CN110105504B

CN110105504B - High slump loss resistant retarding polycarboxylate superplasticizer and preparation and application thereof

Info

Publication number: CN110105504B
Application number: CN201910444070.9A
Authority: CN
Inventors: 马清浩
Original assignee: Shenzhen Wushan New Material Co ltd
Current assignee: SHENZHEN WUSHAN NEW MATERIAL Co.,Ltd.
Priority date: 2019-05-27
Filing date: 2019-05-27
Publication date: 2021-10-01
Anticipated expiration: 2039-05-27
Also published as: CN110105504A

Abstract

The invention discloses a high slump loss resistant retarding polycarboxylic acid water reducing agent, a preparation method and application thereof, wherein the water reducing agent is prepared from the following raw materials in parts by mole: 10-30 parts of micromolecular unsaturated carboxylic acid, 3-8 parts of ester of the micromolecular unsaturated carboxylic acid, 1-5 parts of salt of the micromolecular unsaturated carboxylic acid, 2-6 parts of polyethylene glycol diacrylate, 1-5 parts of unsaturated polyether macromonomer, 8-20 parts of acrylamide monomer, initiator and chain transfer agent; wherein the acrylamide monomer is a group consisting of Acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) and 2-acrylamido-2-phenylethanesulfonic Acid (AMSS). The molecular structure of the water reducing agent is designed according to the workability and slump retention of construction requirements, and the high slump retention retarding polycarboxylic acid water reducing agent with excellent comprehensive performance is finally obtained, in construction, a high water reducing rate can be obtained by low mixing amount, construction can be guaranteed, the slump retention is excellent, slump loss is basically not lost within 3 hours, and the water reducing agent has wide applicability in concrete construction.

Description

High slump loss resistant retarding polycarboxylate superplasticizer and preparation and application thereof

Technical Field

The invention belongs to the field of concrete admixtures, and particularly relates to a polycarboxylic acid water reducing agent, and preparation and application thereof.

Background art:

with the rapid development of economy and improvement of building level in China, rapid rise of high-speed railways, highway bridges, traffic tunnels, urban rail transit and large buildings and development of concrete structures towards large-scale, complicated, high-rise and diversified construction conditions, higher requirements on strength, construction performance and durability of concrete are provided, pumping concrete is almost required to be used, good fluidity and slump retentivity of the concrete in the long-distance pumping conveying process are kept, otherwise slump loss of fresh concrete cannot be constructed, and great economic loss is caused to construction units. In order to maintain good working performance of concrete and meet different engineering requirements, water reducing agents with different functions need to be added into fresh concrete. Among various water reducing agents, polycarboxylic acid-based high performance water reducing agents are high performance water reducing agents which have been developed rapidly in recent years. The polycarboxylic acid water reducing agent has rich and changeable chemical molecular structures, and the structure and the performance of the polycarboxylic acid water reducing agent are different greatly due to the changes of monomer types, functional group positions, molecular weights, molecular weight distribution and the like. The main components of the carboxylic acid group monomer can be classified into modified polyethers, poly (meth) acrylates and maleic acid copolymers. However, the polycarboxylic acid water reducing agents widely used at present often have the problem of too fast slump loss of fresh concrete due to the defects of the polycarboxylic acid water reducing agents in the using process. Particularly, the slump loss of concrete is more serious under the influence of factors such as high-temperature weather and long-distance conveying, and the quality of concrete construction is difficult to ensure.

The existing method for solving the slump loss of concrete mainly comprises 1) compounding a retarder, hopefully playing a synergistic effect, but the addition of the retarder can prolong the setting time of the concrete and has certain influence on the strength of the concrete; 2) a post-mixing method is adopted, namely, the water reducing agent is added after the concrete is mixed for a period of time; 3) the workability of the concrete can be improved to a certain extent by adding the water reducing agent for two or more times; 4) the slump retaining agent and the water reducing agent are compounded for use. In the first method, the slump loss control of concrete by the added retarder still hardly meets the practical application requirement, the second and third methods put high requirements on the mixing amount of the water reducing agent, the mixing amount is small, the requirements cannot be met, and the problem of concrete strength reduction caused by over-mixing is solved. The fourth method is currently studied because it does not adversely affect the setting time and strength of concrete. CN105174795A discloses a concrete slump retaining agent, which is added with methylcellulose to overcome the defect of slump loss of a water reducing agent, but the preparation method is complicated, and particularly when a cellulose structure is introduced, in order to protect active groups on the cellulose structure, a nitrogen protection method which is not suitable for industrial production is required. CN103214206A discloses a slow-release type polycarboxylate superplasticizer which is prepared from a component A: polyoxyethylene ether/polyoxypropylene ether, component B: (meth) acrylic acid/itaconic acid and component C: the water reducer is prepared by copolymerizing three components of (methyl) sodium propylene sulfonate, the preparation process is relatively simple, but the slump retaining property of the obtained water reducer still cannot meet the actual construction requirement. Therefore, the slump-retaining type polycarboxylate superplasticizer is urgently needed to be developed to improve the performance of polycarboxylate superplasticizer products and widen the variety of concrete admixtures to meet the requirements of different projects. CN104692700A discloses a polycarboxylic acid slump retaining agent, which is prepared by copolymerizing isopentenyl polyoxyethylene ether, acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate and 2-acrylamide-2-methylpropanesulfonic acid, but the proportion of hydrophilic monomers added for slump retaining is large, and a high doping amount is required to achieve a high water reducing rate, so that the strength of concrete and the engineering quality are adversely affected.

In the prior art, many documents are that part of amide or other unsaturated carboxylic ester monomers are added to replace part of acrylic acid, and hydrolysis of ester groups and amide groups is performed, such as the methods described in CN106397684A, CN109535342A, CN102898061A, CN107739424A and CN109053967A, but the hydrolysis and environmental impact of ester groups, amide groups or ether bonds in common polycarboxylic acid slump retaining agents is large, and the stable and slow-release effect is difficult to achieve, for example, the strong slow-release effect at a certain time point causes segregation and bleeding of concrete, so that the construction of concrete is affected; or the slump retaining property can be achieved only in the initial stage, and the slump retaining property in the later stage is difficult to guarantee. Therefore, the development of a water reducing agent which has long-term delayed slump retaining property (little slump loss within 3 hours) and high water reducing rate (more than 30 percent) under low mixing amount is urgently needed, and the water reducing agent has practical application and research values for construction of building engineering.

Disclosure of Invention

The invention aims to provide a polycarboxylic acid water reducing agent which has long-term slow setting slump retaining property (slump loss within 3 hours is less than 10%) and has high water reducing rate at low dosage. The technical idea of the invention is to introduce different functional monomers to synthesize polycarboxylic acid macromolecules with a specific structure, and adjust the proportion of each functional monomer to ensure that the prepared polycarboxylic acid type water reducing agent has the advantages of long-time slump retaining property and high water reducing rate, can meet the strict requirement of the current concrete construction, and overcomes the defect of poor later slump retaining property of the common polycarboxylic acid water reducing agent in the prior art.

The above object of the present invention is solved by the following technical solutions:

the high slump retaining retarding polycarboxylic acid water reducing agent is prepared from the following raw materials in parts by mole:

10-30 parts of micromolecular unsaturated carboxylic acid, 3-8 parts of ester of the micromolecular unsaturated carboxylic acid, 1-5 parts of salt of the micromolecular unsaturated carboxylic acid, 2-6 parts of polyethylene glycol diacrylate, 1-5 parts of unsaturated polyether macromonomer, 8-20 parts of acrylamide monomer, initiator and chain transfer agent; wherein the acrylamide monomer comprises 2-acrylamido-2-phenylethanesulfonic Acid (AMSS).

In a preferred technical scheme of the invention, the high slump retaining retarding polycarboxylic acid water reducing agent is prepared from the following raw materials in parts by mole: 10-20 parts of micromolecular unsaturated carboxylic acid, 4-6 parts of micromolecular unsaturated carboxylic acid ester, 2-3 parts of micromolecular unsaturated carboxylic acid salt, 2-4 parts of polyethylene glycol diacrylate, 1-3 parts of unsaturated polyether macromonomer, 10-15 parts of acrylamide monomer, initiator and chain transfer agent; wherein the acrylamide monomer is a group consisting of Acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) and 2-acrylamido-2-phenylethanesulfonic Acid (AMSS).

In the acrylamide monomer, the molar ratio of AM, AMPS and AMSS is 3-10: 1-3: 1-2, preferably 5-8: 1.5-3: 1-2.

Further, the small molecule unsaturated carboxylic acid is selected from at least one of acrylic acid and methacrylic acid; the ester of the small molecular unsaturated carboxylic acid is at least one of methyl ester, ethyl ester, propyl ester and butyl ester of acrylic acid and/or methacrylic acid; the salt of the small molecule unsaturated carboxylic acid is at least one of sodium salt and potassium salt of acrylic acid and/or methacrylic acid; the unsaturated polyether macromonomer is at least one of Allyl Polyoxyethylene Ether (APEG), isoamyl alcohol polyoxyethylene ether (TPEG) and methallyl alcohol polyoxyethylene ether (HPEG), and the data molecular weight of the unsaturated polyether macromonomer is 500-4000, preferably 1500-3000.

Further, the number average molecular weight of polyethylene glycol (PEG) in the polyethylene glycol diacrylate is 200-1000, preferably 400-600.

The initiator and the chain transfer agent for the copolymerization reaction in the present invention are not particularly limited, and may be those conventionally used in polymerization in the art. Examples of the initiator include dibenzoyl oxide (BPO), Azobisisobutyronitrile (AIBN), ammonium persulfate, potassium persulfate; examples of chain transfer agents include mercaptopropionic acid, mercaptoacetic acid, mercaptoethanol, and isopropanol. The dosage of the initiator and the dosage of the chain transfer agent are determined according to the molecular weight of the needed water reducing agent macromolecules, and according to the requirements on the molecular weight and the dispersity of the water reducing agent, the dosage of the initiator is 0.2-2%, preferably 0.6-1% of the total mass of the comonomer; the amount of the chain transfer agent added is 0.4 to 3%, preferably 0.8 to 1.2% of the total amount of comonomer. The initiator is used in a small amount, and the molecular dispersion retentivity of the water reducing agent is poor because the free radical content is low, and the conversion rate of the monomer is reduced. But the dosage of the initiator cannot be too large, otherwise, the number of free radicals is too large, the chain length of the main chain is shortened, the molecular weight of the polymer is reduced, the molecular weight dispersity is also poor, and the slump-retaining steric hindrance effect of the water reducing agent cannot be effectively embodied. Therefore, the amount of the initiator is suitably selected. The dosage of the chain transfer agent is small, and the dispersion retention of the water reducing agent molecules cannot be ensured, but the dosage of the chain transfer agent is too large, the polymerization degree of the polymer is reduced, the molecular weight is low, and the dispersion retention performance is reduced. Therefore, the appropriate amounts of initiator and chain transfer agent have an important influence on the molecular weight, molecular weight distribution, and dispersion retention of the molecules of the water-reducing agent.

Optionally, in the copolymerization reaction for preparing the water reducing agent, a certain amount of polymerization inhibitor can be added, and the polymerization inhibitor is selected from hydroquinone.

The inventor unexpectedly found that adding a certain amount of 2-acrylamide-2-phenylethanesulfonic Acid (AMSS) as a functional monomer and a certain amount of polyethylene glycol diacrylate with two double bonds during the preparation of the polycarboxylic acid water reducer can generate a certain branched structure on the macromolecules of the water reducer, and the initial slump of blended concrete is not obviously improved, but the slump loss of concrete is greatly improved (the slump loss is less than 10% within 3 hours) after time. Therefore, the invention also provides the application of the 2-acrylamide-2-phenylethanesulfonic acid and the polyethylene glycol diacrylate in the polycarboxylic acid water reducing agent, the 2-acrylamide-2-phenylethanesulfonic acid and the polyethylene glycol diacrylate are used as functional monomers to participate in the polymerization reaction of the preparation of the polycarboxylic acid water reducing agent, the prepared water reducing agent as a concrete admixture has excellent slump resistance under low doping amount (less than 0.3%), and the slump loss of the blended concrete is less than 10% within 3 hours. 2-acrylamide-2-phenyl ethanesulfonic Acid (AMSS) is taken as a functional monomer, and the dosage of the 2-acrylamide-2-phenyl ethanesulfonic Acid (AMSS) is 2-7.5 percent of the total substance of the water reducing agent polymerization monomer, and is preferably 3-5 percent; the molecular weight of the (PEG) of the polyethylene glycol in the polyethylene glycol diacrylate is 200-1000, preferably 400-600, and the dosage of the (PEG) is 3-12 percent of the total substance of the polymerization monomers of the water reducing agent, preferably 5-8 percent

The invention also provides a preparation method of the high slump retaining retarding polycarboxylic acid water reducing agent, which comprises the following steps:

adding micromolecular unsaturated carboxylic acid, micromolecular unsaturated carboxylic acid ester, micromolecular unsaturated carboxylic acid salt, polyethylene glycol diacrylate, unsaturated polyether macromonomer, acrylamide monomer, initiator, chain transfer agent and water into a reaction vessel according to the proportion, heating for reaction, cooling after the reaction is finished, and neutralizing with alkaline liquor to obtain the product, namely the high slump retaining and retarding polycarboxylic acid water reducer.

Wherein, the amount of water is not particularly limited, the reaction system can be uniformly mixed, a certain reaction rate is maintained, and the amount of water is 1-2 times of the total mass of the raw materials. The reaction temperature is 40-80 ℃, and the reaction time is 3-6 hours.

Optionally, near the end of the reaction, a polymerization inhibitor selected from hydroquinone may also be added.

The preparation method of the high slump loss resistant retarding polycarboxylic acid water reducer has the advantages of easily available raw materials and simple steps, and the prepared water reducer has the advantages of large number average molecular weight of about 2 ten thousand and narrow molecular weight distribution (less than 2).

The third purpose of the invention is to apply the high slump loss resistant retarding polycarboxylate superplasticizer to the construction of cement/concrete engineering.

The high slump retaining retarding polycarboxylic acid water reducing agent provided by the invention is used as an additive in cement and concrete construction, so that the workability of cement is effectively improved, a higher water reducing rate can be achieved under a low doping amount, and meanwhile, excellent slump retaining property can be maintained. The water reducer high slump loss resistant retarding polycarboxylate water reducer provided by the invention is proved to have excellent comprehensive performance, convenient manufacture and low cost, is a novel green environment-friendly water reducer, and has good market popularization value. In addition, the high slump retaining type polycarboxylate water reducer with the slow release effect, which is prepared by the invention, can also be compounded with a high water reducing type polycarboxylate water reducer for use. And the concrete can be used in common concrete, can also be applied to high-performance concrete, and is compounded with other additives such as an air entraining agent, a retarder, a defoaming agent and the like to achieve better product performance.

Compared with the prior art, the invention has the following beneficial effects:

firstly, a molecular structure of the water reducer is designed and synthesized by selecting specific functional monomers, and the water reducer with delayed coagulation and high slump retaining property is obtained by controlling the proportion of the monomers. The water reducing agent provided by the invention can obviously improve the construction workability of cement/concrete under low mixing amount, and the loss of slump within 3 hours is less than 10 percent over time, thereby effectively meeting the long-distance and long-time requirements of concrete transportation in modern building industry and having wider adaptability.

Secondly, the inventor unexpectedly finds that the addition of a certain amount of polyethylene glycol diacrylate and 2-acrylamido-2-phenylethanesulfonic Acid (AMSS) as functional monomers has an obvious effect of improving the slump loss of the water reducing agent over time.

And thirdly, not only the molecular structure of the water reducing agent is involved, but also the amount of an initiator and a chain transfer agent in the polymerization reaction of the water reducing agent is properly screened, and the prepared polycarboxylic acid water reducing agent has moderate molecular weight distribution and has long-term dispersion retentivity as a concrete admixture.

Detailed Description

The high slump retaining retarding polycarboxylic acid water reducing agent and the preparation method thereof of the present invention will be further illustrated with reference to the following specific examples, but the present invention is not limited to the following examples. The method is a conventional method unless otherwise specified. The starting materials are commercially available from the open literature unless otherwise specified.

Example 1

Adding a certain amount of acrylic acid, methyl acrylate, sodium acrylate, polyethylene glycol diacrylate, methallyl alcohol polyoxyethylene ether (HPEG, number average molecular weight 2400), Acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), 2-acrylamido-2-phenylethanesulfonic Acid (AMSS) and deionized water into a 500mL flask provided with a stirrer, heating to 50 ℃, stirring to completely dissolve raw materials, heating to 70 ℃, dropwise adding an initiator sodium persulfate and a chain transfer agent thioglycolic acid, dropwise adding for 3 hours, keeping the temperature for 1 hour, cooling to room temperature after the reaction is finished, and neutralizing with a NaOH solution to obtain the polycarboxylic acid water reducer.

Wherein the raw materials comprise 0.5mol of acrylic acid, 0.2mol of methyl acrylate, 0.1mol of sodium acrylate, 0.1mol of polyethylene glycol (PEG400) diacrylate, 0.05mol of methallyl alcohol polyoxyethylene ether (HPEG), 0.3mol of Acrylamide (AM), 0.1mol of 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), 0.05mol of 2-acrylamide-2-phenylethanesulfonic Acid (AMSS), 0.01mol of sodium persulfate and 0.013mol of thioglycolic acid.

Example 2

The unsaturated polyether macromonomer was changed to allyl polyoxyethylene ether (APEG, number average molecular weight 1800), and the procedure was otherwise the same as in example 1.

Example 3

The unsaturated polyether macromonomer was replaced by prenyl alcohol polyoxyethylene ether (TPEG, number average molecular weight 2500), and the procedure was otherwise the same as in example 1.

Example 4

The amounts of the acrylamide-based monomers used were changed to 0.3mol of AM, 0.15mol of AMPS and 0.05mol of AMSS, and the procedure was otherwise as in example 1.

Example 5

The amounts of the acrylamide-based monomers used were changed to 0.3mol of AM, 0.05mol of AMPS and 0.1mol of AMSS, and the procedure was otherwise as in example 1.

Example 6

The amounts of the acrylamide-based monomers used were changed to 0.4mol of AM, 0.05mol of AMPS and 0.05mol of AMSS, and the procedure was otherwise as in example 1.

Example 7

The amounts of the acrylamide-based monomers used were changed to 0.3mol of AM, 0.1mol of AMPS and 0.1mol of AMSS, and the procedure was otherwise as in example 1.

Example 8

The amounts of the acrylamide-based monomers used were changed to 0.5mol of AM, 0.1mol of AMPS and 0.05mol of AMSS, and the procedure was otherwise as in example 1.

Example 9

The amounts of the acrylamide-based monomers used were changed to 0.3mol of AM, 0.2mol of AMPS and 0.2mol of AMSS, and the procedure was otherwise as in example 1.

Example 10

The amounts of the acrylamide-based monomers used were changed to 0.3mol of AM, 0.1mol of AMPS and 0.02mol of AMSS, and the procedure was otherwise as in example 1.

Example 11

The amounts of the acrylamide-based monomers used were changed to 0.3mol of AM, 0.1mol of AMPS and 0.15mol of AMSS, and the procedure was otherwise as in example 1.

Example 12

The procedure of example 1 was repeated except that the amount of the initiator used was changed to 0.005mol of sodium persulfate and the amount of the chain transfer agent used was changed to 0.008mol of thioglycolic acid.

Example 13

The procedure of example 1 was repeated except that the amount of the initiator used was changed to 0.015mol of sodium persulfate and the amount of the chain transfer agent used was changed to 0.02mol of thioglycolic acid.

Example 14

The number average molecular weight of polyethylene glycol in the polyethylene glycol diacrylate was 600, and the other examples were the same as example 1.

Comparative example 1

The amount of the acrylamide-based monomer used was changed to 0.3mol of AMPS and 0.15mol of AMSS, and the procedure was otherwise the same as in example 1.

Comparative example 2

The amount of the acrylamide-based monomer used was changed to 0.45mol of AM, and the procedure was otherwise the same as in example 1.

Comparative example 3

The amount of the acrylamide-based monomer used was changed to 0.35mol of AM and 0.1mol of AMPS, and the procedure was otherwise as in example 1.

Comparative example 4

The amount of the acrylamide-based monomer used was changed to 0.35mol of AM and 0.1mol of AMSS, and the procedure was otherwise the same as in example 1.

Comparative example 5

The procedure is as in example 1 except that no polyethylene glycol diacrylate is added.

Application examples

1. Gel chromatography analysis

The water phase gel chromatography analysis uses an instrument of a United states Waters gel permeation chromatograph to test the molecular weight and the distribution of the obtained rosin modified polycarboxylate superplasticizer. When the polycarboxylic acid water reducing agent passes through the chromatographic column at the flow rate of 1.0L/min, molecules with different sizes pass through the chromatographic column at different speeds to be separated, the temperature of the chromatographic column is controlled at 40 ℃, and the eluent is 0.1mol/LNa₂SO₄Aqueous solutions, calibration standard curves were calibrated with different molecular weight monodisperse polyethylene glycols.

2. Neat paste fluidity test

In order to investigate the fluidity and the water reducing rate of the high slump loss resistant retarding polycarboxylic acid water reducer prepared by the invention on cement paste, the test is carried out according to the relevant standards specified in GB/T8077 and 2012, the concrete admixture homogeneity test method. The test measures the net slurry flow of each example to the reference cement at the same loading.

In the examples, the test cement is a standard cement special for testing concrete admixture, and is 42.5 strength grade P.I type portland cement formed by grinding portland cement clinker with the following quality indexes and dihydrate gypsum together. The standard cement not only meets the technical requirement of 42.5 strength grade, but also contains 6-8% of composite tricalcium aluminate, 50-55% of tricalcium silicate, no more than 1.2% of free calcium oxide and alkali (Na)₂O+0.658K₂O) content of not more than 1.0%, and specific surface area of cement320±20m²In terms of/kg. The operation conditions are that the water-cement ratio is 0.30 and the mixing amount of the polycarboxylic acid water reducing agent is 0.16 percent (broken solid).

3. Concrete test

Concrete slump and loss with time were determined with reference to GB8076-2008 "concrete Admixture". Adopts sea snail PO42.5 cement, and the concrete mixing ratio is cement, flyash, sand, stone and water (320: 125: 750: 1110: 180). The mixing amount of the water reducing agent is 0.12 percent (solid by bending) of the cementing material.

The characterization data and the performance detection results of the high slump loss resistant retarding polycarboxylic acid water reducer prepared by the invention are shown in the following table 1:

TABLE 1

TABLE 1

In concrete construction, certain high temperature resistance is required besides the requirements on good fluidity of cement mortar, small slump loss and good workability. In summer with higher temperature, the concrete is ensured to have proper fluidity retentivity and setting time. Therefore, the slump retention at high temperature (45 ℃) of the preferred polycarboxylic acid water reducing agent of the present invention is also tested, and the results are shown in Table 2:

TABLE 2

The judgment standard of the workability is divided into 4 grades according to different slump of the concrete mixture, wherein the grades are T4 (slump is more than or equal to 160mm), T3 (slump is 100-160mm), T2 (slump is 10-100mm) and T1 (slump is less than 10 mm).

As can be seen from the data in tables 1 and 2, the high slump retaining and retarding polycarboxylate superplasticizer provided by the invention has the total performance of slump retaining and high water reducing rate, and the concrete slump loss after the polycarboxylate superplasticizer is blended is very small and basically has no loss after 3 hours (the slump loss after 3 hours is less than 10%). Under the condition of low mixing amount, the cement static slurry fluidity of the polycarboxylate superplasticizer disclosed by the invention can not be reduced or even can be increased along with the prolonging of time, and the polycarboxylate superplasticizer has great advantages compared with the common polycarboxylate superplasticizer that the cement static slurry fluidity can be gradually reduced along with the time. The problem that the final strength is reduced due to the fact that the initial bleeding and the segregation of the concrete are caused by overlarge initial fluidity adjustment of the concrete is avoided. And the concrete mixed with the polycarboxylic acid water reducing agent provided by the invention can keep good workability under high temperature conditions, and the workability can be in the grade of T3 after 3 hours at 45 ℃, so that the construction in summer or in regions with higher temperature is ensured, and the application range of the water reducing agent is expanded. The excellent comprehensive performance of the water reducing agent is realized by molecular design of the water reducing agent, adopting a specific functional monomer and screening the mixture ratio of the monomer, so that the aim of slowly releasing hydrolyzed substances and anions is fulfilled.

Claims

1. The high slump loss resistant retarding polycarboxylic acid water reducing agent is characterized in that the preparation raw materials of the water reducing agent comprise the following raw materials in parts by mole: 10-20 parts of micromolecular unsaturated carboxylic acid, 4-6 parts of micromolecular unsaturated carboxylic acid ester, 2-3 parts of micromolecular unsaturated carboxylic acid salt, 2-4 parts of polyethylene glycol diacrylate, 1-3 parts of unsaturated polyether macromonomer, 10-15 parts of acrylamide monomer, initiator and chain transfer agent; wherein the acrylamide monomer is a group consisting of Acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) and 2-acrylamido-2-phenylethanesulfonic Acid (AMSS).

2. The water reducing agent of claim 1, wherein the molar ratio of AM, AMPS, AMSS is 3-10: 1-3: 1-2.

3. The water reducer of claim 2, wherein the molar ratio of AM, AMPS, AMSS is 5-8: 1.5-3: 1-2.

4. The water-reducing agent according to any of claims 1 to 3, wherein the number average molecular weight of the polyethylene glycol in the polyethylene glycol diacrylate is 200-1000.

5. The water reducer according to any one of claims 1 to 3, wherein the small molecule unsaturated carboxylic acid is selected from at least one of acrylic acid and methacrylic acid; the ester of the unsaturated carboxylic acid is at least one of methyl, ethyl, propyl and butyl esters of acrylic acid and/or methacrylic acid; the salt of the unsaturated carboxylic acid is at least one of sodium salt and potassium salt of acrylic acid and/or methacrylic acid; the unsaturated polyether macromonomer is at least one of Allyl Polyoxyethylene Ether (APEG), isoamyl alcohol polyoxyethylene ether (TPEG) and methallyl alcohol polyoxyethylene ether (HPEG), and the number average molecular weight of the unsaturated polyether macromonomer is 500-4000.

6. The water reducer according to any one of claims 1 to 3, wherein the initiator is selected from at least one of dibenzoyl peroxide (BPO), Azobisisobutyronitrile (AIBN), ammonium persulfate, and potassium persulfate; the chain transfer agent is at least one selected from mercaptopropionic acid, thioglycolic acid, mercaptoethanol, and isopropanol.

7. The water reducer of claim 6, wherein the amount of said initiator is 0.2-2% of the total amount of comonomer; the amount of the chain transfer agent is 0.4-3% of the total amount of the comonomer.

8. The preparation method of the high slump retaining and retarding polycarboxylate water reducer disclosed by any one of claims 1 to 7, comprising the following steps of:

9. The use of the high slump retaining retarding polycarboxylate water reducer as defined in any one of claims 1-7 in the construction of cement/concrete engineering.