The research and application of concrete admixtures has promoted the improvement of concrete engineering quality and the progress of construction technology. In particular, the research of superplasticizers has become an important branch of the scientific research of building materials, and promotes the continuous development of high-strength and high-performance concrete materials. Development, among which polycarboxylic acid superplasticizer is the representative of a new generation of green superplasticizer. High-performance water-reducing agent is an indispensable component of high-performance concrete due to its super-dispersing effect, especially after reaching a very low water-to-binder ratio. It is an indispensable component of high-performance concrete, and polycarboxylic acid-based high-efficiency water-reducing agent The performance of the agent is more superior, and its molecular structure is adjustable, and water-reducing agents with different performances can be prepared according to specific requirements. Therefore, the popularization and application of polycarboxylic acid superplasticizer is an inevitable requirement for the development of concrete in the direction of high performance.
At present, many countries have studied and applied polycarboxylic acid superplasticizers, and the promotion and application in Japan is more successful. my country's polycarboxylic acid water-reducing agent has only obtained rapid development in the past one or two years, and a variety of self-made products have been put into the market, but the overall performance is not too ideal, and there are still problems such as poor stability, single product performance, Compound admixture product formulations remain unchanged and other issues, the use rate of polycarboxylic acid is only about 20%.
Polycarboxylic acid-based high-performance water-reducing agents have the following classification methods, which are divided into different monomers used in the main chain: acrylic acid, methacrylic acid, maleic anhydride and maleic acid, etc.; according to the active monomers used The variety of raw materials is divided into: binary, ternary and other copolymers; according to the nature of surfactants, it is divided into: non-ionic water-reducing agent and anionic water-reducing agent; according to different purposes: for ready-mixed concrete High fluidity retention ability and high early strength polycarboxylic acid superplasticizer for precast concrete products; According to the molecular structure and functional group of polycarboxylic acid superplasticizer, polycarboxylic acid superplasticizer is divided into: A Acrylic acid-methacrylate type, allyl ether type polycarboxylate, imine/imide type polycarboxylate and amphoteric polycarboxylate. In recent years, due to technological innovation, a new type of cement admixture polycarboxylate water-reducing agent Beta-Mercaptopropionic Acid has been developed and used in large quantities. China Thiopropionic Acid is mainly used in the production of polycarboxylate water-reducing agent to control molecular weight and high-performance mediation. It greatly improves the water reduction rate and slump retention performance of concrete.