concrete admixture-water reducing agent
1. the role of water reducing agent
improve the workability of the concrete while keeping the mix ratio unchanged ; or reduce water consumption while maintaining the same workability and improve the strength of concrete; or reduce cement consumption while maintaining the same strength, save cement and reduce costs. at the same time, adding water-reducing agent to the concrete will make it more uniform and dense, improve a series of physical and chemical properties, such as impermeability, frost resistance, erosion resistance, etc., and improve the durability of the concrete. specifically:
(1) increase hydration efficiency, reduce unit water consumption, increase strength, and save cement consumption;
(2) improve the workability of unsolidified concrete and prevent segregation of concrete components;
(3) improve impermeability, reduce water permeability, avoid leakage of concrete building structures, increase durability, and increase chemical corrosion resistance;
(4 ) reduce the shrinkage rate of concrete solidification and prevent cracks in concrete components;
(5) improve frost resistance, which is beneficial to winter construction.
2. the classification of water-reducing agents can be divided into ordinary water-reducing agents (represented by lignosulfonates) and high-efficiency water-reducing agents (including naphthalene series) according to their water-reducing rates. , melamine series, sulfamate series, aliphatic series, etc.) and high-performance water-reducing agents (represented by polycarboxylic acid-based high-performance water-reducing agents).
3. advantages of high-performance water-reducing agents commonly available on the market today. high-performance water-reducing agents have certain air-entraining properties, high water-reducing rates and good slump retention properties. compared with other water-reducing agents, high-performance water-reducing agents have obvious technical advantages and higher cost performance when formulating high-strength concrete and high durability. high-performance water-reducing agents include polycarboxylic acid-based water-reducing agents, aminocarboxylic acid-based water-reducing agents, and other water-reducing agents that can meet the requirements of this standard. our country has gradually begun to conduct research on high-performance water-reducing agents since around 2000. in the past two years, high-performance water-reducing agents represented by polycarboxylic acid-based water-reducing agents have gradually been applied in engineering.
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