CN117645453A - Steaming-free super-early-strength C120 self-compacting concrete and preparation method thereof - Google Patents

Abstract

The invention discloses a steam-curing-free, ultra-early-strength C120 self-compacting concrete and a preparation method thereof. It solves the problem of poor self-compacting properties of ultra-high-strength concrete in the prior art and poor durability using steam curing. For large-scale foundations with dense reinforcement and complex structures, Construction of prefabricated reinforced concrete structures, vibration will cause structural changes or even damage.

Description

A steam-curing-free, super early-strength C120 self-compacting concrete and its preparation method

Technical field

The invention relates to the technical field of concrete materials, and in particular to a steam-curing-free, ultra-early strength C120 self-compacting concrete and a preparation method thereof.

Background technique

The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

As the requirements for energy conservation and environmental protection in the construction industry increase day by day, concrete products are widely used due to their high construction quality, early strength and fast mold turnover efficiency. At the same time, with the construction of large-scale infrastructure such as long-span bridges and wind power generation, the requirements for concrete's working performance, mechanical properties and durability are getting higher and higher.

In the existing technology, traditional ultra-high-strength concrete often has poor working performance while ensuring that the mechanical properties meet the design requirements. Vibration is required to evenly distribute the concrete in the formwork to make the concrete denser. For buildings with dense reinforcement and complex structures, For large-scale infrastructure prefabricated reinforced concrete components, vibration construction is more difficult, and vibration construction can easily cause structural changes or even damage.

For prefabricated reinforced concrete components, steam curing or autoclaved curing is usually used. Steam curing or autoclaved curing can effectively improve the early strength of concrete and improve mold turnover efficiency. However, steam curing and autoclaved curing are costly, consume a lot of energy, and pollute the environment. , and the prepared concrete is thermally damaged, has large autogenous shrinkage deformation, and generates hydration products with poor corrosion resistance, making the prefabricated components brittle and poor in durability. Therefore, there is an urgent need for a steam-curing-free, ultra-early strength C120 self-compacting concrete and its preparation method.

Contents of the invention

In view of the shortcomings of the existing technology, the purpose of the embodiments of the present invention is to provide a steam-curing-free, ultra-early strength C120 self-compacting concrete and a preparation method thereof, so as to solve the problem of poor self-compacting properties of existing ultra-high-strength concrete and durability using steam curing. Sexual defects.

In order to achieve the above objects, embodiments of the present invention provide the following technical solutions:

A steam-curing-free, super early-strength C120 self-compacting concrete, including the following raw materials in parts by weight: 400 to 550 parts of cement, 45 to 105 parts of mineral powder, 70 to 160 parts of fly ash beads, and 28 to 38 parts of silica fume parts, 700 to 790 parts of fine aggregate, 850 to 970 parts of coarse aggregate, 7.5 to 14 parts of water reducing agent, 5 to 15 parts of early strength agent, 3 to 7 parts of viscosity reducing agent, 2 to 6 parts of retarder, 3 to 8 parts of defoaming agent and 110 to 140 parts of water.

The inventor found in practice that existing ultra-high-strength concrete often has low workability and requires mixing and vibration. However, when constructing precast reinforced concrete components for large-scale infrastructure with dense reinforcement and complex structures, vibration construction is more difficult, and Vibration construction can easily destroy the original structure, and the existing ultra-high-strength concrete cannot be applied to the above-mentioned large-scale infrastructure construction with dense reinforcement and complex structure. The present invention enhances the good compactness of the concrete by combining the specific proportions of the above-mentioned raw materials in the concrete. At the same time, the addition of fly ash microspheres further improves the workability of the concrete and ensures the good compactness of the concrete without vibrating. It can be widely used in large-scale prefabricated components with limited construction space such as dense reinforcement and complex structures. It can effectively shorten the construction period and improve mold turnover and engineering efficiency.

Embodiments of the present invention also provide a method for preparing steam-curing-free, ultra-early strength C120 self-compacting concrete, which includes:

S1. Add the cement, mineral powder, fly ash beads and silica fume into the mixer and dry mix until uniform;

S2. Then add water, water reducing agent, early strength agent, viscosity reducer, retardant and defoaming agent into the mixer and stir until uniform;

S3. Then add fine aggregate and coarse aggregate and vibrate and stir until uniform;

S4. After mixing is completed, formwork is installed, and an impermeable film is used to cover the surface of the concrete mixture for curing;

S5. After removing the formwork, place it in a standard curing room for standard curing to obtain the steam-curing-free, ultra-early strength C120 self-compacting concrete.

One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

1. The present invention enhances the good compactness of concrete through the combination of specific proportions of the above-mentioned raw materials in concrete. At the same time, the addition of fly ash microspheres further improves the workability of concrete and ensures good concrete consistency without vibrating. It is dense and can be widely used in large-scale prefabricated components with limited construction space such as dense reinforcement and complex structures. It can effectively shorten the construction period and improve mold turnover and engineering efficiency.

2. The self-compacting concrete provided by the present invention only needs to cover the surface of the concrete mixture with an impermeable film for curing, and does not require steam or autoclave curing, effectively avoiding thermal damage and structural defects inside the concrete during the steam curing process, and improving the performance of prefabricated components. The overall performance reduces enterprise production costs and carbon dioxide emissions.

3. The present invention makes full use of solid waste resources such as fly ash beads, mineral powder and silica fume to replace part of the cement in traditional concrete, reduce cement consumption and carbon dioxide emissions, and meet the requirements of C120 concrete that requires no steam curing, ultra-early strength and self-compacting. , while consuming solid waste and reducing costs.

4. Compared with ordinary concrete, the concrete provided by the present invention has good working performance and mechanical properties. In terms of working performance, various indicators comply with the "Technical Regulations for the Application of Self-Compacting Concrete" (JGJ/T283-2012) for concrete mixtures. Self-compacting performance index, with excellent filling performance (660≤SF2≤750mm, 2s≤T ₅₀ ≤5s) and gap passability (0mm≤PA2≤25mm), while the inverted collapse bucket of concrete is ≤8s. In terms of mechanical properties, the prepared concrete reaches a form removal strength of ≥15MPa within 8 hours, a hoisting strength of ≥40MPa within 12 hours, and a compressive strength of more than 120MPa in 28 days. It can be widely used in large-scale prefabricated components with dense reinforcement (clear spacing of steel bars 60mm to 80mm), complex structures, etc. with limited construction space and high concrete appearance performance requirements. It can effectively shorten the construction period and improve mold turnover and engineering efficiency.

Description of drawings

The description and drawings that constitute a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

Figure 1 is a process flow diagram in an embodiment of the present invention.

The spacing or size of each part is exaggerated to show the location of each part, and the schematic diagram is for illustrative purposes only.

Detailed ways

It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings commonly understood by one of ordinary skill in the art to which this invention belongs.

As introduced in the background art, ultra-high-strength concrete in the prior art has poor self-compacting properties and poor durability using steam curing. In order to solve the above technical problems, the present invention proposes a steam-curing-free, ultra-early-strength C120 self-compacting concrete. Further , this application proposes a preparation method for steam-curing-free, ultra-early strength C120 self-compacting concrete.

A steam-curing-free, super early-strength C120 self-compacting concrete, including the following raw materials in parts by weight: 400 to 550 parts of cement, 45 to 105 parts of mineral powder, 70 to 160 parts of fly ash beads, and 28 to 38 parts of silica fume parts, 700 to 790 parts of fine aggregate, 850 to 970 parts of coarse aggregate, 7.5 to 14 parts of water reducing agent, 5 to 15 parts of early strength agent, 3 to 7 parts of viscosity reducing agent, 2 to 6 parts of retarder, 3 to 8 parts of defoaming agent and 110 to 140 parts of water.

In some embodiments, the cement is PI 52.5 Portland cement, and the loss on ignition is ≤3.0%.

In some embodiments, the loss on ignition of the mineral powder is ≤1.0%, the 28d mortar activity index is ≥95%, and the fluidity ratio is ≥95%.

In some embodiments, the fly ash microbead mobility ratio is ≥105%, and the 28d activity index is ≥90%.

In some embodiments, the specific surface area of silica fume is ≥ 15000 m ² /kg, the loss on ignition is ≤ 4.0%, and the 7d activity index is ≥ 105%.

In some embodiments, the fine aggregate is zone II medium sand, with a fineness modulus of 2.5 to 3.0, and a particle size composition of: 24% from 4 to 16 mesh, 56% from 16 to 50 mesh, and 13% from 50 to 100 mesh.

In some embodiments, the coarse aggregate is basalt, with a particle size of 5-20 mm and a crushing value of ≤8.0%.

In some embodiments, the water-reducing agent is a polycarboxylic acid high-efficiency water-reducing agent with a solid content of 25 to 35%.

In some embodiments, the early strength agent is a nanometer C-S-H-PCE early strength agent with a solid content of 10 to 15%.

In some embodiments, the viscosity reducing agent is M31 viscosity reducing agent, and the solid content is 15-25%.

In some embodiments, the retarder is carboxymethylcellulose sodium retarder, with a solid content of 15% to 25%.

In some embodiments, the defoaming agent is Zhongyan ZY-DF3 defoaming agent with a solid content of 15 to 25%.

A method for preparing steam-curing-free, ultra-early strength C120 self-compacting concrete, including:

S1. Add the cement, mineral powder, fly ash beads and silica fume into the mixer and dry mix until uniform;

S2. Then add water, water reducing agent, early strength agent, viscosity reducer, retardant and defoaming agent into the mixer and stir until uniform;

S3. Then add fine aggregate and coarse aggregate and vibrate and stir until uniform;

S4. After mixing is completed, formwork is installed, and an impermeable film is used to cover the surface of the concrete mixture for curing;

S5. After removing the formwork, put it into standard curing and continue standard curing to obtain the steam-curing-free, ultra-early strength C120 self-compacting concrete.

Adding mineral powder and silica fume to concrete can not only increase the viscosity of the concrete, increase the bonding force between the cement slurry and the coarse and fine aggregates, and prevent concrete segregation during the construction process causing the aggregate to sink, but also the SiO in the mineral powder and silica fume ₂ can produce a secondary volcanic ash effect (gelling reaction) with cement hydration products Ca(OH) ₂ , etc. to generate hydrated calcium silicate (CSH) gel, which can refine the pore structure of concrete after hardening and increase the density of concrete in the later stage. strength, effectively improving the later compressive strength and corrosion resistance of concrete; the "ball effect" in fly ash microspheres can effectively improve the workability of concrete; nano-CSH-PCE early strength agent can form hydrated calcium silicate gel The formation provides crystal nuclei, promotes the formation of hydrated calcium silicate gel and the continued dissolution of Ca ²⁺ and SiO ₄ ^2- , thereby shortening the induction period of cement hydration, and it can also promote the hydration of silicon in the cement slurry. The polymerization of calcium acid gel greatly promotes the hydration reaction, thereby improving the early strength of concrete; the viscosity reducer can effectively improve the viscosity of concrete, improve the passability of concrete gaps, and increase the construction speed; the retarder can ensure that the prepared concrete has It has certain slump-preserving properties to prevent premature condensation of concrete during construction, which affects the construction period and cost; defoaming agents can improve the compactness of poured concrete, improve the compressive strength and aesthetic appearance of concrete.

In the following examples and comparative examples, P·Ⅰ52.5 Portland cement is used as cement, with a loss on ignition of 1.9%; a loss on ignition of ore powder of 0.93%; a 28d mortar activity index of 99%; a fluidity ratio of 100%; pulverized coal The fluidity ratio of ash microbeads is 110%, and the 28d activity index is 102%; the specific surface area of silica fume is 18999m ² /kg, the loss on ignition is 2.12%, and the 7d activity index is 107%; the fine aggregate is zone II medium sand, and the fineness modulus 2.5; the coarse aggregate is basalt with a particle size of 5 to 20 mm and a crushing value of 3.9%; the water-reducing agent is polycarboxylic acid high-efficiency water-reducing agent with a solid content of 28%; the early-strength agent is nano-CSH-PCE early-strength agent. The solid content is 12%; the viscosity reducing agent is M31 viscosity reducing agent, the solid content is 15%; the retarder is carboxymethylcellulose sodium retarder, the solid content is 18%; the defoaming agent is Zhongyan ZY-DF3 defoaming agent , solid content 20%.

Example 1

A steam-curing-free, super early-strength C120 self-compacting concrete, consisting of raw materials with the following weight fractions:

476 parts of cement, 102 parts of mineral powder, 136 parts of fly ash beads, 34 parts of silica fume, 752 parts of fine aggregate, 919 parts of coarse aggregate, 13.6 parts of water reducing agent, 12 parts of early strength agent, 6 parts of viscosity reducer parts, 3 parts of retarder, 4 parts of defoaming agent, and 136 parts of water.

The preparation method of the above-mentioned steam-curing-free, ultra-early strength C120 self-compacting concrete includes the following steps:

S1. Add the cement, mineral powder, fly ash beads and silica fume into the mixer and dry mix until uniform. The dry mixing speed is 50±5r/min and the time is 40s;

S2. Then add water, water reducing agent, early strength agent, viscosity reducer, retardant and defoaming agent into the mixer, stir until uniform, the stirring speed is 50±5r/min, and the time is 180s;

S3. Then add fine aggregate and coarse aggregate and vibrate and stir. The vibration and stirring speed is 50±5r/min and the time is 90s;

S4. Immediately after the mixing is completed, take part of the concrete for work performance testing;

S5. Form the remaining concrete, smooth the concrete surface with a spatula, and cover the concrete surface with an impermeable film for curing;

After S6, remove the mold after 8 hours and put it into a standard curing room for standard curing. The standard curing room conditions are: curing temperature 20±2℃, relative humidity ≥95%.

Example 2

A steam-curing-free, super early-strength C120 self-compacting concrete is different from Example 1 in that it consists of the following raw materials with the following weight fractions:

455 parts of cement, 97.5 parts of mineral powder, 130 parts of fly ash beads, 32.5 parts of silica fume, 786 parts of fine aggregate, 960 parts of coarse aggregate, 9.75 parts of water reducing agent, 13 parts of early strength agent, 4 parts of viscosity reducer 2 parts of retarder, 5 parts of defoaming agent and 117 parts of water.

Its preparation method, process steps and parameters are the same as those in Example 1.

Example 3

A steam-curing-free, super early-strength C120 self-compacting concrete is different from Example 1 in that it consists of the following raw materials with the following weight fractions:

525 parts of cement, 56 parts of mineral powder, 84 parts of fly ash beads, 35 parts of silica fume, 708 parts of fine aggregate, 866 parts of coarse aggregate, 9.3 parts of water reducing agent, 7.5 parts of early strength agent, 6 parts of viscosity reducer parts, 5 parts of retarder, 7 parts of defoaming agent, and 135 parts of water.

Its preparation method, process steps and parameters are the same as those in Example 1.

Example 4

A steam-curing-free, super early-strength C120 self-compacting concrete is different from Example 1 in that it consists of the following raw materials with the following weight fractions:

500 parts of cement, 48 parts of mineral powder, 72 parts of fly ash beads, 30 parts of silica fume, 761 parts of fine aggregate, 930 parts of coarse aggregate, 8.4 parts of water reducing agent, 5.9 parts of early strength agent, 3 parts of viscosity reducer parts, 3 parts of retarder, 3 parts of defoaming agent, and 135 parts of water.

Its preparation method, process steps and parameters are the same as those in Example 1.

Example 5

A steam-curing-free, super-early-strength C120 self-compacting concrete differs from Example 1 in that it is composed of the following raw materials by weight:

407.5 parts of cement, 104 parts of mineral powder, 156 parts of fly ash beads, 32.5 parts of silica fume, 734 parts of fine aggregate, 898 parts of coarse aggregate, 9.6 parts of water reducing agent, 7.3 parts of early strength agent, 3 parts of viscosity reducer parts, 4 parts of retarder, 4 parts of defoaming agent, and 129 parts of water.

Its preparation method, process steps and parameters are the same as those in Example 1.

Comparative example 1

The comparative example provides a concrete consisting of the following weight fractions of raw materials:

476 parts of cement, 102 parts of mineral powder, 136 parts of fly ash beads, 34 parts of silica fume, 752 parts of fine aggregate, 919 parts of coarse aggregate, 13.6 parts of water reducing agent, 0 parts of early strength agent, 6 parts of viscosity reducer parts, 3 parts of retarder, 4 parts of defoaming agent, and 136 parts of water.

The difference between its preparation method, process steps and parameters and Example 1 lies in the use of steam curing. According to the relevant requirement indicators in the "Concrete Quality Control Standard" (GB50164-2011), the steam curing conditions are: after the concrete is formed, it is allowed to stand still at room temperature. Stop for 2 hours. The heating rate of steam curing is 20°C/h, the cooling rate is 20°C/h, and the maximum and constant temperature are 60°C. Before the test, the specimen is taken out of the steam curing equipment. The difference between the surface temperature of the specimen and the outside temperature is not greater than 20°C. .

Comparative example 2

The comparative example provides a concrete consisting of the following weight fractions of raw materials:

455 parts of cement, 97.5 parts of mineral powder, 130 parts of fly ash beads, 32.5 parts of silica fume, 786 parts of fine aggregate, 960 parts of coarse aggregate, 9.75 parts of water reducing agent, 13 parts of early strength agent, 0 parts of viscosity reducer parts, 2 parts of retarder, 0 parts of defoaming agent, and 117 parts of water.

Its preparation method, process steps and parameters are the same as those in Example 1.

Comparative example 3

The comparative example provides a concrete consisting of the following weight fractions of raw materials:

455 parts of cement, 111.5 parts of mineral powder, 148 parts of fly ash beads, 0 parts of silica fume, 786 parts of fine aggregate, 960 parts of coarse aggregate, 9.75 parts of water reducing agent, 13 parts of early strength agent, 4 parts of viscosity reducer 2 parts of retarder, 5 parts of defoaming agent and 117 parts of water.

Its preparation method, process steps and parameters are the same as those in Example 1.

Comparative example 4

The comparative example provides a concrete consisting of the following weight fractions of raw materials:

455 parts of cement, 0 parts of mineral powder, 195 parts of fly ash beads, 65 parts of silica fume, 786 parts of fine aggregate, 960 parts of coarse aggregate, 9.75 parts of water reducing agent, 13 parts of early strength agent, 4 parts of viscosity reducer 2 parts of retarder, 5 parts of defoaming agent and 117 parts of water.

Its preparation method, process steps and parameters are the same as those in Example 1.

Comparative example 5

The comparative example provides a concrete consisting of the following weight fractions of raw materials:

455 parts of cement, 195 parts of mineral powder, 0 parts of fly ash beads, 65 parts of silica fume, 786 parts of fine aggregate, 960 parts of coarse aggregate, 9.75 parts of water reducing agent, 13 parts of early strength agent, 4 parts of viscosity reducer 2 parts of retarder, 5 parts of defoaming agent and 117 parts of water.

Its preparation method, process steps and parameters are the same as those in Example 1.

Comparative example 6

A steam-curing-free, super early-strength C120 self-compacting concrete, consisting of raw materials with the following weight fractions:

600 parts of cement, 30 parts of mineral powder, 30 parts of fly ash beads, 30 parts of silica fume, 600 parts of fine aggregate, 600 parts of coarse aggregate, 8 parts of water reducing agent, 10 parts of early strength agent, 5 parts of viscosity reducer parts, 3 parts of retarder, 5 parts of defoaming agent, and 135 parts of water.

Its preparation method, process steps and parameters are the same as those in Example 1.

Comparative example 7

A self-compacting C120 ready-mixed dry concrete consisting of the following components by weight:

520 parts of cement, 100 parts of mineral powder, 50 parts of fly ash, 40 parts of silica fume, 50 parts of fine stone, 350 parts of quartz sand, 200 parts of artificial sand, 8.5 parts of water reducing agent, and 5 parts of defoaming agent.

The preparation method, process steps and parameters are the same as Comparative Example 1.

Performance Testing

The properties of the concrete prepared in Examples 1 to 5 and Comparative Examples 1 to 7 were tested, and the results are shown in Table 1 below.

Among them, the working performance test: refer to the working performance testing method in the "Technical Regulations for the Application of Self-compacting Concrete" (JGJ/T283-2012) to test the working performance of fresh concrete.

Mechanical property test: Refer to the mechanical property test method in the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB/T50081-2019) to test the cubic compressive strength of concrete. The test block is formed into a test block with a size of 150mm×150mm×150mm. Each mix ratio There are three sets of parallel experiments.

Durability test: Refer to the durability test method in the "Experimental Method Standard for Long-term Performance and Durability of Ordinary Concrete" (GB/T50082-2019) to test the frost resistance and chloride ion diffusion coefficient of concrete.

Compressive strength test period: formwork removal strength test period is 8 hours, and hoisting strength test period is 12 hours.

Table 1 Working properties and mechanical properties of concrete prepared in different embodiments

It can be seen from Examples 1-5 that the present invention rationally adjusts the proportions of mineral admixtures and admixtures in concrete through a combination of specific proportions of the above-mentioned raw materials, thereby enhancing the overall working performance and mechanical properties of concrete, and at the same time The addition of fly ash microbeads further improves the workability of concrete. It ensures good compactness during concrete construction without vibrating, and can obtain steam-curing-free, ultra-early strength C120 self-compacting with excellent working performance and mechanical properties. Concrete.

It can be seen from Example 1 and Comparative Example 1 that the nano-CSH-PCE early strength agent replaces steam or autoclaved curing and can provide crystal nuclei for the formation of hydrated calcium silicate gel and promote the formation and formation of hydrated calcium silicate gel. The continued dissolution of Ca ₂ ⁺ and SiO ₄ ^2- will shorten the induction period of cement hydration, and it can also promote the polymerization of hydrated calcium silicate gel in the cement slurry, greatly promoting the hydration reaction, thereby improving the concrete quality. Early strength, and after incorporating nano-CSH-PCE early strength agent, the maximum pore size of concrete is reduced, the proportion of >14nm pores is reduced, the connectivity of pores is reduced, the frost resistance of concrete is improved, and chloride ions diffuse in concrete. The coefficient decreases; although steam curing or autoclaved curing can significantly improve the early compressive strength of concrete, the 28d compressive strength of concrete is low. This is mainly due to the thermal damage of concrete obtained by steam curing, large autogenous shrinkage deformation, and insufficient hydration. , generate hydration products with poor corrosion resistance, making the prefabricated components brittle and less durable, and reducing the mechanical properties and durability of the prefabricated components.

It can be seen from Example 2 and Comparative Examples 2-5 that adding mineral powder, fly ash beads, and silica fume to concrete can not only increase the viscosity of concrete, but also increase the adhesion between the cement slurry and the coarse and fine aggregates. The bonding force prevents the segregation of concrete during construction and causes the aggregate to sink. Moreover, SiO ₂ in mineral powder and silica fume can have a secondary pozzolanic effect (gelling reaction) with the hydration product Ca(OH) ₂ to generate hydrated silicic acid. Calcium (CSH) gel refines the pore structure of concrete after hardening, increases the density of concrete in the later stage, and effectively improves the compressive strength and corrosion resistance of concrete in the later stage; the "ball effect" in fly ash microspheres can effectively improve concrete Workability; making concrete suitable for precast concrete components with complex structures and dense steel bars, and has good mechanical properties. The rational use of viscosity reducers, retarders and defoaming agents will also significantly improve the working performance and mechanical properties of concrete.

It can be seen from Example 2 and Comparative Example 6 that the proportions of raw materials such as cement, mineral powder, fly ash beads and silica fume need to meet the proportion values proposed by the present invention, and each component must satisfy a reasonable Concrete that meets the requirements of the invention can be prepared only under certain proportions. When certain components of the raw materials exceed the contents of the invention, some of the mechanical properties and working performance of the prepared concrete cannot meet the needs of steam-curing-free, ultra-early strength C120 self-compacting concrete. Require.

It can be seen from Example 2 and Comparative Example 7 that although steam curing can improve the early strength of concrete and improve the mold turnover efficiency, steam curing will also damage the later mechanical properties and durability properties of concrete, making it difficult for the prepared concrete components to meet the expected use scenarios. and service life. The nano C-S-H-PCE early strength agent can not only quickly increase the early strength of concrete without damaging the later strength and durability of concrete components, but can also effectively alleviate the high pollution and high energy consumption caused by steam curing.

Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, they do not limit the scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, those skilled in the art do not need to perform creative work. Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (10)

1. A steam-curing-free, super early-strength C120 self-compacting concrete, characterized in that it includes the following raw materials in parts by weight: 400 to 550 parts of cement, 45 to 105 parts of mineral powder, and 70 to 160 parts of fly ash beads , 28 to 38 parts of silica fume, 700 to 790 parts of fine aggregate, 850 to 970 parts of coarse aggregate, 7.5 to 14 parts of water reducing agent, 5 to 15 parts of early strength agent, 3 to 7 parts of viscosity reducing agent, and retarder 2 to 6 parts of agent, 3 to 8 parts of defoaming agent, and 110 to 140 parts of water. 2. The steam-curing-free, ultra-early strength C120 self-compacting concrete as claimed in claim 1, characterized in that the cement is PPⅠ52.5 Portland cement and the loss on ignition is ≤3.0%. 3. The steam-curing-free, ultra-early strength C120 self-compacting concrete as claimed in claim 1, characterized in that the loss on ignition of mineral powder is ≤1.0%, the 28d mortar activity index is ≥95%, and the fluidity ratio is ≥95%. 4. The steam-curing-free, ultra-early strength C120 self-compacting concrete as claimed in claim 1, characterized in that the fly ash microbead mobility ratio is ≥105% and the 28d activity index is ≥90%. 5. The steam-curing-free, ultra-early strength C120 self-compacting concrete as claimed in claim 1, characterized in that the specific surface area of silica fume is ≥ 15000 m2/kg, the loss on ignition is ≤ 4.0%, and the 7d activity index is ≥ 105%. 6. The steam-curing-free, ultra-early strength C120 self-compacting concrete as claimed in claim 1, characterized in that the fine aggregate is zone II medium sand, the fineness modulus is 2.5~3.0, and the particle size composition is: 4~ 16 mesh 24%, 16~50 mesh 56%, 50~100 mesh 13%. 7. The steam-curing-free, ultra-early strength C120 self-compacting concrete as claimed in claim 1, characterized in that the coarse aggregate is basalt, the particle size is 5-20 mm, and the crushing value is ≤8.0%. 8. The steam-curing-free, ultra-early strength C120 self-compacting concrete as claimed in claim 1, characterized in that the water-reducing agent is a polycarboxylic acid high-efficiency water-reducing agent with a solid content of 25 to 35%; Or, the early strength agent is nanometer C-S-H-PCE early strength agent with a solid content of 10 to 15%. 9. The steam-curing-free, ultra-early strength C120 self-compacting concrete as claimed in claim 1, characterized in that the viscosity reducing agent is M31 viscosity reducing agent and the solid content is 15-25%; Or, the retarder is carboxymethylcellulose sodium retarder, with a solid content of 15 to 25%; Or, the defoaming agent is Zhongyan ZY-DF3 defoaming agent with a solid content of 15 to 25%. 10. A method for preparing steam-curing-free, ultra-early strength C120 self-compacting concrete, including: S1. Add the cement, mineral powder, fly ash beads and silica fume into the mixer and dry mix until uniform; S2. Then add water, water reducing agent, early strength agent, viscosity reducer, retardant and defoaming agent into the mixer and stir until uniform; S3. Then add fine aggregate and coarse aggregate and vibrate and stir until uniform; S4. After mixing is completed, formwork is installed and the surface of the concrete mixture is covered with an impermeable film for curing; S5. After removing the formwork, place it in a standard curing room for standard curing to obtain the steam-curing-free, ultra-early strength C120 self-compacting concrete.