SEGREGATION OF CONCRETE

Segregation Of Concrete

Segregation of concrete is the separation of cement paste and aggregates of concrete from each other during handling and placement.Segregation also occurs due to over-vibration or compaction of concrete, in which cement paste comes to the top and aggregates settles at the bottom.

Generally, it is observed that segregation occurs in plastic stage of concrete, mostly occurs in lean concrete and wet concrete.

Causes Of Segregation In Concrete

• It may cause due to excess water content in the mix.
• It may cause due to the separation of coarser particles.
• It may cause due to the use of poor graded aggregates.
• It occurs due to the use of over vibration of concrete.
• It may cause due to the transporting concrete mixes for long distance.
• It occurs due to poor handling of concrete, i.e drooping concrete more than 1 m.

How To Reduce Segregation In Concrete

• The water cement ratio in the concrete mix should be properly designed.
• The placement of concrete must be from normal height, i.e less than 1.5 m.
• Formwork should be water tight to prevent leakage.
• The combination of cement and sand in the concrete must be according to the design.
• Transport the concrete mix effectively.Select shortest route for transportation of concrete mix.
• Use vibrator correctly and never use the vibrator to spread a heap of concrete over a large area.
• Use admixtures in concrete such as air entraining agents in the mix. Entrained air reduces the danger of segregation.