrete according to an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of an electron microscope microscopic test of a polymer film formed in concrete when the polymer latex powder is styrene-butadiene rubber powder in a method for preparing high-performance geopolymer self-compacting concrete according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0033] Traditional self-compacting concrete has problems such as a large amount of cementitious materials, high hydration heat, easy shrinkage and cracking, and non-compliance with environmental protection concepts. Geopolymer cement is made of industrial solid waste waste such as silicate or natural pozzolanic raw materials as the main components, and is added with an activator. Its production process has low carbon dioxide emissions and can utilize industrial waste, which is in line with environmental protection concepts and can solve the environmental problems caused by the high amount of cementitious materials used in traditional self-compacting concrete. Geopolymer cement has poor anti-carbonation performance and cannot be directly used to prepare self-compacting concrete for structural engineering, which will affect its service life and quality. Based on the above reasons, the present invention provides the following embodiments:

[0034] One aspect of the present invention provides a geopolymer self-compacting concrete. The raw materials, calculated by weight, include the following components: 300-400 parts of geopolymer cement, 100-180 parts of fly ash, 10-30 parts of silica fume, 800-900 parts of medium sand, 780-950 parts of crushed stone, 5-10 parts of water reducer, 2.5-15 parts of polymer latex powder, 0-15 parts of rust inhibitor, 0.25-1 part of defoamer, 2.5-10 parts of early strength agent, and 140-190 parts of water. The present invention aims to produce a geopolymer self-compacting concrete with high fluidity, self-compacting properties, good mechanical properties, and durability by rationally combining various raw materials. This approach addresses the problems of traditional self-compacting concrete, such as high hydration heat, susceptibility to shrinkage and cracking, and environmental concerns.

[0035] Furthermore, the geopolymer cement is used as the core cementitious component of concrete, and its usage is relatively large, in the range of 300-400 parts. It is mainly composed of aluminosilicate industrial solid waste or natural volcanic ash raw materials, and is formed by adding appropriate amounts of alkali activators, sulfate activators, industrial alkali slag and other activators. Its production process has low carbon dioxide emissions, and industrial waste can be used, which is in line with the concept of environmental protection and can solve the environmental problems caused by the high amount of cementitious materials used in traditional self-compacting concrete; compared with traditional cement, the use of geopolymer cement helps to reduce the hydration heat of concrete, reduce the risk of temperature cracks caused by excessive hydration heat, and solve the problem of large amount of cementitious materials used in traditional self-compacting concrete and non-environmental problems. However, calcium aluminate-type geopolymer cement has the disadvantages of low early strength and poor carbonization resistance, so the present invention compensates for these deficiencies through synergy with other materials.

[0036] The fly ash content is 100-180 parts, which is an industrial solid waste. It can effectively improve the workability of concrete and reduce its shrinkage. At the same time, it can also play a certain gelling effect in the later stage to further enhance the strength of concrete. It has high environmental value and is consistent with the environmental protection concept of geopolymer cement, and together help solve the environmental problems of traditional self-compacting concrete.

[0037] As an active mineral admixture, the dosage of silica fume is between 10-30 parts. It has extremely high activity and can effectively fill the internal pores of concrete, improve its density, thereby enhancing the strength and durability of concrete. It is helpful to improve the problem of low early strength of geopolymer cement, and can also improve its anti-carbonation performance.

[0038] For aggregates, medium sand is used in an amount of 800-900 parts. As a fine aggregate, its moderate particle size allows for good bonding with the cementitious material paste to form a uniform concrete mix, ensuring the workability and compatibility of the concrete while also improving its compactness. Crushed stone is used in an amount of 780-950 parts. As a coarse aggregate, it provides the concrete's skeleton structure. Its hardness and strength play a key role in supporting the overall mechanical properties of the concrete. A suitable particle size distribution ensures better workability and strength.

[0039] Among admixtures and functional materials, the dosage of water reducer is 5-10 parts, which is mainly used to reduce the water consumption of concrete mixture, reduce the water-binder ratio while maintaining fluidity, thereby improving the strength and durability of concrete, and also helps to improve the workability of concrete, making it easier to flow and densely fill the mold.

[0040] The dosage of polymer latex powder is between 2.5-15 parts, which can improve the adhesion and toughness of concrete, enhance its crack resistance, play a certain role in reducing the risk of concrete shrinkage cracking, and is also beneficial to improving the concrete's anti-carbonation performance.

[0041] The dosage of rust inhibitor is 0-15 parts, which can be added optionally. If the concrete is in an environment that is prone to steel corrosion, adding rust inhibitor can effectively inhibit steel corrosion, extend the service life of the concrete structure, and ensure its durability.

[0042] The dosage of defoamer is between 0.25-1 part, which is used to eliminate bubbles in concrete mixture, improve the density and strength of concrete, and avoid reducing the quality and performance of concrete due to the presence of bubbles.

[0043] The dosage of early strength agent is in the range of 2.5-10 parts, which can accelerate the early strength development of concrete, make up for the low early strength of geopolymer cement, and enable concrete to achieve higher strength in the early stage, meeting the needs of rapid construction and early load-bearing of the project.

[0044] The water dosage is 140-190 parts, which is an indispensable component for concrete mixing. It undergoes hydration reaction with gelling materials such as geopolymer cement, causing the concrete to gradually harden from a plastic paste into a solid stone-like body. Reasonable control of its dosage has an important influence on the workability and strength of concrete. A lower water-cement ratio helps to improve the strength and durability of concrete.

[0045] The formula of the present invention comprehensively considers the characteristics and functions of various raw materials. On the basis of solving the problems of high hydration heat, easy shrinkage and cracking, and environmental pollution of traditional self-compacting concrete, the high performance of geopolymer self-compacting concrete is achieved by rationally combining geopolymer cement, fly ash, silica fume and other cementitious materials, and using various admixtures and aggregates. It makes it possible to meet the requirements of engineering applications for strength, durability, workability, etc., while complying with the concepts of environmental protection and sustainable development.

[0046] Furthermore, in an embodiment of the present invention, the strength grade of the geopolymer cement is 42.5 or 52.5, and the type belongs to ettringite-type geopolymer cement; it has high strength and can provide good mechanical properties for concrete, but ettringite-type geopolymer cement has the disadvantages of low early strength and poor carbonation resistance, so it often needs to work in synergy with other materials to make up for these shortcomings.

[0047] Furthermore, in an embodiment of the present invention, the fly ash is Class I fly ash, with a sieve residue (45μm square hole sieve) ≤12%; a water requirement ratio ≤95%; and a loss on ignition ≤5%; Class I fly ash is of excellent quality, and a low sieve residue value indicates that its particles are fine, which can effectively fill the gaps between cement particles and improve the density of concrete; a low loss on ignition indicates that the unburned carbon content is low, which helps to reduce the shrinkage and creep of concrete; a low water requirement ratio means that less water is required to achieve the same fluidity, which can reduce the water-cement ratio of concrete and improve strength and durability.

[0048] Furthermore, in an embodiment of the present invention, the silica fume has a silica content of ≥92%, a loss on ignition ≤3.0%, a sieve residue (on a 45μm square mesh sieve) ≤5.0%, and a water requirement ≤125%. The high silica content in the silica fume makes it highly active, allowing it to undergo a secondary reaction with cement hydration products to generate more calcium silicate hydrate and other substances, filling the pores within the concrete and improving its strength and durability. The low loss on ignition and sieve residue indicate its stable quality and fine particles, which can better exert its active properties. The low water requirement helps reduce the water consumption of concrete and improve workability.

[0049] Furthermore, in an embodiment of the present invention, the fineness modulus of the medium sand particle size is 2.4-2.8. Medium sand of this particle size can play a good filling and lubricating role in concrete, and is tightly combined with the cementitious material slurry, so that the concrete has good workability and workability, and is also beneficial to improving the density and strength of the concrete. The particle size of the crushed stone is 5-15mm, which is moderate and can provide sufficient skeleton support for the concrete, ensuring that the concrete has high strength and rigidity, and is also beneficial to the workability and casting of the concrete; the water reducer is a liquid polycarboxylic acid high-efficiency water reducer with a high water reduction rate and good slump retention. It can effectively reduce the water consumption of concrete, reduce the water-cement ratio while ensuring fluidity, thereby significantly improving the strength and durability of concrete, while improving the workability of concrete, making it easier for concrete to flow and densely fill the mold.

[0050] Furthermore, in an embodiment of the present invention, the polymer latex powder is styrene-butadiene rubber powder or styrene-acrylate powder; it plays an important role in concrete, improving the adhesion and toughness of concrete, enhancing crack resistance, and reducing the risk of shrinkage cracking. It is also beneficial to improve the carbonation resistance of concrete, which helps to make up for the shortcomings of ettringite-type geopolymer cement. The rust inhibitor is a phosphate rust inhibitor powder, which can effectively inhibit steel corrosion, extend the service life of concrete structures, and ensure their durability. It is particularly suitable for reinforced concrete structures in harsh environments. The defoaming agent is an organosilicon with an appearance of milky white viscous liquid, a pH value of 6-8, and a solid content of 25%-30%. It can effectively eliminate bubbles in the concrete mixture, improve the density and strength of concrete, and avoid reducing the quality and performance of concrete due to the presence of bubbles. The early strength agent is powdered sodium sulfate, which can accelerate the early strength development of concrete, make up for the low early strength of geopolymer cement, and enable concrete to achieve higher strength at an early stage, meeting the needs of rapid construction and early load-bearing in engineering projects.

[0051] like Figure 1 As shown, the second aspect of the present invention provides a method for preparing geopolymer self-compacting concrete, comprising the following steps:

[0052] S1: Heat tap water to 30-60°C for later use;

[0053] S2: 300-400 parts of geopolymer cement, 100-180 parts of fly ash, 10-30 parts of silica fume, 800-900 parts of medium sand, 780-950 parts of crushed stone, 2.5-15 parts of polymer latex powder, 0-15 parts of rust inhibitor, and 2.5-10 parts of early strength agent were mixed and stirred for 3-5 minutes to obtain mixture A;

[0054] S3: Add 5-10 parts of a water reducer and 0.25-1 part of a defoamer to 140-190 parts of water and stir evenly to obtain a mixture B;

[0055] S4: Adding mixture B to the mixture A mixed evenly in step S2, stirring for 5-10 minutes, and then stirring evenly to obtain the self-compacting concrete.

[0056] The geopolymer cement used in the present invention greatly reduces energy consumption and carbon emissions compared with traditional silicate cement, and the high solid waste utilization rate reduces costs, which can bring economic and environmental benefits; the geopolymer self-compacting concrete prepared by the present invention has micro-expansion, low hydration heat and good sulfate corrosion resistance, which can solve the problems of temperature cracks, shrinkage cracking and poor corrosion resistance of conventional self-compacting concrete; the early strength can be effectively improved by mixing the early strength agent sodium sulfate with hot water, overcoming the defect of low early strength of geopolymer self-compacting concrete; the fluidity is improved by the "balling" effect of silica fume and fly ash, and the silica fume also enhances the collapse retention performance, reduces the porosity, and improves the durability; the shrinkage resistance and corrosion resistance are further improved by adding polymer latex powder; the polymer latex powder forms a polymer film (such as Figure 2 and Figure 3 As shown in the figure), it fills micropores and cracks, prevents crack expansion, reduces the penetration of moisture and harmful substances, improves impermeability and durability, and at the same time improves the shape of ettringite crystals and enhances carbonization resistance. When local polymer self-compacting concrete is used in reinforced structures in medium and high corrosion environments, the addition of phosphate rust inhibitors can effectively improve the corrosion resistance of steel bars and ensure the service safety of the structure.

[0057] Example 1

[0058] Example 1 of the present invention provides a method for preparing geopolymer self-compacting concrete, comprising the following steps:

[0059] S1: Heat tap water to 40°C and keep warm for later use;

[0060] S2: 350 parts of geopolymer cement, 150 parts of fly ash, 0 parts of silica fume, 880 parts of medium sand, 898 parts of crushed stone, 5 parts of polymer latex powder, 0 parts of rust inhibitor, and 5 parts of early strength agent powder were mixed and stirred for 5 minutes to obtain mixture A1;

[0061] S3: 5 parts of water reducer and 0.5 parts of defoamer were added to 175 parts of 40°C hot water and stirred to obtain a mixture B1;

[0062] S4: Add the mixture B1 to the mixture A1 mixed evenly in step S2, and stir for 10 minutes. After stirring evenly, a high-performance geopolymer self-compacting concrete is obtained.

[0063] Example 2

[0064] Example 2 of the present invention provides a method for preparing geopolymer self-compacting concrete, comprising the following steps:

[0065] S1: Heat tap water to 40°C and keep warm for later use;

[0066] S2: 350 parts of geopolymer cement, 120 parts of fly ash, 30 parts of silica fume, 880 parts of medium sand, 898 parts of crushed stone, 5 parts of polymer latex powder, 0 parts of rust inhibitor, and 5 parts of early strength agent powder were mixed and stirred for 5 minutes to obtain mixture A2;

[0067] S3: 5 parts of water reducer and 0.5 parts of defoamer were added to 175 parts of 40°C hot water and stirred to obtain a mixture B2;

[0068] S4: Add the mixture B2 to the mixture A2 mixed in step S2, and stir for 10 minutes. After stirring evenly, a high-performance geopolymer self-compacting concrete is obtained.

[0069] The difference between Example 2 and Example 1 is that: in the preparation of the mixture in step S2, the fly ash is reduced from 150 parts to 120 parts; and 30 parts of silica fume are added; other conditions remain unchanged.

[0070] Example 3

[0071] Example 3 of the present invention provides a method for preparing geopolymer self-compacting concrete, comprising the following steps:

[0072] S1: Heat tap water to 40°C and keep warm for later use;

[0073] S2: 350 parts of geopolymer cement, 150 parts of fly ash, 0 parts of silica fume, 860 parts of medium sand, 860 parts of crushed stone, 5 parts of polymer latex powder, 0 parts of rust inhibitor, and 5 parts of early strength agent powder were mixed and stirred for 5 minutes to obtain mixture A2;

[0074] S3: 5 parts of water reducer and 0.5 parts of defoamer were added to 175 parts of 40°C hot water and stirred to obtain a mixture B2;

[0075] S4: Add the mixture B2 to the mixture A2 mixed in step S2, and stir for 10 minutes. After stirring evenly, a high-performance geopolymer self-compacting concrete is obtained.

[0076] The difference between Example 3 and Example 1 is that in the preparation of the mixture in step S2, the medium sand is reduced to 860 parts and the crushed stone is reduced to 860 parts; other conditions remain unchanged.

[0077] Example 4

[0078] The difference between Example 4 and Example 1 is that in the preparation of the mixture in step S2, the polymer latex powder is increased to 10 parts; other conditions remain unchanged.

[0079] Example 5

[0080] The difference between Example 5 and Example 1 is that in the preparation of the mixture in step S2, the early strength agent powder is increased to 10 parts; other conditions remain unchanged.

[0081] Example 6

[0082] Example 6 of the present invention provides a method for preparing geopolymer self-compacting concrete, comprising the following steps:

[0083] S1: Heat tap water to 60°C and keep warm for later use;

[0084] S2: 350 parts of geopolymer cement, 150 parts of fly ash, 0 parts of silica fume, 860 parts of medium sand, 860 parts of crushed stone, 5 parts of polymer latex powder, 5 parts of inhibitor, and 5 parts of accelerator powder were mixed and stirred for 5 minutes to obtain mixture A6;

[0085] S3: 5 parts of water reducer and 0.5 parts of defoamer were added to 175 parts of hot water at 60° C. and stirred to obtain a mixture B6;

[0086] S4: Add the mixture B2 to the mixture A2 mixed in step S2, and stir for 10 minutes. After stirring evenly, a high-performance geopolymer self-compacting concrete is obtained.

[0087] The difference between Example 6 and Example 1 is that: in step S1, the tap water is 60° C.; in step S2, 5 parts of an attractant are added during the preparation of the mixture; and other conditions remain unchanged.

[0088] Example 7

[0089] The difference between Example 7 and Example 1 is that in the preparation of the mixture in step S2, the fly ash is reduced from 150 parts to 120 parts; 30 parts of silica fume are added; and the early strength agent powder is increased from 5 parts to 10 parts; other conditions remain unchanged.

[0090] The difference between Example 7 and Example 2 is that the accelerator powder is increased from 5 parts to 10 parts; other conditions remain unchanged.

[0091] Example 8

[0092] The difference between Example 8 and Example 1 is that 5 parts of the attractant are added in the preparation of the mixture in step S2; other conditions remain unchanged.

[0093] The difference between Example 8 and Example 6 is that the tap water in step S1 is 40° C.; other conditions remain unchanged.

[0094] In Examples 2-8, based on the method of Example 1, the types and amounts of materials were adjusted. For specific adjustments, please refer to Table 1 below.

[0095] Table 1 Amount of each raw material in Examples 1-8

[0096]

[0097] Comparative Example 1

[0098] Comparative Example 1 of the present invention provides a method for preparing a geopolymer self-compacting concrete, comprising the following steps:

[0099] S1: Heat tap water to 40°C and keep warm for later use;

[0100] S2: 350 parts of ordinary Portland cement, 150 parts of fly ash, 0 parts of silica fume, 880 parts of medium sand, 898 parts of crushed stone, 5 parts of polymer latex powder, 0 parts of rust inhibitor, and 5 parts of early strength agent powder were mixed and stirred for 5 minutes to obtain mixture A2;

[0101] S3: 5 parts of water reducer and 0.5 parts of defoamer were added to 175 parts of 40°C hot water and stirred to obtain a mixture B2;

[0102] S4: Add the mixture B2 to the mixture A2 mixed in step S2, and stir for 10 minutes. After stirring evenly, a high-performance geopolymer self-compacting concrete is obtained.

[0103] The difference between Comparative Example 1 and Example 2 is that: in the preparation of the mixture in step S2, the geopolymer cement is replaced with ordinary Portland cement of the same strength grade and proportion; the fly ash is increased from 120 parts to 150 parts; 30 parts of silica fume are not added; and other conditions remain unchanged.

[0104] Comparative Example 2

[0105] The difference between Comparative Example 2 and Example 2 is that: the tap water in steps S1 and S3 is 20° C.; in the preparation of the mixture in step S2, the fly ash is increased from 120 parts to 150 parts; 30 parts of silica fume are not added; 5 parts of accelerator powder are not added, and other conditions remain unchanged.

[0106] Comparative Example 3

[0107] The difference between Comparative Example 3 and Example 2 is that in the preparation of the mixture in step S2, 5 parts of polymer latex powder and 5 parts of accelerator powder are not added, and 0.5 parts of defoaming agent is not added; other conditions remain unchanged.

[0108] Comparative Example 4

[0109] The difference between Comparative Example 4 and Example 2 is that: in the preparation of the mixture in step S2, the fly ash is increased from 120 parts to 150 parts; 30 parts of silica fume are not added; 5 parts of early strength agent powder are not added; and other conditions remain unchanged.

[0110] Comparative Example 5

[0111] The difference between Comparative Example 5 and Example 2 is that: in the preparation of the mixture in step S2, the fly ash is increased from 120 parts to 150 parts; 30 parts of silica fume are not added; 5 parts of polymer latex powder are not added, and 0.5 parts of defoaming agent are not added, and other conditions remain unchanged.

[0112] Comparative Examples 1-5 were based on the method of Example 2, with changes to the mixing water temperature, material type, etc. See Table 2 below for details.

[0113] Table 2 The amount of each raw material in comparative examples 1-5

[0114] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 water 175 / 40℃ 175 / 20℃ 175 / 40℃ 175 / 40℃ 175 / 40℃ Geopolymer cement 350 (Portland cement) 350 350 350 350 Class I fly ash 150 150 120 150 150 silica fume 0 0 30 0 0 medium sand 880 880 880 880 880 gravel 898 898 898 898 898 polymer latex powder 5 5 0 5 0 water reducer 5 5 5 5 5 Rust inhibitors 0 0 0 0 0 Early strength agent powder 5 0 0 0 5 defoaming agent 0.5 0.5 0 0.5 0

[0115] The high-performance geopolymer self-compacting concrete prepared in Examples 1-8 and Comparative Examples 1-5 was used as a test. The filling property and segregation resistance of the self-compacting concrete were tested according to CECS203:2006 "Technical Specification for the Application of Self-compacting Concrete", the gap passability of the self-compacting concrete was tested according to BS EN 12350-10-2010 "Testing Fresh Concrete Part 10: Self-compacting Concrete-L Box Test", the mechanical properties of the self-compacting concrete were tested according to GB / T 50081-2019 "Standard for Test Methods for Mechanical Properties of Ordinary Concrete", the carbonation resistance test and the sulfate erosion resistance test were performed according to GB / T 50082-2024 "Standard for Test Methods for Long-term Performance and Durability of Concrete", and the corrosion rate of the steel bars was tested according to JTS153-2015 "Standard for Durability Design of Water Transport Engineering Structures". The test results are shown in Table 3.

[0116] Table 3 Comparison of test results of concrete obtained from various embodiments and comparative examples

[0117]

[0118] The experimental results in Table 3 clearly show the performance comparison between Examples 1-8 of the present invention and Comparative Examples 1-5. The concrete of Examples 1-8 of the present invention exhibits good fluidity, filling properties, anti-segregation and durability; this is mainly due to the synergistic effect of geopolymer cement, fly ash and silica fume. These materials not only improve the workability of concrete, but also enhance its density and strength. In particular, the addition of silica fume has a positive effect on improving the early strength and durability of concrete. The application of early strength agent sodium sulfate and hot water mixing also effectively improves the early strength, solving the problem of low early strength of geopolymer self-compacting concrete. In addition, the addition of polymer latex powder improves impermeability and durability, and improves carbonization resistance. Phosphate rust inhibitors enhance the corrosion resistance of steel bars.

[0119] However, the concrete performance of Comparative Examples 1-5 is relatively poor. Comparative Example 1 has poor sulfate erosion resistance due to the replacement of geopolymer cement with ordinary Portland cement. Comparative Example 2 has low water temperature and no early strength agent is added, resulting in insufficient early strength. Comparative Example 3 does not add polymer latex powder and early strength agent, resulting in low early strength, poor carbonization resistance, and poor corrosion resistance. Comparative Example 4 does not add early strength agent, which affects the development of early strength. Comparative Example 5 does not add polymer latex powder and defoamer, resulting in poor carbonization resistance and durability. These comparative results show that the present invention successfully overcomes many problems of traditional self-compacting concrete by optimizing the raw material formula and preparation process, achieves high performance, and meets the high requirements of engineering applications.

[0120] This invention uses geopolymer cement as its core cementitious material. Compared to traditional Portland cement, it reduces energy consumption by over 80% and carbon emissions by over 90%. Its industrial solid waste utilization rate is ≥95%, significantly reducing energy consumption and environmental pollution during the production process. It achieves efficient utilization of industrial solid waste and offers significant economic and environmental benefits. While leveraging the environmental advantages of geopolymer cement, this invention also improves its early strength and carbonation resistance, enabling it to meet the demands of practical engineering applications.

[0121] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high performance geopolymer self-compacting concrete, characterized in that: The raw materials, calculated by mass, include the following components: 300-400 parts of geopolymer cement, 100-180 parts of fly ash, 10-30 parts of silica fume, 800-900 parts of medium sand, 780-950 parts of crushed stone, 5-10 parts of water reducer, 2.5-15 parts of polymer latex powder, 0-15 parts of rust inhibitor, 0.25-1 part of defoaming agent, 2.5-10 parts of early strength agent, and 140-190 parts of water.

2. The high performance geopolymer self-compacting concrete according to claim 1, characterized in that: The strength grade of the geopolymer cement is 42.5 or 52.5, and the type is ettringite-type geopolymer cement; The fly ash is Class I fly ash, with a sieve residue of ≤12%; a water requirement ratio of ≤95%; and a loss on ignition of ≤5%; The silica fume has a silicon dioxide content of ≥92%, a loss on ignition of ≤3.0%, a sieve residue of ≤5.0%, and a water requirement of ≤125%.

3. The high performance geopolymer self-compacting concrete according to claim 2, characterized in that: The fineness modulus of the medium sand particle size is 2.4-2.8; The particle size of the crushed stone is 5-15 mm.

4. A high performance geopolymer self-compacting concrete according to any one of claims 1 to 3, characterized in that: The water reducer is a liquid polycarboxylic acid high-efficiency water reducer.

5. A high performance geopolymer self-compacting concrete according to any one of claims 1 to 3, characterized in that: The polymer latex powder is styrene-butadiene rubber powder or styrene-acrylate powder.

6. A high performance geopolymer self-compacting concrete according to any one of claims 1 to 3, characterized in that: The rust inhibitor is phosphate rust inhibitor powder.

7. A high performance geopolymer self-compacting concrete according to any one of claims 1 to 3, characterized in that: The early strength agent is powdered sodium sulfate.

8. A high performance geopolymer self-compacting concrete according to any one of claims 1 to 3, characterized in that: The defoaming agent is organic silicon, and has the appearance of milky white viscous liquid, a pH value of 6-8, and a solid content of 25%-30%.

9. A method for preparing high-performance geopolymer self-compacting concrete, characterized in that: The method for preparing high-performance geopolymer self-compacting concrete according to any one of claims 1 to 8 comprises the following steps: S1: Heat tap water to 30-60°C for later use; S2: 300-400 parts of geopolymer cement, 100-180 parts of fly ash, 10-30 parts of silica fume, 800-900 parts of medium sand, 780-950 parts of crushed stone, 2.5-15 parts of polymer latex powder, 0-15 parts of rust inhibitor, and 2.5-10 parts of early strength agent were mixed and stirred for 3-5 minutes to obtain mixture A; S3: Add 5-10 parts of a water reducer and 0.25-1 part of a defoamer to 140-190 parts of water and stir evenly to obtain a mixture B; S4: Adding mixture B to the mixture A mixed evenly in step S2, stirring for 5-10 minutes, and then stirring evenly to obtain the self-compacting concrete.

10. Use of the high-performance geopolymer self-compacting concrete according to any one of claims 1 to 8 in infrastructure construction projects.

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