Concept of concrete segregation and bleeding

1.1 Bleeding

After the concrete mixture is poured and vibrated, during the setting process, part of the mixed water floats to the surface of the concrete along with the sinking of the granular materials. This phenomenon is called For bleeding. A small amount of bleeding on the surface of the concrete is normal and has no effect on the performance of the concrete mixture and hardening. However, excessive bleeding will bring many adverse consequences.

1.2 Segregation

Due to the difference in particle size and density of the components in the concrete mixture, the phenomenon of component separation and unevenness is called segregation. This uneven distribution of components will lead to differences in the performance of each part of the concrete, which can easily cause some defects inside or on the surface of the concrete, affecting the performance and normal use of the concrete. Therefore, it is necessary to take effective measures to prevent segregation and ensure that the concrete mixture has good cohesion and homogeneity, thereby ensuring the consistency of the performance of each part of the concrete.

There are two kinds of segregation in concrete. One is that the coarse aggregate in the concrete is easy to separate and fall off, and the other is that the cement slurry is easy to separate from the mixture during mixing. Cement slurry with higher viscosity is helpful to prevent segregation, so when the concrete water-cement ratio is small, the segregation tendency is small; while the concrete mixture with a small amount of cementitious material is prone to segregation of coarse aggregate when the fluidity is high; large Fluid concrete is prone to cement slurry separation. </p