Action mechanism of water reducing agent
Steric hindrance effect
In the cement slurry mixed with high performance superplasticizer, the long chain of organic molecules of high performance superplasticizer actually shows various adsorption states on the surface of cement particles. The different adsorption states are caused by the different molecular chain structure of superplasticizers, which directly affects the temporal variation of slump of concrete mixed with such superplasticizers. Studies have shown that the adsorption state of naphthalene series and melamine series water reducer is rod-like chain, so it is a flat adsorption, and the electrostatic repulsion is weak. The result is that the Zeta potential decreases rapidly, the electrostatic balance is easy to be destroyed with the development of cement hydration process, so that the van der Waals gravity dominates and the slump changes greatly over time. On the surface of cement particles, the sulfinic acid superplasticizer…