Segregation
Segregation may be defined as separation of concrete ingredients from whole mixture of concrete. When there is a tendency of separation of coarse aggregates from the concrete mixture and concrete loses its homoginity and also loses its hardening property then, segregation of concrete is occurred.
Segregation may be classified as in three types,
a. When coarse aggregate separating out from whole concrete mixture.
b. When binder material paste separating out from concrete mixture.
c. When water seperating out through out the concrete mixture due lower specific gravity.
There are several reasons for which segregation may occurred.
- Due to bad proportion of concrete mixing as a ingredients.
- Excess water content
- Excessive height of fall of dropping of concrete and placing of concrete in wrong manner.
- Poor performance of mixing machine.
- Very long time operation of vibrating machine
To avoid this type of segregation cohesive concrete mixture is required.Certain workabiity agent and pozzolonic material helps to reduce segregation.Also air entraining agent reduce segregation.