CN114163185A

CN114163185A - Elastic concrete and preparation method thereof

Info

Publication number: CN114163185A
Application number: CN202111397317.XA
Authority: CN
Inventors: 万建平; 程子豪
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-11-23
Filing date: 2021-11-23
Publication date: 2022-03-11

Abstract

The invention discloses elastic concrete which is characterized by being prepared from the following components in parts by weight: 30-35 parts of cement, 2-3 parts of sesbania powder, 8-10 parts of surface hydrophilic silicon rubber, 0.5-1.2 parts of carboxylic group modified amino-terminated water-soluble hyperbranched polyamide, 4-8 parts of silica residue powder, 8-10 parts of broken stone, 1-3 parts of rare earth porcelain sand, 4-6 parts of vermiculite tailings, 30-40 parts of fine river sand, 1-3 parts of hydrophilic feather fiber and 10-15 parts of water. The invention also discloses a preparation method of the elastic concrete. The elastic concrete disclosed by the invention has the advantages of good elasticity, high strength, good impermeability and compactness, sufficient toughness, and excellent aging resistance, durability and construction performance.

Description

Elastic concrete and preparation method thereof

Technical Field

The invention relates to the technical field of concrete materials, in particular to elastic concrete and a preparation method thereof.

Background

Along with the rapid development of economy and the deepening of modern construction, a great number of expressways, urban overpasses and high-speed railways emerge, the application of concrete is more and more, and the requirement on the performance of the concrete is higher and more. If it has a certain elasticity, it is required to ensure the durability of the road surface. The existing concrete has the characteristic of high compressive strength, but the existing concrete lacks toughness and has low flexural strength. Therefore, the expansion joint of the bridge is frequently loaded with heavy objects or is frequently pressed down by heavy force, and the surface is easy to crack and damage, so that construction workers need to frequently repair the expansion joint.

The elastic concrete is an engineering concrete material provided by American scholars in the late 80 th of the 20 th century, the engineering performance of the elastic concrete material is between that of ordinary concrete (rigidity) and that of asphalt concrete (flexibility), and the elastic concrete material integrates the characteristics of rubber and ordinary concrete. When the composite material is used for road engineering, on one hand, the elasticity of the road surface can be effectively improved, the noise of the road surface is reduced, and meanwhile, the construction cost is not greatly improved. Therefore, the development of the elastic concrete with excellent comprehensive performance has very important significance for improving the toughness and the breaking strength of common concrete and improving the durability of a pavement.

The existing elastic concrete is mostly prepared by adding rubber materials into common concrete, the rubber particles used in the elastic concrete are few, the elasticity is limited, the compatibility of the rubber particles and inorganic materials such as cement is poor, the caking property is low, and the strength, the impermeability and the compactness of the concrete are influenced. In addition, the elastic concrete on the market has the defects of poor ageing resistance, short service life and insufficient toughness.

The patent publication No. CN 16999256 discloses a composite additive for high-strength elastic concrete, which is composed of group A powder 65-75% of silicon dioxide, 2-10% of hydroxyl carboxylate, 10-20% of limestone powder, 0.1-0.8% of dispersant, 0.05-0.2% of water reducing agent and 3-6% of rubber powder. The group B liquid consists of: adding 20-300 g of polyacrylamide into 100L of water, and stirring to obtain polyacrylamide solution; adding 10-200 g of polyether into 100L of water, and stirring to obtain a polyether solution; mixing the polyether solution and the polyacrylamide solution in a ratio of 1:2-4, and stirring to obtain a group B liquid; the composite additive is mixed with concrete and filled into expansion joints of buildings such as bridges and the like to increase toughness, but when the mixing amount of rubber powder in the additive is large, the compression strength of the buildings at the expansion joints is seriously influenced, the mixing amount of rubber particles is not more than 6 percent, the elasticity of the buildings at the expansion joints is small, and the buildings are difficult to recover to the original flatness after being deformed by heavy pressure to generate depressions.

Therefore, the elastic concrete with good elasticity, high strength, good impermeability and compactness, sufficient toughness, excellent aging resistance, durability and construction performance and the preparation method thereof are still needed in the field.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides the elastic concrete which has good elasticity, high strength, good impermeability and compactness, sufficient toughness, and excellent aging resistance, durability and construction performance; meanwhile, the invention also provides a preparation method of the elastic concrete.

In order to achieve the purpose, the invention relates to elastic concrete which is characterized by being prepared from the following components in parts by weight: 30-35 parts of cement, 2-3 parts of sesbania powder, 8-10 parts of surface hydrophilic silicon rubber, 0.5-1.2 parts of carboxylic group modified amino-terminated water-soluble hyperbranched polyamide, 4-8 parts of silica residue powder, 8-10 parts of broken stone, 1-3 parts of rare earth porcelain sand, 4-6 parts of vermiculite tailings, 30-40 parts of fine river sand, 1-3 parts of hydrophilic feather fiber and 10-15 parts of water.

Preferably, the hydrophilic feather fibers can be any waste feather fibers with hydrophilic surfaces, such as hydrophilic feather fibers prepared by the method of example 1 of the chinese patent application No. 201710130403.1.

Preferably, the particle size of the vermiculite tailings is 50-150 meshes; the maximum grain size of the fine river sand is less than 2 mm.

Preferably, the particle size of the rare earth porcelain sand is 0.5-1mm, and the rare earth porcelain sand is purchased from Lenzhong Jindalai chemical filler Co.

Preferably, the crushed stone has a particle size of 5-10 mm.

Preferably, the particle size of the silicon slag powder is 50-100 meshes.

Preferably, the preparation method of the carboxylic acid group modified amino-terminated water-soluble hyperbranched polyamide comprises the following steps: adding chloropropionic diacid, amino-terminated water-soluble hyperbranched polyamide and a basic catalyst into a high-boiling point solvent, stirring and reacting for 4-6 hours at the temperature of 30-40 ℃, then performing rotary evaporation to remove the solvent, dissolving the product in deionized water, placing the product in a dialysis bag, dialyzing for 10-15 hours in the deionized water, and then performing rotary evaporation to remove the water in the dialysis bag to obtain the carboxylic group modified amino-terminated water-soluble hyperbranched polyamide.

Preferably, the mass ratio of the chloropropionic diacid to the amino-terminated water-soluble hyperbranched polyamide to the basic catalyst to the high-boiling-point solvent is (0.8-1.5) to (3-4) to (0.3-0.5) to (20-30).

Preferably, the amino-terminated water-soluble hyperbranched polyamide may be an amino-terminated water-soluble hyperbranched polyamide prepared according to the method in example 1 of CN 02111578.8.

Preferably, the basic catalyst is at least one of sodium carbonate and potassium carbonate; the high boiling point solvent is at least one of dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.

Preferably, the surface hydrophilic silicone rubber is the surface hydrophilic silicone rubber prepared by the method of chinese patent application No. 201210240295.0, inventive example 1.

Preferably, the particle size of the sesbania powder is 100-300 meshes.

Preferably, the cement is ordinary portland cement with one or more of the reference numbers 52.5, 52.5R, 62.5 or 62.5R.

Another object of the present invention is to provide a method for preparing the elastic concrete, which comprises the following steps: the components are uniformly mixed according to the parts by weight, ground, sieved by a 100-mesh and 200-mesh sieve, poured and vibrated, and then the test piece is subjected to standard maintenance or natural maintenance to obtain the elastic concrete.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:

(1) the preparation method of the elastic concrete provided by the invention has the advantages of simple process, convenience in construction and high preparation efficiency, and has low price due to effective utilization of the waste feather fiber, the silicon slag powder and the vermiculite tailings, and higher environmental protection value, economic value and social value.

(2) The elastic concrete provided by the invention overcomes the defects that the existing elastic concrete is mostly prepared by adding rubber materials into common concrete, the rubber particles used in the elastic concrete are few, the elasticity is limited, the rubber particles are poor in compatibility with inorganic materials such as cement and the like, the caking property is low, and the strength, the impermeability and the compactness of the concrete are influenced; in addition, the elastic concrete on the market has the defects of poor ageing resistance, short service life and insufficient toughness; through the synergistic effect of the components, the prepared concrete has good elasticity, high strength, good impermeability and compactness, sufficient toughness, and excellent aging resistance, durability and construction performance.

(3) According to the elastic concrete provided by the invention, the surface hydrophilic silicone rubber and the carboxyl-modified amino-terminated water-soluble hyperbranched polyamide have a synergistic effect, and due to the introduction of the hyperbranched structure and the silicone rubber structure, the concrete has better toughness and elasticity, so that the impact resistance of the material is improved. Meanwhile, the concrete can be endowed with excellent wear resistance and durability. The surface of the silicon rubber is modified in a hydrophilic manner, so that the silicon rubber has better compatibility with inorganic components, thereby enhancing the bonding property among the components of the concrete material and further improving the comprehensive performance and the performance stability of the concrete material. The carboxyl-modified amino-terminated water-soluble hyperbranched polyamide introduces carboxyl groups, can effectively improve the retarding and water reducing performances through the bridge adsorption effect, forms an internal network structure, effectively improves the comprehensive performance, and improves the waterproofness, the aging resistance and the breaking tensile strength.

(4) According to the elastic concrete provided by the invention, the addition of the sesbania powder can effectively improve the plasticity, the workability and the green strength of concrete slurry, improve the compatibility among all components and improve the anti-cracking and anti-permeability effects; the addition of the silicon slag powder, the broken stone, the rare earth porcelain sand, the vermiculite tailing sand and the fine river sand has a synergistic effect, so that the concrete is more compact, in addition, the shrinkage can be reduced, the damage of strong impact force to the member can be reduced, and the durability of the concrete member and the structure can be improved; improve the comprehensive performance and performance stability of the material.

(5) According to the elastic concrete provided by the invention, the strength of the concrete can be improved by adding the hydrophilic feather fibers, so that the elastic concrete has good anti-permeability performance and good durability; the raw materials are from waste feathers, and have wide sources and high ecological value.

Detailed Description

In order to make the technical solutions of the present invention better understood and make the above features, objects, and advantages of the present invention more comprehensible, the present invention is further described with reference to the following examples. The examples are intended to illustrate the invention only and are not intended to limit the scope of the invention; in the embodiment, the hydrophilic feather fiber is the hydrophilic feather fiber prepared by the method of the Chinese patent application No. 201710130403.1 in the embodiment 1; the amino-terminated water-soluble hyperbranched polyamide can be an amino-terminated water-soluble hyperbranched polyamide prepared by the method in example 1 of CN 02111578.8; the surface hydrophilic silicone rubber is prepared by the method of the Chinese patent application No. 201210240295.0 in the embodiment 1; the room temperature vulcanized silicone rubber in the comparative example was also room temperature vulcanized silicone rubber prepared by the method of chinese patent application No. 201210240295.0, inventive example 1.

Example 1

The elastic concrete is characterized by being prepared from the following components in parts by weight: 30 parts of cement, 2 parts of sesbania powder, 8 parts of surface hydrophilic silicone rubber, 0.5 part of carboxylic group modified amino-terminated water-soluble hyperbranched polyamide, 4 parts of silica slag powder, 8 parts of broken stone, 1 part of rare earth porcelain sand, 4 parts of vermiculite tailings, 30 parts of fine river sand, 1 part of hydrophilic feather fiber and 10 parts of water.

The particle size of the vermiculite tailings is 50 meshes; the maximum grain size of the fine river sand is less than 2 mm; the particle size of the rare earth porcelain sand is 0.5mm, and the rare earth porcelain sand is purchased from Pingxiang Jindalai chemical filler Co., Ltd; the particle size of the crushed stone is 5 mm; the grain diameter of the silicon slag powder is 50 meshes.

The preparation method of the carboxylic acid group modified amino-terminated water-soluble hyperbranched polyamide comprises the following steps: adding chloropropionic acid, amino-terminated water-soluble hyperbranched polyamide and a basic catalyst into a high-boiling point solvent, stirring and reacting for 4 hours at the temperature of 30 ℃, then performing rotary evaporation to remove the solvent, dissolving the product in deionized water, placing the product in a dialysis bag, dialyzing for 10 hours in the deionized water, and then performing rotary evaporation to remove water in the dialysis bag to obtain carboxylic group modified amino-terminated water-soluble hyperbranched polyamide; the mass ratio of the chloropropionic diacid to the amino-terminated water-soluble hyperbranched polyamide to the basic catalyst to the high-boiling-point solvent is 0.8:3:0.3: 20; the alkaline catalyst is sodium carbonate; the high boiling point solvent is dimethyl sulfoxide.

The grain diameter of the sesbania powder is 100 meshes; the cement is ordinary portland cement designated 52.5.

The preparation method of the elastic concrete is characterized by comprising the following steps: the components are uniformly mixed according to the parts by weight, ground, sieved by a 100-mesh sieve, poured and vibrated, and then the test piece is subjected to standard maintenance for 28 days to obtain the elastic concrete.

Example 2

The elastic concrete is characterized by being prepared from the following components in parts by weight: 32 parts of cement, 2.3 parts of sesbania powder, 8.5 parts of surface hydrophilic silicon rubber, 0.7 part of carboxylic group modified amino-terminated water-soluble hyperbranched polyamide, 5 parts of silicon slag powder, 8.5 parts of crushed stone, 1.5 parts of rare earth porcelain sand, 4.5 parts of vermiculite tailings, 32 parts of fine river sand, 1.5 parts of hydrophilic feather fiber and 11 parts of water.

The particle size of the vermiculite tailings is 70 meshes; the maximum grain size of the fine river sand is less than 2 mm; the particle size of the rare earth porcelain sand is 0.6mm, and the rare earth porcelain sand is purchased from Pingxiang Jindalai chemical filler Co., Ltd; the particle size of the crushed stone is 6 mm; the grain diameter of the silicon slag powder is 65 meshes.

The preparation method of the carboxylic acid group modified amino-terminated water-soluble hyperbranched polyamide comprises the following steps: adding chloropropionic acid, amino-terminated water-soluble hyperbranched polyamide and a basic catalyst into a high-boiling point solvent, stirring and reacting for 4.5 hours at 32 ℃, then performing rotary evaporation to remove the solvent, dissolving the product in deionized water, placing the product in a dialysis bag, dialyzing for 12 hours in the deionized water, and then performing rotary evaporation to remove water in the dialysis bag to obtain the carboxylic group modified amino-terminated water-soluble hyperbranched polyamide; the mass ratio of the chloropropionic diacid to the amino-terminated water-soluble hyperbranched polyamide to the basic catalyst to the high-boiling-point solvent is 1:3.2:0.35: 22; the alkaline catalyst is potassium carbonate; the high boiling point solvent is N, N-dimethylformamide.

The grain diameter of the sesbania powder is 150 meshes; the cement is ordinary portland cement with the reference number of 52.5R.

The preparation method of the elastic concrete is characterized by comprising the following steps: the components are uniformly mixed according to the parts by weight, ground, sieved by a 120-mesh sieve, poured and vibrated, and then the test piece is naturally cured for 28 days to obtain the elastic concrete.

Example 3

The elastic concrete is characterized by being prepared from the following components in parts by weight: 33 parts of cement, 2.5 parts of sesbania powder, 9 parts of surface hydrophilic silicon rubber, 0.9 part of carboxylic group modified amino-terminated water-soluble hyperbranched polyamide, 6 parts of silicon slag powder, 9 parts of broken stone, 2 parts of rare earth porcelain sand, 5 parts of vermiculite tailings, 35 parts of fine river sand, 2 parts of hydrophilic feather fiber and 13 parts of water.

The particle size of the vermiculite tailings is 100 meshes; the maximum grain size of the fine river sand is less than 2 mm; the particle size of the rare earth porcelain sand is 0.8mm, and the rare earth porcelain sand is purchased from Pingxiang Jindalai chemical filler Co., Ltd; the particle size of the crushed stone is 7 mm; the grain diameter of the silicon slag powder is 80 meshes.

The preparation method of the carboxylic acid group modified amino-terminated water-soluble hyperbranched polyamide comprises the following steps: adding chloropropionic acid, amino-terminated water-soluble hyperbranched polyamide and a basic catalyst into a high-boiling point solvent, stirring and reacting for 5 hours at 35 ℃, then performing rotary evaporation to remove the solvent, dissolving the product in deionized water, placing the product in a dialysis bag, dialyzing for 13 hours in the deionized water, and then performing rotary evaporation to remove water in the dialysis bag to obtain the carboxylic group modified amino-terminated water-soluble hyperbranched polyamide; the mass ratio of the chloropropionic diacid to the amino-terminated water-soluble hyperbranched polyamide to the basic catalyst to the high-boiling-point solvent is 1.1:3.5:0.4: 25; the alkaline catalyst is potassium carbonate; the high boiling point solvent is N, N-dimethylacetamide.

The grain diameter of the sesbania powder is 200 meshes; the cement is ordinary portland cement designated 62.5.

The preparation method of the elastic concrete is characterized by comprising the following steps: the components are uniformly mixed according to the parts by weight, ground, sieved by a 150-mesh sieve, poured and vibrated, and then the test piece is subjected to standard maintenance for 28 days to obtain the elastic concrete.

Example 4

The elastic concrete is characterized by being prepared from the following components in parts by weight: 34 parts of cement, 2.8 parts of sesbania powder, 9.5 parts of surface hydrophilic silicon rubber, 1.1 parts of carboxylic group modified amino-terminated water-soluble hyperbranched polyamide, 7 parts of silica slag powder, 9.5 parts of crushed stone, 2.5 parts of rare earth porcelain sand, 5.5 parts of vermiculite tailings, 38 parts of fine river sand, 2.5 parts of hydrophilic feather fiber and 14 parts of water.

The particle size of the vermiculite tailings is 130 meshes; the maximum grain size of the fine river sand is less than 2 mm; the particle size of the rare earth porcelain sand is 0.9mm, and the rare earth porcelain sand is purchased from Pingxiang Jindalai chemical filler Co., Ltd; the particle size of the crushed stone is 9 mm; the grain diameter of the silicon slag powder is 90 meshes.

The preparation method of the carboxylic acid group modified amino-terminated water-soluble hyperbranched polyamide comprises the following steps: adding chloropropionic acid, amino-terminated water-soluble hyperbranched polyamide and a basic catalyst into a high-boiling point solvent, stirring and reacting for 5.5 hours at 38 ℃, then performing rotary evaporation to remove the solvent, dissolving the product in deionized water, placing the product in a dialysis bag, dialyzing for 14 hours in the deionized water, and then performing rotary evaporation to remove water in the dialysis bag to obtain the carboxylic group modified amino-terminated water-soluble hyperbranched polyamide; the mass ratio of the chloropropionic diacid to the amino-terminated water-soluble hyperbranched polyamide to the basic catalyst to the high-boiling-point solvent is 1.3:3.8:0.45: 28; the alkaline catalyst is formed by mixing sodium carbonate and potassium carbonate according to the mass ratio of 3: 5; the high boiling point solvent is formed by mixing dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone according to a mass ratio of 1:2:2: 3.

The grain size of the sesbania powder is 250 meshes; the cement is prepared by mixing common Portland cement with the labels of 52.5, 52.5R, 62.5 and 62.5R according to the mass ratio of 1:1:3: 2.

The preparation method of the elastic concrete is characterized by comprising the following steps: the components are uniformly mixed according to the parts by weight, ground, sieved by a 180-mesh sieve, poured and vibrated, and then the test piece is naturally cured for 28 days to obtain the elastic concrete.

Example 5

The elastic concrete is characterized by being prepared from the following components in parts by weight: 35 parts of cement, 3 parts of sesbania powder, 10 parts of surface hydrophilic silicone rubber, 1.2 parts of carboxylic group modified amino-terminated water-soluble hyperbranched polyamide, 8 parts of silica slag powder, 10 parts of broken stone, 3 parts of rare earth porcelain sand, 6 parts of vermiculite tailings, 40 parts of fine river sand, 3 parts of hydrophilic feather fiber and 15 parts of water.

The particle size of the vermiculite tailings is 150 meshes; the maximum grain size of the fine river sand is less than 2 mm; the particle size of the rare earth porcelain sand is 1mm, and the rare earth porcelain sand is purchased from Pingxiang Jindalai chemical filler Co., Ltd; the particle size of the crushed stone is 10 mm; the grain diameter of the silicon slag powder is 100 meshes.

The preparation method of the carboxylic acid group modified amino-terminated water-soluble hyperbranched polyamide comprises the following steps: adding chloropropionic acid, amino-terminated water-soluble hyperbranched polyamide and a basic catalyst into a high-boiling point solvent, stirring and reacting for 6 hours at 40 ℃, then performing rotary evaporation to remove the solvent, dissolving the product in deionized water, placing the product in a dialysis bag, dialyzing for 15 hours in the deionized water, and then performing rotary evaporation to remove water in the dialysis bag to obtain the carboxylic group modified amino-terminated water-soluble hyperbranched polyamide; the mass ratio of the chloropropionic diacid to the amino-terminated water-soluble hyperbranched polyamide to the basic catalyst to the high-boiling-point solvent is 1.5:4:0.5: 30; the alkaline catalyst is sodium carbonate; the high boiling point solvent is N-methyl pyrrolidone.

The grain diameter of the sesbania powder is 300 meshes; the cement is ordinary portland cement with the reference number of 62.5R.

The preparation method of the elastic concrete is characterized by comprising the following steps: the components are uniformly mixed according to the parts by weight, ground, sieved by a 200-mesh sieve, poured and vibrated, and then the test piece is subjected to standard maintenance for 28 days to obtain the elastic concrete.

Comparative example 1

The formula and preparation method of the elastic concrete are basically the same as those of example 1, except that sesbania powder and rare earth porcelain sand are not added.

Comparative example 2

An elastic concrete having substantially the same formulation and preparation method as in example 1, except that no silica slag powder and no vermiculite tailings were added.

Comparative example 3

An elastic concrete having substantially the same formulation and preparation as in example 1 except that a surface hydrophilic silicone rubber was replaced with a room temperature vulcanized silicone rubber.

Comparative example 4

The formula and the preparation method of the elastic concrete are basically the same as those of the elastic concrete in example 1, except that a polycarboxylic acid water reducing agent SP409 is used for replacing carboxylic acid group modified amino-terminated water-soluble hyperbranched polyamide.

Comparative example 5

An elastic concrete having substantially the same formulation and preparation method as in example 1, except that no hydrophilic feather fibers were added.

In order to further illustrate the beneficial technical effects of the elastic concrete in the embodiments of the invention, the elastic concrete in the embodiments 1-5 and the comparative examples 1-5 is subjected to related performance tests, the test methods are described in GB/T50081-2002 Standard test methods for mechanical Properties of common concrete, and the test results are shown in Table 1.

TABLE 1 Properties of samples of examples and comparative examples

Item	Compressive strength (MPa)	Modulus of elasticity (GPa)
			Example 1	58.8	57.2
Example 2	61.2	55.4
			Example 3	65.0	55.0
Example 4	63.4	53.6
			Example 5	66.3	52.8
Comparative example 1	54.6	56.1
			Comparative example 2	53.4	55.3
Comparative example 3	52.7	49.7
			Comparative example 4	56.1	51.9
Comparative example 5	55.3	56.5

As can be seen from Table 1, the elastic concrete disclosed by the invention has higher compressive strength and elastic modulus, which are the result of the synergistic action of the components; the addition of the surface hydrophilic silicone rubber and the carboxylic group modified amino-terminated water-soluble hyperbranched polyamide has an obvious effect of improving the elasticity of concrete.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The elastic concrete is characterized by being prepared from the following components in parts by weight: 30-35 parts of cement, 2-3 parts of sesbania powder, 8-10 parts of surface hydrophilic silicon rubber, 0.5-1.2 parts of carboxylic group modified amino-terminated water-soluble hyperbranched polyamide, 4-8 parts of silica residue powder, 8-10 parts of broken stone, 1-3 parts of rare earth porcelain sand, 4-6 parts of vermiculite tailings, 30-40 parts of fine river sand, 1-3 parts of hydrophilic feather fiber and 10-15 parts of water.

2. The elastic concrete according to claim 1, wherein the particle size of the vermiculite tailings is 50-150 meshes; the maximum grain size of the fine river sand is less than 2 mm.

3. The elastic concrete according to claim 1, wherein the rare earth porcelain sand has a particle size of 0.5-1 mm.

4. The elastic concrete according to claim 1, wherein the crushed stone has a particle size of 5 to 10 mm; the grain diameter of the silicon slag powder is 50-100 meshes.

5. The elastic concrete according to claim 1, wherein the preparation method of the carboxylic acid group modified amino-terminated water-soluble hyperbranched polyamide comprises the following steps: adding chloropropionic diacid, amino-terminated water-soluble hyperbranched polyamide and a basic catalyst into a high-boiling point solvent, stirring and reacting for 4-6 hours at the temperature of 30-40 ℃, then performing rotary evaporation to remove the solvent, dissolving the product in deionized water, placing the product in a dialysis bag, dialyzing for 10-15 hours in the deionized water, and then performing rotary evaporation to remove the water in the dialysis bag to obtain the carboxylic group modified amino-terminated water-soluble hyperbranched polyamide.

6. The elastic concrete of claim 5, wherein the mass ratio of the chloropropionic acid, the amino-terminated water-soluble hyperbranched polyamide, the basic catalyst and the high-boiling-point solvent is (0.8-1.5): (3-4): (0.3-0.5): (20-30).

7. The elastic concrete according to claim 5, wherein the basic catalyst is at least one of sodium carbonate and potassium carbonate; the high boiling point solvent is at least one of dimethyl sulfoxide, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.

8. The elastic concrete as claimed in claim 1, wherein the sesbania powder has a particle size of 100-300 mesh.

9. An elastic concrete according to claim 1, characterised in that said cement is ordinary portland cement with one or more of the references 52.5, 52.5R, 62.5 or 62.5R.

10. A method for preparing an elastic concrete according to any one of claims 1 to 9, characterized in that it comprises the following steps: the components are uniformly mixed according to the parts by weight, ground, sieved by a 100-mesh and 200-mesh sieve, poured and vibrated, and then the test piece is subjected to standard maintenance or natural maintenance to obtain the elastic concrete.