Preparation method of low-standard machine-made sand concrete for super high-rise pumping

Abstract

The invention relates to the technical field of concrete, and discloses a low-standard machine-made sand concrete for super high-rise pumping, which comprises the following components: 240-270 parts by weight of cement, 60-80 parts by weight of mineral powder, 90-120 parts by weight of fly ash, 800-860 parts by weight of machine-made sand, 900-950 parts by weight of stone, 160-170 parts by weight of clear water, 4-6 parts by weight of admixture and 4-6 parts by weight of cellulose ether. According to the preparation method of the low-standard machine-made sand concrete for super high-rise pumping, by optimizing the mass ratio of the mineral powder to the fly ash to the machine-made sand to the stone to the clear water to the additive, it is ensured that the concrete has excellent fluidity and stability, so that the concrete can smoothly pass through pumping equipment and has excellent performance in high-altitude operation; by means of the accurate proportioning and mixing process, the concrete obtains good workability, high pumpability can be maintained even under the pumping condition of a super high-rise building, the pump damage phenomenon is reduced, the common problems of pipe burst and pump blockage in the construction process are effectively avoided, and therefore the construction efficiency and safety are improved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to a method for preparing low-standard machine-made sand concrete for super-high-rise pumping. Background Art

[0002] With the rapid advancement of urbanization, super-high-rise buildings continue to emerge as landmark buildings in modern cities. This has not only changed the city's skyline, but also put forward higher requirements on construction technology, especially for concrete pumping technology. As the building height increases, the height of concrete pumping is also constantly increasing, which poses a severe challenge to the pumping performance of concrete. Although traditional high-strength concrete has certain advantages in super-high-rise pumping, for low-standard concrete, the existing pumping technology often faces problems such as large pumping loss, pipe bursting and pump blockage during pumping. These problems not only increase the difficulty of construction, but may also lead to delays in construction progress and increased costs.

[0003] In addition, due to the lack of comprehensive understanding of the pumping performance of low-standard concrete, a complete low-standard concrete pumping technology system has not been formed at present. This means that in the actual construction process, there is a lack of effective technical support for the pumping control of low-standard concrete, especially in the control indicators of concrete fluidity, cohesion and other aspects. Clear standards have not yet been established, which constitutes an obstacle to ensuring the quality and efficiency of super-high-rise building construction. Therefore, a new method for preparing low-standard machine-made sand concrete is urgently needed to solve the problems existing in the existing technology and improve the application effect of low-standard concrete in super-high-rise pumping. Therefore, we proposed a method for preparing low-standard machine-made sand concrete for super-high-rise pumping. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the shortcomings of the prior art, the present invention provides a method for preparing low-standard machine-made sand concrete for super-high-rise pumping. By optimizing the mix ratio of concrete, its pumping performance is improved, pump loss is reduced, and the stability of concrete in the process of super-high-rise pumping is ensured. The problem that there is no comprehensive understanding of the pumping performance of low-standard concrete and there is currently no complete low-standard concrete pumping technology system has been formed. This means that in the actual construction process, there is a lack of effective technical support for the pumping control of low-standard concrete, especially in terms of control indicators such as the fluidity and cohesion of concrete. Clear standards have not yet been established, which constitutes an obstacle to ensuring the quality and efficiency of super-high-rise building construction. Therefore, a new method for preparing low-standard machine-made sand concrete is urgently needed to solve the problems existing in the prior art and improve the application effect of low-standard concrete in super-high-rise pumping.

[0006] (II) Technical solution

[0007] In order to achieve the above-mentioned purpose of optimizing the mix ratio of concrete, improving its pumping performance, reducing pump loss, and ensuring the stability of concrete during super-high-rise pumping, the present invention provides the following technical solution: a low-standard machine-made sand concrete for super-high-rise pumping, comprising the following raw materials in proportion by weight: 240-270 parts by weight of cement, 60-80 parts by weight of mineral powder, 90-120 parts by weight of fly ash, 800-860 parts by weight of machine-made sand, 900-950 parts by weight of stone, 160-170 parts by weight of clean water, 4-6 parts by weight of admixture, and 4-6 parts by weight of cellulose ether.

[0008] Preferably, the machine-made sand is medium sand in zone II, the stone is a mixture of stones with diameters of 15-20 mm, 10-15 mm and 5-10 mm, and the admixture is a polycarboxylic acid water-reducing agent with a high water-reducing rate and good collapse-preventing effect.

[0009] Preferably, the cement is ordinary Portland cement; the mineral powder is granulated blast furnace slag powder, and its dosage accounts for 22.5% of the total cementitious material; and the dosage of the admixture is 1.55% of the weight of the cement.

[0010] Preferably, the fineness modulus of the machine-made sand is between 2.6 and 3.0, and the grading of the stones is used in a mass ratio of 44:31:25.

[0011] A method for preparing low-standard machine-made sand concrete for super-high-rise pumping, comprising low-standard machine-made sand concrete for super-high-rise pumping, and further comprising the following steps:

[0012] S1, weighing 240-270 parts by weight of cement, 60-80 parts by weight of mineral powder, 90-120 parts by weight of fly ash, 800-860 parts by weight of machine-made sand, 900-950 parts by weight of stone, 160-170 parts by weight of clean water, 4-6 parts by weight of admixture and 4-6 parts by weight of cellulose ether;

[0013] S2. Put the weighed mineral powder and fly ash into the mixer, start the mixer for preliminary mixing, ensure that the dry materials are fully dispersed and avoid agglomeration;

[0014] S3. After the dry materials are preliminarily mixed evenly, gradually add the machine-made sand into the mixer and continue to stir to ensure that the machine-made sand is evenly mixed with the previous dry materials;

[0015] S4. After the machine-made sand is completely added and mixed evenly, put the stones into the mixer and adjust the mixing speed to 120 to 150 revolutions per minute to ensure that the stones are evenly mixed with the mixture;

[0016] S5. When the stones are completely added and mixed evenly, slowly add clean water and adjust the stirring speed to 150 revolutions per minute to accelerate the uniformity of the mixture;

[0017] S6. After adding clean water and mixing evenly, add the admixture and cellulose ether into the mixer, and reduce the stirring speed to 120 revolutions per minute to reduce the involvement of air and ensure the homogeneity of the mixture;

[0018] S7. Continue stirring for 2 to 3 minutes to ensure that all materials are fully mixed while avoiding over-stirring that may cause concrete segregation;

[0019] S8. After mixing, conduct performance tests before pumping to ensure that the concrete's slump, slump expansion, expansion time T500, difference between slump and J-ring expansion, slump loss over time, pressure water seepage rate, air content test, V-funnel time test, inversion time test, and plastic viscosity index meet the requirements of the specification;

[0020] S9. Pour the mixed concrete into the mold or pump it into place.

[0021] Preferably, the mixing process is carried out in a mixer, the mixing time is 2 to 3 minutes, and the mixing speed is 120 to 150 revolutions per minute.

[0022] Preferably, specific indicators of the performance test include: slump greater than 230mm, slump expansion greater than 650mm and less than 750mm, expansion time T500 greater than 3s and less than 7s, difference between slump and J-ring expansion less than 15mm, slump loss over time not more than 10mm, and pressure water seepage rate not more than 10%.

[0023] Preferably, the performance test before pumping also includes the air content, V-funnel time, inversion time and plastic viscosity of the concrete to ensure the fluidity and cohesion of the concrete during the pumping process.

[0024] Preferably, the pumping construction is completed before the initial setting time of the concrete to ensure that the pumping performance of the concrete is not affected.

[0025] (III) Beneficial effects

[0026] Compared with the prior art, the present invention provides a method for preparing low-standard machine-made sand concrete for super-high-rise pumping, which has the following beneficial effects:

[0027] 1. The preparation method of low-standard machine-made sand concrete for super-high-rise pumping significantly improves the pumping performance of concrete. By optimizing the mass ratio between mineral powder, fly ash, machine-made sand, stone, clean water and admixtures, it ensures that the concrete has excellent fluidity and stability, so that it can pass through pumping equipment smoothly and perform well in high-altitude operations. More importantly, through precise batching and mixing processes, the concrete has good workability and can maintain high pumpability even under the pumping conditions of super-high-rise buildings, reducing the occurrence of pump damage. This not only reduces the construction difficulty, but also effectively avoids the common problems of pipe burst and pump blockage during construction, thereby improving construction efficiency and safety.

[0028] 2. The preparation method of low-standard machine-made sand concrete for super-high-rise pumping introduces a polycarboxylic acid water-reducing agent with a high water-reducing rate and good collapse-preventing effect, and strictly controls the mixing time and speed of the concrete, so that the internal structure of the concrete is tighter, thereby effectively reducing the pressure water seepage rate to ensure that it does not exceed 20%, and at the same time enhancing the homogeneity of the concrete. Such improvements not only ensure the fluidity and cohesiveness of the concrete during the pumping process, but also enable the concrete to maintain good working performance after pumping, thereby ensuring the quality of super-high-rise building construction and reducing the risk of project delays due to concrete quality problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a preparation flow chart of low-standard machine-made sand concrete;

[0030] Figure 2 It is a schematic diagram of the concrete pre-pumping performance test process of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] See also Figure 1-2 A low-standard machine-made sand concrete for super-high-rise pumping includes the following raw materials in proportion by weight: 240-270 parts by weight of cement, 60-80 parts by weight of mineral powder, 90-120 parts by weight of fly ash, 800-860 parts by weight of machine-made sand, 900-950 parts by weight of stone, 160-170 parts by weight of clean water, 4-6 parts by weight of admixture and 4-6 parts by weight of cellulose ether.

[0033] A method for preparing low-standard machine-made sand concrete for super-high-rise pumping, comprising low-standard machine-made sand concrete for super-high-rise pumping, and further comprising the following steps:

[0034] S1, weighing 240-270 parts by weight of cement, 60-80 parts by weight of mineral powder, 90-120 parts by weight of fly ash, 800-860 parts by weight of machine-made sand, 900-950 parts by weight of stone, 160-170 parts by weight of clean water, 4-6 parts by weight of admixture and 4-6 parts by weight of cellulose ether;

[0035] S2. Put the weighed mineral powder and fly ash into the mixer, start the mixer for preliminary mixing, ensure that the dry materials are fully dispersed and avoid agglomeration;

[0036] S3. After the dry materials are preliminarily mixed evenly, gradually add the machine-made sand into the mixer and continue to stir to ensure that the machine-made sand is evenly mixed with the previous dry materials;

[0037] S4. After the machine-made sand is completely added and mixed evenly, put the stones into the mixer and adjust the mixing speed to 120 to 150 revolutions per minute to ensure that the stones are evenly mixed with the mixture;

[0038] S5. When the stones are completely added and mixed evenly, slowly add clean water and adjust the stirring speed to 150 revolutions per minute to accelerate the uniformity of the mixture;

[0039] S6. After adding clean water and mixing evenly, add the admixture and cellulose ether into the mixer, and reduce the stirring speed to 120 revolutions per minute to reduce the involvement of air and ensure the homogeneity of the mixture;

[0040] S7. Continue stirring for 2 to 3 minutes to ensure that all materials are fully mixed while avoiding over-stirring that may cause concrete segregation;

[0041] S8. After mixing, conduct performance tests before pumping to ensure that the concrete's slump, slump expansion, expansion time T500, difference between slump and J-ring expansion, slump loss over time, pressure water seepage rate, air content test, V-funnel time test, inversion time test, and plastic viscosity index meet the requirements of the specification;

[0042] S9. Pour the mixed concrete into the mold or pump it into place.

[0043] Specifically, mineral powder refers to granulated blast furnace slag powder, which plays a role in partially replacing cement in concrete; it can not only improve the workability of concrete, but also enhance the density and durability of concrete, while reducing the hydration heat and improving the anti-permeability of concrete;

[0044] Fly ash is a byproduct of coal-fired power plant emissions. It acts as a volcanic ash active material in concrete, which can increase the later strength of concrete, improve the fluidity of concrete, and help reduce shrinkage cracks in concrete and improve its resistance to sulfate attack;

[0045] Machine-made sand refers to sand produced through processes such as mechanical crushing and screening. It has good particle shape and gradation, can improve the fluidity of concrete, reduce the void ratio, and thus improve the overall strength and stability of concrete;

[0046] The main function of stone is to bear the structural load, limit the deformation of concrete, and play an important role in the volume stability of concrete; by selecting stones with appropriate grading, the filling and density of concrete can be improved;

[0047] Polycarboxylate water reducer has a high water reduction rate and good collapse prevention effect. It can significantly reduce the water consumption of concrete and improve the fluidity of concrete without sacrificing strength. At the same time, it can also improve the pumping performance of concrete and reduce water seepage during pumping.

[0048] Specifically, the machine-made sand used is medium sand from Zone II, with a fineness modulus between 2.6 and 3.0, ensuring that the machine-made sand has an appropriate particle distribution to enhance the fluidity of the concrete; the stones are a mixture of 5-25mm in diameter and 5-10mm in diameter in a mass ratio of 1:1; this specific stone grading helps to improve the filling and density of the concrete, and the admixture used is polycarboxylate water reducer, which has a high water reduction rate and good collapse prevention effect, and the addition amount is 1.55% of the cement weight.

[0049] Specifically, cellulose ether is a common concrete additive, which is mainly obtained by etherification modification of natural cellulose. In concrete, cellulose ether acts as a thickener and water-retaining agent, which can form a film on the surface of cement particles, increase the viscosity of the slurry, and improve the working performance of fresh concrete. The addition of cellulose ether can improve the water retention capacity of concrete, reduce water bleeding and segregation, and also give concrete a certain thixotropy, which helps to enhance the stability of concrete, especially in the pumping process, which can prevent the concrete from losing water prematurely and causing hardening or loss of fluidity;

[0050] In this embodiment, the amount of cellulose ether used is 4-6 parts by weight. Its main function is to improve the workability of concrete. Especially under pumping conditions, cellulose ether helps maintain the uniformity and stability of concrete, prevents separation or water loss during pumping, ensures that concrete can pass through the pumping equipment smoothly, and exhibits good fluidity and stability during high-altitude operations. By accurately controlling the amount of cellulose ether added, the pumpability of concrete can be further improved, pump loss can be reduced, and common pipe burst and pump blockage problems during construction can be avoided, thereby improving construction efficiency and safety.

[0051] In the method of use of this embodiment, cellulose ether is added after all dry materials and water are evenly mixed. The specific steps are as follows: after clean water is added and evenly mixed, the stirring speed is reduced to 120 revolutions per minute, and then the cellulose ether is added to the mixer. The purpose of this is to reduce the involvement of air, ensure the homogeneity of the mixture, and avoid excessive bubbles or segregation in the concrete due to excessive stirring. The cellulose ether is added together with other admixtures to work together to ensure that the concrete has excellent workability and pumpability.

[0052] Specifically, the specific indicators of the performance test include: slump test, slump expansion test, expansion time T500 test, slump and J-ring expansion difference, slump loss over time test, pressure water seepage test, air content test, V-funnel time test, inversion time test and plastic viscosity test, among which:

[0053] 1. The slump test includes the following steps:

[0054] H11. Place the steel plate on a level and solid surface;

[0055] H11. Place the slump cone vertically on the steel plate and press the base firmly with your feet;

[0056] H12. Use a shovel to fill the concrete into the slump cone in three layers. After each layer is filled, tamp it 25 times with a tamping rod.

[0057] H13. After the last layer is filled, use a shovel to scrape the top of the cylinder to make the concrete surface smooth;

[0058] H14. Lift the slump cone vertically upwards to allow the concrete to collapse naturally;

[0059] H15. Use a ruler to measure the distance from the highest point of the concrete cone to the bottom plate, which is the slump. Acceptable condition: the slump is between 180mm and 220mm; Unqualified condition: the slump is lower than 180mm or higher than 220mm.

[0060] 2. The slump spread test includes the following steps:

[0061] H21. Repeat the first few steps of the slump test on the steel plate;

[0062] H22. After lifting the slump cone, allow the concrete to expand freely until it stops expanding;

[0063] H23, measure the maximum diameter and the diameter perpendicular to it;

[0064] H24. Take the average value of the two diameters as the expansion degree; qualified condition: the expansion degree is between 500mm and 600mm; unqualified condition: the expansion degree is less than 500mm or greater than 600mm.

[0065] 3. Extended time T500 test includes the following steps:

[0066] H31. Place the steel plate horizontally and place the slump cone on top;

[0067] H32. Pour the concrete into the slump cone and start timing after the cone is lifted;

[0068] H31. Record the time required for concrete to expand to a diameter of 500mm; qualified condition: expansion time T500 is no more than 30 seconds; unqualified condition: expansion time exceeds 30 seconds.

[0069] 4. The slump and J-ring spread difference test includes the following steps:

[0070] H41. After completing the slump test, record the slump;

[0071] H42. Place the J ring on the steel plate, pour the concrete after the slump test into the J ring, lift the J ring and measure the diameter of the expanded concrete;

[0072] H43. Calculate the difference between the slump and the J-ring extension. Acceptable condition: the difference between the slump and the J-ring extension is between 25mm and 50mm. Unqualified condition: the difference is less than 25mm or greater than 50mm.

[0073] 5. The slump loss over time test includes the following steps:

[0074] H51. Carry out the first slump test and record the initial slump;

[0075] H52. Allow the concrete to stand for a period of time (e.g. 30 minutes) and then perform the slump test again;

[0076] H51. Calculate the difference between two slumps. Acceptable condition: the loss of slump over time is not more than 10mm. Unqualified condition: the loss of slump over time is more than 10mm.

[0077] 6. The pressure water seepage rate test includes the following steps:

[0078] H61. Place the concrete sample into the pressure chamber of the pressure water seepage instrument;

[0079] H61. Apply a certain pressure (such as 0.5MPa) to the concrete;

[0080] H61. Collect the exuded water and calculate the percentage of exuded water in the total volume of concrete; qualified condition: pressure water seepage rate is not more than 20%; unqualified condition: pressure water seepage rate exceeds 20%.

[0081] 7. The gas content test includes the following steps:

[0082] H71. Place the concrete sample into the container of the air content measuring instrument;

[0083] H72. Read the gas content value displayed on the instrument; qualified condition: gas content is between 3% and 5%; unqualified condition: gas content is lower than 3% or higher than 5%.

[0084] 8. The V-funnel time test includes the following steps:

[0085] H81. Fix the V-shaped funnel on a horizontal surface;

[0086] H81. Pour concrete into the V-shaped funnel and start timing;

[0087] H81. Record the time required for the concrete to completely flow out of the funnel; acceptance condition: the time meets the expected fluidity standard; failure condition: the time exceeds the expected range.

[0088] 9. The inversion time test includes the following steps:

[0089] H91. Pour concrete into an inverted container;

[0090] H92. Turn the container over and start timing;

[0091] H93. Record the time required for concrete to flow out; acceptance condition: the time meets the expected cohesiveness standard; failure condition: the time exceeds the expected range.

[0092] 10. Plastic viscosity test includes the following steps:

[0093] H101. Place the concrete sample into the test cup of the rotational viscometer;

[0094] H102, set the shear rate and measure the shear stress;

[0095] H103. Calculate the plastic viscosity based on the relationship curve between shear stress and shear rate; qualified condition: the plastic viscosity meets the balance standard between fluidity and cohesion; unqualified condition: the plastic viscosity does not meet the expected standard.

[0096] In summary, the preparation method of low-standard machine-made sand concrete for super-high-rise pumping significantly improves the pumping performance of concrete. By optimizing the mass ratio between mineral powder, fly ash, machine-made sand, stone, clean water and admixtures, it ensures that the concrete has excellent fluidity and stability, so that it can pass through pumping equipment smoothly and perform well in high-altitude operations. More importantly, through precise batching and mixing processes, the concrete has good workability and can maintain high pumpability even under the pumping conditions of super-high-rise buildings, reducing the occurrence of pump loss. This not only reduces the construction difficulty, but also effectively avoids common pipe burst and pump blockage problems during construction, thereby improving construction efficiency and safety.

[0097] In addition, the preparation method of the low-standard machine-made sand concrete for super-high-rise pumping introduces a polycarboxylate water-reducing agent with a high water-reducing rate and a good collapse-preserving effect, and strictly controls the mixing time and speed of the concrete, so that the internal structure of the concrete is more compact, thereby effectively reducing the pressure water seepage rate to ensure that it does not exceed 20%, and at the same time enhancing the homogeneity of the concrete. Such an improvement not only ensures the fluidity and cohesion of the concrete during the pumping process, but also enables the concrete to maintain good working performance after pumping, thereby ensuring the quality of super-high-rise building construction, reducing the risk of project delays caused by concrete quality problems, and solving the problem that due to the lack of comprehensive understanding of the pumping performance of low-standard concrete, a complete set of low-standard concrete pumping technology system has not been formed at present, which means that in the actual construction process, there is a lack of effective technical support for the pumping control of low-standard concrete, especially in the control indicators of concrete fluidity, cohesion and other aspects, no clear standards have been established, which constitutes an obstacle to ensuring the quality and efficiency of super-high-rise building construction. Therefore, a new preparation method of low-standard machine-made sand concrete is urgently needed to solve the problems existing in the prior art and improve the application effect of low-standard concrete in super-high-rise pumping.

[0098] The relevant modules involved in this system are all hardware system modules or functional modules that combine computer software programs or protocols with hardware in the prior art. The computer software programs or protocols involved in the functional modules are themselves technologies that are well known to those skilled in the art and are not improvements of this system. The improvements of this system are the interaction or connection relationships between the modules, that is, improvements to the overall structure of the system to solve the corresponding technical problems to be solved by this system.

[0099] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low-standard machine-made sand concrete for super-high-rise pumping, characterized in that: The invention comprises the following raw materials in proportion by weight: 240-270 parts by weight of cement, 60-80 parts by weight of mineral powder, 90-120 parts by weight of fly ash, 800-860 parts by weight of machine-made sand, 900-950 parts by weight of stone, 160-170 parts by weight of clean water, 4-6 parts by weight of admixture and 4-6 parts by weight of cellulose ether.

2. The low-standard machine-made sand concrete for super-high-rise pumping according to claim 1 is characterized in that: The machine-made sand is medium sand in zone II, the stone is a mixture of stones with diameters of 15-20 mm, 10-15 mm and 5-10 mm, and the admixture is a polycarboxylic acid water-reducing agent with high water-reducing rate and good collapse-preventing effect.

3. The low-standard machine-made sand concrete for super-high-rise pumping according to claim 1 is characterized in that: The cement is ordinary Portland cement; the mineral powder is granulated blast furnace slag powder, and its dosage accounts for 22.5% of the total cementitious materials; and the dosage of the admixture is 1.55% of the weight of the cement.

4. The low-standard machine-made sand concrete for super-high-rise pumping according to claim 1 is characterized in that: The fineness modulus of the machine-made sand is between 2.6 and 3.0, and the grading of the stones is matched and used in a mass ratio of 44:31:

25.

5. A method for preparing low-standard machine-made sand concrete for super-high-rise pumping, characterized in that: The low-standard machine-made sand concrete for super-high-rise pumping according to claims 1 to 4 also includes the following steps: S1, weighing 240-270 parts by weight of cement, 60-80 parts by weight of mineral powder, 90-120 parts by weight of fly ash, 800-860 parts by weight of machine-made sand, 900-950 parts by weight of stone, 160-170 parts by weight of clean water, 4-6 parts by weight of admixture and 4-6 parts by weight of cellulose ether; S2. Put the weighed cement, mineral powder and fly ash into the mixer, start the mixer for preliminary mixing, ensure that the dry materials are fully dispersed and avoid agglomeration; S3. After the dry materials are preliminarily mixed evenly, gradually add the machine-made sand into the mixer and continue to stir to ensure that the machine-made sand is evenly mixed with the previous dry materials; S4. After the machine-made sand is completely added and mixed evenly, put the stones into the mixer and adjust the mixing speed to 120 to 150 revolutions per minute to ensure that the stones are evenly mixed with the mixture; S5. When the stones are completely added and mixed evenly, slowly add clean water and adjust the stirring speed to 150 revolutions per minute to accelerate the uniformity of the mixture; S6. After adding clean water and mixing evenly, add the admixture and cellulose ether into the mixer, and reduce the stirring speed to 120 revolutions per minute to reduce the involvement of air and ensure the homogeneity of the mixture; S7. Continue stirring for 2 to 3 minutes to ensure that all materials are fully mixed while avoiding over-stirring that may cause concrete segregation; S8. After mixing, conduct performance tests before pumping to ensure that the concrete's slump, slump expansion, expansion time T500, difference between slump and J-ring expansion, slump loss over time, pressure water seepage rate, air content test, V-funnel time test, inversion time test, and plastic viscosity index meet the requirements of the specification; S9. Pour the mixed concrete into the mold or pump it into place.

6. The method for preparing low-standard machine-made sand concrete for super-high-rise pumping according to claim 5, characterized in that: In S2, the mixing process is carried out in a mixer, the mixing time is 2 to 3 minutes, and the mixing speed is 120 to 150 revolutions per minute.

7. The method for preparing low-standard machine-made sand concrete for super-high-rise pumping according to claim 5, characterized in that: The specific indicators of the S3 performance test include: slump greater than 230mm, slump expansion greater than 650mm and less than 750mm, expansion time T500 greater than 3s and less than 7s, the difference between slump and J-ring expansion less than 15mm, slump loss over time not more than 10mm, and pressure water seepage rate not more than 10%.

8. The method for preparing low-standard machine-made sand concrete for super-high-rise pumping according to claim 5, characterized in that: The S3, pre-pumping performance test also includes the air content, V-funnel time, inversion time and plastic viscosity of the concrete to ensure the fluidity and cohesion of the concrete during the pumping process.

9. The method for preparing low-standard machine-made sand concrete for super-high-rise pumping according to claim 5, characterized in that: The S4, pumping construction is completed before the initial setting time of the concrete to ensure that the pumping performance of the concrete is not affected.

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