Concrete admixtures are mainly divided into the following categories according to their functions:
(1) Admixtures that improve the rheological properties of concrete mixtures, including various water-reducing agents, air-entraining agents and pumping agents agent.
(2) Admixtures that adjust the setting time and hardening properties of concrete, including retarder, early strength agent, accelerator, etc.
(3) Admixtures that improve the durability of concrete, including air-entraining agents, water-reducing agents, waterproofing agents, antifreeze agents, and rust inhibitors.
(4) Admixtures that improve the deformation properties of concrete, including expansion agents and recently developed shrinkage reducing agents. Shrinkage reducing agent is a newly developed concrete admixture in recent years. It is mainly a non-ionic organic substance with the oxide of low-grade ethanol as the main component.
(5) Admixtures that improve other properties of concrete, such as air-entraining agents, colorants, curing agents and release agents.
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