The cement concrete in which no reinforcement is provided is called Plain cement concrete(PCC). It is sometimes called mass cement concrete. It is considerably stronger in compression but weak in tension and shear.
Ingredients of Plain cement concrete
2) Sand(Fine aggregate)
3) Coarse aggregates
Uses of PCC
It is commonly used in the construction of the column foundation, bedrocks, massive gravity dams, heavy foundation, etc.
1) Selection and preparation of ingredients.
2) Mixing of ingredients
3) Transportation and placing
4) Compaction of Concrete
5) Finishing of surface
6) Curing of concrete
1) Selection and preparation of ingredients:
Various ingredients such as cement, sand, aggregate and water should be carefully selected according to the purpose and strength of concrete desired. These ingredients are then stored separately and properly.
2) Mixing of ingredients:
Ingredients of PCC are mixed properly with their relative proportion. Mixing may be of two types:
i) Hand mixing
ii) Machine mixing
i) Hand mixing:
It is the manual process of mixing of ingredients by labourers. This method of mixing is less suitable because more Cement is required than in machine mixing.
ii) Machine mixing:
Machine mixing is the process of mixing the ingredients of concrete by the use of a machine and such concrete is called the machine mixed concrete.
A machine used for the mixing of the concrete is called a mixer. A machine used for the mixing can be operated manually or electrically. Machine mixed concrete is suitable if the large quantity of concrete to be prepared.
3) Transportation and placing:
The prepared concrete is transported manually in an iron pan or mechanically through wheelbarrow or by buckets or by the pump. The media used in transportation depends upon the types and nature of the work.
The placing of concrete means the process of depositing to concrete in its required place and position as fast as possible.
4) Compaction of Concrete:
To remove air bubbles or air voids and to make concrete more dense and compacted; the freshly placed concrete should be compacted with rollers, rod, and vibrators. This process is called compaction of concrete.
There may be needed needle vibrator and surface vibrator. Needle vibrator is generally used to compact the concrete in the small, narrow and deep area like a beam, column etc and Some time used in flat area but the surface vibrator is used in compaction of a flat area like road construction.
5) Finishing of surface:
Finishing of a surface is also one of the important processes. Finishing means the removing of irregularities, voids etc present on the surface. After concreting the rough concrete surface; it is labelled and smoothen during the finishing process.
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