Definition of concrete chemical admixtures

The so-called concrete chemical admixtures are substances that are added during the process of mixing concrete (can be added at the same time as the mixing water, or can be added later than the water) to improve the properties of the concrete. The dosage is generally no more than 5% of the cement mass.
The earliest concrete chemical admixtures used in China were sulfite pulp waste liquid, which was a by-product of the papermaking industry and was called "plasticizer" at the time. The pulp waste liquid can significantly improve the workability of concrete mixtures. Improve its strength and durability.
Since the 1990s, my country's chemical admixtures have developed rapidly. There are now thousands of manufacturers, with an annual output of 2.8 million tons and hundreds of product varieties.
With the development of science and technology, many new requirements have been put forward for the performance of concrete. For example, new pumping technology requires high-fluidity concrete, large-span buildings require high-strength and high-durability concrete, and winter construction requires early-strength concrete. By mixing These requirements can be met with appropriate types of admixtures. Therefore, the successful development of high-quality, diverse concrete chemical admixtures is a major change and innovation in the history of concrete technology development. Concrete chemical admixtures are recognized by countries around the world as one of the essential components in concrete.
The purpose of adding concrete chemical admixtures is mainly to improve certain aspects of the properties of concrete mixtures or hardened concrete. It does not include grinding aids and grinding aids added during the cement production process to increase cement output or adjust certain properties of cement. Setting agent (such as gypsum), etc.