阅读说明：本技术 一种混凝土膨胀剂的制备方法 (Preparation method of concrete expanding agent ) 是由 谭桂红 于 2021-01-08 设计创作，主要内容包括：本发明涉及一种混凝土膨胀剂的制备方法,属于混凝土技术领域。本发明以铝灰、氧化钡作为基础原料,通过硝酸进行溶解,随后利用聚丙烯酰胺进行絮凝,使其中的金属离子进行充分的接触,再与混合铁盐进行搅拌,通过与尿素、造孔剂的作用,形成负载钡及磁性颗粒的多孔高活性氧化铝颗粒,再与磷石膏及氧化钙进行高温蒸汽养护,是形成的氢氧化钙及氧化钙负载在多孔颗粒内部,在使用包裹剂进行包裹,从而得到混凝土膨胀剂,进而有效解决了混凝土膨胀剂的膨胀效果的持续稳定性较差的问题。(The invention relates to a preparation method of a concrete expanding agent, belonging to the technical field of concrete. According to the invention, aluminum ash and barium oxide are used as basic raw materials, are dissolved by nitric acid, and are flocculated by polyacrylamide to enable metal ions in the aluminum ash and barium oxide to be in full contact with each other, and are stirred with mixed iron salts, porous high-activity alumina particles loaded with barium and magnetic particles are formed under the action of urea and a pore-forming agent, and are subjected to high-temperature steam curing with phosphogypsum and calcium oxide, so that the formed calcium hydroxide and calcium oxide are loaded in the porous particles and are wrapped by a wrapping agent, and thus the concrete expanding agent is obtained, and the problem of poor continuous stability of the expansion effect of the concrete expanding agent is effectively solved.)

1. The preparation method of the concrete expanding agent is characterized by comprising the following steps:

(1) taking the mixture and a nitric acid solution to perform ultrasonic vibration according to the mass ratio of 3: 13-16, adding an additive accounting for 30-40% of the mass of the mixture, uniformly stirring, collecting a stirred mixture, and taking 130-150 parts of the stirred mixture, 30-40 parts of an auxiliary material, 20-25 parts of urea, 15-20 parts of a pore-forming agent and 3-6 parts of a dispersing agent according to parts by weight;

(2) firstly, putting a stirred mixture and urea into a reaction kettle, using nitrogen for protection, preheating, adding an auxiliary material, heating, using ammonia water to adjust the pH value to 8.0-8.5, cooling, adding a pore-forming agent and a dispersing agent, stirring and mixing, freeze-drying, calcining, and collecting a calcined substance;

(3) crushing the calcined substance, sieving, collecting sieved particles, ball-milling the sieved particles, phosphogypsum and calcium oxide according to a mass ratio of 4: 6-9: 3-7, collecting ball-milled substances, and putting the ball-milled substances into a curing box for steam curing at a set temperature of 100 ℃;

(4) and after curing is finished, collecting a curing mixture, calcining the curing mixture at 500 ℃, collecting a calcined product A, carrying out ultrasonic oscillation on the calcined product A, the mixed solvent and the wrapping agent according to the mass ratio of 10: 20-23: 6-13, freeze-drying, and collecting a freeze-dried product A to obtain the concrete expanding agent.

2. The preparation method of the concrete expanding agent according to claim 1, wherein the preparation method of the mixture in the step (1) comprises the following steps: stirring and mixing aluminum ash, barium oxide and nitric acid solution according to the mass ratio of 1: 0.1-0.3: 5-7, adding polyacrylamide accounting for 8-11% of the mass of the aluminum ash, stirring, standing, and spray drying to obtain a mixture.

3. The preparation method of the concrete expanding agent according to claim 1, wherein the additive in the step (1) is prepared by mixing ferric sulfate and ferrous chloride according to a mass ratio of 4: 3-6.

4. The preparation method of the concrete expanding agent according to claim 1, wherein the auxiliary material is a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and tung oil which are mixed according to a mass ratio of 3: 1-2.

5. The method for preparing a concrete expanding agent according to claim 1, wherein the pore-forming agent is any one of ammonium bicarbonate and sodium bicarbonate.

6. The method for preparing a concrete expansive agent according to claim 1, wherein the dispersant is any one of polyethylene glycol and fatty acid polyethylene glycol ester.

7. The preparation method of the concrete expanding agent according to claim 1, wherein the mixed solvent in the step (4) is a sodium hydroxide solution and acetone which are mixed according to a volume ratio of 8: 3-5.

8. The preparation method of the concrete expanding agent according to claim 1, wherein the wrapping agent in the step (4) is formed by mixing sodium alginate and maleic anhydride according to a mass ratio of 9: 2-4.

Technical Field

The invention relates to a preparation method of a concrete expanding agent, belonging to the technical field of concrete.

Background

Concrete is one of the most important civil engineering materials in the present generation, and is widely applied to aspects of the construction field. However, the concrete generally has a shrinkage phenomenon, which causes the concrete to crack and the performances of strength, seepage prevention, corrosion resistance and the like to be reduced. The concrete expanding agent as a novel concrete additive can react with cement and water to generate crystals with enlarged volume, so that the concrete expands in volume to generate certain prestress, thereby being beneficial to controlling the shrinkage and cracking of the concrete and protecting a concrete structure.

The concrete expanding agent can be widely applied to various fields such as underground parking lots, highway pavements, tunnels, foundation pits, bridge concrete surface layers, self-waterproof rigid roofs, house construction and the like. The ingredients can be classified as follows: calcium sulphoaluminate expanding agents, calcium oxide expanding agents, magnesium oxide expanding agents, calcium oxide-calcium sulphoaluminate composite expanding agents, composite fiber expanding agents and the like. Due to the shortage of mineral resources and the rising price, the expansion sources of calcium oxide and magnesium oxide are valued, developed and utilized by people. However, due to the inherent characteristics of the calcium oxide expanding agent, a large amount of water is consumed in hydration, certain influence is necessarily brought to the fluidity of the self-compacting concrete, especially the slump loss, and higher requirements are put forward on the selection of raw materials and the design of the mixing proportion.

The concrete expanding agent in the prior art as a shrinkage-compensating concrete material has the obvious defects that: the concrete has the problems of high hydration heat, large shrinkage deformation, low expansion rate, inconsistent expansion rate and concrete strength development, poor sustained stability of expansion effect and the like, and the phenomena of concrete cracking, leakage and the like are easy to occur.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: aiming at the problem that the continuous stability of the expansion effect of the concrete expanding agent is poor, the preparation method of the concrete expanding agent is provided.

In order to solve the technical problems, the invention adopts the following technical scheme:

a preparation method of a concrete expanding agent comprises the following steps:

(1) taking the mixture and a nitric acid solution to perform ultrasonic vibration according to the mass ratio of 3: 13-16, adding an additive accounting for 30-40% of the mass of the mixture, uniformly stirring, collecting a stirred mixture, and taking 130-150 parts of the stirred mixture, 30-40 parts of an auxiliary material, 20-25 parts of urea, 15-20 parts of a pore-forming agent and 3-6 parts of a dispersing agent according to parts by weight;

(2) firstly, putting a stirred mixture and urea into a reaction kettle, using nitrogen for protection, preheating, adding an auxiliary material, heating, using ammonia water to adjust the pH value to 8.0-8.5, cooling, adding a pore-forming agent and a dispersing agent, stirring and mixing, freeze-drying, calcining, and collecting a calcined substance;

(3) crushing the calcined substance, sieving, collecting sieved particles, ball-milling the sieved particles, phosphogypsum and calcium oxide according to a mass ratio of 4: 6-9: 3-7, collecting ball-milled substances, and putting the ball-milled substances into a curing box for steam curing at a set temperature of 100 ℃;

(4) and after curing is finished, collecting a curing mixture, calcining the curing mixture at 500 ℃, collecting a calcined product A, carrying out ultrasonic oscillation on the calcined product A, the mixed solvent and the wrapping agent according to the mass ratio of 10: 20-23: 6-13, freeze-drying, and collecting a freeze-dried product A to obtain the concrete expanding agent.

The preparation method of the mixture in the step (1) comprises the following steps: stirring and mixing aluminum ash, barium oxide and nitric acid solution according to the mass ratio of 1: 0.1-0.3: 5-7, adding polyacrylamide accounting for 8-11% of the mass of the aluminum ash, stirring, standing, and spray drying to obtain a mixture.

The preparation method of the additive in the step (1) is characterized in that ferric sulfate and ferrous chloride are mixed according to a mass ratio of 4: 3-6.

The auxiliary material is prepared by mixing polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and tung oil according to the mass ratio of 3: 1-2.

The pore-forming agent is any one of ammonium bicarbonate and sodium bicarbonate.

The dispersant is any one of polyethylene glycol and fatty acid polyglycol ester.

The mixed solvent in the step (4) is formed by mixing a sodium hydroxide solution and acetone according to a volume ratio of 8: 3-5.

The wrapping agent in the step (4) is formed by mixing sodium alginate and maleic anhydride according to a mass ratio of 9: 2-4.

Compared with other methods, the method has the beneficial technical effects that:

(1) the invention takes aluminum ash and barium oxide as basic raw materials, the aluminum ash and the barium oxide are dissolved by nitric acid, polyacrylamide is utilized for flocculation, metal ions in the aluminum ash and the barium oxide are in full contact, the aluminum ash and the barium oxide are stirred with mixed iron salt, porous high-activity alumina particles loaded with barium and magnetic particles are formed under the action of urea and pore-forming agent, then the calcium hydroxide and the calcium oxide are loaded in the porous particles, wrapping is carried out by using wrapping agent, when the calcium hydroxide and the calcium oxide are used, the wrapping material can be used by destroying the wrapping material, the wrapping material can aggregate calcium ions, then the excitation performance of the calcium hydroxide is promoted by using the porous particles with high activity, the aluminum oxide in the porous particles reacts with calcium sulfate to generate ettringite, and early expansion is provided for concrete, after the ettringite completely reacts, the free CaO left in the raw materials and the CaO in the added calcium source are continuously hydrated to cause the volume expansion of the concrete, so that the later-stage expansion is provided for the concrete, the expanding agent enables the volume of the concrete to be continuously and uniformly expanded, the early-stage and later-stage shrinkage of the concrete can be effectively compensated, the stability of a concrete structure is ensured, and the phosphogypsum has certain hydration activity and potential expansibility, and can be effectively used as a later-stage expansion source to compensate the later-stage shrinkage;

(2) the calcium hydroxide is generated by oxidation and calcification, and meanwhile, the phosphogypsum can continuously supplement the calcium oxide to increase OH in the slurry^-And Ca²⁺The concentration of the porous particles promotes the hydration of cement, improves the early strength of concrete, increases the surface area contacted with water under the action of the porous particles ground in the later period, promotes the effective performance of expansion performance, and can fill the gaps between aggregate and the hydration of the cement through the substances loaded by the porous particles, so that the gaps are refined, the porosity is reduced, the pore structure is improved, the compactness is increased, and the strength is improved.

Detailed Description

The preparation method of the mixture comprises the following steps: stirring and mixing aluminum ash, barium oxide and nitric acid solution according to the mass ratio of 1: 0.1-0.3: 5-7, adding polyacrylamide accounting for 8-11% of the mass of the aluminum ash, stirring at 800r/min for 30min, standing for 1-3 h, and spray drying to obtain a mixture.

The preparation method of the additive is characterized in that ferric sulfate and ferrous chloride are mixed according to the mass ratio of 4: 3-6.

The auxiliary material is a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and tung oil which are mixed according to the mass ratio of 3: 1-2 to obtain the high-performance polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer.

The pore-forming agent is one of ammonium bicarbonate and sodium bicarbonate.

The dispersant is any one of polyethylene glycol and fatty acid polyglycol ester.

The mixed solvent is formed by mixing sodium hydroxide solution and acetone according to the volume ratio of 8: 3-5.

The wrapping agent is formed by mixing sodium alginate and maleic anhydride according to a mass ratio of 9: 2-4.

A preparation method of a concrete expanding agent comprises the following steps:

(1) taking the mixture and a nitric acid solution according to a mass ratio of 3: 13-16, performing ultrasonic oscillation for 30min, adding an additive accounting for 30-40% of the mass of the mixture, uniformly stirring, and collecting a stirred mixture, wherein 130-150 parts by weight of the stirred mixture, 30-40 parts by weight of an auxiliary material, 20-25 parts by weight of urea, 15-20 parts by weight of a pore-forming agent and 3-6 parts by weight of a dispersing agent are taken;

(2) firstly, putting a stirred mixture and urea into a reaction kettle, using nitrogen for protection, preheating for 50min at 40-45 ℃, adding an auxiliary material, heating to 60-70 ℃, preserving heat for 5h, using ammonia water to adjust the pH value to 8.0-8.5, cooling to room temperature, adding a pore-forming agent and a dispersing agent, stirring and mixing, freeze-drying, calcining for 2h at 700 ℃, and collecting a calcined substance;

(3) crushing the calcined substance, sieving, collecting sieved particles, ball-milling the sieved particles, phosphogypsum and calcium oxide according to a mass ratio of 4: 6-9: 3-7, collecting ball-milled substances, putting the ball-milled substances into a curing box, and performing steam curing for 3 hours at a set temperature of 100 ℃;

(4) and after curing is finished, collecting a curing mixture, calcining the curing mixture at 500 ℃ for 2 hours, collecting a calcined product A, carrying out ultrasonic oscillation on the calcined product A, the mixed solvent and the wrapping agent according to the mass ratio of 10: 20-23: 6-13, freeze-drying, and collecting a freeze-dried product A to obtain the concrete expanding agent.

Example 1

The preparation method of the mixture comprises the following steps: stirring and mixing aluminum ash, barium oxide and nitric acid solution according to the mass ratio of 1:0.3:7, adding polyacrylamide accounting for 11% of the mass of the aluminum ash, stirring at the speed of 800r/min for 30min, standing for 3h, and spray drying to obtain a mixture.

The preparation method of the additive is to mix ferric sulfate and ferrous chloride according to the mass ratio of 4: 6.

The auxiliary material is prepared by mixing polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and tung oil according to the mass ratio of 3: 2.

The pore-forming agent is sodium bicarbonate.

The dispersant is fatty acid polyglycol ester.

The mixed solvent is prepared by mixing sodium hydroxide solution and acetone according to the volume ratio of 8: 5.

The wrapping agent is formed by mixing sodium alginate and maleic anhydride according to the mass ratio of 9: 4.

A preparation method of a concrete expanding agent comprises the following steps:

(1) taking the mixture and a nitric acid solution according to the mass ratio of 3:16, carrying out ultrasonic oscillation for 30min, adding an additive accounting for 40% of the mass of the mixture, uniformly stirring, and collecting a stirred mixture, wherein 150 parts of the stirred mixture, 40 parts of an auxiliary material, 25 parts of urea, 20 parts of a pore-forming agent and 6 parts of a dispersing agent are taken according to parts by weight;

(2) firstly, putting a stirred mixture and urea into a reaction kettle, using nitrogen for protection, preheating for 50min at 45 ℃, adding an auxiliary material, heating to 70 ℃, preserving heat for 5h, using ammonia water to adjust the pH value to 8.5, cooling to room temperature, adding a pore-forming agent and a dispersing agent, stirring, mixing, freeze-drying, calcining for 2h at 700 ℃, and collecting a calcined substance;

(3) crushing the calcined substance, sieving, collecting sieved particles, ball-milling the sieved particles, phosphogypsum and calcium oxide according to the mass ratio of 4:9:7, collecting ball-milled substances, putting the ball-milled substances into a curing box for steam curing for 3 hours, and setting the temperature to be 100 ℃;

(4) and after curing is finished, collecting a curing mixture, calcining the curing mixture at 500 ℃ for 2h, collecting a calcined product A, carrying out ultrasonic oscillation on the calcined product A, the mixed solvent and the wrapping agent according to the mass ratio of 10:23:13, freeze-drying, and collecting the freeze-dried product A to obtain the concrete expanding agent.

Example 2

The preparation method of the mixture comprises the following steps: stirring and mixing aluminum ash, barium oxide and nitric acid solution according to the mass ratio of 1:0.2:6, adding polyacrylamide accounting for 8-11% of the mass of the aluminum ash, stirring for 30min at the speed of 800r/min, standing for 2h, and spray drying to obtain a mixture.

The preparation method of the additive is to mix ferric sulfate and ferrous chloride according to the mass ratio of 4: 5.

The auxiliary material is prepared by mixing polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and tung oil according to the mass ratio of 3: 1.5.

The pore-forming agent is ammonium bicarbonate.

The dispersant is polyethylene glycol.

The mixed solvent is prepared by mixing sodium hydroxide solution and acetone according to the volume ratio of 8: 4.

The wrapping agent is formed by mixing sodium alginate and maleic anhydride according to the mass ratio of 9: 3.

A preparation method of a concrete expanding agent comprises the following steps:

(1) taking the mixture and a nitric acid solution according to the mass ratio of 3:15, carrying out ultrasonic oscillation for 30min, adding an additive accounting for 35% of the mass of the mixture, uniformly stirring, and collecting a stirred mixture, wherein 140 parts of the stirred mixture, 35 parts of an auxiliary material, 23 parts of urea, 18 parts of a pore-forming agent and 5 parts of a dispersing agent are taken according to parts by weight;

(2) firstly, putting a stirred mixture and urea into a reaction kettle, using nitrogen for protection, preheating for 50min at 43 ℃, adding an auxiliary material, heating to 65 ℃, preserving heat for 5h, adjusting the pH to 8.0 by using ammonia water, cooling to room temperature, adding a pore-forming agent and a dispersing agent, stirring, mixing, freeze-drying, calcining for 2h at 700 ℃, and collecting a calcined substance;

(3) crushing the calcined substance, sieving, collecting sieved particles, ball-milling the sieved particles, phosphogypsum and calcium oxide according to the mass ratio of 4:8:5, collecting ball-milled substances, putting the ball-milled substances into a curing box for steam curing for 3 hours, and setting the temperature to be 100 ℃;

(4) and after curing is finished, collecting a curing mixture, calcining the curing mixture at 500 ℃ for 2h, collecting a calcined product A, carrying out ultrasonic oscillation on the calcined product A, the mixed solvent and the wrapping agent according to the mass ratio of 10:21:10, freeze-drying, and collecting the freeze-dried product A to obtain the concrete expanding agent.

Example 3

The preparation method of the mixture comprises the following steps: stirring and mixing aluminum ash, barium oxide and nitric acid solution according to the mass ratio of 1:0.1:5, adding polyacrylamide with the mass of 8% of the aluminum ash, stirring for 30min at the speed of 800r/min, standing for 1h, and spray drying to obtain a mixture.

The preparation method of the additive is to mix ferric sulfate and ferrous chloride according to the mass ratio of 4: 3.

The auxiliary material is prepared by mixing polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and tung oil according to the mass ratio of 3:1.

The pore-forming agent is ammonium bicarbonate.

The dispersant is polyethylene glycol.

The mixed solvent is prepared by mixing sodium hydroxide solution and acetone according to the volume ratio of 8: 3.

The wrapping agent is formed by mixing sodium alginate and maleic anhydride according to the mass ratio of 9: 2.

A preparation method of a concrete expanding agent comprises the following steps:

(1) taking the mixture and a nitric acid solution according to the mass ratio of 3:13, carrying out ultrasonic oscillation for 30min, adding an additive accounting for 30% of the mass of the mixture, uniformly stirring, and collecting a stirred mixture, wherein 130 parts of the stirred mixture, 30 parts of an auxiliary material, 20 parts of urea, 15 parts of a pore-forming agent and 3 parts of a dispersing agent are taken according to parts by weight;

(2) firstly, putting a stirred mixture and urea into a reaction kettle, using nitrogen for protection, preheating for 50min at 40 ℃, adding an auxiliary material, heating to 60 ℃, preserving heat for 5h, adjusting the pH to 8.0 by using ammonia water, cooling to room temperature, adding a pore-forming agent and a dispersing agent, stirring, mixing, freeze-drying, calcining for 2h at 700 ℃, and collecting a calcined substance;

(3) crushing the calcined substance, sieving, collecting sieved particles, ball-milling the sieved particles, phosphogypsum and calcium oxide according to the mass ratio of 4:6:3, collecting ball-milled substances, putting the ball-milled substances into a curing box for steam curing for 3 hours, and setting the temperature to be 100 ℃;

(4) and after curing is finished, collecting a curing mixture, calcining the curing mixture at 500 ℃ for 2h, collecting a calcined product A, carrying out ultrasonic oscillation on the calcined product A, the mixed solvent and the wrapping agent according to the mass ratio of 10:20:6, freeze-drying, and collecting the freeze-dried product A to obtain the concrete expanding agent.

Comparative example 1

The preparation method of the additive is to mix ferric sulfate and ferrous chloride according to the mass ratio of 4: 5.

The auxiliary material is prepared by mixing polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and tung oil according to the mass ratio of 3: 1.5.

The pore-forming agent is ammonium bicarbonate.

The dispersant is polyethylene glycol.

The mixed solvent is prepared by mixing sodium hydroxide solution and acetone according to the volume ratio of 8: 4.

The wrapping agent is formed by mixing sodium alginate and maleic anhydride according to the mass ratio of 9: 3.

A preparation method of a concrete expanding agent comprises the following steps:

(1) according to the weight parts, 35 parts of auxiliary materials, 23 parts of urea, 18 parts of pore-forming agent and 5 parts of dispersing agent are taken;

(2) firstly, putting urea into a reaction kettle, using nitrogen for protection, preheating for 50min at 43 ℃, adding auxiliary materials, heating to 65 ℃, preserving heat for 5h, adjusting the pH to 8.0 by using ammonia water, cooling to room temperature, adding a pore-forming agent and a dispersing agent, stirring and mixing, freeze-drying, calcining for 2h at 700 ℃, and collecting calcined substances;

(3) crushing the calcined substance, sieving, collecting sieved particles, ball-milling the sieved particles, phosphogypsum and calcium oxide according to the mass ratio of 4:8:5, collecting ball-milled substances, putting the ball-milled substances into a curing box for steam curing for 3 hours, and setting the temperature to be 100 ℃;

(4) and after curing is finished, collecting a curing mixture, calcining the curing mixture at 500 ℃ for 2h, collecting a calcined product A, carrying out ultrasonic oscillation on the calcined product A, the mixed solvent and the wrapping agent according to the mass ratio of 10:21:10, freeze-drying, and collecting the freeze-dried product A to obtain the concrete expanding agent.

Comparative example 2

The preparation method of the mixture comprises the following steps: stirring and mixing aluminum ash, barium oxide and nitric acid solution according to the mass ratio of 1:0.2:6, adding polyacrylamide accounting for 8-11% of the mass of the aluminum ash, stirring for 30min at the speed of 800r/min, standing for 2h, and spray drying to obtain a mixture.

The auxiliary material is prepared by mixing polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and tung oil according to the mass ratio of 3: 1.5.

The pore-forming agent is ammonium bicarbonate.

The dispersant is polyethylene glycol.

The mixed solvent is prepared by mixing sodium hydroxide solution and acetone according to the volume ratio of 8: 4.

The wrapping agent is formed by mixing sodium alginate and maleic anhydride according to the mass ratio of 9: 3.

A preparation method of a concrete expanding agent comprises the following steps:

(1) taking the mixture and the nitric acid solution according to the mass ratio of 3:15, carrying out ultrasonic oscillation for 30min, uniformly stirring, collecting a stirred mixture, and taking 140 parts of the stirred mixture, 35 parts of auxiliary materials, 23 parts of urea, 18 parts of pore-forming agent and 5 parts of dispersing agent according to parts by weight;

(2) firstly, putting a stirred mixture and urea into a reaction kettle, using nitrogen for protection, preheating for 50min at 43 ℃, adding an auxiliary material, heating to 65 ℃, preserving heat for 5h, adjusting the pH to 8.0 by using ammonia water, cooling to room temperature, adding a pore-forming agent and a dispersing agent, stirring, mixing, freeze-drying, calcining for 2h at 700 ℃, and collecting a calcined substance;

(3) crushing the calcined substance, sieving, collecting sieved particles, ball-milling the sieved particles, phosphogypsum and calcium oxide according to the mass ratio of 4:8:5, collecting ball-milled substances, putting the ball-milled substances into a curing box for steam curing for 3 hours, and setting the temperature to be 100 ℃;

(4) and after curing is finished, collecting a curing mixture, calcining the curing mixture at 500 ℃ for 2h, collecting a calcined product A, carrying out ultrasonic oscillation on the calcined product A, the mixed solvent and the wrapping agent according to the mass ratio of 10:21:10, freeze-drying, and collecting the freeze-dried product A to obtain the concrete expanding agent.

The concrete expansive agents of examples 1 to 3 and comparative examples 1 to 2 were examined.

The concrete expanding agent prepared by the invention and the concrete expanding agent in the comparative example are detected, and the detection results are shown in table 1:

mechanical Property test

The test is carried out according to the standard regulation of the standard GB/T50081-2002 'test method for mechanical properties of common concrete'.

Limiting expansion Rate test

The limited expansion rate of the expanding agent is the key quality and technical index of the expanding agent product, and is determined according to the method specified in the current national standard of concrete expanding agent GB 23439-2009.

The samples of the examples and comparative examples prepared by the present invention were mixed with the same lot of cement mortar of the same quality and formed. And directly placing the molded test piece into a curing box with the temperature of 20 ℃ and the humidity of 60%, removing the mold for 16h to measure the initial length of the test piece, then placing the test piece into water to cure the test piece according to the age, and calculating the limited expansion rate.

Dry shrinkage test

The limited expansion rate of the compensating shrinkage concrete is an engineering design index, and is determined according to a method specified in the current national standard of technical Specification for concrete admixture application GB 50119-2013.

TABLE 1 measurement results of Properties

According to the data in the table 1, the concrete prepared by adding the concrete expanding agent can generate proper expansion, compensate the concrete shrinkage, greatly reduce the cracks caused by the concrete shrinkage, have good continuous and stable effect and have wide application prospect.