There are hard effects of segregation and bleeding on the workability and strength of concrete. So before the job frequently we are asked in the interview or on-site, that how to avoid segregation or how to avoid bleeding in concrete.
At that time can only answer it, if you really know the definition or difference between segregation and bleeding. So, a friend here I have described them in detail.
Difference between segregation and bleeding
It can be defined as separating out the ingredients of the concrete mix so that the mix is no longer in a homogeneous condition. It Separates out of coarser particles from the rest of the matrix Like Cement (cement slurry), Sand, etc.
Cause of Segregation
1) Segregation depends upon handling, transportation, and placing
2) More workability i.e. slump value means susceptible to segregation.
3) Dropping concrete from heights will result in segregation
4) Insufficient mixed concrete with excess water is prone to segregation.
5) Excess vibration i.e. vibration for long time results ins in segregation.
6) Segregation may also occur when we use a vibration needle to spread a heap of concrete.
Disadvantages of segregation?
1) It reduces the lifespan of concrete structures.
2) It makes the structure weak.
3) It makes the structure unstable due to eccentric loading caused by unequal distribution of concrete materials.
4) It generates the extra cost of labor and materials to repair and maintenance of segregated concrete.
5) It spoils the appearance of the concrete structure.
How to avoid segregation?
Avoid excessive compaction in concrete.
Use the suitable size of aggregate in concrete.
The dropping of aggregate in form-work should not be greater than 1.5 meters.
There should be an excessive gap between steel bars to enter the concrete slurry in it.
What is Bleeding?
It is a form of segregation in which some of the water in the mix tends to rise to the surface of freshly placed concrete. This is caused by the inability of a solid constituent of the mix to hold all the mixing water when they settle down during compaction.
Effect and remedies of Bleeding
1) It causes the formation of the porous, weak & nondurable concrete layer at the top of placed concrete.
2) Bleeding may be reduced by proper proportioning, uniform & complete controlled compaction.
3) It also can be reduced by the use of pozzolanic materials and air-entraining agents.
4) According to ASTM code 232, Bleeding is expressed in terms of the amount of accumulated water as % of the net mixing water sample.
5) Bleeding causes lack of water in concrete so, It decreases the strength of concrete due to not proper hydration.
Difference between segregation and bleeding in Concrete
|1||It is the separation of concrete ingredients from each other.||It is the Separation of cement water from the remaining mass of concrete.|
|2||It is caused due to improper mixing of concrete materials and placing of concrete from a height above 1.5 m.||It is caused due to over-compaction of concrete and excessive water in concrete.|
|3||It makes concrete porous and decreases its strength of concrete.||It leads to creating a honeycomb in concrete and decreases the strength.|
|4||It can be repaired after formation.||It can not be repaired after formation.|
|5.||Segregation weakens the durability and strength of the concrete||Bleeding results in surface scaling, weakened bonds, and poor surface finish|
Video for Difference between Segregation and Bleeding
Remember that bleeding and segregation are two dangerous outcomes in concrete construction. Bleeding can cause surface flaws and decreased bond strength and segregation can lead to uneven concrete strength and limited durability.
So it is important to take care while the concrete mixing and pouring to get the best results of the concrete structure.
I hope you liked my written article on “Difference between Segregation and Bleeding in Concrete and its Cause” and remains helpful for you.