Durable concrete preparation method

Abstract

The invention relates to the technical field of concrete, in particular to a durable concrete preparation method, the concrete comprises cement, aggregate and water, the cement accounts for 10%-15% of the total mass of the concrete, the water accounts for 5%-8% of the total mass of the concrete, the aggregate accounts for 60%-80% of the total mass of the concrete, the water-binder ratio is controlled within the range of 0.25-0.5, and 20% of the cement is replaced with fly ash; the mixing amount is 0.5-1.0, the water reducing rate of the high-efficiency water reducing agent is greater than 25%, the water-cement ratio is reduced to below 0.38, the high-efficiency water reducing agent and the mixing water are simultaneously added into a stirring machine during mixing, the stirring time is prolonged by 20-30 minutes, an additive is added, and a high-efficiency active mineral admixture is mixed; and stirring and mixing by adopting a secondary stirring method, a sand wrapping method or a sandstone wrapping method. According to the invention, the pH value of water is strictly controlled, the aggregate is strictly required, and the fly ash, the water reducer and the like are added to control the minimum dosage of the cement, so that the alkalinity of concrete is maintained, the amount of free water is reduced, the water consumption is reduced, the cement with high durability is obtained, and the service life of a concrete building is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, in particular to a method for preparing durable concrete. Background Art

[0002] Concrete has poor durability. When the concrete structure is in an environment below freezing, some of the water in the gaps within the concrete will freeze, causing volume expansion. The supercooled water will migrate and form various pressures. When the pressure reaches a certain level, it will cause damage to the concrete. In severe cases, the surface will fall off and expose stones. Summary of the invention

[0003] The object of the present invention is to provide a method for preparing durable concrete to solve the problem in the above background technology that poor durability of concrete will affect the use of concrete structures.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for preparing durable concrete, the components of the concrete include cement, aggregate and water, wherein the cement accounts for 10% to 15% of the total mass of the concrete, the water accounts for 5% to 8%, the aggregate accounts for 60% to 80%, the water-binder ratio is controlled within the range of 0.25 to 0.5, and 20% of the cement is replaced by fly ash;

[0006] The high-efficiency water-reducing agent with a dosage of 0.5-1.0, the water-reducing rate of the high-efficiency water-reducing agent is greater than 25%, and the water-cement ratio is reduced to below 0.38. When adding, add it into the mixer at the same time as the mixing water, extend the mixing time by 20-30 minutes, add admixtures, and mix in high-efficiency active mineral admixtures;

[0007] The mixing is carried out by adopting the secondary mixing method, the sand wrapping method or the sand and gravel wrapping method.

[0008] As a further description of the above technical solution:

[0009] The aggregate comprises fine aggregate and coarse aggregate, the particle size of the fine aggregate is in the range of 0.15 mm to 5 mm, the particle size of the coarse aggregate is in the range of 5 mm to 40 mm, and crushed stone is used.

[0010] As a further description of the above technical solution:

[0011] The apparent density of the aggregate is greater than 2.65, and the bulk density is greater than 1450kg / m 3 , water absorption is less than 1.0%, and mud content is less than 1.0%.

[0012] As a further description of the above technical solution:

[0013] The admixture is a retarder, an air entraining agent, a pumping agent, an expansion agent, a colorant, an antifreeze agent or a waterproofing agent.

[0014] As a further description of the above technical solution:

[0015] The air entraining agent is an air entraining type water reducing agent, and the air entraining amount is 4% to 8%.

[0016] As a further description of the above technical solution:

[0017] The high-efficiency active mineral admixtures are silicon powder and slag.

[0018] As a further description of the above technical solution:

[0019] The pH value of the water must not be less than 4.

[0020] As a further description of the above technical solution:

[0021] The cement is No. 62.5 cement.

[0022] Compared with the prior art, the present invention provides a method for preparing durable concrete, which has the following advantages:

[0023] Beneficial effects:

[0024] In the present invention, by strictly controlling the pH value of water, further strict requirements are imposed on aggregates, fly ash, water reducing agent and the like are added to reduce the amount of cement, and the minimum amount of cement is controlled to maintain the alkalinity of concrete, reduce the amount of free water, reduce the amount of water used, obtain highly durable cement, and extend the service life of concrete buildings. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe 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 making creative work are within the scope of protection of the present invention.

[0026] Example:

[0027] The present invention provides a method for preparing durable concrete, wherein the components of the concrete include cement, aggregate and water, wherein the cement accounts for 10% to 15% of the total mass of the concrete, the water accounts for 5% to 8%, the aggregate accounts for 60% to 80%, the water-binder ratio is controlled within the range of 0.25 to 0.5, and 20% of the cement is replaced by fly ash;

[0028] The high-efficiency water-reducing agent with a dosage of 0.5-1.0, the water-reducing rate of the high-efficiency water-reducing agent is greater than 25%, and the water-cement ratio is reduced to below 0.38. When adding, add it into the mixer at the same time as the mixing water, extend the mixing time by 20-30 minutes, add admixtures, and mix in high-efficiency active mineral admixtures;

[0029] The mixing is carried out by adopting the secondary mixing method, the sand wrapping method or the sand and gravel wrapping method.

[0030] Specifically, the aggregate includes fine aggregate and coarse aggregate. The particle size of the fine aggregate ranges from 0.15mm to 5mm, and the particle size of the coarse aggregate ranges from 5mm to 40mm. Crushed stone is used. The apparent density of the aggregate is greater than 2.65, and the bulk density is greater than 1450kg / m 3 , water absorption is less than 1.0%, mud content is less than 1.0%, high-performance concrete has relatively high requirements on the strength of the aggregate itself. When such aggregate is selected, its porosity will be as low as possible. When the same fluidity is achieved, the amount of cement slurry is low, the self-shrinkage deformation of the concrete is low, the hydration heat is low, the volume stability is good, the strength and durability are good, and the elastic modulus of the concrete increases accordingly.

[0031] Specifically, the admixture is a retarder, an air entraining agent, a pumping agent, an expansion agent, a colorant, an antifreeze agent or a waterproofing agent. The air entraining agent is an air-entraining water-reducing agent with an air entraining amount of 4% to 8%, which can form a certain number of uniformly distributed, stable and closed spherical pores in the concrete, cut off the path of capillary water seepage, achieve the effect of improving high impermeability, and improve the frost resistance, corrosion resistance and durability of the concrete.

[0032] Specifically, high-efficiency active mineral admixtures are silica powder and slag, which can enhance the strength of concrete.

[0033] Specifically, the pH value of the water shall not be less than 4, and shall not contain any substances that may have a harmful effect on the steel bars.

[0034] Specifically, the cement is No. 62.5 cement, which has low water requirement.

[0035] Working principle:

[0036] According to the ratio requirement, first replace 20% of the cement with fly ash, and then put the fly ash and other parts of the cement into the mixing device according to the ratio, mix them, and add 0.5-1.0% of the high-efficiency water-reducing agent, the water reduction rate of the high-efficiency water-reducing agent is greater than 25%, and the water-cement ratio is reduced to below 0.38. In the process of mixing, add high-efficiency water-reducing agent, admixtures and high-efficiency active mineral admixtures, and the mixing method adopts the current secondary mixing method, sand wrapping method or sand and gravel wrapping method.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing durable concrete, characterized in that: The components of the concrete include cement, aggregate and water, wherein cement accounts for 10% to 15% of the total mass of the concrete, water accounts for 5% to 8%, aggregate accounts for 60% to 80%, the water-binder ratio is controlled within the range of 0.25 to 0.5, and 20% of the cement is replaced by fly ash; The high-efficiency water-reducing agent with a dosage of 0.5-1.0, the water-reducing rate of the high-efficiency water-reducing agent is greater than 25%, and the water-cement ratio is reduced to below 0.

38. When adding, add it into the mixer at the same time as the mixing water, extend the mixing time by 20-30 minutes, add admixtures, and mix in high-efficiency active mineral admixtures; The mixing is carried out by adopting the secondary mixing method, the sand wrapping method or the sand and gravel wrapping method.

2. A method for preparing durable concrete according to claim 1, characterized in that: The aggregate comprises fine aggregate and coarse aggregate, the particle size of the fine aggregate is in the range of 0.15 mm to 5 mm, the particle size of the coarse aggregate is in the range of 5 mm to 40 mm, and crushed stone is used.

3. A method for preparing durable concrete according to claim 2, characterized in that: The apparent density of the aggregate is greater than 2.65, and the bulk density is greater than 1450kg / m 3 , water absorption is less than 1.0%, and mud content is less than 1.0%.

4. The method for preparing durable concrete according to claim 1, characterized in that: The admixture is a retarder, an air entraining agent, a pumping agent, an expansion agent, a colorant, an antifreeze agent or a waterproofing agent.

5. A method for preparing durable concrete according to claim 4, characterized in that: The air entraining agent is an air entraining type water reducing agent, and the air entraining amount is 4% to 8%.

6. A method for preparing durable concrete according to claim 1, characterized in that: The high-efficiency active mineral admixtures are silicon powder and slag.

7. The method for preparing durable concrete according to claim 1, characterized in that: The pH value of the water must not be less than 4.

8. The method for preparing durable concrete according to claim 1, characterized in that: The cement is No. 62.5 cement.