CN115477492B

CN115477492B - Seawater erosion bare concrete additive and preparation method thereof

Info

Publication number: CN115477492B
Application number: CN202211123166.3A
Authority: CN
Inventors: 黄清林; 陈星�; 黄智峰; 蒋亚
Original assignee: Zhejiang Zhifeng Technology Co ltd
Current assignee: Zhejiang Zhifeng Technology Co ltd
Priority date: 2022-09-15
Filing date: 2022-09-15
Publication date: 2023-03-14
Anticipated expiration: 2042-09-15
Also published as: CN115477492A

Abstract

The invention belongs to the technical field of building materials, and discloses a seawater erosion fair-faced concrete additive and a preparation method thereof. The invention relates to a seawater erosion bare concrete admixture which comprises the following components in parts by weight: 70-90 parts of mineral admixture, 1-2 parts of hybrid fiber, 12-16 parts of activated red mud and 1-3 parts of rust inhibitor. The seawater erosion bare concrete admixture can greatly improve the durability of concrete in the marine environment on the basis of effectively ensuring or further improving the strength of the concrete, reduce the repair cost and prolong the service life of a concrete building in the marine environment.

Description

Seawater erosion bare concrete additive and preparation method thereof

Technical Field

The invention relates to the technical field of building materials, in particular to a seawater erosion bare concrete additive and a preparation method thereof.

Background

The construction of ocean engineering infrastructure is not only concerned with the economic and social development of China and the promotion of international status, but also is the need of national defense construction and national safety. Under the global environment of economy and increasingly complex international environments, coastal and ocean engineering such as ports, docks, seawalls, sea-crossing bridges, island reef construction and the like are about to meet new construction climax.

In a complex marine environment, under the combined action of various external factors such as high salt, microorganisms and the like, the marine engineering concrete can be seriously corroded by corrosion of internal reinforcing steel bars, concrete carbonization, corrosion of chloride and sulfate, seawater scouring wear, microorganism corrosion and the like, so that the internal structure of the marine engineering concrete is weakened, and the durability of the marine engineering concrete is greatly reduced. The chloride ions are ions with larger content in the seawater, the ionic radius of the chloride ions is smaller, and the chloride ions easily enter the concrete through the osmosis action under the action of water, so that the concrete is damaged; the sulfate corrosion is that sulfate ions enter concrete and hydration products of cement to generate chemical reaction under the action of water to generate products such as ettringite and the like so as to destroy the concrete structure. On one hand, the ocean microorganisms are attached to the surface of the ocean engineering concrete in a large quantity, so that the appearance is influenced, and on the other hand, the acidic metabolism products of the ocean engineering concrete can aggravate the corrosion of the concrete.

Therefore, the prevention work of the ocean engineering concrete is an important way for prolonging the service life of the ocean engineering concrete material.

Disclosure of Invention

In view of the above, the invention provides an additive for seawater erosion fair-faced concrete and a preparation method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

the seawater erosion fair-faced concrete additive comprises the following components in parts by weight: 70-90 parts of mineral admixture, 1-2 parts of hybrid fiber, 12-16 parts of activated red mud and 1-3 parts of rust inhibitor.

Preferably, the mineral admixture comprises the following components in parts by weight: 30-35 parts of tuff, 15-20 parts of waste oyster shell, 15-20 parts of rice hull ash and 10-15 parts of metakaolin.

Preferably, the hybrid fiber consists of the following components in parts by weight: 0.5-1 part of polypropylene fiber and 0.5-0.8 part of carbon fiber.

Preferably, the rust inhibitor is one of D-sodium gluconate, sodium petroleum sulfonate, diethanolamine and sodium molybdate.

Preferably, the rust inhibitor is sodium D-gluconate.

Preferably, the components also comprise 0.2-1 part of nano silicon dioxide and 2-10 parts of water.

Preferably, the preparation method of the activated red mud comprises the following steps:

(1) placing the red mud in an environment of 80-100 ℃ for quick drying, then placing the red mud in an environment of 800-1200 ℃ for sintering, cooling the red mud to room temperature, and then soaking the red mud in a sodium hydroxide solution with the concentration of 100mg/L for 10-12 hours to obtain porous red mud for later use;

(2) and (2) soaking the porous red mud prepared in the step (1) in Shewah type bacterial liquid for 10-12h, and drying in an environment at 40-45 ℃ to obtain the activated red mud.

The preparation method of the seawater erosion bare concrete additive specifically comprises the following steps:

1) Weighing the raw materials according to the proportion, wherein the raw materials and the weight portion thereof comprise: 30-35 parts of tuff, 15-20 parts of waste oyster shells, 15-20 parts of rice hull ash, 10-15 parts of metakaolin, 0.5-1 part of polypropylene fiber, 0.5-1 part of carbon fiber, 0.2-1 part of nano silicon dioxide, 1-3 parts of rust inhibitor, 12-16 parts of activated red mud and 2-10 parts of water;

2) Mixing tuff, waste oyster shells, metakaolin and activated red mud, and grinding into powder by crushing and ball milling, wherein the grinding fineness is 0.1 mm, and the screen residue of a square-hole sieve accounts for 1-6% of the total weight for later use;

3) Mixing nano silicon dioxide and water, performing ultrasonic treatment for 10-15min, adding polypropylene fiber and carbon fiber, uniformly stirring to prepare a mixture, adding the mixed powder prepared in the step 1) and rice hull ash into the mixture, stirring for 3-10min, adding a rust inhibitor into the mixture, and continuously stirring for 5-10min to obtain the rust inhibitor.

Preferably, the specific surface area of the mixed powder in the step 2) is 352m ² /kg-452m ² /kg。

According to the technical scheme, compared with the prior art, the seawater corrosion bare concrete additive is disclosed, 10% -15% of the additive prepared by the invention is doped into concrete during use, so that the concrete in seawater has the functions of corrosion resistance and microcrack self-repairing while the performances of compression resistance, freeze-thaw resistance, rust resistance and the like of the concrete are improved, the durability of the seawater concrete is improved, the repair cost is reduced, the service life of a concrete building in a marine environment is prolonged, and the seawater corrosion resistance bare concrete additive is simple and convenient to use, and easy to operate and control; high cost performance and good social and economic benefits.

1. When the marine concrete encounters a low-temperature freezing environment, in the process that moisture in the moisture holes freezes gradually, the volume expansion can generate an outward extrusion acting force on the internal air hole wall of the concrete, micro cracks can be generated on the air hole wall, the moisture gradually permeates into the internal air holes through the micro cracks, the damage is further caused to the deep inside of the structure, and the service life of the seawater concrete building is further shortened. In view of the above, the technical scheme of the invention is that the activated red mud is added, the red mud is calcined after being dried to form a porous material, and then the activated red mud is loaded with the shiwa-type bacteria to obtain the activated red mud, on one hand, the waste oyster shell powder is added, so that the oyster shell powder is doped to fill the pore structure in the red mud, the pore structure of the red mud is optimized, the pore wall strength is improved, in a low-temperature freezing environment, the generation of micro-cracks of a concrete building is reduced, and the freeze-thaw resistance performance of seawater concrete is improved.

2. According to the technical scheme, the tuff is added to fill the pores in the concrete, so that the penetration and the migration of water are reduced, the frost heaving force generated by water freezing expansion is reduced, and the mass loss and the elastic modulus loss of the concrete in the sea are reduced.

3. According to the technical scheme, the rice husk ash and the metakaolin are cooperatively added to play a filling role and a volcanic ash industrial building effect, so that the micro-pore structure of the concrete can be changed, the internal density of the concrete is increased, the compressive strength of the concrete in the sea is improved, and the water absorption of the concrete in the sea is reduced.

4. According to the technical scheme, the polypropylene fibers and the carbon fibers are added, the polypropylene fibers are uniformly dispersed in the concrete to form a reliable three-dimensional grid system, and the carbon fibers are attached to the surface of the polypropylene fibers, so that the compressive strength of the seawater concrete is improved, microcracks in the concrete are prevented from generating and expanding better, and the reaction of corrosive sulfate and chloride in seawater with the concrete is slowed down.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a seawater erosion bare concrete additive, which can greatly improve the durability of concrete in the marine environment on the basis of effectively ensuring or further improving the strength of the concrete, reduce the repair cost and prolong the service life of a concrete building in the marine environment; the seawater erosion fair-faced concrete additive does not use toxic, harmful and dangerous chemicals in the production process, and the production and use processes meet the environmental protection requirement.

The seawater erosion bare concrete additive comprises the following components in parts by weight: 30-35 parts of tuff, 15-20 parts of waste oyster shells, 15-20 parts of rice hull ash, 10-15 parts of metakaolin, 0.5-1 part of polypropylene fiber, 0.5-1 part of carbon fiber, 0.2-1 part of nano silicon dioxide, 1-3 parts of rust inhibitor, 12-16 parts of activated red mud and 2-10 parts of water.

The production method comprises the following steps: 1) Weighing the raw materials according to the proportion; 2) Mixing tuff, waste oyster shells, metakaolin and activated red mud, grinding into mixed powder with specific surface area of 352m 2/kg-452m 2/kg by a crushing and ball milling method, wherein the grinding fineness is 0.1 mm, and the screen residue of a square-hole sieve accounts for 1-6% of the total weight for later use; 3) Mixing nano silicon dioxide and water, performing ultrasonic treatment for 10-15min, then adding polypropylene fiber and carbon fiber, uniformly stirring to prepare a mixture, then adding the mixed powder prepared in the step 1) and rice hull ash into the mixture, stirring for 3-10min, then adding the rust inhibitor into the mixture, and continuously stirring for 5-10min to obtain the rust inhibitor.

The using method comprises the following steps: when the product is used for preparing the seawater corrosion resistant concrete, 10-15% of the total amount of the cementing material (equivalent amount of the cementing material can be replaced) is uniformly added, the mixture is uniformly stirred after the addition, the stirring time is prolonged by 20-30s, standard curing is immediately carried out after the concrete is poured and condensed, and the curing time is 14-28 days.

The following are specific examples

Example 1

The seawater corrosion fair-faced concrete additive comprises the following components in parts by weight: 30 parts of tuff, 15 parts of waste oyster shells, 15 parts of rice hull ash, 10 parts of metakaolin, 0.5 part of polypropylene fiber, 0.5 part of carbon fiber, 12 parts of activated red mud, 1 part of petroleum sodium sulfonate, 0.2 part of nano-silica and 2 parts of water.

The preparation method of the activated red mud comprises the following steps:

(1) placing the red mud in an environment of 80 ℃ for quick drying, then placing the red mud in an environment of 800 ℃ for sintering, cooling the red mud to room temperature, and then soaking the red mud in a sodium hydroxide solution with the concentration of 100mg/L for 10 hours to obtain porous red mud for later use;

(2) and (2) soaking the porous red mud prepared in the step (1) in Shewash type bacterial liquid for 10 hours, and drying in an environment at 40 ℃ to obtain the activated red mud.

1) Weighing the raw materials according to the proportion, wherein the raw materials and the weight portion thereof comprise: 30 parts of tuff, 15 parts of waste oyster shells, 15 parts of rice hull ash, 10 parts of metakaolin, 0.5 part of polypropylene fiber, 0.5 part of carbon fiber, 12 parts of activated red mud, 1 part of petroleum sodium sulfonate, 0.2 part of nano-silica and 2 parts of water;

2) Mixing tuff, waste oyster shells, metakaolin and activated red mud, grinding into mixed powder with specific surface area of 352m & lt 2 & gt/kg by a crushing and ball milling method, wherein the grinding fineness is 0.1 mm, and the surplus sieved powder of a square-hole sieve accounts for 6 percent of the total weight for standby;

3) Mixing nano silicon dioxide and water, performing ultrasonic treatment for 10min, then adding polypropylene fiber and carbon fiber, uniformly stirring to prepare a mixture, then adding the mixed powder prepared in the step 1) and rice hull ash into the mixture, placing the mixture into a stirrer, stirring for 3min, then adding a rust inhibitor into the mixture, and continuing stirring for 5min to obtain the seawater erosion fair-faced concrete admixture.

Example 2

The seawater erosion fair-faced concrete additive comprises the following components in parts by weight: 35 parts of tuff, 20 parts of waste oyster shells, 20 parts of rice hull ash, 15 parts of metakaolin, 1 part of polypropylene fiber, 0.8 part of carbon fiber, 16 parts of activated red mud, 3 parts of sodium molybdate, 1 part of nano silicon dioxide and 10 parts of water.

The preparation method of the activated red mud comprises the following steps:

(1) placing the red mud in an environment of 100 ℃ for quick drying, then placing the red mud in a environment of 1200 ℃ for sintering, cooling the red mud to room temperature, and then soaking the red mud in a sodium hydroxide solution with the concentration of 100mg/L for 12 hours to obtain porous red mud for later use;

(2) and (2) soaking the porous red mud prepared in the step (1) in Shewah bacterial liquid for 12 hours, and drying in an environment at 45 ℃ to obtain the activated red mud.

1) Weighing the raw materials according to the proportion, wherein the raw materials and the weight portions thereof comprise: 35 parts of tuff, 20 parts of waste oyster shells, 20 parts of rice hull ash, 15 parts of metakaolin, 1 part of polypropylene fiber, 0.8 part of carbon fiber, 16 parts of activated red mud, 3 parts of sodium molybdate, 1 part of nano silicon dioxide and 10 parts of water;

2) Mixing tuff, waste oyster shells, metakaolin and activated red mud, grinding into mixed powder with a specific surface area of 452m < 2 >/kg by a crushing and ball milling method, wherein the grinding fineness is 0.1 mm, and the screen residue of a square-hole sieve accounts for 6 percent of the total weight for standby;

3) Mixing nano silicon dioxide and water, performing ultrasonic treatment for 15min, then adding polypropylene fiber and carbon fiber, uniformly stirring to prepare a mixture, then adding the mixed powder prepared in the step 1) and rice hull ash into the mixture, placing the mixture into a stirrer, stirring for 10min, then adding a rust inhibitor into the mixture, and continuing stirring for 10min to obtain the seawater erosion fair-faced concrete admixture.

Example 3

The seawater erosion fair-faced concrete additive comprises the following components in parts by weight: 32 parts of tuff, 18 parts of waste oyster shells, 16 parts of rice hull ash, 12 parts of metakaolin, 0.8 part of polypropylene fiber, 0.6 part of carbon fiber, 14 parts of activated red mud, 2 parts of D-sodium gluconate, 0.6 part of nano silicon dioxide and 8 parts of water.

The preparation method of the activated red mud comprises the following steps:

(1) placing the red mud in an environment with the temperature of 90 ℃ for quick drying, then placing the red mud in an environment with the temperature of 1000 ℃ for sintering, cooling the red mud to the room temperature, and then soaking the red mud in a sodium hydroxide solution with the concentration of 100mg/L for 11 hours to obtain porous red mud for later use;

(2) and (2) soaking the porous red mud prepared in the step (1) in Shewash type bacterial liquid for 11h, and drying in an environment at 42 ℃ to obtain the activated red mud.

1) Weighing the raw materials according to the proportion, wherein the raw materials and the weight portions thereof comprise: 32 parts of tuff, 18 parts of waste oyster shells, 16 parts of rice hull ash, 12 parts of metakaolin, 0.8 part of polypropylene fiber, 0.6 part of carbon fiber, 14 parts of activated red mud, 2 parts of D-sodium gluconate, 0.6 part of nano silicon dioxide and 8 parts of water;

2) Mixing tuff, waste oyster shell, metakaolin and activated red mud, and grinding into specific surface area of 400m by crushing and ball milling ² The powder is ground into 0.1 mm square-hole sieve residue which is 4 percent of the total weight for standby;

3) Mixing nano silicon dioxide and water, performing ultrasonic treatment for 12min, then adding polypropylene fiber and carbon fiber, uniformly stirring to prepare a mixture, then adding the mixed powder prepared in the step 1) and rice hull ash into the mixture, stirring for 6min, then adding a rust inhibitor into the mixture, and continuously stirring for 7min to obtain the seawater erosion fair-faced concrete admixture.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Test for Corrosion resistance

1. The obtained seawater erosion bare concrete admixture is applied to concrete, and the specific application method is as follows: the admixtures prepared in examples 1-3 and comparative examples 1 and 2 of the present invention were uniformly added to the concrete in an amount of 12% of the total amount of the cementitious material (equivalent amount of the cementitious material can be substituted), and after the admixtures were added, they were stirred uniformly for 30 seconds, and after the concrete was poured and set, standard curing was immediately carried out for 28 days. Then, testing the performances of the obtained concrete, such as strength, chloride ion diffusion coefficient, sulfate corrosion resistance, corrosion grade, wear resistance and the like, by referring to GB/T50080-2016 (Standard for Performance test methods of general concrete mixtures), JGJ/T283-2012 (technical Specification for application of self-compacting concrete), GB/T50082-2009 (Standard for Performance test methods of Long-term Performance and durability of general concrete) and GB/T749-2008 (method for testing Corrosion of sulfate corrosion resistance of cement); the specific test results are shown in tables 2 and 3.

Comparative example 1A commercially available seawater erosion As-cast finish concrete admixture (FMA-H001 anti-corrosive agent manufactured by Zhejiang san Shi group Special Cement Co., ltd.)

Comparative example 2A commercially available seawater erosion As-cast finish concrete admixture (sulfate-resistant corrosion inhibitor for concrete manufactured by Beijing Shunjiao engineering and engineering Co., ltd.)

TABLE 1 concrete mix proportion

Note: the concrete mixing proportion is (kg/m 3), and the cement type is P.0.42.5# ordinary cement; the fineness modulus of the sand is 2.7; the particle size of the stones is 5-20 mm; the water reducing agent is an N-type naphthalene water reducing agent.

TABLE 2 concrete Performance test results

As is apparent from Table 2, the admixture for seawater erosion bare concrete prepared by the invention can effectively improve the compression resistance of concrete, reduce the diffusion performance of chloride ions and improve the erosion resistance and sulfate corrosion resistance of concrete when being applied to the concrete.

TABLE 3 abrasion resistance of seawater erosion bare concrete admixture of the present invention

As is apparent from Table 3, the abrasion resistance of the concrete with the additive is greatly improved compared with the cement without the additive, so that the seawater concrete building has seawater scouring resistance.

Claims

1. The seawater erosion fair-faced concrete additive comprises the following components in parts by weight: 70-90 parts of mineral admixture, 1-2 parts of hybrid fiber, 12-16 parts of activated red mud and 1-3 parts of rust inhibitor;

the preparation method of the activated red mud comprises the following steps:

(1) placing the red mud in an environment of 80-100 ℃ for quick drying, then placing the red mud in an environment of 800-1200 ℃ for sintering, cooling the red mud to room temperature, and then soaking the red mud in a sodium hydroxide solution with the concentration of 100mg/L for 10-12h to obtain porous red mud for later use;

(2) soaking the porous red mud prepared in the step (1) in Shewah type bacterial liquid for 10-12h, and drying in an environment at 40-45 ℃ to obtain active red mud;

the mineral admixture comprises the following components in parts by weight: 30-35 parts of tuff, 15-20 parts of waste oyster shell, 15-20 parts of rice hull ash and 10-15 parts of metakaolin;

the hybrid fiber comprises the following components in parts by weight: 0.5-1 part of polypropylene fiber and 0.5-0.8 part of carbon fiber;

according to the weight portion, the nano silicon dioxide also comprises 0.2-1 portion of nano silicon dioxide and 2-10 portions of water.

2. The seawater erosion bare concrete admixture according to claim 1, wherein: the rust inhibitor is one of D-sodium gluconate, sodium petroleum sulfonate, diethanolamine and sodium molybdate.

3. The seawater erosion bare concrete admixture according to claim 2, wherein: the rust inhibitor is D-sodium gluconate.

4. A method for preparing an admixture for seawater erosion fair-faced concrete according to any one of claims 1 to 3, which comprises the following steps:

1) Weighing the raw materials according to the proportion, wherein the raw materials and the weight portions of the raw materials are as follows: 30-35 parts of tuff, 15-20 parts of waste oyster shells, 15-20 parts of rice hull ash, 10-15 parts of metakaolin, 0.5-1 part of polypropylene fiber, 0.5-0.8 part of carbon fiber, 0.2-1 part of nano silicon dioxide, 1-3 parts of rust inhibitor, 12-16 parts of activated red mud and 2-10 parts of water;

5. The method for preparing the seawater corrosion fair-faced concrete additive according to claim 4, which is characterized in that: the specific surface area of the mixed powder in the step 2) is 352m2/kg-452 m2/kg.