Building gravel aggregate concrete and preparation method thereof

Abstract

The invention discloses building gravel aggregate concrete and a preparation method thereof, and relates to the technical field of concrete. According to the scheme, building macadam, coal gangue and sand are used as aggregate, cement, modified steel fibers, fly ash, water, a water reducing agent and other components are added, epoxy resin mixed liquid is doped in the aggregate, the high-strength concrete is obtained, the dosage of all the components is limited, polymer coating modification is conducted on the coal gangue and the steel fibers, and the high-strength concrete is obtained. The finally obtained concrete has excellent compressive strength and breaking strength, and due to the existence of the epoxy resin mixed solution, the wear resistance and chloride ion corrosion resistance of the concrete are both improved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, in particular to a building crushed stone aggregate concrete and a preparation method thereof. Background Art

[0002] With the rapid development of industrialization in my country, the transportation industry has also progressed rapidly, and the consumption of cement concrete has become increasingly larger. Nowadays, the main research point of concrete is its mechanical properties, such as compressive strength, flexural strength, etc., or for special projects, such as water conservancy, underground foundations, roof waterproofing and other fields, to improve the concrete's anti-seepage performance.

[0003] The mechanical properties and corrosion resistance of concrete materials currently on the market cannot meet the requirements of practical applications. Therefore, in order to improve the comprehensive performance of concrete, polymers are generally used to modify concrete. Commonly used polymers are emulsions such as epoxy resins or polyurethanes. Based on this situation, this application attempts to provide a building crushed stone aggregate concrete and a preparation method thereof to achieve an improvement in the comprehensive performance of concrete. Summary of the invention

[0004] The object of the present invention is to provide a building crushed stone aggregate concrete and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing building crushed stone aggregate concrete, comprising the following steps:

[0006] Step (1): dopamine and Tris-HCl buffer are mixed and stirred to obtain a dopamine solution; coal gangue or steel fiber is placed in the dopamine solution, allowed to stand at 30-35° C. for 6-8 hours, rinsed with deionized water, and vacuum dried at 50-60° C. to obtain pretreated coal gangue or pretreated steel fiber;

[0007] Step (2): performing surface polymer modification on the pretreated coal gangue or pretreated steel fiber to obtain modified coal gangue or modified steel fiber;

[0008] The surface polymer modification step comprises: placing the raw material in isopropanol, adding polyvinyl pyrrolidone, stirring evenly, adding reaction monomer A and catalyst, reacting at 25-30°C for 4-6h, then adding reaction monomer B, continuing to react for 6-8h, washing after the reaction, and vacuum drying at 50-60°C; the reaction monomer A is pentaerythritol tetrakis-3-mercaptopropionate and polypropylene glycol diglycidyl ether; the reaction monomer B is triethylenetetramine and polypropylene glycol diglycidyl ether;

[0009] Step (3): mixing the epoxy resin and the curing agent, stirring evenly to obtain an epoxy resin mixed solution;

[0010] The epoxy resin mixed liquid, cement, modified coal gangue, building crushed stone, modified steel fiber, fly ash, sand, water and water reducing agent are mixed and stirred evenly to obtain high-strength concrete.

[0011] In a more optimized solution, in step (1), the preparation method of Tris-HCl buffer is: mixing Tris reagent with deionized water, stirring until dissolved, and adjusting the pH to 8.5 to obtain Tris-HCl buffer; the concentration of the dopamine solution is 2 to 3 g / L.

[0012] According to a more optimized scheme, in step (2), in reaction monomer A, the molar ratio of the mercapto group of pentaerythritol tetrakis-3-mercaptopropionate and the epoxy group of polypropylene glycol diglycidyl ether is 1:1; in reaction monomer B, the molar ratio of triethylenetetramine and polypropylene glycol diglycidyl ether is (2-3):1; and the molar ratio of polypropylene glycol diglycidyl ether in reaction monomer A and polypropylene glycol diglycidyl ether in reaction monomer B is 1:1.

[0013] In a more optimized solution, in step (3), the amounts of the components are: by mass, 380-420 parts of cement, 900-1050 parts of modified coal gangue, 200-300 parts of building gravel, 15-25 parts of modified steel fiber, 60-70 parts of fly ash, 630-680 parts of sand, 160-185 parts of water, and 3-5 parts of water reducer; the epoxy resin mixture is 6-8wt% of the total mass of the system.

[0014] A more optimized scheme, in step (3), the preparation steps of the curing agent are: polypropylene glycol diglycidyl ether and triethylenetetramine are mixed, heated to 60-65°C under a nitrogen environment, reacted for 4-5 hours, distilled under reduced pressure, and then slowly dripped with propylene glycol methyl ether solution of epoxy resin, continued to react for 3-4 hours, added phenyl glycidyl ether, kept warm at 65-70°C for 2-3 hours, diluted with deionized water, and obtained a curing agent with a solid content of 40-50%.

[0015] In a more optimized solution, the molar ratio of the polypropylene glycol diglycidyl ether to triethylenetetramine is 1:(2.4-2.6); the molar ratio of the polypropylene glycol diglycidyl ether, epoxy resin, and phenyl glycidyl ether is (0.8-1):1:1.

[0016] In a more optimized solution, in step (3), the epoxy resin is E-44; and the water reducer is a polycarboxylic acid water reducer.

[0017] A more optimized solution is a building crushed stone aggregate concrete prepared according to any of the preparation methods described above.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0019] The invention discloses a building crushed stone aggregate concrete and a preparation method thereof. The scheme uses building crushed stone, coal gangue and sand as aggregates, adds components such as cement, modified steel fiber, fly ash, water and water reducing agent, and dopes the concrete with epoxy resin mixed liquid to obtain high-strength concrete. The scheme limits the amount of each component, and performs polymer coating modification on the coal gangue and steel fiber. The finally obtained concrete has excellent compressive strength and flexural strength, and due to the presence of the epoxy resin mixed liquid, the wear resistance and chloride ion corrosion resistance of the concrete are improved.

[0020] In this scheme, the present application preliminarily deposits polydopamine on coal gangue or steel fiber, and then uses polydopamine to provide active sites, and polymerizes monomers on its surface. The scheme defines that the reaction monomer A is pentaerythritol tetra-3-mercaptopropionate and polypropylene glycol diglycidyl ether, and uses mercapto and epoxy groups to click to polymerize on the surface of the matrix to form polymer particles, and then uses reaction monomer B to coat, and reaction monomer B is limited to reaction monomer B is triethylenetetramine and polypropylene glycol diglycidyl ether, to obtain modified coal gangue or modified steel fiber, the prepared modified coal gangue or modified steel fiber has improved dispersibility, and can be cross-linked with the epoxy resin mixed liquid in the system, thereby improving the internal cross-linking system of concrete, and further improving the chloride ion corrosion resistance and mechanical properties of concrete. In this process, the scheme defines the molar ratio of triethylenetetramine and polypropylene glycol diglycidyl ether as (2-3): 1, and the excess amino group is used to further allow the coal gangue or steel fiber to participate in the cross-linking system in the concrete.

[0021] On this basis, the scheme also limits the curing agent in the epoxy resin mixture, utilizes the reaction of polypropylene glycol diglycidyl ether and triethylenetetramine, then adds epoxy resin for cross-linking, and finally uses phenyl glycidyl ether for end-capping. The epoxy resin here is E-44, which is the same as the main resin in the epoxy resin mixture, so as to improve the compatibility of the curing agent in the system. At the same time, polypropylene glycol diglycidyl ether and triethylenetetramine are selected to react here, and polypropylene glycol diglycidyl ether and triethylenetetramine are also polymerized in the modification process of modified coal gangue or modified steel fiber, so as to improve the compatibility of aggregate in concrete and improve the effect of aggregate-epoxy resin cross-linking system, so as to obtain concrete with the best mechanical properties. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In this embodiment, the preparation method of Tris-HCl buffer is as follows: 1.2g Tris reagent is mixed with 1L deionized water, stirred until dissolved, and the pH is adjusted to 8.5 to obtain Tris-HCl buffer. The epoxy resins are all E-44; the polypropylene glycol diglycidyl ether is item number P135735, provided by Aladdin; the water reducer is a polycarboxylic acid water reducer, model SPC-100. The particle size of coal gangue is 8-10mm; the steel fiber is 13mm long, 0.22mm in diameter, and has a tensile strength of 2850MPa; the cement is silicate cement P.O42.5; the fly ash is first-grade fly ash, with a specific surface area of ​​695m 2 / Kg; the sand is river sand, the fineness modulus is 2.7, and the apparent density is 2.67g / cm 3 , bulk density is 1.51g / cm 3 The building gravel is obtained by crushing and screening the waste concrete, with a particle size distribution of 4.75-9.5 mm and an apparent density of 2580 kg / cm 3 , bulk density is 1700g / cm 3 , the crushing index is 25% and the mud content is 4.5%.

[0024] Embodiment 1: A method for preparing building crushed stone aggregate concrete, comprising the following steps:

[0025] Step (1): dopamine and Tris-HCl buffer are mixed and stirred to obtain a dopamine solution; coal gangue or steel fiber is placed in the dopamine solution, allowed to stand for 8 hours at 30° C., rinsed with deionized water, and vacuum dried at 60° C. to obtain pretreated coal gangue or pretreated steel fiber; the concentration of the dopamine solution is 2 g / L.

[0026] Step (2): performing surface polymer modification on the pretreated coal gangue or pretreated steel fiber to obtain modified coal gangue or modified steel fiber;

[0027] The surface polymer modification step is as follows: placing the raw material in 50 mL of isopropanol, adding 2 g of polyvinyl pyrrolidone, stirring evenly, adding reaction monomer A and 0.5 mL of catalyst, reacting at 25°C for 6 h, then adding reaction monomer B, continuing the reaction for 6 h, cleaning after the reaction, and vacuum drying at 60°C; the reaction monomer A is 1 mmol of pentaerythritol tetra-3-mercaptopropionate and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of the mercapto group of the pentaerythritol tetra-3-mercaptopropionate to the epoxy group of the polypropylene glycol diglycidyl ether is 1:1; the reaction monomer B is 5 mmol of triethylenetetramine and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of triethylenetetramine to polypropylene glycol diglycidyl ether is 2.5:1; the molar ratio of the polypropylene glycol diglycidyl ether in the reaction monomer A and the polypropylene glycol diglycidyl ether in the reaction monomer B is 1:1. The catalyst is 1,8-diazabicycloundec-7-ene.

[0028] Step (3): In parts by mass, epoxy resin and curing agent are mixed and stirred evenly to obtain an epoxy resin mixed solution; the mass ratio of the epoxy resin to the curing agent is 1.1:1.

[0029] The preparation steps of the curing agent are as follows: polypropylene glycol diglycidyl ether and triethylenetetramine are mixed, heated to 60°C in a nitrogen environment, reacted for 5 hours, distilled under reduced pressure, and then slowly dripped with propylene glycol methyl ether solution of epoxy resin, continued to react for 3 hours, added phenyl glycidyl ether, kept warm at 65°C for 3 hours, diluted with deionized water, and obtained a curing agent with a solid content of 50%. The molar ratio of polypropylene glycol diglycidyl ether to triethylenetetramine is 1:2.6; the molar ratio of polypropylene glycol diglycidyl ether, epoxy resin, and phenyl glycidyl ether is 0.8:1:1.

[0030] The epoxy resin mixture, 395 parts of cement, 1050 parts of modified coal gangue, 210 parts of building gravel, 20 parts of modified steel fiber, 70 parts of fly ash, 630 parts of sand, 185 parts of water and 4 parts of water reducing agent were mixed and stirred evenly to obtain high-strength concrete. The epoxy resin mixture is 6wt% of the total mass of the system.

[0031] Embodiment 2: A method for preparing building crushed stone aggregate concrete, comprising the following steps:

[0032] Step (1): dopamine and Tris-HCl buffer are mixed and stirred to obtain a dopamine solution; coal gangue or steel fiber is placed in the dopamine solution, allowed to stand for 7 hours at 35° C., rinsed with deionized water, and vacuum dried at 60° C. to obtain pretreated coal gangue or pretreated steel fiber; the concentration of the dopamine solution is 2 g / L.

[0033] Step (2): performing surface polymer modification on the pretreated coal gangue or pretreated steel fiber to obtain modified coal gangue or modified steel fiber;

[0034] The surface polymer modification step is as follows: placing the raw material in 50 mL of isopropanol, adding 2 g of polyvinyl pyrrolidone, stirring evenly, adding reaction monomer A and 0.5 mL of catalyst, reacting at 25°C for 5 h, then adding reaction monomer B, continuing the reaction for 7 h, cleaning after the reaction, and vacuum drying at 60°C; the reaction monomer A is 1 mmol of pentaerythritol tetra-3-mercaptopropionate and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of the mercapto group of the pentaerythritol tetra-3-mercaptopropionate to the epoxy group of the polypropylene glycol diglycidyl ether is 1:1; the reaction monomer B is 5 mmol of triethylenetetramine and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of triethylenetetramine to polypropylene glycol diglycidyl ether is 2.5:1; the molar ratio of the polypropylene glycol diglycidyl ether in the reaction monomer A and the polypropylene glycol diglycidyl ether in the reaction monomer B is 1:1. The catalyst is 1,8-diazabicycloundec-7-ene.

[0035] Step (3): In parts by mass, epoxy resin and curing agent are mixed and stirred evenly to obtain an epoxy resin mixed solution; the mass ratio of the epoxy resin to the curing agent is 1.1:1.

[0036] The preparation steps of the curing agent are as follows: polypropylene glycol diglycidyl ether and triethylenetetramine are mixed, heated to 65°C in a nitrogen environment, reacted for 4.5 hours, distilled under reduced pressure, and then slowly dripped with a propylene glycol methyl ether solution of epoxy resin, continued to react for 4 hours, added phenyl glycidyl ether, kept warm at 65°C for 2.5 hours, and diluted with deionized water to obtain a curing agent with a solid content of 50%. The molar ratio of polypropylene glycol diglycidyl ether to triethylenetetramine is 1:2.6; the molar ratio of polypropylene glycol diglycidyl ether, epoxy resin, and phenyl glycidyl ether is 0.8:1:1.

[0037] The epoxy resin mixture, 395 parts of cement, 1050 parts of modified coal gangue, 210 parts of building crushed stone, 20 parts of modified steel fiber, 70 parts of fly ash, 630 parts of sand, 185 parts of water and 4 parts of water reducing agent were mixed and stirred evenly to obtain high-strength concrete. The epoxy resin mixture was 7wt% of the total mass of the system.

[0038] Embodiment 3: A method for preparing building crushed stone aggregate concrete, comprising the following steps:

[0039] Step (1): dopamine and Tris-HCl buffer are mixed and stirred to obtain a dopamine solution; coal gangue or steel fiber is placed in the dopamine solution, allowed to stand for 8 hours at 35° C., rinsed with deionized water, and vacuum dried at 60° C. to obtain pretreated coal gangue or pretreated steel fiber; the concentration of the dopamine solution is 2 g / L.

[0040] Step (2): performing surface polymer modification on the pretreated coal gangue or pretreated steel fiber to obtain modified coal gangue or modified steel fiber;

[0041] The surface polymer modification step is as follows: placing the raw material in 50 mL of isopropanol, adding 2 g of polyvinyl pyrrolidone, stirring evenly, adding reaction monomer A and 0.5 mL of catalyst, reacting at 30°C for 4 h, then adding reaction monomer B, continuing the reaction for 8 h, cleaning after the reaction, and vacuum drying at 60°C; the reaction monomer A is 1 mmol of pentaerythritol tetra-3-mercaptopropionate and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of the mercapto group of the pentaerythritol tetra-3-mercaptopropionate to the epoxy group of the polypropylene glycol diglycidyl ether is 1:1; the reaction monomer B is 5 mmol of triethylenetetramine and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of triethylenetetramine to polypropylene glycol diglycidyl ether is 2.5:1; the molar ratio of the polypropylene glycol diglycidyl ether in the reaction monomer A and the polypropylene glycol diglycidyl ether in the reaction monomer B is 1:1. The catalyst is 1,8-diazabicycloundec-7-ene.

[0042] Step (3): In parts by mass, epoxy resin and curing agent are mixed and stirred evenly to obtain an epoxy resin mixed solution; the mass ratio of the epoxy resin to the curing agent is 1.1:1.

[0043] The preparation steps of the curing agent are as follows: polypropylene glycol diglycidyl ether and triethylenetetramine are mixed, heated to 65°C under nitrogen environment, reacted for 4 hours, distilled under reduced pressure, and then slowly dripped with propylene glycol methyl ether solution of epoxy resin, continued to react for 4 hours, added phenyl glycidyl ether, kept warm at 70°C for 2 hours, and diluted with deionized water to obtain a curing agent with a solid content of 50%. The molar ratio of polypropylene glycol diglycidyl ether to triethylenetetramine is 1:2.6; the molar ratio of polypropylene glycol diglycidyl ether, epoxy resin, and phenyl glycidyl ether is 0.8:1:1.

[0044] The epoxy resin mixture, 395 parts of cement, 1050 parts of modified coal gangue, 210 parts of building crushed stone, 20 parts of modified steel fiber, 70 parts of fly ash, 630 parts of sand, 185 parts of water and 4 parts of water reducing agent were mixed and stirred evenly to obtain high-strength concrete. The epoxy resin mixture was 8wt% of the total mass of the system.

[0045] Comparative Example 1: Compared with Comparative Example 3, in Comparative Example 1, the steel fiber was not modified by polymer.

[0046] A method for preparing building crushed stone aggregate concrete comprises the following steps:

[0047] Step (1): dopamine and Tris-HCl buffer are mixed and stirred to obtain a dopamine solution; coal gangue or steel fiber is placed in the dopamine solution, allowed to stand for 8 hours at 35° C., rinsed with deionized water, and vacuum dried at 60° C. to obtain pretreated coal gangue or pretreated steel fiber; the concentration of the dopamine solution is 2 g / L.

[0048] Step (2): modifying the surface of the pretreated coal gangue with a polymer to obtain modified coal gangue;

[0049] The surface polymer modification step is as follows: placing the raw material in 50 mL of isopropanol, adding 2 g of polyvinyl pyrrolidone, stirring evenly, adding reaction monomer A and 0.5 mL of catalyst, reacting at 30°C for 4 h, then adding reaction monomer B, continuing the reaction for 8 h, cleaning after the reaction, and vacuum drying at 60°C; the reaction monomer A is 1 mmol of pentaerythritol tetra-3-mercaptopropionate and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of the mercapto group of the pentaerythritol tetra-3-mercaptopropionate to the epoxy group of the polypropylene glycol diglycidyl ether is 1:1; the reaction monomer B is 5 mmol of triethylenetetramine and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of triethylenetetramine to polypropylene glycol diglycidyl ether is 2.5:1; the molar ratio of the polypropylene glycol diglycidyl ether in the reaction monomer A and the polypropylene glycol diglycidyl ether in the reaction monomer B is 1:1. The catalyst is 1,8-diazabicycloundec-7-ene.

[0050] Step (3): In parts by mass, epoxy resin and curing agent are mixed and stirred evenly to obtain an epoxy resin mixed solution; the mass ratio of the epoxy resin to the curing agent is 1.1:1.

[0051] The preparation steps of the curing agent are as follows: polypropylene glycol diglycidyl ether and triethylenetetramine are mixed, heated to 65°C under nitrogen environment, reacted for 4 hours, distilled under reduced pressure, and then slowly dripped with propylene glycol methyl ether solution of epoxy resin, continued to react for 4 hours, added phenyl glycidyl ether, kept warm at 70°C for 2 hours, and diluted with deionized water to obtain a curing agent with a solid content of 50%. The molar ratio of polypropylene glycol diglycidyl ether to triethylenetetramine is 1:2.6; the molar ratio of polypropylene glycol diglycidyl ether, epoxy resin, and phenyl glycidyl ether is 0.8:1:1.

[0052] The epoxy resin mixture, 395 parts of cement, 1050 parts of modified coal gangue, 210 parts of building crushed stone, 20 parts of pre-treated steel fiber, 70 parts of fly ash, 630 parts of sand, 185 parts of water and 4 parts of water reducing agent were mixed and stirred evenly to obtain high-strength concrete. The epoxy resin mixture was 8wt% of the total mass of the system.

[0053] Comparative Example 2: Compared with Comparative Example 3, in Comparative Example 2, the steel fiber and coal gangue were not modified by polymer.

[0054] A method for preparing building crushed stone aggregate concrete comprises the following steps:

[0055] Step (1): dopamine and Tris-HCl buffer are mixed and stirred to obtain a dopamine solution; coal gangue or steel fiber is placed in the dopamine solution, allowed to stand for 8 hours at 35° C., rinsed with deionized water, and vacuum dried at 60° C. to obtain pretreated coal gangue or pretreated steel fiber; the concentration of the dopamine solution is 2 g / L.

[0056] Step (2): In parts by mass, epoxy resin and curing agent are mixed and stirred evenly to obtain an epoxy resin mixed liquid; the mass ratio of the epoxy resin to the curing agent is 1.1:1.

[0057] The preparation steps of the curing agent are as follows: polypropylene glycol diglycidyl ether and triethylenetetramine are mixed, heated to 65°C under nitrogen environment, reacted for 4 hours, distilled under reduced pressure, and then slowly dripped with propylene glycol methyl ether solution of epoxy resin, continued to react for 4 hours, added phenyl glycidyl ether, kept warm at 70°C for 2 hours, and diluted with deionized water to obtain a curing agent with a solid content of 50%. The molar ratio of polypropylene glycol diglycidyl ether to triethylenetetramine is 1:2.6; the molar ratio of polypropylene glycol diglycidyl ether, epoxy resin, and phenyl glycidyl ether is 0.8:1:1.

[0058] The epoxy resin mixture, 395 parts of cement, 1050 parts of pre-treated coal gangue, 210 parts of building gravel, 20 parts of pre-treated steel fiber, 70 parts of fly ash, 630 parts of sand, 185 parts of water and 4 parts of water reducing agent were mixed and stirred evenly to obtain high-strength concrete. The epoxy resin mixture was 8wt% of the total mass of the system.

[0059] Comparative Example 3: Compared with Comparative Example 3, the amount of epoxy resin mixed solution added in Comparative Example 3 is reduced.

[0060] A method for preparing building crushed stone aggregate concrete comprises the following steps:

[0061] Step (1): dopamine and Tris-HCl buffer are mixed and stirred to obtain a dopamine solution; coal gangue or steel fiber is placed in the dopamine solution, allowed to stand for 8 hours at 35° C., rinsed with deionized water, and vacuum dried at 60° C. to obtain pretreated coal gangue or pretreated steel fiber; the concentration of the dopamine solution is 2 g / L.

[0062] Step (2): performing surface polymer modification on the pretreated coal gangue or pretreated steel fiber to obtain modified coal gangue or modified steel fiber;

[0063] The surface polymer modification step is as follows: placing the raw material in 50 mL of isopropanol, adding 2 g of polyvinyl pyrrolidone, stirring evenly, adding reaction monomer A and 0.5 mL of catalyst, reacting at 30°C for 4 h, then adding reaction monomer B, continuing the reaction for 8 h, cleaning after the reaction, and vacuum drying at 60°C; the reaction monomer A is 1 mmol of pentaerythritol tetra-3-mercaptopropionate and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of the mercapto group of the pentaerythritol tetra-3-mercaptopropionate to the epoxy group of the polypropylene glycol diglycidyl ether is 1:1; the reaction monomer B is 5 mmol of triethylenetetramine and 2 mmol of polypropylene glycol diglycidyl ether, and the molar ratio of triethylenetetramine to polypropylene glycol diglycidyl ether is 2.5:1; the molar ratio of the polypropylene glycol diglycidyl ether in the reaction monomer A and the polypropylene glycol diglycidyl ether in the reaction monomer B is 1:1. The catalyst is 1,8-diazabicycloundec-7-ene.

[0064] Step (3): In parts by mass, epoxy resin and curing agent are mixed and stirred evenly to obtain an epoxy resin mixed solution; the mass ratio of the epoxy resin to the curing agent is 1.1:1.

[0065] The preparation steps of the curing agent are as follows: polypropylene glycol diglycidyl ether and triethylenetetramine are mixed, heated to 65°C under nitrogen environment, reacted for 4 hours, distilled under reduced pressure, and then slowly dripped with propylene glycol methyl ether solution of epoxy resin, continued to react for 4 hours, added phenyl glycidyl ether, kept warm at 70°C for 2 hours, and diluted with deionized water to obtain a curing agent with a solid content of 50%. The molar ratio of polypropylene glycol diglycidyl ether to triethylenetetramine is 1:2.6; the molar ratio of polypropylene glycol diglycidyl ether, epoxy resin, and phenyl glycidyl ether is 0.8:1:1.

[0066] The epoxy resin mixture, 395 parts of cement, 1050 parts of modified coal gangue, 210 parts of building crushed stone, 20 parts of modified steel fiber, 70 parts of fly ash, 630 parts of sand, 185 parts of water and 4 parts of water reducing agent were mixed and stirred evenly to obtain high-strength concrete. The epoxy resin mixture was 3wt% of the total mass of the system.

[0067] Comparative Example 4: Compared with Comparative Example 3, Comparative Example 4 did not undergo polydopamine pretreatment and polymer modification.

[0068] A method for preparing building crushed stone aggregate concrete comprises the following steps:

[0069] Step (1): In parts by mass, epoxy resin and curing agent are mixed and stirred evenly to obtain an epoxy resin mixed solution; the mass ratio of the epoxy resin to the curing agent is 1.1:1.

[0070] The preparation steps of the curing agent are as follows: polypropylene glycol diglycidyl ether and triethylenetetramine are mixed, heated to 65°C under nitrogen environment, reacted for 4 hours, distilled under reduced pressure, and then slowly dripped with propylene glycol methyl ether solution of epoxy resin, continued to react for 4 hours, added phenyl glycidyl ether, kept warm at 70°C for 2 hours, and diluted with deionized water to obtain a curing agent with a solid content of 50%. The molar ratio of polypropylene glycol diglycidyl ether to triethylenetetramine is 1:2.6; the molar ratio of polypropylene glycol diglycidyl ether, epoxy resin, and phenyl glycidyl ether is 0.8:1:1.

[0071] The epoxy resin mixture, 395 parts of cement, 1050 parts of coal gangue, 210 parts of building gravel, 20 parts of steel fiber, 70 parts of fly ash, 630 parts of sand, 185 parts of water and 4 parts of water reducing agent were mixed and stirred evenly to obtain high-strength concrete. The epoxy resin mixture was 8wt% of the total mass of the system.

[0072] Detection experiment:

[0073] The concrete prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was poured into a mold after stirring, vibrated 50 times, sealed after smoothing, demolded after 24 hours, and cured at 20° C. and relative humidity above 95% to obtain a sample.

[0074] 1. Refer to the method disclosed in GB / T50081 to test the compressive strength of the sample. The sample size is 100mm×100mm×100mm, and the loading rate is 2.4kN / s.

[0075] 2. Wear resistance: Clean and weigh the sample after curing for 28 days, then grind it at a constant speed for 30 revolutions under a load of 300N, clean it and weigh it again, and record the amount of wear. The sample size is 150mm×150mm×150mm.

[0076] 3. Chloride ion diffusion coefficient test: The sample cured for 28 days was vacuum saturated with water, and the sodium chloride solution was 4 mol / L. The chloride ion diffusion coefficient was tested. The sample size was 100 mm × 100 mm × 50 mm.

[0077] project Compressive strength MPa <![CDATA[Wear amount Kg / m 2 > <![CDATA[Chloride ion diffusion coefficient 10 -8 cm / s]]> Example 1 52.3 0.46 7.4 Example 2 53.8 0.43 7.3 Example 3 54.6 0.41 7.2 Comparative Example 1 53.9 0.42 7.3 Comparative Example 2 49.7 0.53 7.9 Comparative Example 3 47.4 0.61 8.5 Comparative Example 4 49.2 0.56 8.1

[0078] Conclusion: The scheme uses building crushed stone, coal gangue and sand as aggregates, adds cement, modified steel fiber, fly ash, water and water reducer and other components, and dopes it with epoxy resin mixture to obtain high-strength concrete. The scheme limits the amount of each component, and polymer-coated and modified the coal gangue and steel fiber. The final concrete has excellent compressive strength and flexural strength. Due to the presence of epoxy resin mixture, the wear resistance and chloride ion corrosion resistance of the concrete are improved.

[0079] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing building crushed stone aggregate concrete, characterized in that: The following steps are involved: Step (1): dopamine and Tris-HCl buffer are mixed and stirred to obtain a dopamine solution; coal gangue or steel fiber is placed in the dopamine solution, allowed to stand at 30-35° C. for 6-8 hours, rinsed with deionized water, and vacuum dried at 50-60° C. to obtain pretreated coal gangue or pretreated steel fiber; Step (2): performing surface polymer modification on the pretreated coal gangue or pretreated steel fiber to obtain modified coal gangue or modified steel fiber; The surface polymer modification step comprises: placing the raw material in isopropanol, adding polyvinyl pyrrolidone, stirring evenly, adding reaction monomer A and catalyst, reacting at 25-30°C for 4-6h, then adding reaction monomer B, continuing to react for 6-8h, washing after the reaction, and vacuum drying at 50-60°C; the reaction monomer A is pentaerythritol tetrakis-3-mercaptopropionate and polypropylene glycol diglycidyl ether; the reaction monomer B is triethylenetetramine and polypropylene glycol diglycidyl ether; Step (3): mixing the epoxy resin and the curing agent, stirring evenly to obtain an epoxy resin mixed solution; The epoxy resin mixed liquid, cement, modified coal gangue, building crushed stone, modified steel fiber, fly ash, sand, water and water reducing agent are mixed and stirred evenly to obtain high-strength concrete.

2. The method for preparing a building crushed stone aggregate concrete according to claim 1, characterized in that: In step (1), the concentration of the dopamine solution is 2 to 3 g / L.

3. The method for preparing a building crushed stone aggregate concrete according to claim 1, characterized in that: In step (2), in reaction monomer A, the molar ratio of the mercapto group of pentaerythritol tetrakis-3-mercaptopropionate and the epoxy group of polypropylene glycol diglycidyl ether is 1:1; in reaction monomer B, the molar ratio of triethylenetetramine and polypropylene glycol diglycidyl ether is (2-3):1; and the molar ratio of polypropylene glycol diglycidyl ether in reaction monomer A and polypropylene glycol diglycidyl ether in reaction monomer B is 1:

1.

4. The method for preparing a building crushed stone aggregate concrete according to claim 1, characterized in that: In step (3), the amount of each component is: by mass, 380-420 parts of cement, 900-1050 parts of modified coal gangue, 200-300 parts of building gravel, 15-25 parts of modified steel fiber, 60-70 parts of fly ash, 630-680 parts of sand, 160-185 parts of water, and 3-5 parts of water reducer; the epoxy resin mixture is 6-8wt% of the total mass of the system.

5. The method for preparing building crushed stone aggregate concrete according to claim 1, characterized in that: In step (3), the preparation steps of the curing agent are as follows: polypropylene glycol diglycidyl ether and triethylenetetramine are mixed, heated to 60-65° C. under a nitrogen environment, reacted for 4-5 hours, distilled under reduced pressure, and then slowly dripped with a solution of propylene glycol methyl ether of epoxy resin, continued to react for 3-4 hours, added phenyl glycidyl ether, kept warm at 65-70° C. for 2-3 hours, and diluted with deionized water to obtain a curing agent.

6. The method for preparing building crushed stone aggregate concrete according to claim 5, characterized in that: The molar ratio of the polypropylene glycol diglycidyl ether to triethylenetetramine is 1:(2.4-2.6); the molar ratio of the polypropylene glycol diglycidyl ether, epoxy resin and phenyl glycidyl ether is (0.8-1):1:

1.

7. The method for preparing building crushed stone aggregate concrete according to claim 1, characterized in that: In step (3), the epoxy resin is E-44; and the water reducer is a polycarboxylic acid water reducer.

8. A building crushed stone aggregate concrete prepared according to the preparation method according to any one of claims 1 to 7.