CN108821682A - A kind of low cost alternate resources high crack-resisting and its preparation method - Google Patents

Abstract

The invention belongs to the technical field of concrete, and discloses a low-cost alternative resource high-crack-resistant concrete and a preparation method thereof. The components and dosage of the high-crack-resistant concrete are 280-450 parts of cement and 20-60 parts of fly ash by weight. 50-80 parts of slag powder, 10-30 parts of calcium mineral admixture, 0-200 parts of natural sand, 300-500 parts of machine-made sand, 200-400 parts of tailings sand, 800-1200 parts of stone, compound chemical admixture 4‑8 parts, water 90‑270 parts. The invention solves the problem of lack of natural river sand resources and the problem of high pollution and high energy consumption in the cement production process, and greatly reduces the cost of single-party concrete; adopts machine-made sand, tailings sand and calcareous mineral admixtures, and can improve the quality of concrete Excellent interface bonding strength, improve the crack resistance of concrete; effectively solve the problem of poor cohesion of concrete and easy bleeding and segregation.

Description

A low-cost alternative resource high crack-resistant concrete and its preparation method

technical field

The invention belongs to the technical field of concrete, and in particular relates to a low-cost alternative resource high-crack-resistant concrete and a preparation method thereof.

Background technique

At present, the existing technologies commonly used in the industry are as follows:

With the gradual increase in the demand for national infrastructure and the continuous development of concrete technology, the amount of concrete is also gradually increasing, and high-quality concrete raw materials are becoming more and more scarce, especially natural river sand resources. River sand makes the cost and difficulty of preparing high-quality concrete gradually increase. On the other hand, in the process of preparing concrete, cement is a high-pollution, high-energy-consumption and high-cost component. How to reduce carbon and environmental protection, save energy and reduce emissions, and reduce the cost of single-square concrete to a certain extent is what all engineering units are looking for. the problem we are facing.

At present, in terms of fine aggregate, machine-made sand is mainly used to replace part or all of natural river sand, so as to save natural sand, protect river channels and reduce the cost of concrete production in line with the national green environmental protection policy. In terms of cementitious materials, at present, low-activity or inactive admixtures such as fly ash and slag powder are mainly used to replace part of the cement, which can reduce the concrete to a certain extent under the premise of complying with the national low-carbon environmental protection, energy saving and emission reduction. The heat of hydration reduces the risk of concrete cracking. However, other alternative resources, such as tailings sand and calcareous mineral admixtures, have not been widely used to prepare concrete. On the basis of meeting various performance indicators of concrete, it can reduce the cost of single concrete, consume industrial by-products, and improve the resistance of concrete. crack performance.

In summary, the problems in the prior art are:

(1) In the prior art, natural river sand resources are scarce, high pollution, high energy consumption and high concrete cost in the process of cement production;

(2) In the prior art, machine-made sand and tailings sand contain a certain amount of stone powder, which affects the working performance and volume stability of concrete, and fresh concrete is easy to segregate and bleed, and hardened concrete is easy to crack;

(3) In the prior art, there are no examples of concrete prepared jointly by machine-made sand, tailings sand and calcareous mineral admixtures.

The difficulty and significance of solving the above technical problems:

Difficulty: Use machine-made sand and tailings sand to partially or completely replace natural river sand. Due to the mechanical crushing process used in the preparation process of machine-made sand and tailings sand, the sand grains are uneven, the gradation is poor, and the sand contains different degrees of Stone powder will significantly affect the working performance and volume stability of concrete. Therefore, in the process of using machine-made sand and tailings sand, it is necessary to redistribute the gradation of sand, and it is also very difficult to solve the problem of stone powder in sand without causing waste and consumption of resources and energy . On the other hand, the activity of calcareous mineral admixture itself is relatively poor. In the case of partially replacing cement, it is also difficult to solve various performance indicators of hardened concrete through compound chemical admixtures.

Significance: If an alternative resource concrete can be prepared, on the one hand, the use of machine-made sand, tailings sand and calcareous mineral admixtures can save natural resources and consume industrial by-products, which is in line with the national low-carbon environmental protection, energy conservation and emission reduction. On the other hand, under the premise of various performance indicators of concrete, the cost of single concrete can be significantly reduced. Therefore, the present invention will bring a major breakthrough to the application of practical engineering, and has great significance.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a low-cost alternative resource high crack-resistant concrete and its preparation method,

The present invention is achieved in this way, a low-cost alternative resource high crack-resistant concrete, said low-cost alternative resource high crack-resistant concrete consists of 280-450 parts by weight of cement, 20-60 parts of fly ash, slag 50-80 parts of powder, 10-30 parts of calcium mineral admixture, 0-200 parts of natural sand, 300-500 parts of machine-made sand, 200-400 parts of tailings sand, 800-1200 parts of stone, compound chemical admixture 4 -8 parts and 90-270 parts of water.

Further, the cement is P.I cement or ordinary Portland cement.

Further, the fly ash is Class II fly ash, the specific surface area is not less than 250m ² /kg, and the water demand ratio is not more than 105%.

Further, the specific surface area of the slag powder is not less than 350m ² /kg, the 28d activity index is not less than 75%, and the loss on ignition is not more than 3%.

Further, the chemical composition of the calcareous mineral admixture is calcium carbonate, and the mesh number is 150-1200 mesh;

The natural sand is medium sand, the fineness modulus is 2.3-3.0, the particle size is not greater than 5mm, and the mud content is not greater than 1.0%;

The fineness modulus of the machine-made sand is 2.3-3.0, continuously graded, and the stone powder content is 1.0-20%;

The tailings sand has a fineness modulus of 2.3-3.0, continuous gradation, and a stone powder content of 1.0-10%.

Further, the stones have a nominal particle size of 5-20 mm, a mud content of no more than 1.0%, and a mud content of no more than 0.6%, and are continuously graded;

The composite chemical admixture consists of 20-30wt.% of slump-preserving polycarboxylate high-performance water reducer, 0.5-1wt.% of retarder, 0.1-5wt.% of viscosity modifier, and shrinkage reducing agent according to the content ratio. 1-5wt.% and 0.1-2wt.% adsorbent, the balance is water; wherein the retarder is one or more of sodium gluconate, sodium tripolyphosphate, sucrose or sodium citrate;

The thickener is one or more of Wenlun gum, xanthan gum or gellan gum;

The shrinkage reducing agent is a series of polyether polyols with a molecular weight of 2000-10000g/mol;

The adsorbent is polyethylene glycol with low molecular weight, and the molecular weight is 800-5000 g/mol.

Another object of the present invention is to provide a preparation method of low-cost alternative resource high crack-resistant concrete comprising:

Step 1, select 280-450 parts of cement, 20-60 parts of fly ash, 50-80 parts of slag powder, 10-30 parts of calcareous mineral admixture, 0-200 parts of natural sand, 300-500 parts of machine-made sand, 200-400 parts of tailings sand, 800-1200 parts of gravel, 4-8 parts of compound chemical admixture and 90-270 parts of water;

Step 2, 280-450 parts of cement, 20-60 parts of fly ash, 50-80 parts of slag powder, 10-30 parts of calcareous mineral admixture, 0-200 parts of natural sand, 300-500 parts of machine-made sand, Put 200-400 parts of tailings sand and 800-1200 parts of gravel into the mixer, and stir for 1 minute;

Step 3: Add 4-8 parts of compound chemical admixture and 90-270 parts of water, and stir for 3 minutes to prepare high-crack-resistant concrete.

Another object of the present invention is to provide a ring-country road paved with high crack-resistant concrete using the low-cost substitute resource.

Another object of the present invention is to provide a campus road paved with high-crack-resistant concrete using the low-cost alternative resource.

Another object of the present invention is to provide a road in urban greening areas paved with the low-cost substitute resource and high-crack-resistant concrete.

In summary, the advantages and positive effects of the present invention are:

(1) Replace natural sand with machine-made sand and tailings sand, and replace cement with fly ash, slag powder and calcareous mineral admixture, respectively solve the problem of lack of natural river sand resources and high pollution and high energy consumption in the process of cement production problem, and greatly reduce the cost of unilateral concrete;

(2) Compared with the raw materials used in traditional concrete, the use of machine-made sand, tailings sand and calcareous mineral admixtures can improve the interface bonding strength of concrete and improve the crack resistance of concrete;

(3) The use of compound chemical admixtures can improve the working performance of concrete and effectively solve the problems of poor cohesion and easy bleeding and segregation of concrete.

Description of drawings

Fig. 1 is a flow chart of the preparation method of low-cost alternative resource high crack-resistant concrete provided by the embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The concrete prepared by the present invention uses machine-made sand and tailings sand to replace natural sand in whole or in part, and uses fly ash, slag powder and calcareous mineral admixture to partially replace cement. On the one hand, it consumes part of waste resources and saves existing Resources reduce costs. On the other hand, the use of alternative resources and compound admixtures can improve the interface bond strength of concrete, improve the crack resistance of concrete, and effectively solve the problems of poor cohesion and easy bleeding and segregation of concrete. .

The low-cost alternative resource high crack-resistant concrete provided by the present invention has the following components and dosages by weight: 280-450 parts of cement, 20-60 parts of fly ash, 50-80 parts of slag powder, and calcareous mineral admixture 10-30 parts, 0-200 parts of natural sand, 300-500 parts of machine-made sand, 200-400 parts of tailings sand, 800-1200 parts of stone, 4-8 parts of compound chemical admixture and 90-270 parts of water.

The cement that the embodiment of the present invention provides is P.I cement or ordinary Portland cement;

The fly ash provided by the embodiment of the present invention is Class II fly ash, the specific surface area is not less than 250m ² /kg, and the water demand ratio is not more than 105%;

The specific surface area of the slag powder provided by the embodiment of the present invention is not less than 350m ² /kg, the 28d activity index is not less than 75%, and the loss on ignition is not more than 3%;

The main chemical composition of the calcareous mineral admixture provided by the embodiments of the present invention is calcium carbonate, and the mesh number is between 150-1200 mesh;

The natural sand provided in the embodiment of the present invention is medium sand, the fineness modulus is 2.3-3.0, the particle size is not greater than 5mm, and the mud content is not greater than 1.0%;

The fineness modulus of the machine-made sand provided by the embodiment of the present invention is 2.3-3.0, continuously graded, and the stone powder content is 1.0-20%;

The tailings sand fineness modulus provided by the embodiment of the present invention is 2.3-3.0, continuously graded, and the stone powder content is 1.0-10%;

The stones provided by the embodiment of the present invention have a nominal particle size of 5-20 mm, a mud content of no more than 1.0%, a mud content of no more than 0.6%, and continuous gradation;

The composite chemical admixture provided by the embodiment of the present invention is mainly composed of slump-preserving polycarboxylate high-performance water reducer, retarder, thickener, shrinkage reducer, adsorbent, etc., wherein the retarder is sodium gluconate , one or more of sodium tripolyphosphate, sucrose or sodium citrate, one or more of thickener Wenlun gum, xanthan gum or gellan gum, and the shrinkage reducer is polyether polyol series products , the molecular weight is between 2000-10000g/mol, and the adsorbent is mainly low-molecular-weight polyethylene glycol, and the molecular weight is between 800-5000g/mol.

The composite chemical admixture consists of 20-30wt.% of slump-preserving polycarboxylate high-performance water reducer, 0.5-1wt.% of retarder, 0.1-5wt.% of viscosity modifier, and 1-5wt.% of shrinkage reducing agent according to the content ratio. 5wt.% and 0.1-2wt.% of adsorbent, and the balance is composed of water.

The application principle of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the preparation technology of low-cost alternative resource high crack-resistant concrete provided by the present invention specifically comprises the following steps:

S101, select raw materials, stone, cement, fly ash, slag powder, calcareous mineral admixture, natural sand, machine-made sand, tailings sand, compound chemical admixture and water;

S102, according to the concrete ratio, pour stones, cement, fly ash, slag powder, calcareous mineral admixture, natural sand, machine-made sand, tailing sand into the mixer, and stir for 1 min;

S103, add compound chemical admixture and water, stir for 3 minutes, and prepare high-crack-resistant concrete.

According to the concrete ratio provided by the embodiment of the present invention, pour stones, cement, fly ash, slag powder, calcareous mineral admixture, natural sand, machine-made sand, and tailings sand into the mixer, and stir for 1 minute to make the materials evenly mixed ;

The compound chemical admixture and water provided in the embodiment of the present invention are added and stirred for 3 minutes, so that the admixture, water and materials are mixed evenly and fully contacted.

The present invention will be further described below in conjunction with specific embodiments.

Example 1

The low-cost alternative resource high crack-resistant concrete provided by the present invention has the following components and dosages by weight: 280 parts of cement, 20 parts of fly ash, 50 parts of slag powder, 10 parts of calcareous mineral admixture, and 300 parts of machine-made sand 200 parts of tailings sand, 800 parts of gravel, 90 parts of compound chemical admixture 4 and water.

Example 2

The low-cost alternative resource high-crack-resistant concrete provided by the present invention has the following components and dosages by weight: 2450 parts of cement, 60 parts of fly ash, 80 parts of slag powder, 30 parts of calcareous mineral admixture, and 200 parts of natural sand 500 parts of machine-made sand, 400 parts of tailings sand, 1200 parts of gravel, 8 parts of compound chemical admixture and 270 parts of water.

Example 3

The low-cost alternative resource high-crack-resistant concrete provided by the present invention has the following components and dosages by weight: 380 parts of cement, 40 parts of fly ash, 70 parts of slag powder, 20 parts of calcareous mineral admixture, and 100 parts of natural sand 400 parts of machine-made sand, 300 parts of tailings sand, 1000 parts of gravel, 6 parts of compound chemical admixture and 180 parts of water.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention.

Any modifications, equivalent replacements and improvements made within the spirit and principles of the invention shall be included in this

within the scope of protection of the invention.

Claims (10)

1. a kind of low cost alternate resources high crack-resisting, which is characterized in that the high cracking resistance of inexpensive alternate resources is mixed Solidifying soil is blended according to each ingredient of parts by weight by 280-450 parts of cement, 20-60 parts of flyash, 50-80 parts of slag powders, calcareous mineral It is 10-30 parts of material, 0-200 parts of natural sand, 300-500 parts of Machine-made Sand, 200-400 parts of CHARACTERISTICS OF TAILINGS SAND, 800-1200 parts of stone, compound 4-8 parts of chemical admixture and 90-270 parts of water compositions.

2. low cost alternate resources high crack-resisting as described in claim 1, which is characterized in that the cement is P.I water Mud or ordinary portland cement.

3. low cost alternate resources high crack-resisting as described in claim 1, which is characterized in that the flyash is II grades Flyash, specific surface area are not less than 250m²/ kg, water demand ratio are not more than 105%.

4. low cost alternate resources high crack-resisting as described in claim 1, which is characterized in that the slag powders specific surface Product is not less than 350m²/ kg, 28d activity index are not less than 75%, and loss on ignition is not more than 3%.

5. low cost alternate resources high crack-resisting as described in claim 1, which is characterized in that the calcareous mineral blend Material chemical component is calcium carbonate, and mesh number is in 150-1200 mesh；

The natural sand is middle sand, and fineness modulus 2.3-3.0, partial size is no more than 5mm, and clay content is no more than 1.0%；

The mechanism grain fineness number modulus is 2.3-3.0, continuous grading, content of stone powder 1.0-20%；

The tailing grain fineness number modulus is 2.3-3.0, continuous grading, content of stone powder 1.0-10%.

6. low cost alternate resources high crack-resisting as described in claim 1, which is characterized in that the stone nominal particle diameter 5-20mm, clay content are not more than 1.0%, and clod content is not more than 0.6%, continuous grading；

The compound chemical admixture is by content ratio by 20~30wt.% of collapse protective poly-carboxylic acid series high-performance dehydragent, slow setting 0.5~1wt.% of agent, 0.1~2wt.% of 0.1~5wt.% of viscosity modifier, 1~5wt.% of economization agent and adsorbent, surplus are Water composition；

Wherein retarder is one of sodium gluconate, sodium tripolyphosphate, sucrose or sodium citrate or a variety of；

Viscosity modifier is one of welan gum, xanthan gum or gellan gum or a variety of；

Economization agent is polyether polyol series of products, and molecular weight is 2000~10000g/mol；

Adsorbent is small-molecular-weight polyethylene glycol, and molecular weight is 800~5000g/mol.

7. a kind of preparation method of inexpensive alternate resources high crack-resisting as described in claim 1, which is characterized in that institute The preparation method for the inexpensive alternate resources high crack-resisting stated includes：

Step 1 chooses cement 280-450 parts, 20-60 parts of flyash, 50-80 parts of slag powders, calcareous mineral admixture 10-30 Part, 0-200 parts of natural sand, 300-500 parts of Machine-made Sand, 200-400 parts of CHARACTERISTICS OF TAILINGS SAND, 800-1200 parts of stone, compound chemistry are outer Add 4-8 parts of agent and 90-270 parts of water；

Step 2, by 280-450 parts of cement, 20-60 parts of flyash, 50-80 parts of slag powders, it is mineral admixture 10-30 parts calcareous, 0-200 parts of natural sand, 300-500 parts of Machine-made Sand, 200-400 parts of CHARACTERISTICS OF TAILINGS SAND, 800-1200 parts of stone enter in blender, stir 1min；

Step 3 is added compound chemical admixture 4-8 parts and 90-270 parts of water, stirs 3min, and high crack-resisting is made.

8. a kind of ring country road being laid with using inexpensive alternate resources high crack-resisting described in claim 1.

9. a kind of campus highway being laid with using inexpensive alternate resources high crack-resisting described in claim 1.

10. a kind of town greenery highway being laid with using inexpensive alternate resources high crack-resisting described in claim 1.