Polycarboxylic acid water reducer is a high-performance water reducer and a cement dispersant in the application of cement concrete. It is widely used in highways, bridges, dams, tunnels, high-rise buildings and other projects.
The product is environmentally friendly, non-flammable, non-explosive, and can be safely transported by trains and cars.
According to the difference of the main chain structure, the polycarboxylic acid superplasticizer products can be divided into two categories:
one type uses acrylic acid or methacrylic acid as the main chain and grafts polyethers with different side chain lengths. The other is polyethers with maleic anhydride as the main link and different side chain lengths. Based on this, a series of high-performance water-reducing agent products with different characteristics have been derived.
Before the emergence of polycarboxylic acid admixtures, there were lignosulfonate admixtures, naphthalene sulfonate formaldehyde condensate, melamine formaldehyde condensate, acetone sulfonate formaldehyde condensate, sulfamate formaldehyde condensate, etc. In the early 1980s, Japan took the lead in successfully developing polycarboxylic acid water reducers.
The new generation of polycarboxylate superplasticizer overcomes some of the disadvantages of traditional superplasticizers. It has the advantages of low dosage, good slump retention performance, low concrete shrinkage, strong adjustability in molecular structure, and great potential for high performance. Outstanding advantages such as not using formaldehyde in the process.
For the synthesis of polycarboxylic acid water-reducing agent, the design of molecular structure is very important, including the main chain group, side chain density and side chain length in the molecule. The synthesis methods mainly include in-situ polymerization grafting method, polymerization first and then functionalization method and monomer direct copolymerization method.
In many concrete projects, traditional high-efficiency concretes such as naphthalene series are increasingly unable to meet the needs of the project due to the limitations of technical performance.
A new generation of water-reducing agent that has attracted much attention at home and abroad, polycarboxylic acid-based high-performance water-reducing agent, because it has truly designed an effective molecular structure based on the mechanism of dispersed cement, it has a super-dispersed type and can prevent concrete slump loss Without causing obvious retardation, it can exert a higher plasticizing effect at low content, good fluidity retention, a large degree of freedom for the cement to adapt to a wide range of molecular structures, multiple synthesis technologies, and a large room for high performance, which can enhance concrete The effect is remarkable, it can reduce the shrinkage of concrete, the content of harmful substances is very low and other technical performance characteristics, which endow the concrete with excellent workability, good strength development, excellent durability, and the polycarboxylic acid-based high-performance water-reducing agent has good Comprehensive technical performance advantages and environmental protection characteristics meet the needs of modern concrete engineering.
Therefore, polycarboxylic acid-based high-performance water-reducing agents are gradually becoming the preferred admixture for the preparation of high-performance concrete. According to reports, the use of polycarboxylic acid admixtures in Japan has accounted for more than 80% of all high-performance admixture products, and North America and Europe have also accounted for more than 50%. In my country, polycarboxylate water-reducing agents have been successfully applied only in the Three Gorges Dam, Sutong Bridge, Tianwan Nuclear Power Station, Beijing-Shanghai High-speed Railway and other national large-scale water conservancy, bridge, nuclear power, and railway projects, and have achieved remarkable results.