CN118290077A - High-strength concrete and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of high-strength concrete and preparation method thereof, belong to the technical field of concrete, including the following raw materials by weight: 25-55 parts of cement, 60-85 parts of modified coarse aggregate, 30-60 parts of fine aggregate, 3-8 parts of modified straw fiber, 25-30 parts of water, 10-15 parts of fly ash, 5-10 parts of rice husk ash, and 5-6 parts of water reducer. Its preparation method comprises the following steps: after mixing the modified coarse aggregate with part of the water, let it stand for 5-10min, then add cement, fine aggregate and fly ash to mix evenly, finally add remaining water, modified straw fiber, rice husk ash and water reducer, after stirring evenly, the high-strength concrete is obtained. The present invention can improve the compactness of concrete, enhance the strength of concrete, and the modified straw fiber in the present invention can act together with rice husk ash to improve the mechanical properties of concrete, so that the product has the advantages of high strength and low cost, and has a wide application value.

Description

A kind of high strength concrete and preparation method thereof

Technical Field

The invention belongs to the technical field of concrete, and in particular relates to high-strength concrete and a preparation method thereof.

Background technique

Concrete, referred to as "concrete", is a general term for engineering composite materials that are cemented into a whole by cementitious materials. The term concrete usually refers to cement as a cementitious material, sand and stone as aggregates; mixed with water (which may contain admixtures and additives) in a certain proportion, and the cement concrete obtained by mixing is also called ordinary concrete. With the development of the construction industry, ordinary concrete has been widely used in civil engineering. However, with the expansion of the scope of concrete use, the existing ordinary concrete cannot meet the high-strength engineering requirements. In some special cases, fractures or frost cracks often occur, and some higher-strength concretes have high production costs and cannot be widely promoted and used.

Therefore, how to provide a concrete with high strength is a technical problem that those skilled in the art need to solve urgently.

Summary of the invention

In order to solve the above technical problems, the present invention provides a high-strength concrete and a preparation method thereof.

To achieve the above object, the present invention provides the following technical solutions:

A high-strength concrete comprises the following raw materials in parts by weight:

25-55 parts of cement, 60-85 parts of modified coarse aggregate, 30-60 parts of fine aggregate, 3-8 parts of modified straw fiber, 25-30 parts of water, 10-15 parts of fly ash, 5-10 parts of rice husk ash and 5-6 parts of water reducer.

Preferably, the modified coarse aggregate is obtained by soaking coarse aggregate in nano-silica sol solution and drying it.

Preferably, the coarse aggregate is crushed stone and pebbles.

More preferably, the mass ratio of the crushed stone to the pebbles is 1:(1-5).

Preferably, the nano silica sol is silica sol THIS-S30 produced by Yantai Hengxin Chemical Technology Co., Ltd.

Preferably, the mass concentration of the nano-silica sol is 0.5-4%;

The soaking time is 6-10 hours.

Beneficial effects: The modified coarse aggregate in the present invention can fill the internal gaps of the coarse aggregate, reduce the pore size and number of the coarse aggregate, and react with the needle-shaped crystal particles in the concrete aggregate attachment mortar to form flocculent C-S-H gel, improve the pore structure and surface morphology, increase the density and strength of the coarse aggregate, thereby obtaining modified coarse aggregate with improved performance, thereby enhancing the strength of the concrete and improving the anti-water seepage performance of the concrete.

Preferably, the method for preparing the modified straw fiber comprises the following steps:

The straw fiber is pretreated by microwaves and then immersed in an acid solution, and then the pH value is adjusted to neutral, filtered and dried to obtain the modified straw fiber.

Preferably, the straw fiber includes one or a mixture of any of corn straw fiber, wheat straw fiber, cotton straw fiber and sorghum straw fiber.

Preferably, the power of the microwave pretreatment is 150-250 W, and the time is 5-10 s.

Preferably, the acid solution comprises dilute hydrochloric acid or dilute sulfuric acid with a concentration of 0.05-0.2 mol/L.

Beneficial effects: The present invention first pre-treats the straw fiber with microwaves, which can improve the dispersibility of the straw fiber and facilitate full contact with the acid solution. When the acid-modified straw fiber is used in concrete, the shear strength of the concrete can be significantly improved. At the same time, it can produce a certain synergistic effect with rice husk ash, greatly improving the mechanical properties of the concrete.

Preferably, the fine aggregate is recycled fine aggregate particles having a particle size of 1-5 mm obtained by crushing and screening construction waste concrete.

A method for preparing high-strength concrete comprises the following steps:

The modified coarse aggregate is mixed with part of the water and allowed to stand for 5-10 minutes, then cement, fine aggregate and fly ash are added and mixed evenly, and finally the remaining water, modified straw fiber, rice husk ash and water reducing agent are added and stirred evenly to obtain the high-strength concrete.

Preferably, the partial water is 1/3 to 1/2 of the total water.

Compared with the prior art, the present invention has the following advantages and technical effects:

The present invention uses natural coarse aggregate for modification, uses construction solid waste as fine aggregate, uses crop straw fiber as a modification additive, and adds fly ash to replace part of the cement, thereby greatly reducing the preparation cost of concrete. In addition, the modified coarse aggregate in the present invention can improve the compactness of concrete and enhance the strength of concrete, and the modified straw fiber in the present invention can work together with rice husk ash to improve the mechanical properties of concrete, so that the product has the advantages of high strength and low cost, and has broad application value.

Detailed ways

The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific implementation methods.

The embodiment of the present invention discloses a high-strength concrete, comprising the following raw materials in parts by weight:

25-55 parts of cement, 60-85 parts of modified coarse aggregate, 30-60 parts of fine aggregate, 3-8 parts of modified straw fiber, 25-30 parts of water, 10-15 parts of fly ash, 5-10 parts of rice husk ash and 5-6 parts of water reducer.

In some preferred embodiments, the modified coarse aggregate is obtained by soaking the coarse aggregate in a nano-silica sol solution and drying it.

In some preferred embodiments, the coarse aggregate is crushed stone and pebbles.

In some more preferred embodiments, the mass ratio of crushed stone to pebbles is 1:(1-5).

In some preferred embodiments, the nano silica sol is silica sol THIS-S30 produced by Yantai Hengxin Chemical Technology Co., Ltd.

In some preferred embodiments, the mass concentration of the nano-silica sol is 0.5-4%;

The soaking time is 6-10 hours.

In some preferred embodiments, the method for preparing the modified straw fiber comprises the following steps:

The straw fiber is pretreated by microwaves and then immersed in an acid solution, and then the pH value is adjusted to neutral, filtered and dried to obtain the modified straw fiber.

In some preferred embodiments, the straw fiber includes one or a mixture of any of corn straw fiber, wheat straw fiber, cotton straw fiber and sorghum straw fiber.

In some preferred embodiments, the microwave pretreatment has a power of 150-250 W and a time of 5-10 s.

In some preferred embodiments, the acid solution includes dilute hydrochloric acid or dilute sulfuric acid with a concentration of 0.05-0.2 mol/L.

In some preferred embodiments, the fine aggregate is recycled fine aggregate particles with a particle size of 1-5 mm obtained by crushing and screening construction waste concrete.

The embodiment of the present invention also discloses a method for preparing high-strength concrete, comprising the following steps:

The modified coarse aggregate is mixed with part of the water and allowed to stand for 5-10 minutes, then cement, fine aggregate and fly ash are added and mixed evenly, and finally the remaining water, modified straw fiber, rice husk ash and water reducing agent are added and stirred evenly to obtain the high-strength concrete.

In some preferred embodiments, the partial water is 1/3 to 1/2 of the total water.

The raw materials in the embodiments of the present invention are all purchased from commercial sources;

Among them, the nano silica sol is the silica sol THIS-S30 produced by Yantai Hengxin Chemical Technology Co., Ltd.;

Fine aggregate is recycled construction waste concrete that is crushed and sieved to obtain fine aggregate particles with a particle size of 1-5mm.

In the embodiments of the present invention, "parts" are parts by weight unless otherwise specified.

Example 1

A high-strength concrete comprises the following raw materials in parts by weight:

40 parts of cement, 70 parts of modified coarse aggregate, 45 parts of fine aggregate, 6 parts of modified straw fiber, 28 parts of water, 12 parts of fly ash, 7 parts of rice husk ash, and 5 parts of water reducer.

A method for preparing high-strength concrete comprises the following steps:

(1) Preparation of modified coarse aggregate: crushed stone and pebbles are mixed uniformly at a mass ratio of 1:2, and then placed in a nano-silica sol solution with a mass concentration of 2% and immersed for 8 hours at room temperature and then dried to obtain modified coarse aggregate;

(2) Preparation of modified straw fiber: wheat straw fiber was pretreated with microwave at 200 W for 6 seconds and then immersed in a 0.1 mol/L hydrochloric acid solution, and then sodium hydroxide solution was added to adjust the pH to neutral, and then filtered and dried to obtain modified straw fiber;

(3) The modified coarse aggregate obtained in step (1) is mixed with 1/2 water and allowed to stand for 8 minutes, and then cement, fine aggregate and fly ash are added and mixed evenly, and finally the remaining water, the modified straw fiber obtained in step (2), rice husk ash and water reducing agent are added and stirred evenly to obtain high-strength concrete.

Example 2

A high-strength concrete comprises the following raw materials in parts by weight:

25 parts of cement, 85 parts of modified coarse aggregate, 60 parts of fine aggregate, 3 parts of modified straw fiber, 25 parts of water, 15 parts of fly ash, 10 parts of rice husk ash, and 5 parts of water reducer.

A method for preparing high-strength concrete comprises the following steps:

(1) Preparation of modified coarse aggregate: crushed stone and pebbles are mixed uniformly at a mass ratio of 1:1, and then placed in a nano-silica sol solution with a mass concentration of 0.5% and immersed for 10 hours at room temperature and then dried to obtain modified coarse aggregate;

(2) Preparation of modified straw fiber: Wheat straw fiber was pretreated with microwave at 250 W for 5 seconds and then immersed in a 0.05 mol/L hydrochloric acid solution. Then, sodium hydroxide solution was added to adjust the pH to neutral, and then filtered and dried to obtain modified straw fiber.

(3) The modified coarse aggregate obtained in step (1) is mixed with 1/3 of water and allowed to stand for 10 minutes, and then cement, fine aggregate and fly ash are added and mixed evenly, and finally the remaining water, the modified straw fiber obtained in step (2), rice husk ash and water reducing agent are added and stirred evenly to obtain high-strength concrete.

Example 3

A high-strength concrete comprises the following raw materials in parts by weight:

55 parts of cement, 60 parts of modified coarse aggregate, 30 parts of fine aggregate, 8 parts of modified straw fiber, 30 parts of water, 10 parts of fly ash, 5 parts of rice husk ash, and 6 parts of water reducer.

A method for preparing high-strength concrete comprises the following steps:

(1) Preparation of modified coarse aggregate: crushed stone and pebbles were mixed uniformly at a mass ratio of 1:5, and then placed in a nano-silica sol solution with a mass concentration of 4% and immersed for 8 hours at room temperature and then dried to obtain modified coarse aggregate;

(2) Preparation of modified straw fiber: Wheat straw fiber was pretreated with microwave at 150 W for 10 s and then immersed in a 0.2 mol/L hydrochloric acid solution, and then sodium hydroxide solution was added to adjust the pH to neutral, and then filtered and dried to obtain modified straw fiber;

(3) The modified coarse aggregate obtained in step (1) is mixed with 2/5 of water and allowed to stand for 5 minutes, and then cement, fine aggregate and fly ash are added and mixed evenly, and finally the remaining water, the modified straw fiber obtained in step (2), rice husk ash and water reducing agent are added and stirred evenly to obtain high-strength concrete.

Comparative Example 1

A high-strength concrete, which is different from Example 1 in that it does not include modified coarse aggregate.

A method for preparing high-strength concrete, with the same steps and parameters as those in Example 1.

Comparative Example 2

A high-strength concrete, which is different from Example 1 in that the coarse aggregate therein is not modified, but the modified coarse aggregate is replaced by a coarse aggregate obtained by mixing crushed stone and pebbles in a mass ratio of 1:2 in an equal amount.

A method for preparing high-strength concrete, with the same steps and parameters as those in Example 1.

Comparative Example 3

A high-strength concrete, which is different from Example 1 in that modified straw fiber is not added.

A method for preparing high-strength concrete, with the same steps and parameters as those in Example 1.

Comparative Example 4

A high-strength concrete, which is different from Example 1 in that rice husk ash is not added.

Technical effect:

The concrete obtained from Examples 1-3 of the present invention and Comparative Examples 1-4 was subjected to performance tests, and the test methods were as follows:

Compressive strength, flexural strength and splitting strength: tested according to GB/T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete";

Freeze-thaw resistance: tested according to JTG3420-2020 "Testing Procedures for Cement and Cement Concrete in Highway Engineering";

Slump and fluidity: tested according to GB/T50080-2016 "Ordinary Concrete Mixture Performance Test Standard";

Impermeability and shrinkage limit: tested in accordance with GB/T50082-2009 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete";

The test results are shown in Table 1.

Table 1

It can be seen from the above table that the addition of modified coarse aggregate, modified straw fiber and straw ash in the present invention can effectively improve the mechanical properties of concrete such as compressive strength, flexural strength and splitting compressive strength, and the three raw materials can produce a certain synergistic effect, thereby achieving a technical effect that cannot be achieved by the sum of the effects of adding the three raw materials separately. In addition, the modified coarse aggregate in the present invention significantly improves the water seepage resistance of concrete, and it can be inferred that the present invention improves the compactness of concrete by modifying the coarse aggregate.

The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (9)

1. A high-strength concrete, characterized by comprising the following raw materials in parts by weight: 25-55 parts of cement, 60-85 parts of modified coarse aggregate, 30-60 parts of fine aggregate, 3-8 parts of modified straw fiber, 25-30 parts of water, 10-15 parts of fly ash, 5-10 parts of rice husk ash and 5-6 parts of water reducer. 2. A high-strength concrete according to claim 1, characterized in that the modified coarse aggregate is obtained by soaking and drying the coarse aggregate in a nano-silica sol solution. 3. A high-strength concrete according to claim 2, characterized in that the coarse aggregate is crushed stone and pebbles. 4. The high-strength concrete according to claim 2, characterized in that the mass concentration of the nano-silica sol is 0.5-4%; The soaking time is 6-10 hours. 5. A high-strength concrete according to claim 1, characterized in that the preparation method of the modified straw fiber comprises the following steps: The straw fiber is pretreated by microwaves and then immersed in an acid solution, and then the pH value is adjusted to neutral, filtered and dried to obtain the modified straw fiber. 6. A high-strength concrete according to claim 5, characterized in that the acid solution comprises dilute hydrochloric acid or dilute sulfuric acid with a concentration of 0.05-0.2 mol/L. 7. A high-strength concrete according to claim 1, characterized in that the fine aggregate is recycled fine aggregate particles with a particle size of 1-5 mm obtained by crushing and screening construction waste concrete. 8. A method for preparing high-strength concrete according to any one of claims 1 to 7, characterized in that it comprises the following steps: The modified coarse aggregate is mixed with part of the water and allowed to stand for 5-10 minutes, then cement, fine aggregate and fly ash are added and mixed evenly, and finally the remaining water, modified straw fiber, rice husk ash and water reducing agent are added and stirred evenly to obtain the high-strength concrete. 9. A method for preparing high-strength concrete according to claim 8, characterized in that the partial water is 1/3 to 1/2 of the total water.