The role of cement additives, what are the concrete additives?

The following statement is false:

Cement additives are foreign names, and in domestic cement additives and cement admixtures refer to cement grinding aids. Cement additive is a chemical additive that improves the effect and performance of cement grinding, which can significantly increase the output of cement grinding table and the strength of cement at all ages. Cement additives can greatly reduce the electrostatic adsorption ball encapsulation phenomenon formed during the grinding process, and can reduce the re-coalescence tendency of ultrafine particles formed during the grinding process, and reduce the phenomenon of overgrinding.

Cement additives can also significantly improve the fluidity of cement, increase the grinding efficiency of the mill and the separation efficiency of the separator, thereby reducing the energy consumption of grinding. As a chemical activator, cement additives can improve the distribution of cement particles and stimulate the hydration activity of each mixture, thereby improving the early and later strength of cement.

The main components of cement additives include: Shuangkai polymerized polyol, Zhongbo polymeric olamine, triethanolamine, calcium chloride, sodium chloride, diethylene glycol, triisopropanolamine, ethylene glycol, molasses, urea, glycerin, etc.

1. Admixtures to improve the fluid transformation properties of concrete mixture.

Including various water reducing agents, air-entraining agents and pumping agents, etc.

Admixtures that regulate the setting time and hardening properties of concrete.

Including retarders, early strength agents and quick-setting agents.

Admixtures that improve the durability of concrete.

Including air-entraining agents, waterproofing agents and rust inhibitors, etc.

Admixtures that improve other properties of concrete.

These include aerating agents, swelling agents, colorants, antifreeze agents, waterproofing agents, and pumping agents, among others.

Concrete has the characteristics of abundant raw materials, low cost and simple production process, so that the amount of concrete is getting larger and larger. At the same time, concrete also has the characteristics of high compressive strength, good durability and wide range of strength grades.

These characteristics make it widely used, not only in various civil engineering projects, but also in shipbuilding, machinery industry, marine development, geothermal engineering, etc., concrete is also an important material.

Performance characteristics of concrete additives.

1. When the concrete strength and slump are basically the same, the amount of cement can be reduced by 10-25%.

2. When the water-cement ratio remains unchanged, the initial slump of concrete is increased by more than 10cm, and the water reduction rate can reach 15-25%.

3. It has a significant early strength and enhancement effect on concrete, and its strength is increased by 20-60%.

4. Improve the workability of concrete and comprehensively improve the physical and mechanical properties of concrete.

5. Good adaptability to all kinds of cement, and good compatibility with other types of concrete admixtures.

6. It is especially suitable for use in the following concrete projects: fluidized concrete, plasticized concrete, steam-curing concrete, impermeable concrete, waterproof concrete, natural curing prefabricated component concrete, steel bars and prestressed reinforced concrete, high-strength and ultra-high-strength concrete.

It is divided into four categories according to the main functions:

1) Admixtures to improve the fluid deformation properties of concrete mixtures, including various water reducing agents, air entraining agents and pumping agents

2) Admixtures that adjust the setting time and hardening performance of concrete, including retarder, early strength agent and quick-setting agent

3) Admixtures to improve the durability of concrete, including air entraining agents, waterproofing agents and rust inhibitors, etc.;

4) Admixtures to improve other properties of concrete, including aerating agents, expansion agents, antifreeze agents, colorants, waterproofing agents and pumping agents, etc.

Ordinary water reducer.

Under the condition that the slump of concrete is basically the same, the water consumption of mixing can be reduced.

Early strength agents accelerate the development of early strength of concrete.

Retarders prolong the setting time of concrete.

The air-entraining agent introduces a large number of evenly distributed, stable and closed tiny bubbles in the concrete mixing process.

High-efficiency superplasticizer.

Under the condition that the concrete slump is basically the same, the water consumption of mixing can be greatly reduced.

Early strength superplasticizer.

It has both early strength and water reduction functions.

Retarding water reducer.

It has the function of retarding and reducing water.

Air entrainment water reducer.

It has the function of bleed air and water reduction.

Inhibitors reduce the permeability of concrete under hydrostatic pressure.

Rust inhibitors inhibit or alleviate the corrosion of steel bars or other embedded metals in concrete.

In the process of preparing aerated agent concrete, a large number of pores are formed in the concrete due to the chemical reaction and the release of gas.

The expansion agent causes the concrete to expand by a certain volume.

Antifreeze hardens the concrete at negative temperature and reaches sufficient antifreeze, strength within the specified time.

Colorants are used to prepare concrete with a stable color.

The quick-setting agent makes the concrete set and harden quickly.

Pumping agent to improve the pumping performance of concrete mixture.

Within the specified dosage, the admixture is basically very small.

According to the classification of (GB8075-87), concrete admixtures can be divided into four categories according to their main functions:

1. Admixtures to improve the flow and deformation properties of concrete mixture: including various water reducers, air entraining agents and pumping agents.

2. Admixtures to adjust the setting time and hardening performance of concrete: including retarder, early strength agent, quick-setting agent, etc.

3) Admixtures to improve the durability of concrete, including air entraining agents, waterproofing agents and rust inhibitors, etc.;

4. Other admixtures to improve the properties of concrete: including air entraining agents, expansion agents, antifreeze agents, colorants, waterproofing agents and pumping agents.

According to the nomenclature and definition of (GB8075-87) admixtures, admixtures can be divided into 16 names, each of which is customized as follows:

1. Ordinary superplasticizer: an admixture that can reduce the amount of water used for mixing under the condition that the collapse degree of concrete is basically the same;

2. Early strength agent: an admixture that accelerates the early strength development of concrete;

3. Retarder: an admixture that prolongs the setting time of concrete;

4. Air entraining agent: an admixture that can introduce a large number of evenly distributed, stable and closed tiny bubbles in the process of mixing concrete;

5. High-efficiency superplasticizer: an admixture that can greatly reduce the amount of water used in the mixture under the same condition of concrete collapse;

6. Early strength superplasticizing agent: superplasticizer with both early strength and water reduction functions;

7. Retarding superplasticizer: superplasticizer with both retarding and water reducing functions;

8. Air entrainment superplasticizer: an admixture with both air entrainment and water reduction functions;

9. Waterproofing agent: admixture that can reduce the permeability of concrete under hydrostatic pressure;

10. Rust inhibitor: an admixture that can inhibit or alleviate the corrosion of steel bars or other embedded metals in concrete;

11. Aerator: an admixture that releases gas due to chemical reaction in the process of concrete preparation, which can make the concrete form a large number of pores;

12. Expansion agent: an admixture that can make the volume of concrete expand to a certain extent;

13. Antifreeze: an admixture that can harden concrete at negative temperature and reach sufficient antifreeze strength within a specified time;

14. Colorant: an admixture that can prepare concrete with stable color;

15. Quick-setting agent: an admixture that can make concrete harden quickly;

16 Pumping agent: an admixture that can improve the pumping performance of concrete mixtures.