Self-compacting concrete for prefabricated member and preparation method of self-compacting concrete
By optimizing the proportion of self-contained concrete, using its own gravity to achieve a dense state, the problems of low efficiency, low quality, environmental pollution and high cost of traditional concrete are solved, and efficient, environmentally friendly and economical concrete construction is achieved.
Patent Information
- Application Number
- CN202510138652.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-08
- Publication Date
- 2025-05-27
AI Technical Summary
In the prior art, there are problems such as low construction efficiency, low construction quality, pollution in the construction environment and high production costs.
Self-solid concrete with optimized ratio is adopted to achieve a compact state through its own gravity, reduce or eliminate vibration operations, and combine batch mixing and stand-alone technology to improve the uniformity and construction efficiency of concrete.
It improves construction efficiency and quality, reduces construction noise and dust pollution, reduces production costs, and extends the service life of the building.
Smart Images
Figure CN120040126A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of concrete, and particularly to a self-compacting concrete for precast components and a preparation method thereof. Background Art
[0002] In modern construction projects, construction efficiency, quality, and environmental protection are key indicators for evaluating the superiority of a technology. Traditional concrete requires long-term vibration operations during pouring, which not only increases the construction difficulty and cost but also prolongs the construction period. In addition, the surface of manually vibrated concrete is prone to defects such as air bubbles and cavities, affecting the quality and aesthetics of the concrete. At the same time, the vibration operations of traditional concrete generate significant noise and dust pollution, causing adverse effects on construction workers and the surrounding environment. To solve these problems, self-compacting concrete came into being.
[0003] Self-compacting concrete reaches a dense state through its own gravity without external vibration, greatly improving construction efficiency. This type of concrete has good fluidity and self-leveling properties and can flow and fill itself under the action of its own gravity to form a high-quality concrete structure. Compared with traditional concrete, self-compacting concrete can fill all voids in the formwork, reducing the generation of air bubbles and cavities and improving the quality of the concrete. At the same time, due to the absence of vibration, the construction process of self-compacting concrete is quieter and cleaner, reducing the generation of noise and dust and improving the construction environment.
[0004] In addition, self-compacting concrete also has the advantage of resource conservation. Through optimizing the mix design, self-compacting concrete reduces the consumption of cement and water, lowering the production cost. At the same time, its excellent self-compacting property reduces air bubbles and cavities in the concrete, improving the density and durability of the concrete, thereby prolonging the service life of buildings. Therefore, applying self-compacting concrete to the production of precast components can not only improve production efficiency and product quality but also reduce environmental pollution and resource consumption, having significant economic and social benefits. Summary of the Invention
[0005] (1) Technical Problems to be Solved
[0006] Aiming at the deficiencies of the prior art, the present invention provides a self-compacting concrete for precast components and a preparation method thereof, which have the advantages of high construction efficiency, high construction quality, pollution-free construction environment, and low production cost, and solve the problems of low construction efficiency, low construction quality, polluted construction environment, and high production cost in the prior art.
[0007] (2) Technical Solutions
[0008] To achieve the above object, the present invention provides the following technical solutions: a self-compacting concrete for precast components, the concrete is composed of main raw materials and auxiliary raw materials, and the raw materials and their weight ranges are: sand 13-16 parts; stone 45-50 parts; cement 3-6 parts; silica fume 5-8 parts; polypropylene fiber 6-9 parts; slag powder 5-10 parts; fly ash 4-9 parts; water 12-17 parts; admixture 1-3 parts.
[0009] Preferably, the main raw materials are composed of sand, stone, cement, silica fume, polypropylene fiber, and slag powder, and the auxiliary raw materials are composed of fly ash, water, and admixture.
[0010] Preferably, the admixture is composed of a water reducer, an expansion agent, a thickening agent, and a strength-enhancing and shrinkage-reducing agent in a ratio of 3:2:5:2. The sand is composed of river sand and manufactured sand in a ratio of 3:1. The stone is composed of pebbles and coarse gravel in a ratio of 4:1. The pebbles are crushed to 15 mm - 20 mm, and the coarse gravel is construction gravel with a particle size of 25 mm - 60 mm.
[0011] Preferably, the raw materials and their weight parts are: sand 14 parts; stone 50 parts; cement 3 parts; silica fume 6 parts; polypropylene fiber 9 parts; slag powder 10 parts; fly ash 4 parts; water 12 parts; admixture 1 part.
[0012] Preferably, the raw materials and their weight parts are: sand 16 parts; stone 45 parts; cement 4 parts; silica fume 8 parts; polypropylene fiber 6 parts; slag powder 5 parts; fly ash 6 parts; water 15 parts; admixture 1.5 parts.
[0013] Preferably, a preparation method of a self-compacting concrete for precast components is prepared according to the raw materials and their weight parts of the above-mentioned self-compacting concrete for precast components, and includes the following preparation steps:
[0014] Step 1. Weighing the raw materials: Prepare river sand, manufactured sand, pebbles, coarse gravel, cement, silica fume, polypropylene fiber, slag powder, fly ash, water, water reducer, expansion agent, thickening agent, and strength-enhancing and shrinkage-reducing agent according to the formula weight parts;
[0015] Step 2. Transporting the raw materials to a mixer for mixing: After uniformly mixing the pebbles and coarse gravel, divide them into three portions of stone materials E, F, and G, and divide the water into two portions of water X and Y. Then, use the batch feeding method to mix the raw materials to form concrete;
[0016] Step 3. Discharging into a torpedo tank: Batchwise discharge the uniformly mixed concrete in Step 2 into the torpedo tank;
[0017] Step 4. Transporting to the production line: Transport the concrete in the torpedo tank to the production line to prepare for the next pouring work;
[0018] Step 5: Pour concrete with a concrete distributor: Use a concrete distributor to evenly pour the concrete in the torpedo ladle into the mold.
[0019] Step 6: Stand still: Let the poured concrete stand still for 5 - 8 minutes.
[0020] Step 7: Finish troweling and roughening: Before the concrete starts to set, perform finish troweling and roughening treatments.
[0021] Step 8: Cure: Spray-cure the completed concrete components.
[0022] Step 9: Lift the component: After the preliminary inspection of the concrete is qualified, use a lifting device to lift the precast component out of the mold, and prepare for subsequent inspection, repair, and storage.
[0023] Preferably, the process of transporting to the mixer for mixing in Step 2 is as follows:
[0024] S2.1: Select a compulsory mixer as the mixing equipment.
[0025] S2.2: After the pebbles and coarse gravel are preliminarily mixed in the compulsory mixer, discharge the mixture, divide it into three portions of stone materials E, F, and G, and divide the water into two portions of water X and Y.
[0026] S2.3: Add portion E of the stone materials, river sand, manufactured sand, slag powder, and fly ash to the mixer, and mix at a rotational speed of 50 - 100 r / min for 6 - 9 minutes.
[0027] S2.4: Continue to add portion F of the stone materials, cement, silica fume, polypropylene fiber, portion X of the water, water reducer, and thickening agent to the mixer, and mix at a rotational speed of 100 - 150 r / min for 3 - 7 minutes.
[0028] S2.5: Finally, add portion G of the stone materials, portion Y of the water, expansion agent, and strength-enhancing and shrinkage-reducing agent to the mixer, and mix at a rotational speed of 150 - 200 r / min for 5 - 8 minutes to obtain the concrete.
[0029] Preferably, the slump flow of the concrete detected in Step 2 is between 750 - 800 mm, and the time taken for the detected concrete to flow out 500 mm from the slump cone is between 1.5 - 2.5 s.
[0030] Preferably, the segregation rate of the concrete detected in Step 2 is between 10% and 14% to ensure the uniformity of the concrete, and the pressure bleeding rate detected is between 20% and 35%.
[0031] Preferably, the concrete is divided into 4 - 6 batches and put into the torpedo ladle in Step 3.
[0032] Compared with the prior art, the present invention provides a self-compacting concrete for precast members and a preparation method thereof, having the following beneficial effects:
[0033] 1. By optimizing the raw material ratio of pebbles and coarse gravel materials, the present invention balances strength and fluidity, thereby ensuring that the concrete has sufficient bearing capacity, is easy to construct and pour, and can improve its strength without sacrificing fluidity. By using polypropylene fibers, the toughness of the concrete is improved and the generation of cracks is reduced. By adopting a batch mixing process to disperse the raw material components, the uniformity and overall performance of the concrete are improved, so as to increase the slump spread and reduce the outflow time.
[0034] 2. By comparing the construction process of self-compacting concrete with that of traditional concrete, in the pouring process of the self-compacting concrete of the present invention, by optimizing the material composition and mix proportion design of the concrete, and then standing the poured concrete, the concrete can reach a dense state by relying on its own gravity during the pouring process, without the need for long-term vibration operations. It can also improve the construction efficiency while reducing construction noise and dust pollution. Moreover, the self-compacting concrete can fill all voids in the formwork, reduce the generation of bubbles and cavities, improve the density and durability of the concrete, and integrate automated processes, solving the problems of low construction efficiency, low construction quality, environmental pollution during construction, and high production cost in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Figure 1 It is a flowchart for the preparation of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0037] Please refer to Figure 1 , a self-compacting concrete for precast members, the concrete is composed of main raw materials and auxiliary raw materials, and the raw materials and their weight ranges are as follows: sand 13 - 16 parts; stone 45 - 50 parts; cement 3 - 6 parts; silica fume 5 - 8 parts; polypropylene fiber 6 - 9 parts; slag powder 5 - 10 parts; fly ash 4 - 9 parts; water 12 - 17 parts; admixture 1 - 3 parts.
[0038] The advantages are as follows: By optimizing the mix design, self-compacting concrete helps reduce the consumption of cement and water, thereby lowering production costs. At the same time, the optimized mix design enables the self-compacting performance to reduce air bubbles and voids in the concrete, meeting the requirements for fluidity, cohesiveness, and strength of self-compacting concrete, thus enhancing the density and durability of the concrete and extending the service life of buildings.
[0039] Specifically, the main raw materials consist of sand, stone, cement, silica fume, polypropylene fiber, and slag powder. Using high-quality cementitious materials can ensure that the concrete has sufficient strength and stability, enabling good strength development of self-compacting concrete in both the early and late stages, thereby enhancing the durability of the concrete. Incorporating mineral admixtures such as fly ash and slag powder can improve the workability of the concrete, reduce the cement consumption, lower the hydration heat of the concrete, and enhance the crack resistance and durability of the concrete. The auxiliary raw materials consist of fly ash, water, and admixtures.
[0040] Specifically, the admixtures are composed of water reducer, expansive agent, thickening agent, and strength-enhancing and shrinkage-reducing agent in a ratio of 3:2:5:2. The sand is composed of river sand and manufactured sand in a ratio of 3:1. Using a high-efficiency water reducer can not only enable the concrete to obtain good fluidity at a lower water-binder ratio but also significantly reduce the water consumption of the concrete, enhancing the density and strength of the concrete. The thickening agent can not only increase the cohesiveness of the concrete but also prevent the segregation and bleeding of the concrete, enabling self-compacting concrete to maintain good uniformity during the pouring process;
[0041] The advantages are as follows: By introducing new admixtures and mineral admixtures such as high-efficiency water reducer, expansive agent, and silica fume, the fluidity and self-compacting performance of the concrete can be improved.
[0042] The stone is composed of pebbles and coarse gravel in a ratio of 4:1. The pebbles are crushed to 15 mm - 20 mm, and the coarse gravel is construction crushed stone with a particle size of 25 mm - 60 mm, minimizing the voids between the aggregates. By adopting a reasonable aggregate gradation, the voids between the aggregates are minimized, enhancing the density of the concrete.
[0043] Specifically, a preparation method for self-compacting concrete for precast components is prepared according to the raw materials and their weight parts of the self-compacting concrete for precast components described above, including the following preparation steps:
[0044] Step 1: Weighing the raw materials: Prepare river sand, manufactured sand, pebbles, coarse gravel, cement, silica fume, polypropylene fiber, slag powder, fly ash, water, water reducer, expansive agent, thickening agent, and strength-enhancing and shrinkage-reducing agent according to the formula weight parts;
[0045] Step 2: Transport the raw materials to the mixer for mixing: After evenly mixing the pebbles and coarse gravel materials, divide them into three portions of materials, namely E, F, and G, and divide the water into two portions of water, namely X and Y. Then, use the method of feeding in batches to mix the raw materials to form concrete.
[0046] Step 3: Discharge the materials into the torpedo ladle: Put the evenly mixed concrete in Step 2 into the torpedo ladle in batches to ensure that the raw materials are fully mixed.
[0047] Step 4: Transport to the production line: Transport the concrete in the torpedo ladle to the production line to prepare for the next pouring work. Adopt advanced concrete mixing and transportation technologies to ensure the uniformity and stability of the concrete during the mixing, transportation, and pouring processes.
[0048] Step 5: Pour the concrete with a concrete placer (hopper): Use a concrete placer or hopper to evenly pour the concrete in the torpedo ladle into the mold to ensure that the concrete is evenly filled without voids.
[0049] Step 6: Stand still: Let the poured concrete stand still for 5 - 8 minutes to remove the air bubbles in the concrete, improve the density and strength of the concrete. The construction of self-compacting concrete does not require vibration, reduces the generation of noise and dust, and improves the construction environment.
[0050] Step 7: Finish and roughen: Before the concrete begins to set, perform a finishing treatment to make the surface smooth and flat; then perform a roughening treatment to increase the roughness of the concrete surface and improve the bonding force with the subsequent construction layer.
[0051] Step 8: Cure: Spray-cure the cast concrete components to ensure that the concrete maintains good humidity and temperature during the hardening process and prevent the generation of cracks.
[0052] Step 9: Lift the component: After the preliminary inspection of the concrete is qualified, use a lifting device to lift the precast component out of the mold and prepare for subsequent inspection, repair, and storage.
[0053] Advantages: The above construction process of self-compacting concrete has obvious improvements compared with traditional concrete. During the pouring process, by optimizing the material composition and mix proportion design of the concrete, and then letting the poured concrete stand still, the concrete can reach a dense state by its own gravity during the pouring process, without external vibration and without long-term vibration operations. It can also improve the construction efficiency while reducing construction noise and dust pollution. Moreover, self-compacting concrete can fill all the voids in the formwork, reduce the generation of air bubbles and cavities, and improve the density and durability of the concrete.
[0054] Specifically, the process of transporting to the mixer for mixing in Step 2 is as follows:
[0055] S2.1. Select a compulsory mixer as the mixing equipment. By using a compulsory mixer, it is ensured that all components of the concrete are fully mixed.
[0056] S2.2. After initially mixing the pebbles and coarse gravel materials in the compulsory mixer, discharge the materials and divide them into three portions of materials, namely E, F, and G. Divide the water into two portions of water, namely X and Y.
[0057] S2.3. Add portion E of the materials, river sand, manufactured sand, slag powder, and fly ash into the mixer. At a rotation speed of 50 - 100 r / min of the mixer, mix for 6 - 9 minutes.
[0058] S2.4. Continuously add portion F of the materials, cement, silica fume, polypropylene fiber, portion X of the water, water reducer, and thickening agent into the mixer. At a rotation speed of 100 - 150 r / min of the mixer, mix for 3 - 7 minutes.
[0059] S2.5. Finally, add portion G of the materials, portion Y of the water, expansion agent, and strength - enhancing and shrinkage - reducing agent into the mixer. At a rotation speed of 150 - 200 r / min of the mixer, mix for 5 - 8 minutes to obtain the concrete.
[0060] The advantages are as follows: By adopting the method of feeding materials in batches, first evenly mix the cementitious materials and some aggregates, and then add the remaining aggregates and admixtures for mixing. This process can improve the uniformity of the concrete. By appropriately extending the mixing time, it can ensure that the admixtures fully play their roles, enabling the concrete to achieve good workability.
[0061] Specifically, in step two, the slump flow of the concrete detected is between 750 - 800 mm, ensuring that the concrete can freely flow within the formwork and fill into every corner. The time taken for the detected concrete to flow out 500 mm from the slump cone is between 1.5 - 2.5 s, reflecting the flow rate of the concrete.
[0062] Specifically, in step two, the segregation rate of the concrete detected is between 10% - 14%, to ensure the uniformity of the concrete. The pressure bleeding rate detected is between 20% - 35%, indicating that the concrete has less bleeding under pressure.
[0063] Specifically, in step three, the concrete is divided into 4 - 6 batches and put into the torpedo ladle to ensure the full mixing of raw materials.
[0064] Example 1
[0065] Specifically, the raw materials and their parts by weight are as follows: sand 14 parts; stone 50 parts; cement 3 parts; silica fume 6 parts; polypropylene fiber 9 parts; slag powder 10 parts; fly ash 4 parts; water 12 parts; admixture 1 part.
[0066] Example 2
[0067] Specifically, the raw materials and their parts by weight are: 16 parts of sand; 45 parts of stone; 4 parts of cement; 8 parts of silica fume; 6 parts of polypropylene fiber; 5 parts of slag powder; 6 parts of fly ash; 15 parts of water; 1.5 parts of admixture.
[0068] Example 3
[0069] Specifically, the process of transporting the concrete of Example 1 to the mixer for mixing is as follows:
[0070] S2.1. Select a forced mixer as the mixing equipment;
[0071] S2.2. After initially mixing the pebbles and coarse gravel in the forced mixer, discharge the materials and divide them into three parts of stone, namely E, F, and G, and divide the water into two parts of water, namely X and Y;
[0072] S2.3. Add part E of the stone, river sand, manufactured sand, slag powder, and fly ash to the mixer and mix for 6 minutes at a rotation speed of 100 r / min of the mixer;
[0073] S2.4. Continue to add part F of the stone, cement, silica fume, polypropylene fiber, part X of water, water reducer, and thickening agent to the mixer and mix for 4 minutes at a rotation speed of 150 r / min of the mixer;
[0074] S2.5. Finally, add part G of the stone, part Y of water, expansive agent, and strength-enhancing and shrinkage-reducing agent to the mixer and mix for 6 minutes at a rotation speed of 200 r / min of the mixer to obtain the concrete.
[0075] Specifically, the slump flow of the concrete in Example 1 is 750 mm, and the time taken for the concrete to flow out 500 mm from the slump cone is 1.5.
[0076] Specifically, the segregation rate of the concrete in Example 1 is 10%, and the pressure bleeding rate is 25%.
[0077] Specifically, the concrete in Example 1 is divided into 5 batches and put into the torpedo ladle to ensure full mixing of the raw materials.
[0078] Comparative Example 1
[0079] Specifically, the raw materials and their parts by weight are: 14 parts of sand; 60 parts of stone; 6 parts of cement; 6 parts of silica fume; 9 parts of polypropylene fiber; 10 parts of slag powder; 4 parts of fly ash; 12 parts of water; 1 part of admixture (increase the stone from 50 parts in Example 1 to 60 parts, and increase the cement from 3 parts to 6 parts).
[0080] The increased stone and cement will reduce the mixing fluidity, and this change will affect the fluidity of the concrete.
[0081] Comparative Example 2
[0082] Specifically, the raw materials and their parts by weight are as follows: 16 parts of sand; 45 parts of stone; 4 parts of cement; 8 parts of silica fume; 6 parts of glass fiber; 5 parts of slag powder; 6 parts of fly ash; 15 parts of water; 1.5 parts of admixture (replacing the polypropylene fiber in Example 2 with glass fiber).
[0083] The brittleness of glass fiber is greater than that of polypropylene fiber, and this change will affect the toughness and crack resistance of concrete.
[0084] Comparative Example 3
[0085] Specifically, the process of transporting the concrete made in Comparative Example 1 to the mixer for mixing is as follows:
[0086] S2.1. Select a compulsory mixer as the mixing equipment;
[0087] S2.2. First add water, stone, river sand, manufactured sand, slag powder and fly ash into the mixer, and mix for 3 minutes at a rotation speed of 150 r / min of the mixer;
[0088] S2.3. Continue to add cement, silica fume, polypropylene fiber, water reducing agent and thickening agent into the mixer, and mix for 2 minutes at a rotation speed of 200 r / min of the mixer;
[0089] S2.4. Finally, add an expansion agent and a strength enhancing and shrinkage reducing agent into the mixer, and mix for 1.5 minutes at a rotation speed of 200 r / min of the mixer to obtain concrete.
[0090] Specifically, the slump flow of the concrete in Comparative Example 1 detected is 450 mm, and the time taken for the concrete to flow out 500 mm from the slump cone is 3.
[0091] Specifically, the segregation rate of the concrete in Comparative Example 1 detected is 25%, and the pressure bleeding rate detected is 40%.
[0092] Specifically, the concrete in Comparative Example 1 is directly put into a torpedo ladle to ensure the full mixing of raw materials.
[0093] Performance Index Example 1 Comparative Example 1 Example 2 Comparative Example 2 Flowability 750mm 450mm 700mm 500mm Toughness 8 6 9 7 Crack Resistance 80 60 90 70 Uniformity 90 70 95 80 Hardness 30MPa 25MPa 28MPa 24MPa Compressive Strength (MPa) 35 37 30 32 Elastic Modulus (GPa) 30 32 28 31 Flexural Strength (MPa) 4.5 4.8 4.0 4.3 Carbonation Resistance (mm) ≤20 ≤18 ≤22 ≤21 Shrinkage Performance (%) <0.03％ <0.02％ <0.04％ <0.03％ Process Efficiency High Low High Low Raw Material Cost <![CDATA[$110 / m 3 > <![CDATA[$120 / m 3 > <![CDATA[$125 / m 3 > <![CDATA[$135 / m 3 >
[0094] According to the analysis of the above examples and comparative examples in the table, it is obtained that:
[0095] The comparison between Example 1 and Comparative Example 1 shows that increasing the content of stone and cement will reduce its fluidity.
[0096] The comparison between Example 2 and Comparative Example 2 shows that the change in fiber type (from polypropylene fiber to glass fiber) will reduce the toughness and crack resistance of concrete.
[0097] The comparison between Example 3 and Comparative Example 3:
[0098] The raw materials and their parts by weight are the same, but the mixing process is different. In Example 3, a step-by-step mixing method is adopted. First, the stone, river sand, manufactured sand, slag powder and fly ash in Comparative Example 3 are mixed, then cement, silica fume, polypropylene fiber, water reducer and thickening agent are added, and finally expansion agent and strength-enhancing and shrinkage-reducing agent are added. In Comparative Example 3, all raw materials are added to the mixer at one time for mixing.
[0099] In terms of the properties of the concrete, the slump flow of Example 1 is 750 mm, the outflow time is 1.5 seconds, the segregation rate is 10%, and the pressure bleeding rate is 25%. While the slump flow of Comparative Example 1 is 450 mm, the outflow time is 3 seconds, the segregation rate is 25%, and the pressure bleeding rate is 40%. It can be seen that the concrete properties of Example 1 are better than those of Comparative Example 1.
[0100] The comparison between Example 1 and Comparative Example 1 shows that Example 1 can balance strength and fluidity, thus ensuring that the concrete has sufficient bearing capacity and is easy to construct and pour. And through the optimized material ratio of Example 1, the strength of the concrete can be improved without sacrificing fluidity.
[0101] The comparison between Example 2 and Comparative Example 2 shows that the change in fiber type (from polypropylene fiber to glass fiber) will affect the toughness and crack resistance of the concrete. The polypropylene fiber in Example 2 can improve the toughness of the concrete and reduce the generation of cracks.
[0102] The comparison between Example 3 and Comparative Example 3. By the step-by-step mixing method of first mixing the stone, river sand, manufactured sand, slag powder and fly ash in Comparative Example 3, then adding cement, silica fume, polypropylene fiber, water reducer and thickening agent, and finally adding expansion agent and strength-enhancing and shrinkage-reducing agent, Example 3 can improve the workability and properties of the concrete, and this step-by-step mixing method helps to better disperse various components, thus improving the uniformity and overall performance of the concrete. In contrast, the mixing method of adding all raw materials at one time in Comparative Example 3 will lead to poor concrete properties, such as a lower slump flow and a longer outflow time.
[0103] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A self-compacting concrete for prefabricated components, characterized in that: The concrete is composed of main raw materials and auxiliary raw materials, and the raw materials and their weight parts range are: sand 13-16 parts; stone 45-50 parts; cement 3-6 parts; silica fume 5-8 parts; polypropylene fiber 6-9 parts; slag powder 5-10 parts; fly ash 4-9 parts; 12-17 parts of water; 1-3 parts of admixture.
2. The self-compacting concrete for prefabricated components according to claim 1, characterized in that: The main raw materials are composed of sand, stone, cement, silica fume, polypropylene fiber, and slag powder, and the auxiliary raw materials are composed of fly ash, water, and admixtures.
3. The self-compacting concrete for prefabricated components according to claim 1, characterized in that: The admixture consists of a water reducer, an expansion agent, a thickener and a strength-promoting shrinkage-reducing agent in a ratio of 3:2:5:2; the sand consists of river sand and machine-made sand in a ratio of 3:1; the stone consists of pebbles and coarse gravel in a ratio of 4:1; the pebbles are crushed to 15mm-20mm; the coarse gravel is building crushed stone with a particle size of 25mm-60mm.
4. The self-compacting concrete for prefabricated components according to claim 1, characterized in that: The raw materials and their weight parts are: 14 parts of sand; 50 parts of stone; 3 parts of cement; 6 parts of silica fume; 9 parts of polypropylene fiber; 10 parts of slag powder; 4 parts of fly ash; 12 parts of water; and 1 part of admixture.
5. The self-compacting concrete for prefabricated components according to claim 1, characterized in that: The raw materials and their weight parts are: 16 parts of sand; 45 parts of stone; 4 parts of cement; 8 parts of silica fume; 6 parts of polypropylene fiber; 5 parts of slag powder; 6 parts of fly ash; 15 parts of water; 1.5 parts of admixture.
6. A method for preparing self-compacting concrete for prefabricated components, characterized in that: The prefabricated component according to claim 1 is prepared by using parts by weight of raw materials of self-compacting concrete, comprising the following preparation steps: Step 1: Weighing and measuring raw materials: prepare river sand, machine-made sand, pebbles, coarse gravel, cement, silica fume, polypropylene fiber, slag powder, fly ash, water, water reducing agent, expansion agent, thickener and strength-promoting shrinkage-reducing agent according to the formula weight; Step 2: transport the raw materials to the mixer for mixing: after the pebbles and coarse gravel are evenly mixed, they are divided into three parts of stone, E, F, and G, and the water is divided into two parts of water, X and Y, and then the raw materials are mixed by the batch feeding method to form concrete; Step 3: Discharging into torpedo tanks: Put the concrete mixed evenly in step 2 into torpedo tanks in batches; Step 4: Transport to the production line: transport the concrete in the torpedo tank to the production line, ready for the next step of pouring; Step 5: Use a concrete placing machine to pour concrete: Use a concrete placing machine to evenly pour the concrete in the torpedo tank into the mold; Step 6: Let the poured concrete stand for 5-8 minutes; Step 7: Finishing and roughening: Before the concrete sets, finish and roughen it; Step 8: Maintenance: spray maintenance on the poured concrete components; Step 9: Component lifting: After the concrete is initially tested and qualified, use lifting equipment to lift the prefabricated components out of the mold in preparation for subsequent inspection, repair and storage.
7. A method for preparing self-compacting concrete for prefabricated components according to claim 6, characterized in that: The process of transporting to the mixer for stirring in step 2 is as follows: S2.
1. Select a forced mixer as the mixing equipment; S2.2, after preliminary mixing of pebbles and coarse gravel in a forced mixer, the materials are discharged and divided into three parts of stone, E, F, and G, and the water is divided into two parts of water, X and Y; S2.3, add E parts of stone, river sand, machine-made sand, slag powder and fly ash into the mixer, and mix for 6-9 minutes at a speed of 50-100r / min; S2.4, continue to add F parts of stone, cement, silica fume, polypropylene fiber, X parts of water, water reducer and thickener into the mixer, and mix for 3-7 minutes at a speed of 100-150r / min; S2.
5. Finally, add G parts of stone, Y parts of water, expansion agent and strengthening and shrinkage reducing agent into the mixer, mix for 5-8 minutes at a speed of 150-200r / min to obtain concrete.
8. The method for preparing self-compacting concrete for prefabricated components according to claim 6, characterized in that: The slump expansion of the concrete tested in step 2 is between 750 and 800 mm, and the time taken for the tested concrete to flow 500 mm out of the slump cone is between 1.5 and 2.5 seconds.
9. The method for preparing self-compacting concrete for prefabricated components according to claim 6, characterized in that: The segregation rate of the concrete detected in step 2 is between 10% and 14% to ensure the uniformity of the concrete, and the pressure water seepage rate detected is between 20% and 35%.
10. The method for preparing self-compacting concrete for prefabricated components according to claim 6, characterized in that: In step 3, the concrete is divided into 4-6 batches and placed in torpedo tanks.