ew and higher requirements for the performance of concrete.Since the promotion of concrete admixtures in the 1940s, its development has not only changed the internal structure of hardened concrete from the microscopic and submicroscopic levels, but also changed the structure of fresh concrete in the process. Concrete admixture, also known as dispersant or plasticizer, is the most commonly used and important admixture.

To prepare fresh concrete with good flow properties, the viscous structure that reduces the flow between cement particles must be disassembled, so that the cement particles can be fully dispersed in the water medium. There are many properties that affect cement fusion, such as the mineral composition of cement, the shape and size of cement particles, the integrity of mineral crystallization, and operating conditions and environmental factors. The above factors directly or indirectly control the stability of the cement particles in the slurry. Different medium conditions may change the value of the electric charge of the cement particles in the slurry, that is, change the electrostatic repulsion between the particles.

When an appropriate amount of concrete admixture is added to the fresh concrete, the points of the cement particles increase, and the electrical repulsion between the cement particles increases greatly, resulting in a decrease in the viscosity of the fresh concrete, which promotes the stability of the entire dispersion system. increased, and liquidity improved.

Generally, adding an appropriate amount of concrete admixture into the cement paste can promote the fresh concrete to show strong thixotropy. This is due to the formation of a solvated film layer on the surface of the cement particles adsorbed to the water reducing agent and the increase of the potential. If there is a little vibration, it will show better fluidity. The thixotropy of fresh concrete without superplasticizer is much weaker.