Concrete and its type

Concrete in fresh state 

     Concrete and its type   

Concrete may be defined as a composite mixture of binding material like cement or lime generally hydraulic lime, fine aggregate (course sand) and coarse aggregate (generally crushed stone or gravel) in definite proportion along the water. Freshly prepared concrete till it has not yet set is called wet or green concrete. When it has throughly sat and fully hardened it is called set concrete or just concrete.

 Qualities of good concrete

1. It has high compressive strength.
2. It is free from corrosion and their is no applicable effect of atmospheric agents on it.
3. It hardens with age (time) and the process of hardening continuous for a long time after the concrete has to become a sufficient strain.
4. It is quiet strong in compression but weak in tension. As such it is saftely used in the construction of load carry structure like piers and abutment of bridge, column etc. In case of member subjected to tensile stress it has to be rain frost with steel bar.
5. The density of concrete is very high it with 3000 kg per metre cube.
6. It should be easily workable.
7. It form hard surface capable of resisting abrasion.
8. It should be able to withstand the action of chemical salts.
9. It should be strong, desirable, dense, workable and being able to resist wear and tear.

 Plain Cement Concrete

It is defined as a composite mixture of cement, sand ( generally course sand) crushed stone or gravel in definite proportion along with water. As per IS : 456 - 2001 Concrete is designated in 7 grades as  M10, M15, M20, M25, M30, M35, M40. The letter M refers to mix and the number indicate the specified characteristic compressive strength of that mix at 28 days of curing in N/mm2 (Newton per mm square).

Lean Concrete

Lean Concrete is a term used to describe low grade concrete. It does not contain many of high density rock material that regular concrete does. Lean concrete often consist of reclaimed concrete material, low cement contain fly ash and discarded sand. It is cheaper alternative to regular concrete.
The main function of lean concrete is to provide the uniform surface foundation and to prevent the direct contact of foundation from the soil. It is also used to fill abundant wells and cavities.

Reinforced Cement Concrete

RCC is very strong in compression but very weak in tension and shear. In the construction of those members that are subject to tension or shear, Steel bars in various forms is embedded (reinforced) in those member. This concrete in which Steel bars have been embedded to handle it take a tension or shear stress safely is known as Reinforced Cement Concrete and is designated simply as RCC. It is extensively used in construction of all type of buildings, bridges arches, tanks massive dams and retaining walls.