In terms of absolute volume, cement consists of 75% aggregate, 10% cement and 15% water. If need be, admixtures can be added on condition of not exceeding 2% of the cement weight.
The plant where ready-mixed concrete constituents are stocked and mixed under control and ready-mixed concrete is produced and loaded to truck mixers is called “concrete batch plant”. Concrete batch plants are divided into two classes according to the types of batching, namely wet and dry batching plants, and again into two classes according to the types of storage, namely bunker type and star-type.
In wet batching system, concrete constituents, including water, are loaded to the truck mixer after having been batched in the plant. 
However, there is no batching in dry batching system; all constituents, except for water, are loaded to the truck mixer respectively and after the truck mixer has arrived at the site, mixing water is added into the mixing truck and batching operation is performed within the truck mixer.
In star type batching plants, there is a star shaped stocking area in front of the batching plant and aggregates are transferred into the batching tank by means of a bucket.
On the other hand, in bunker-type batching plants, aggregates and sands are stocked in the bunkers in front of the batching plant and transferred into the batching tank through a band system.
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