Concrete water reducer is one of the most commonly used admixtures. As early as the 1940s, the development and research of lignin-based water reducers and various water reducers with the same effect had developed. In the early 1960s, the second-generation high-efficiency water reducers represented by naphthalene-based water reducers came out, and in the 1980s, the third-generation high-performance water reducers represented by polycarboxylic acid-based water reducers appeared. As an ideal replacement product for the second-generation water reducers such as naphthalene-based water reducers, the performance of polycarboxylic acid-based high-efficiency water reducers has been comprehensively improved, with a qualitative leap in both water reduction effect and technical performance.
What is the main difference between polycarboxylic acid water reducers and naphthalene-based water reducers? The water reduction mechanism is different. The former is mainly based on steric repulsion, while the latter is mainly based on electrostatic repulsion. The water reduction effect is different. In addition to steric repulsion, the former also has a strong air entrainment isolation "ball" effect and a solid-liquid interface energy reduction effect; the latter is mainly based on electrostatic repulsion effect, and there is almost no other effect that is beneficial to water reduction. Usually, the former dosage is between 0.05% and 0.3%, and the water reduction rate is 25% to 35%, and the highest can reach 40%; the latter dosage is 0.3% to 1.5%, the optimal dosage is 0.5% to 1.0%, and the water reduction rate is between 15% and 30%.
Like naphthalene water reducers, polycarboxylate high-efficiency water reducers still have the problem of adaptability to cement. However, compared with naphthalene water reducers, when using different types of cement concrete with the same other components, the optimal dosage of naphthalene high-efficiency water reducers is very different, and the maximum difference can be 20 to 40%. The optimal dosage of polycarboxylate high-efficiency water reducers is not much different, because the polycarboxylate water reducer has a high rate. The water reduction rate of polycarboxylic acid mother liquor is as high as 40%, while the water reduction rate of naphthalene is 15% to 20%. It has a significant advantage in dosage.
Polycarboxylic acid is more environmentally friendly in synthesis and use, and the synthesis process is simple. However, the synthesis of naphthalene is both energy-consuming and polluting, and the production process is complicated.
The newly mixed concrete using polycarboxylate high-efficiency water reducer has good workability, does not stick to the bottom, and is easier to vibrate and compact; the initial setting time is faster and it is easier to plaster and survive; the early strength increases quickly and the demoulding strength is high. Polycarboxylate high-efficiency water reducer has good adaptability to fluctuations in raw material quality, especially fluctuations in sand moisture content, and can obtain more stable concrete products.
From an economic perspective, by selecting cement with good adaptability, the cost of concrete per cubic meter can be basically unchanged, or even slightly reduced. If factors such as saving steam maintenance fees are considered, the use of polycarboxylate high-efficiency water reducer can achieve better economic benefits. Under normal circumstances, the use of polycarboxylate high-efficiency water reducer can save about 30kg of cement per cubic meter of concrete, and the strength of concrete in 28 days can be increased by 5~10Mpa.
You can browse the relevant product links in our website for more information.
DS-3 Retarding Water-reducer
Welcome to contact us
Contact: Ricky Li
Whatsapp: +86 152 5199 6760
Wechat: +86 152 5199 6760
Email: rickyli@hydget.com
