New Technology of Building Construction: High-efficiency Water Reducer
High-efficiency water reducer is also called super-plasticizer, which is mainly divided into two categories. One is sulfonated coal tar water reducer represented by naphthyl sulfonate formaldehyde condensate, the other is resin water reducer represented by melamine sulfonate formaldehyde condensate. Domestic commercial high-efficiency water reducer almost belongs to the first category. The high-efficiency water reducers are high molecular weight (20000-30000) anionic surfactant. Its long hydrocarbon chain contains a lot of polar groups. When they are adsorbed on the cement particle surface, diffused double-potential layer is formed around the particles, and therefore cement particles repel each other and keep good dispersion state. The surface tension of the water is lowered, thereby greatly improving the cement paste fluidity. The concrete slump is greatly increased under the condition of lower water-cement ratio. Because water-cement ratio is lower, the compactness of concrete is increased, and the concrete strength is also improved
