CN116283133A

CN116283133A - Super-retarding concrete and preparation method thereof

Info

Publication number: CN116283133A
Application number: CN202310152010.6A
Authority: CN
Inventors: 王波; 刘波沣; 杨楠; 张志强; 杨波; 庞永龙; 文俊强; 杨荣俊; 李彦昌; 张硕; 韩帅; 张子翕
Original assignee: Beijing Gaoqiang Concrete Co ltd
Current assignee: Beijing Gaoqiang Concrete Co ltd
Priority date: 2023-02-22
Filing date: 2023-02-22
Publication date: 2023-06-23

Abstract

The application relates to the technical field of concrete, and particularly discloses super-retarding concrete and a preparation method thereof. The super-retarding concrete disclosed by the application comprises the following components in parts by weight: 390-450 parts of cementing material; 720-840 parts of sand; 920-1080 parts of crushed stone; 9-13 parts of water reducer; 8-12 parts of retarder; 150-200 parts of water; wherein, the cementing material comprises the following components in percentage by weight (280-320): (70-90): (37-57), cement, fly ash and slag powder. The application also provides a preparation method of the super-retarding concrete. The super-retarding concrete prepared by the formula and the preparation method provided by the application has the advantages of longer setting time, lower bleeding rate, better slump retaining effect and better compressive strength after final setting.

Description

Super-retarding concrete and preparation method thereof

Technical Field

The application relates to the technical field of concrete, in particular to super-retarding concrete and a preparation method thereof.

Background

Due to the increasingly tense land resources in China, the urban high-rise buildings and the high-speed development of rail transit construction are realized, the development engineering of underground space is continuously increased, and the depth of a basement foundation pit is continuously expanded. The cover-excavation reverse construction method is a commonly adopted construction method, and has the technical characteristics that the deformation of the enclosure structure is small, the influence on the ground is small, and the original ground traffic can be quickly restored; the method is based on the principle that firstly, a containment system (piles and underground continuous walls) and a bearing system (steel pipe columns) of a top plate are constructed, then a top plate structure is constructed, an earth outlet is reserved on the top plate, earth excavation and side wall, middle plate and bottom plate structure construction are completed from top to bottom, and finally, top plate reserved hole sealing, waterproof layer laying and earth backfilling above the top plate are carried out, so that a complete permanent structure is finally formed.

The bearing system of the top plate generally adopts a hydraulic vertical insertion method (HPE), and utilizes a full hydraulic jacketing machine and an automatic positioner to complete the hoisting, vertical insertion and core concrete pouring of the steel pipe column and carry out a complete set of construction method for timely protecting the steel pipe column.

At present, the hydraulic vertical insertion method has higher quality requirements on concrete, and the concrete needs to have good workability and fluidity, because the underwater concrete pouring construction does not have vibrating conditions, the concrete generates flowing to be flattened and tamped at the bottom of a pile foundation by self weight, if the fluidity is poor, pouring is difficult, pipe blocking is caused, normal pouring cannot be carried out, even pile breaking occurs, and serious quality accidents are caused; meanwhile, the underwater poured concrete has good cohesiveness and water retention property so as to prevent broken stones from locally gathering in a conduit in the pouring process of the concrete, thereby causing 'clamping pipe' and causing quality accidents; the workability of the concrete is good when the concrete is poured, and the slump is 200+/-20 mm; after the concrete is poured, when the steel pipe column is inserted, the concrete has no massive bleeding, good homogeneity and no layering. Secondly, the concrete needs to have good compressive strength, the concrete strength is reduced along with the addition of the retarder, and the mixing proportion design must meet the requirement of 28 days of compressive strength. Thirdly, the concrete needs to have a long setting time, and the initial setting time of the cast-in-place pile is not less than 48 hours in consideration of the requirement of the cast-in-place pile to be inserted into the steel pipe column, and the slump of the concrete in the period from the time when the concrete is transported to the time when the cast-in-place pile is inserted into the steel pipe column is not less than 16cm. If the requirement is not met, the permanent steel pipe column cannot be smoothly pressed in, the pile foundation is disabled, and the construction needs to be redesigned, so that huge loss is caused. Meanwhile, the coagulation time cannot be too long, otherwise, the occupied time of the steel pipe column stabilizing equipment is too long, and the engineering progress is affected.

Disclosure of Invention

In order to prolong the setting time of concrete and improve the slump retaining effect and simultaneously ensure the compressive strength of the concrete, the application provides super-retarding concrete and a preparation method thereof.

The application discloses super retarding concrete comprises the following components in parts by weight: 390-450 parts of cementing material; 720-840 parts of sand; 920-1080 parts of crushed stone; 9-13 parts of water reducer; 8-12 parts of retarder; 150-200 parts of water;

wherein, the cementing material comprises the following components in percentage by weight (280-320): (70-90): (37-57), cement, fly ash and slag powder.

The cement, the fly ash and the slag powder with proper weight ratio are used as cementing materials, the cementing materials, sand, broken stone, a water reducing agent and a retarder are used as raw materials of the super-retarding concrete, the dosage of each raw material is controlled, the prepared super-retarding concrete has longer setting time and lower bleeding rate, the slump retaining effect is better, and the compressive strength after final setting is higher.

Preferably, the cement is p.o42.5 cement.

Preferably, the fly ash adopts class F class II fly ash, the fineness is 15.0%, the water demand ratio is 98%, and the loss on ignition is 3.8%.

Preferably, the specification parameters of the slag powder are as follows: specific surface area 442m2/kg, fluidity 99%,7d activity index 77%,28d activity index 96%.

In a specific embodiment, the cement, fly ash, and slag powder may be present in a weight ratio of 280:90: 57. 280:70: 51. 280:80: 37. 295:81: 51. 295:70: 57. 295:90: 37. 320:70: 37. 320:80: 57. 320:90:51.

in some specific embodiments, the weight ratio of cement, fly ash, and slag powder may also be 280: (70-80): 57. 280: (80-90): 51. 280: (70-90): 37. (280-295): 81: 51. 295: (70-81): 57. 295:90: (37-51), 320: (70-80): 37. 320:80: (37-51), 320:90: (51-57).

The high-quality sand, the fly ash and the cement are selected as the cementing materials, so that the yield stress and the plastic viscosity of the concrete can be effectively reduced, and the fluidity is improved; on the premise of ensuring the workability of the concrete, the unilateral water consumption of the concrete mixture can be effectively reduced, and the guarantee rate of the strength of the concrete is improved. Meanwhile, the comprehensive performance of the super-retarding concrete is further improved by controlling the weight ratio of cement, fly ash and slag powder.

Preferably, the sand comprises (400-460) by weight: artificial sand and natural sand of (320-380).

Preferably, the fineness modulus of the artificial sand is 2.8, the stone powder content is 5.0%, the mud block content is 0%, and the MB value is 0.75.

Preferably, the fineness modulus of the natural sand is 2.4, the mud content is 2.7%, and the mud block content is 0%.

In a specific embodiment, the weight ratio of the artificial sand to the natural sand may be 400: 320. 400: 355. 400: 380. 433). 320. 433). 355. 433). 380. 460: 320. 460: 355. 460:380.

in some specific embodiments, the weight ratio of the artificial sand to the natural sand may also be 400: (320-355), 400: (355-380), 400: 380. (400-433): 320. 433). (355-380), 433: (320-355), (433-460): 320. (433-460): 355. 460: (355-380).

The quality of the fine aggregate as a main framework material in concrete directly influences the performance of the concrete. The inventor of the application finds that when natural sand is used as fine aggregate, the adsorption quantity of powder in the natural sand on the polycarboxylate water reducer is large, the adsorption quantity of powder in the artificial sand on the polycarboxylate water reducer is lower than that of cement, and the artificial sand has obvious advantages in the aspect of reducing the admixture dosage, but the artificial sand has small adsorption quantity of the admixture and is sensitive to the admixture dosage fluctuation, and segregation is easy to cause in the actual production process. Through experimental analysis, the artificial sand and the natural sand with the weight ratio are selected as fine aggregates, so that the bleeding rate can be reduced, and the service performance of the super-retarding concrete in HPE construction is improved.

Preferably, the water reducing agent is a polycarboxylate water reducing agent.

In a specific embodiment, the water reducing agent may be 9 parts, 11 parts, 13 parts by weight.

The water reducer influences the adsorptivity of the concrete material, causes fluidity loss, has an ultra-long branched chain, and can ensure that the ultra-delayed coagulation concrete does not bleed water and water does not lose in a long-time delayed coagulation state; the application adjusts the self consumption of the polycarboxylate superplasticizer and is matched with other raw materials for use, so that the water retention capacity of the super-retarding concrete is improved.

Preferably, the retarder comprises the following components in percentage by weight (7-9): sodium gluconate and sodium potassium tartrate of (1-3).

Further, the retarder comprises the following components in percentage by weight (7-9): (1-3): (0.5-1.5) sodium gluconate, potassium sodium tartrate and methylcellulose.

In a specific embodiment, the weight ratio of sodium gluconate, potassium sodium tartrate and methylcellulose may be 7:1:0.5, 7:2: 1. 7:3:1.5, 8:1:0.5, 8:2: 1. 8:3:1.5, 9:1:0.5, 9:2: 1. 9:3:1.5.

in some specific embodiments, the weight ratio of sodium gluconate, potassium sodium tartrate and methylcellulose may also be 7: (1-2): 0.5, 7: (2-3): 1. 7:3: (0.5-1.5), 8: (1-2): 0.5, 8:2: (1-1.5), 8: (2-3): 1.5, (7-8): 1:0.5, (8-9): 2: 1. 9: (1-3): 1.5.

further, the viscosity of the methyl cellulose is 350-550mPa.s.

The hydroxy carboxylate and the polysaccharide are used as retarder, so that omnibearing hydration inhibition can be formed on tricalcium aluminate, tricalcium silicate and tetracalcium aluminoferrite in cement clinker, the hydration of cement in 24 hours is greatly inhibited, the free water consumption is greatly reduced, the hydration of cement is hindered, the hydration speed of cement is delayed, the retarding effect is further achieved, and the fluidity retention capacity is improved.

The inventor of the application finds that the addition of methylcellulose, sodium gluconate and sodium potassium tartrate to be used as retarder can effectively delay the hydration time of the gel material, further promote the retarding effect and reduce the setting time of concrete.

Preferably, the crushed stone is continuous graded crushed stone with the thickness of 5-25mm, the mud content is 0.7%, the mud block content is 0% and the needle-shaped content is 5%.

Preferably, the super retarding concrete further comprises 5-8 parts by weight of water-retaining agent; the water-retaining agent comprises polysorbate 40 and polyethylenimine.

Further, the water-retaining agent comprises the following components in percentage by weight (2-4): polysorbate 40 and polyethyleneimine of (3-5).

After the sand stone and the water reducing agent are used, segregation and bleeding phenomena exist in the super-retarding concrete; the polysorbate 40 and the polyethyleneimine are used as the water-retaining agent, so that the problems of segregation and bleeding caused by concrete doped with a large amount of retarder can be solved, and the stability of the fresh concrete in the use process is improved.

Further, the specific surface area is 420-460m2/kg, the fluidity is 99%, the 7d activity index is 77%, and the 28d activity index is 96%.

On the other hand, the application also provides a preparation method of the super-retarding concrete, which specifically comprises the following steps:

mixing and stirring the cement, the fly ash, the slag powder, the sand, the broken stone and 70-80wt% of water required uniformly to obtain a primary mixed material;

mixing other raw material components and the rest water uniformly to obtain a premixed material;

and putting the premixed material into the primary mixed material to stir so as to obtain the super-retarding concrete.

In the preparation method of the super-retarding concrete, cement, fly ash and slag powder are used as gel materials and are mixed with sand and broken stone to obtain a primary mixed material; adding other premixed materials; the water reducer can be completely dispersed on the outer surface of the gel material, so that the retarder is favorable to be permeated into raw material components, the fluidity of the freshly mixed concrete is enhanced, the water retention property is increased, the stability is better, the initial setting time of the super-retarding concrete is effectively prolonged, and the compressive strength of the super-retarding concrete is ensured.

In summary, the technical scheme of the application has the following effects:

According to the method, the artificial sand and the natural sand with the proper weight ratio are selected, the types and the proportions of the retarder are screened simultaneously, and the water-retaining agent is added, so that the performance of the super-retarding concrete is further improved.

Detailed Description

In a first aspect, the present application provides an ultra-retarding concrete comprising the following components in parts by weight: 390-450 parts of cementing material; 720-840 parts of sand; 920-1080 parts of crushed stone; 9-13 parts of water reducer; 8-12 parts of retarder; 150-200 parts of water; wherein, the cementing material comprises the following components in percentage by weight (280-320): (70-90): (37-57), cement, fly ash and slag powder.

Specifically, the sand comprises the following components in percentage by weight (400-460): artificial sand and natural sand of (320-380); the water reducer is a polycarboxylate water reducer.

The retarder comprises the following components in percentage by weight (7-9): sodium gluconate and sodium potassium tartrate of (1-3); further, the retarder comprises the following components in percentage by weight (7-9): (1-3): (0.5-1.5) sodium gluconate, sodium potassium tartrate and methylcellulose; further, the viscosity of the methylcellulose is 350-550mpa.s.

The crushed stone is continuous graded crushed stone with the diameter of 5-25 mm.

Further, the super retarding concrete also comprises 5-8 parts by weight of water-retaining agent; the water-retaining agent comprises the following components in percentage by weight (2-4): polysorbate 40 and polyethyleneimine of (3-5).

Meanwhile, the specification parameters of the slag powder are as follows: the specific surface area is 420-460m2/kg, the fluidity is 99%, the 7d activity index is 77%, and the 28d activity index is 96%.

On the other hand, the application also provides a preparation method of the super-retarding concrete, which specifically comprises the following steps: mixing and uniformly stirring cement, fly ash, slag powder, sand, broken stone and 70-80wt% of water required to obtain a primary mixed material;

and (3) adding the premixed material into the primary mixed material to stir, thereby obtaining the super-retarding concrete.

The present application is described in further detail below in conjunction with examples, comparative examples, and performance test runs, which should not be construed as limiting the scope of the claimed application.

The cement used in the application adopts P.O42.5 cement produced by Tangshan Hongtai cement Co., ltd, the specific surface area is 343m2/kg, and the standard consistency is 28.0%; the fly ash adopts class F class II fly ash, the fineness is 15.0%, the water demand ratio is 98%, and the loss on ignition is 3.8%; the sand adopts the Maillard poly source artificial sand and Hebei Fengning natural sand, the fineness modulus of the artificial sand is 2.8, the stone powder content is 5.0%, the mud block content is 0%, the MB value is 0.75, and the methylene blue test is rapidly tested to be qualified; the fineness modulus of the natural sand is 2.6, the mud content is 4.0%, and the mud block content is 0%; the broken stone adopts continuous graded broken stone with the Maillard aggregation source of 5-25mm, the mud content is 0.4%, the mud block content is 0% and the needle-shaped content is 1%; the water reducer is an HS-209 type polycarboxylate water reducer; methylcellulose and polyethylenimine were purchased from Shanghai Seiyaka Biotech Inc. The remaining raw materials are all commercially available.

Examples

Examples 1 to 7

Examples 1-7 each provide an ultra-retarded concrete.

The amounts of the components in the super-retarding concrete in the above examples are shown in table 1, and the preparation method of the super-retarding concrete comprises the following steps:

according to the dosage of each component in the table 1, cement, fly ash, slag powder, sand, broken stone and 75wt% of water required are mixed and stirred uniformly to obtain a primary mixed material;

according to 8:2:1, mixing sodium gluconate, potassium sodium tartrate and methyl cellulose (with the viscosity of 350-550 mPa.s), and weighing 11g as retarder;

mixing and stirring the HS-209 type polycarboxylate superplasticizer, retarder and the rest water uniformly to obtain a premix;

TABLE 1 amounts of the components in examples 1-7

Example 8

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 1 in that: according to 7:3:1.5 mixing sodium gluconate, potassium sodium tartrate and methylcellulose (viscosity 350-550 mPa.s), and weighing 11g as retarder; other components of the super retarding concrete and the preparation method thereof are the same as those of the example 1.

Example 9

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 1 in that: according to 9:1: mixing sodium gluconate, potassium sodium tartrate and methylcellulose (viscosity 350-550 mPa.s) in a weight ratio of 0.5, and weighing 11g as retarder; other components of the super retarding concrete and the preparation method thereof are the same as those of the example 1.

Example 10

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 1 in that: according to 8:2, mixing sodium gluconate and sodium potassium tartrate, and weighing 11g as retarder; other components of the super retarding concrete and the preparation method thereof are the same as those of the example 1.

Example 11

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 1 in that: according to 6:1: mixing sodium gluconate, potassium sodium tartrate and methylcellulose (viscosity 350-550 mPa.s) in a weight ratio of 0.5, and weighing 11g as retarder; other components of the super retarding concrete and the preparation method thereof are the same as those of the example 1.

Example 12

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 1 in that: the viscosity of methylcellulose is 25mpa.s; other components of the super-retarding concrete and preparation methods thereof are the same as the examples.

Example 13

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 1 in that: the viscosity of methylcellulose is 4000mpa.s; other components of the super retarding concrete and the preparation method thereof are the same as those of the example 1.

Example 14

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 1 in that: the super-retarding concrete also comprises the following components in percentage by weight: 4 and polyethylenimine (99%, molecular weight 10000) as water-retaining agents; the preparation method of the super-retarding concrete in the embodiment comprises the following steps:

mixing and stirring the HS-209 type polycarboxylate superplasticizer, retarder, water retention agent and the rest water uniformly to obtain a premix; and (3) adding the premixed material into the primary mixed material to stir, thereby obtaining the super-retarding concrete.

Example 15

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 14 in that: the weight ratio is 1:4 and polyethylenimine (99%, molecular weight 10000) as water-retaining agents; other components and preparation methods of the super retarding concrete in this example are the same as those of example 14.

Example 16

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 14 in that: the weight ratio is 3:2 and polyethylenimine (99%, molecular weight 10000) as water-retaining agents; other components and preparation methods of the super retarding concrete in this example are the same as those of example 14.

Example 17

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 14 in that: the weight ratio is 3: polysorbate 40 and polyethylenimine (99% molecular weight 1800) of 4 as water retention agents; other components and preparation methods of the super retarding concrete in this example are the same as those of example 14.

Example 18

The embodiment provides super-retarding concrete.

This embodiment differs from embodiment 14 in that: the weight ratio is 3:4 and polyethylenimine (99% with molecular weight 2-3 ten thousand) as water-retaining agents; other components and preparation methods of the super retarding concrete in this example are the same as those of example 14.

Comparative example

Comparative examples 1 to 6

Comparative examples 1-6 comparative examples provide an ultra-retarded concrete.

The above comparative example is different from example 1 in that: the amounts of the components in the super-retarding concrete are different, and are shown in the table 2; the preparation method of the super retarding concrete is the same as that of the example 1.

Table 2 amounts of the components in comparative examples 1 to 6

Performance test the performance of the super-retarding concrete provided in examples 1-18 and comparative examples 1-6 was tested by the following test method criteria:

testing the initial setting time, final setting time, bleeding rate and slump of super-retarding concrete at different times according to the method specified in GB/T50080 method for testing the mixing properties of common concrete; the compressive strength of the super-retarding concrete is tested according to GB/T50081 test method for mechanical properties of common concrete.

Detection result: as shown in table 3.

TABLE 3 Performance test results of ultra-retarded concretes provided in examples 1-18 and comparative examples 1-6

According to the detection results of examples 1-18 and comparative examples 1-6, according to the combination of Table 3, cement, fly ash and slag powder with proper weight ratio are used as cementing materials, sand, broken stone, a water reducing agent and a retarder are used as raw materials of the super-retarding concrete, the setting time of the prepared super-retarding concrete is more than or equal to 62 hours, the bleeding rate is less than or equal to 4.8%, the slump for 20 hours is more than or equal to 165mm, and the compressive strength for 28d is more than or equal to 49.5Mpa; whereas the ultra-retarded concretes prepared in comparative examples 1 to 6 were inferior in performance. The detection result shows that the super-retarding concrete provided by the application has longer setting time and lower bleeding rate, better slump retaining effect, capability of quickly recovering strength increase after final setting and higher 28d compressive strength.

By comparing the results of the tests of examples 1-3 and comparative examples 1-2, a weight ratio of (280-320) was selected: (70-90): when the cement, the fly ash and the slag powder (37-57) are used as cementing materials for preparing super-retarding concrete, the super-retarding concrete with long setting time, low bleeding rate and higher 20h slump can be obtained, and the super-retarding concrete can quickly recover the strength increase after final setting, so that the super-retarding concrete has excellent compressive strength.

According to the detection results of comparative examples 1 and 3-4, when the dosage of the water reducer is less than 9 parts, the prepared super-retarding concrete has shorter setting time, higher bleeding rate (10.2%) and smaller compressive strength; when the dosage of the water reducer is more than 13 parts, the prepared super-retarding concrete has shorter setting time and smaller compressive strength; the dosage of the water reducer is controlled within the range of 9-13 parts, and when the water reducer is used for preparing super-retarding concrete, the super-retarding concrete with long setting time, low bleeding rate and excellent compressive strength can be obtained.

According to the detection results of comparative examples 1 and 4-7, when only artificial sand or only natural sand is adopted, the super-retarding concrete has poor performance, so that the artificial sand and the natural sand are selected to be used together, and the weight ratio of the artificial sand to the natural sand is controlled to be (400-460): (320-380), and further obtaining the super-retarding concrete with excellent performance.

The results of the tests of comparative examples 1, 8 to 11 and comparative examples 5 to 6, when used in a weight ratio of (7 to 9): (1-3): and (0.5-1.5) sodium gluconate, sodium potassium tartrate and methyl cellulose are used as retarder, and when the addition amount of the retarder is controlled within the range of 8-12 parts, super-retarding concrete with long setting time, low bleeding rate, higher 20h slump and excellent compressive strength can be obtained.

Further, by the detection results of comparative examples 1, 12 to 13, when the viscosity of methylcellulose in the retarder was 25mpa.s or 4000mpa.s, the super-retarding concrete was inferior in performance; the methyl cellulose with the viscosity of 350-550mPa.s is used as retarder in combination with sodium gluconate and potassium sodium tartrate, so that super-retarding concrete with long setting time, low bleeding rate, higher 20h slump and excellent compressive strength can be obtained.

By comparing the results of examples 1, 14 to 18, when the weight ratio is (2 to 4): when the polysorbate 40 and the polyethyleneimine of the (3-5) are used as water-retaining agents to be added into the super-retarding concrete, the bleeding rate of the super-retarding concrete can be further obviously reduced.

While the invention has been described in detail in the foregoing general description and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that modifications and improvements can be made thereto. Accordingly, such modifications or improvements may be made without departing from the spirit of the invention and are intended to be within the scope of the invention as claimed.

Claims

1. The super-retarding concrete is characterized by comprising the following components in parts by weight: 390-450 parts of cementing material; 720-840 parts of sand; 920-1080 parts of crushed stone; 9-13 parts of water reducer; 8-12 parts of retarder; 150-200 parts of water;

2. The super retarding concrete according to claim 1, wherein the sand comprises (400-460) by weight: artificial sand and natural sand of (320-380).

3. The super retarding concrete of claim 1, wherein said water reducing agent is a polycarboxylate water reducing agent.

4. The ultra-retarding concrete according to claim 1, wherein the retarder comprises (7-9) by weight: sodium gluconate and sodium potassium tartrate of (1-3).

5. The ultra-retarding concrete according to claim 1, wherein the retarder comprises (7-9) by weight: (1-3): (0.5-1.5) sodium gluconate, potassium sodium tartrate and methylcellulose.

6. The super retarding concrete according to claim 5, wherein said methyl cellulose has a viscosity of 350-550mpa.s.

7. The super retarding concrete according to claim 1, wherein said crushed stone is 5-25mm continuous graded crushed stone.

8. The super retarding concrete according to claim 1, further comprising 5-8 parts by weight of a water retaining agent; the water-retaining agent comprises polysorbate 40 and polyethylenimine.

9. The super retarding concrete according to claim 8, wherein the water retaining agent comprises the components in the weight ratio of (2-4): polysorbate 40 and polyethyleneimine of (3-5).

10. The method for preparing super retarding concrete according to any one of claims 1 to 9, comprising the following steps: