A Low-Shrinkage, High-Crack-Resistant Concrete and Its Application

Abstract

This invention discloses a low-shrinkage, high-crack-resistant concrete, belonging to the field of concrete technology. Based on mix proportions, the raw materials include 130-160 kg / m³ of cement. 3 50-70 kg / m³ of fly ash 3 Mineral powder 50-70 kg / m³ 3 Sand 600-750 kg / m³ 3 Crushed stone 1300-1500 kg / m³ 3 Water-reducing agent 3-5 kg / m³ 3 Water 90-130 kg / m 3 Anti-cracking agent 3-4 kg / m 3 The crack-resistant agent is composed of cellulose grafted with hyperbranched polycarboxylic acid and diacetone glucose polyacrylate. Through the dual effects of high water absorption and slowing settling, it allows the heat of hydration to proceed slowly, providing the necessary time for the exchange of heat of hydration with the environment. The crack-resistant agent has the advantages of good dispersibility, small particle size, high water absorption rate and long slow release time.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of concrete, and particularly relates to a low-shrinkage high-anti-cracking concrete and application thereof. BACKGROUND

[0002] Mass concrete refers to concrete with a pouring thickness, length and width size of not less than 1 m, or concrete that is expected to cause harmful cracks due to temperature changes and shrinkage caused by hydration of cementitious materials in the concrete. After mass concrete is poured, a large amount of hydration heat is generated during the hardening and cement hydration process of the concrete. Due to the thick volume of the concrete, the exchange path of hydration heat and the environment is long, causing uneven temperature distribution in the structure. Since the heat inside the concrete dissipates slowly, while the surface dissipates quickly, a large temperature difference between the inside and the outside is formed, which leads to temperature stress on the surface of the concrete inside. When the temperature stress is greater than the tensile strength of the same age concrete, cracks are easily generated on the surface of the concrete. When the concrete inside gradually cools and shrinks, due to constraints, a very large tensile stress will be generated at the contact. When the tensile stress exceeds the ultimate tensile strength of the same age concrete, cracks will be generated at the contact, and even the entire concrete block may be penetrated, thereby causing serious quality accidents. Therefore, mass concrete engineering construction should be strictly controlled.

[0003] At present, the crack control of mass concrete mainly has the following ways, 1) optimization of reinforcement, anti-cracking grid, shrinkage-compensating concrete, gradient concrete; 2) optimization of layering and blocking, setting of sliding layer, crack induction, preheating and cooperative deformation; 3) low-shrinkage high-anti-cracking concrete, hydration heat inhibitor, heat and moisture preservation curing, intelligent temperature control, etc. Superabsorbent materials have a three-dimensional network structure with low cross-linking, and have the ability to absorb and store several times of water solution of their own dry weight. The superabsorbent material can store water in the concrete and release it again during the hydration process, thereby reducing the self-shrinkage caused by low water-cement ratio and pore self-drying; and after the release of water, the polymer shrinks, leaving corresponding micropores in the microstructure, which plays a role in enhancing the mechanical properties and anti-cracking after air entrainment; it can also improve the crack resistance by expanding and plugging cracks and promoting self-healing. The above high-performance water-absorbing materials have been verified in the documents Journal of Building Engineering 51 (2022) 104219, Berlin. Beton- und Stahlbetonbau 119 (2024), Heft 7 and Cement and Concrete Composites 150 (2024) 105563. However, the current superabsorbent materials are mainly composed of cross-linked materials, with a particle size of about 100 μm, which will have a certain impact on the mixing of cement, and the remaining air holes have a large particle size. SUMMARY

[0004] In order to overcome the above-mentioned deficiencies of the prior art, the present application provides a low-shrinkage high-anti-cracking concrete, the anti-cracking agent is a structure of cellulose grafted hyperbranched polycarboxylic acid and diacetone glucose polyacrylate, through the dual action of high water absorption and retarding, the hydration heat release is slowly carried out, giving the time required for the exchange of hydration heat and environment; the anti-cracking agent is a high water absorption material, which can be used as an internal water supply agent, stores water in the concrete, and releases again during the hydration process, thereby reducing the self-shrinkage caused by low water-cement ratio and pore self-drying.

[0005] The technical scheme for achieving the object of the present application is as follows: a low-shrinkage high-anti-cracking concrete, in terms of mix proportion, raw materials include cement 130-160 kg / m 3 , fly ash 50-70 kg / m 3 , mineral powder 50-70 kg / m 3 , sand 600-750 kg / m 3 , gravel 1300-1500 kg / m 3 , water reducing agent 3-5 kg / m 3 , water 90-130 kg / m 3 , anti-cracking agent 3-4 kg / m 3 ; the preparation method of the anti-cracking agent is as follows:

[0006] Under an inert gas atmosphere, carboxymethyl cellulose sodium, carboxylic acid monomer, diacetone glucose monomer and peroxide are dispersed in an aqueous solution, silver nitrate is dispersed in acetonitrile, after mixing, stirring at 50-70 ℃ for 4-6 h, vacuum filtration, washing with ethanol and water at least twice in turn, after filtration, the obtained solid is vacuum dried to obtain the anti-cracking agent.

[0007] The carboxylic acid monomer is at least one of methacrylic acid and acrylic acid; the diacetone glucose monomer has at least one of the following formula I and formula II molecular structures:

[0008] , formula I; , formula II.

[0009] Preferably, the water is an ice-water mixture, the ice content of the ice-water mixture is 50-70 kg / m 3 ; the peroxide is sodium persulfate.

[0010] Preferably, the sodium carboxymethyl cellulose in the aqueous solution is 1-2 w.t%; the carboxylic acid monomer in the aqueous solution is 2-3 w.t%; the diacetone glucose monomer in the aqueous solution is 0.5-1 w.t%; the peroxide in the aqueous solution is 2.5-3.5 w.t%; the silver nitrate in acetonitrile is 0.05-0.25 w.t%; the volume ratio of the aqueous solution to acetonitrile is 1:1.

[0011] Preferably, the carboxylic acid monomer is acrylic acid; the diacetone glucose monomer is the above-mentioned molecular structure of formula I; and the preparation method of the molecular structure of formula I is as follows:

[0012] In a reaction kettle, 1.0 eq of diacetone glucose is added and dissolved in dichloromethane, then 2-3 eq of triethylamine is added, stirred under ice bath conditions, 1.5-2.0 eq of acryloyl chloride diluted in 20-30 eq of dichloromethane is added dropwise using a constant pressure dropping funnel, and the above-mentioned ice bath mixed solution is added dropwise under stirring, after the dropwise addition is completed, the reaction solution is restored to room temperature, and stirred for 10-12 h, after the reaction is completed, the reaction solution is washed with saturated sodium bicarbonate solution and distilled water at least twice, the organic phase is collected, the solvent is removed, and the colorless transparent oily liquid is separated by column chromatography.

[0013] Preferably, the preparation method of the molecular structure of formula II is that acryloyl chloride in the preparation method of formula I is replaced by methacryloyl chloride.

[0014] Preferably, a preparation method of low-shrinkage high-anti-crack concrete comprises the following steps:

[0015] 1) dispersing the anti-crack agent in water, 8-12 kg of normal temperature water is dispersed for every 1 kg of anti-crack agent;

[0016] 2) after the sand and gravel are pre-cooled, the cement, fly ash, and mineral powder are added into the sand and gravel cement mixer, stirred for 1-2 min, then the ice-water mixture is added, stirred for 2-5 min, and then the water reducing agent and the anti-crack agent dispersed in water obtained in step 1) are added, and the stirring is continued until the ice blocks are fully melted, and the concrete temperature out of the machine is ≤16 ℃;

[0017] 3) the concrete is layered and poured by a pump truck, each layer is uniformly distributed with a thickness of 30-50 cm, the concrete is vibrated by a φ50 mm plug-in type manual vibrator, the vibration points are arranged in a plum blossom pattern, the vibration sequence starts from the near formwork to the middle, the vibrator is vertically inserted into the concrete, the insertion depth into the lower layer is not less than 5 cm, the insertion is fast and the pulling is slow, and the vibration time at each point is determined by the fact that the cement paste on the surface of the concrete no longer sinks and the surface basically does not bubble;

[0018] 4) Water cooling, the horizontal spacing of cooling water pipe is 1.2~1.5 m, the cooling water is controlled at 14 ℃~16 ℃, the water flow is not less than 2.0 m 3 / h, the direction of cooling water is changed once every 24 h;

[0019] 5) Maintenance, the plane and inclined plane are kept warm and moist: after watering, high polymer water-saving and moisture maintenance film is covered, then the heat preservation plate is covered; the vertical plane is kept warm and moist: the vertical plane is covered with high polymer water-saving and moisture maintenance film, the heat preservation plate or tarpaulin heat preservation is hung outside, the structure is sealed with the top heat preservation plate, and the top is sprayed and maintained, and the maintenance age is not less than 28 d.

[0020] Beneficial effects

[0021] The application comprises the following beneficial effects: the application reduces the peak value of hydration heat by adding high water absorption material as an anti-cracking agent in mass concrete, and the peak value is reduced by two ways of slowly releasing water and slowly releasing glucose small molecules to be adsorbed on part of cement, thereby reducing cracks caused by self-shrinkage due to low water-cement ratio and pore self-drying; the high water absorption material is obtained by grafting polycarboxylic acid and diacetone glucose on carboxymethyl cellulose, when the high water absorption material is initially added into cement and stirred, the high water absorption material is a comb structure with a cellulose main chain and linear or branched polycarboxyl, polydiacetone glucose side chains, has good dispersibility and certain water absorption capacity, with stirring in the alkaline environment of concrete, the external diacetone glucose is hydrolyzed to expose four hydroxyl groups, and the comb structure molecules are crosslinked through hydrogen bonds, at this time, the three-dimensional network structure of the well-dispersed high water absorption material and the four hydroxyl structures respectively provide storage capacity and hydrophilicity, so that the water absorption capacity is further increased; with the hydration of cement, the temperature is further increased, and the glucose connected with the carboxyl group begins to hydrolyze, the hydrogen-bonded structure of the high water absorption material gradually detaches, the water storage capacity of the high water absorption material begins to weaken, and water is gradually released, and the released glucose can be combined with cement as a retarder, further reducing the hydration rate of cement and the peak value of hydration heat. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structure schematic diagram of the flood discharge gate chamber in the mass concrete of the application;

[0023] Figure 2 It is a synthesis route and structure schematic diagram of the anti-cracking agent of the application;

[0024] Figure 3 It is a nuclear magnetic spectrum of the diacetone glucose monomer prepared in the application;

[0025] Figure 4 It is an infrared spectrum of carboxymethyl cellulose sodium and the anti-cracking agent of the application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0027] In the embodiments, the experimental methods used are conventional methods, and the materials, reagents, etc. used are commercially available unless otherwise specified.

[0028] The raw materials and equipment used in the embodiments and comparative examples are described as follows.

[0029] Cement: medium-heat Portland cement, P.MH 42.5, purchased from Huarun Cement;

[0030] Fly ash: fineness (45 um square hole sieve residue) of 21.8%, purchased from Guodian Sheneng Huayunshan Power Co., Ltd.;

[0031] Slag: S95 slag, purchased from Xiangtan Iron and Steel Co., Ltd. Yangchun New Iron and Steel Co., Ltd.;

[0032] Sand: II-grade medium sand, purchased from Liuzhou Urban Area;

[0033] Gravel: 5-20 mm, 20-40 mm, and 40-80 mm three-grade gravel, purchased from Liuzhou Urban Area;

[0034] Water reducing agent: polycarboxylic acid type water reducing agent, PCA®-IV, purchased from Jiangsu Subote;

[0035] Water: Liuzhou tap water, meeting the requirements of the standard “Mixing Water for Concrete” (JGJ 63-2006);

[0036] Sodium carboxymethyl cellulose: viscosity of 50-200 mPa.s, item number C299502, purchased from Shanghai Aldrich;

[0037] Acrylic acid: item number M102640, purchased from Shanghai Aldrich;

[0038] Double acetone glucose: item number 1036610, purchased from Shanghai Leyue;

[0039] Silver nitrate: national reagent;

[0040] Sodium persulfate: national reagent;

[0041] Crushed ice: flake ice unit, model FIP63E;

[0042] Cold water: cold water unit, model LS-510;

[0043] Stirring station: HZS270-1Q4500 type water stirring station;

[0044] Air-cooled aggregate system: model AC600EPC;

[0045] Diacetone glucose monomer

[0046] In a reaction kettle, 1.0 eq of diacetone glucose was added and dissolved in dichloromethane, then 2.5 eq of triethylamine was added, stirred under ice bath conditions, 2.0 eq of acryloyl chloride diluted in 30 eq of dichloromethane was added dropwise to the above ice bath mixed solution under stirring, after the dropwise addition was completed, the reaction solution was restored to room temperature, and stirred for 12 h. After the reaction was completed, it was washed with saturated sodium bicarbonate solution and distilled water for 3 times, respectively, the organic phase was collected, the solvent was removed, and the colorless transparent oily liquid was obtained by column chromatography purification and separation.

[0047] Anti-cracking agent 1

[0048] Under a nitrogen atmosphere, 1 g of sodium carboxymethyl cellulose, 2.5 g of acrylic acid, 0.5 g of diacetone glucose monomer, and 3 g of sodium persulfate were dispersed in 100 ml of aqueous solution, 0.05 g of silver nitrate was dispersed in 100 ml of acetonitrile, and after stirring at 60°C for 5 h, vacuum filtration, washing with ethanol and water for 3 times, respectively, after filtration, the obtained solid was vacuum dried to obtain anti-cracking agent 1.

[0049] Anti-cracking agent 2

[0050] Compared with the preparation method of anti-cracking agent 1, the difference is that 0.05 g of silver nitrate is replaced by 0.10 g.

[0051] Anti-cracking agent 3

[0052] Compared with the preparation method of anti-cracking agent 1, the difference is that 0.05 g of silver nitrate is replaced by 0.15 g.

[0053] Anti-cracking agent 4

[0054] Compared with the preparation method of anti-cracking agent 1, the difference is that 0.05 g of silver nitrate is replaced by 0.20 g.

[0055] Anti-cracking agent 5

[0056] Compared with the preparation method of anti-cracking agent 1, the difference is that 0.05 g of silver nitrate is replaced by 0.25 g.

[0057] Anti-cracking agent 6

[0058] Compared with the preparation method of anti-cracking agent 1, the difference is that 0.5 g of diacetone glucose monomer is replaced by 0.5 g of acrylic acid.

[0059] Anti-cracking agent 7

[0060] Compared with the preparation method of the anti-cracking agent 1, the difference lies in that 2.5 g of acrylic acid is replaced by 2.5 g of diacetone glucose monomer.

[0061] Anti-cracking agent 8

[0062] 0.5 g of the anti-cracking agent 1 is added and dissolved in 33 mL of dichloromethane, then 15 mL of trifluoroacetic acid and 1.5 mL of water are added in sequence, and the reaction is stirred at room temperature for 24 h. After the reaction is completed, dichloromethane is removed by rotary evaporation, then an appropriate amount of water is added, and the solution is precipitated in acetone for multiple times until the solution no longer shows acidity. The precipitate is centrifuged and vacuum dried overnight to obtain the deprotected anti-cracking agent 8.

[0063] The following are the test methods for performance parameters involved in the present application:

[0064] Determination of water absorption: accurately weigh 0.1 g of the sample in a 500 ml beaker, add 400 ml of deionized water, and stand at room temperature for 24 h. After the sample reaches liquid saturation, filter and stand for 30 min until no liquid drops fall. Weigh the mass of the anti-cracking agent after swelling equilibrium, and calculate according to formula I:

[0065]

[0066] Water absorption, unit: g·g -1 ;

[0067] M1 - total mass of the gel and the filter bag at the time of water absorption saturation, unit: g;

[0068] M2 - mass of the dry filter bag; unit: g;

[0069] M0 - mass of the dry sample, unit: g.

[0070] Anti-cracking agent length and rotation radius test: small-angle neutron scattering test;

[0071] Temperature monitoring: the test piece size is 1000 mm x 1000 mm x 1000 mm, the internal and external temperatures of the concrete are monitored and calculated according to JTS-T 202-1-2022 “Technical Specification for Temperature Crack Control of Mass Concrete in Water Transport Engineering”, and the pre-embedded temperature measuring elements directly reflect the internal temperature of the concrete pouring body at three height positions of the upper, middle and lower concrete, and 9 measuring points are arranged from the surface to the inside of each layer, and a total of 27 measuring points are arranged on each level of the pile cap, to monitor the highest temperature of the concrete and the internal surface temperature difference in real time.

[0072] Compressive strength: the specimen size is 150 mm x 150 mm x 150 mm, and the test is performed according to the relevant provisions of standard GB / T 50081-2019;

[0073] Crack: the crack is measured by standard point line gauge film ruler and card, and the maximum crack is recorded.

[0074] Table 1 Performance characterization of anti-cracking agent

[0075]

[0076] From the data in Table 1, the length of anti-cracking agents 1-5 is basically consistent because the same sodium carboxymethyl cellulose is used, but the radius of gyration gradually decreases. This is because as the content of the catalyst silver nitrate increases, the side groups of cellulose gradually change from linear to branched, resulting in a decrease in length. As the degree of branching increases, the water absorption rate first increases and then decreases. At the beginning, the linear structure changes to a branched structure, which can improve the water locking ability of the anti-cracking agent. However, as the branched structure further increases, the water molecules entering the branched structure are hindered to a certain extent, resulting in a decrease in water absorption rate. From the data of anti-cracking agents 6-8, the water absorption capacity of the acrylic group is better than that of unhydrolyzed diacetone glucose. When diacetone glucose is hydrolyzed to expose four hydroxyl groups, the comb-shaped polymers are cross-linked by hydrogen bonds. At this time, the formation of three-dimensional network structure of well-dispersed superabsorbent material and four hydroxyl groups provides water storage capacity and hydrophilicity, respectively, thereby further increasing the water absorption capacity.

[0077] A low-shrinkage high-anti-cracking concrete is a thin-walled, large length-width ratio, and wide-section structure in a pivotal engineering structure. In a specific embodiment, the size of the flood discharge gate bottom plate is 35 m x 16.5 m x 2.6 m, the size of the gate pier pouring block is 35 m x 1.75 m x 3 m, the size of the power plant bottom plate is 42 m x 29 m x 2.6 m, the size of the ship lock chamber wall bottom plate is 32.8 m x 21.4 m x 1.5 m, and the size of the upper lock head bottom plate is 40 m x 23.5 m x 1.5 m. The specific size can be adjusted according to the project situation or construction needs.

[0078] In a specific embodiment, the mass concrete is a laboratory specimen, and the specific size of the concrete structure is 1 m x 1 m x 1 m.

[0079] A preparation method of a low-shrinkage high-anti-cracking concrete, comprising the following steps:

[0080] 1) Disperse the anti-cracking agent in water, 1 kg of anti-cracking agent is dispersed in 10 kg of normal temperature water;

[0081] 2) Cement, fly ash, slag, sand and gravel are added into the cement mixer, after stirring for 2 min, then add ice water mixture, stir for 5 min, then add water reducing agent and anti-cracking agent dispersed in water obtained in step 1), continue to stir until the ice is fully melted, the concrete temperature out of the machine is ≤ 16 ℃;

[0082] 3) The concrete is poured by layer using a pump truck, each layer is 40 cm, the concrete is vibrated using a φ50 mm plug-in manual vibrator, the vibration points are arranged in a plum blossom pattern, the vibration sequence starts from the near formwork to the middle, the vibrator is vertically inserted into the concrete, the insertion into the lower layer is not less than 5 cm, fast insertion and slow pulling, up and down pumping, the vibration time of each point is determined by that the concrete surface presents cement paste that does not sink and the surface basically does not bubble;

[0083] 4) Cooling water is passed, the horizontal spacing of the cooling water pipe is 1.2 m, the cooling water is controlled at 16 ℃, the flow of the cooling water is not less than 2.0 m 3 / h, the direction of the cooling water is changed once every 24 h;

[0084] 5) Curing, the flat and inclined surfaces are kept warm and moist: after watering, a high-molecular water-saving and moisture-retaining curing film is covered, then a heat preservation plate is covered; the vertical surface is kept warm and moist: the vertical surface is covered with a high-molecular water-saving and moisture-retaining curing film, a heat preservation plate or a tarpaulin is hung outside, a heat preservation plate is sealed on the structure, and the top is sprayed for curing, the curing period is not less than 28 d.

[0085] Table 2 Concrete formula of examples 1~7 and comparative examples 1~5 (unit: kg / m 3 )

[0086]

[0087] Table 3 Concrete performance test

[0088]

[0089] From the data in Table 3, it can be seen that the maximum temperature difference of examples 1~7 is less than 20 ℃, the compressive strength is greater than 45 Mpa, and there is no visible crack. From the data of comparative example 1, it can be seen that not adding the anti-cracking agent prepared in the application will cause a large temperature difference and cracks. From the data of comparative example 2, it can be seen that too much anti-cracking agent prepared in the application will cause a decrease in compressive strength, which is due to the generation of bubbles caused by too much anti-cracking agent. From comparative examples 3~5, it can be seen that the carboxylic acid and the structure of diacetone glucose in the anti-cracking agent of the application play a complementary role, and the effect of a single component is not excellent, among which the strength of comparative examples 4 and 5 is low, it is guessed that the dispersibility of 7~8 is poor, which causes the generation of too many harmful pores with large pore size.

[0090] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application and get the best results from the application. The application is only limited by the claims and their full scope and equivalents.

Claims

1. A low shrinkage high crack resistance concrete, characterized by, The raw materials include cement 130-160 kg / m 3 , fly ash 50-70 kg / m 3 , mineral powder 50-70 kg / m 3 , sand 600-750 kg / m 3 , gravel 1300-1500 kg / m 3 , water reducing agent 3-5 kg / m 3 , water 90-130 kg / m 3 , anti-cracking agent 3-4 kg / m 3 ; the preparation method of the anti-cracking agent is as follows: In an inert gas atmosphere, sodium carboxymethyl cellulose, carboxylic acid monomer, diacetone glucose monomer and peroxide are dispersed in an aqueous solution, silver nitrate is dispersed in acetonitrile, after mixing, stirring at 50-70℃ for 4-6h, vacuum filtration, washed with ethanol and water at least twice, after filtration, the obtained solid is vacuum dried to obtain the anti-cracking agent; The carboxylic acid monomer is at least one of methacrylic acid and acrylic acid; the diacetone glucose monomer has at least one of the following formula I and formula II molecular structures: , formula I; , formula II.

2. The low shrinkage high crack resistance concrete as claimed in claim 1, wherein, The water is an ice-water mixture, the ice content of the ice-water mixture is 50-70 kg / m 3 ; the peroxide is sodium persulfate.

3. The low shrinkage and high crack resistance concrete as claimed in claim 1, wherein, The content of sodium carboxymethyl cellulose in the aqueous solution is 1-2 w.t%; the content of carboxylic acid monomer in the aqueous solution is 2-3 w.t%; the content of diacetone glucose monomer in the aqueous solution is 0.5-1 w.t%; the content of peroxide in the aqueous solution is 2.5-3.5 w.t%; the content of silver nitrate in acetonitrile is 0.05-0.25 w.t%; the volume ratio of the aqueous solution to acetonitrile is 1:

1.

4. The low shrinkage high crack resistance concrete as claimed in claim 1, wherein, The carboxylic acid monomer is acrylic acid; the diacetone glucose monomer has a formula I molecular structure; the preparation method of the formula I molecular structure is as follows: In a reaction kettle, 1.0 eq of diacetone glucose is added and dissolved in dichloromethane, then 2-3 eq of triethylamine is added, stirred under ice bath conditions, under stirring conditions, 1.5-2.0 eq of acryloyl chloride diluted in 20-30 eq of dichloromethane is added dropwise to the above ice bath mixed solution using a constant pressure dropping funnel, after the dropwise addition is completed, the reaction solution is restored to room temperature, and stirring is carried out for 10-12 h, after the reaction is completed, the organic phase is collected after washing with saturated sodium bicarbonate solution and distilled water at least twice, the solvent is removed, and the colorless transparent oily liquid is obtained by column chromatography purification and separation.

5. The method for preparing low-shrinkage and high-anti-crack concrete according to any one of claims 1 to 4, characterized in that, Comprising the following steps: 1) disperse the anti-cracking agent in water, disperse 8-12 kg of normal temperature water per 1 kg of anti-cracking agent; 2) add cement, fly ash, mineral powder, sand and gravel into the cement mixer, stir for 1-2 min, then add ice water mixture, stir for 2-5 min, then add water reducing agent and the anti-cracking agent dispersed in water obtained in step 1), continue to stir until the ice blocks are fully melted, and the concrete temperature out of the machine is ≤16℃; 3) the concrete is poured by layer using a pump truck, each layer is 30-50 cm, the concrete is vibrated and compacted using φ50 mm plug-in type manual vibration, the vibration points are arranged in the form of plum blossom, the vibration sequence starts from the near formwork to the middle, the vibrator is vertically inserted into the concrete, the insertion depth into the lower layer is not less than 5 cm, the vibrator is inserted quickly and pulled out slowly, and the vibration time at each point is determined according to whether the cement paste on the surface of the concrete no longer falls and whether the surface basically does not bubble; 4) water cooling, the horizontal spacing of cooling water pipe is 1.2~1.5 m, the cooling water is controlled at 14℃~16℃, the water flow is not less than 2.0 m 3 / h, the direction of cooling water is changed once every 24 h; 5) curing, temperature and humidity preservation for plane and inclined surface: after watering, cover the high polymer water-saving and moisture preservation curing film, then cover the insulation board; temperature and humidity preservation for vertical surface: cover the high polymer water-saving and moisture preservation curing film on the vertical surface, hang the insulation board or tarpaulin insulation on the outside, seal the top with insulation board, and spray the top for curing, and the curing period is not less than 28 d.

6. The application of low-shrinkage and high-anti-crack concrete according to any one of claims 1-4 to the chamber of a flood discharge gate, the bottom plate of a power station plant, the bottom plate of a wall in the chamber of a ship lock, and the bottom plate of an upper lock head.

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