Types, functions and classification of admixtures: Admixture technology is classified according to (GB8075—87),

Concrete admixtures can be divided into four categories according to their main functions:

1. Additives to improve the rheological properties of concrete mixtures: including various water reducing agents, air-entraining agents and pumping agents, etc.

2. Admixtures for adjusting the setting time and hardening performance of concrete: including retarders, early-strength agents, quick-setting agents, etc.

3. Additives to improve the durability of concrete: including air-entraining agents, waterproofing agents, and rust inhibitors.

4. Additives to improve other properties of concrete: include air-entraining agents, expansion agents, antifreeze agents, coloring agents, waterproofing agents and pumping agents. 

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

1. Ordinary water reducing agent: an admixture that can reduce the amount of water used for mixing when the concrete slump 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 uniformly distributed, stable and closed tiny bubbles in the process of mixing concrete;

5. High-efficiency water reducing agent: an admixture that can greatly reduce the water consumption of the mixture under basically the same conditions of concrete collapse;

6. Early-strength water-reducing agent: a water-reducing agent with both early-strength and water-reducing functions;

7. Slow-setting and water-reducing agent: a water-reducing agent with both retarding and water-reducing functions;

8. Air-entraining and water-reducing agent: an admixture with both air-entraining and water-reducing functions;

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

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

11. Air-entraining agent: an admixture that emits gas due to a chemical reaction during the preparation of concrete, 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 achieve sufficient antifreeze strength within a specified time;

14. Coloring agent: an admixture capable of preparing concrete with stable colors;

15. Accelerating agent: an admixture that can quickly harden concrete;

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