Segregation
Segregation
can be defined as the separation of the constituent materials of concrete. A
good concrete is one in which all the ingredients are properly distributed to
make a homogeneous mixture.If a sample of concrete exhibits a tendency for
separation of say ,coarse aggregate from the rest of the ingredients then, that
sample is said to be showing the tendency for segregation. Such concrete is
only going to be weak ; lack of homogeneity is also going to induce all
undesirable properties in the hardened concrete.
Prevention of segregation of concrete
➤The concrete mix should be properly designed with optimum quantity of water i.e. not too wet nor too dry.
➤Make sure the concrete is properly mixed at the correct speed in a transit mixture for at least two minutes. Regularly check the performance of mixer with respect to adequate uniformity of distribution of constituents in each batch.
➤Transport the concrete mix correctly. Choose the shortest route for transportation of concrete mix.
➤Place the concrete in its final position as soon as possible. Never place a concrete fromlarge heights.
➤Formwork should be water tight so that paste should leakage from the forms. Do not vibrate formwork.
➤Do not allow concrete to flow.
➤Use the vibrator correctly and never use the vibrator to spread a heap of concrete over a large area.
➤Vibrate the concrete for just the right time-not too long, not too less.
➤Use Chemical Admixture such as air entraining agent in the mix. Entrained air reduces the danger of segregation.
➤If any segregation is observed in concrete, remixing should be done so to make it homogeneous again.
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