This OER will enable you to
- Explain RCC
- Describe Types of steel bars
- Identify different elements of RCC Construction
- Describe each element of RCC construction
- Prepare a RCC column
You must have seen that in the construction of a building, the columns and the beams are constructed first and then the slab is built on this grid. The walls of such structures are constructed after the slab is in place. Have you ever wondered about this process of the roof first and then the walls?
Most of the high rise buildings use RCC technique which you have come across in the OER on “types of construction”. In an RCC framed structure, the load is transferred from a slab to the beams, then to the columns, and further to lower columns and finally to the foundation which in turn transfers it to the soil.
Meaning of RCC:
The full form of RCC is Reinforced Cement Concrete. Cement concrete is strong in compressive strength but weak in tensile strength. To increase the tensile strength, mild steel bars are used in cement concrete thereby reinforcing it. These steel bars are plain in surface or round sections (diameter from 6 to 50 mm.) These rods are manufactured in long lengths and can be cut quickly and be bent easily without damage. Steel bars used in cement concrete provide good strength to the structure.
Usually steel bars are roughened or corrugated to further improve the bond or cohesion between the concrete and steel. Care must be taken that there should be no joints in steel bars used for RCC work. Therefore you might have observed that steel bars used for RCC work are long. If full length steel bars are not available, proper overlap should be given in steel bars and overlap should be staggered. A care must be taken that the steel bars should not be disturbed during concreting. Steel rods should have proper bonding and planks or plates must be provided for walking of the people carrying concrete.
Observe the PowerPoint presented here.
- What is the difference between other types of construction and RCC Construction?
- Draw a sketch of a beam and a column to distinguish between them.
To prepare simple RCC work:
To prepare simple construction work we must know the proportion of cement, sand, gravels, how to prepare Mortar/Concrete required for different types of construction work:
Following table shows the type of work and the ratio of cement, sand, and gravel for construction.
|Type of Work||Proportion of Cement : Sand|
|Bricks work (burnt)||1:6|
|Finishing||1:2 ( or cement + water)|
|Type of Work||Proportion of Cement : Sand : Gravel|
|Making foundation||1:3:6 or 1:3:5|
|R.C.C. column or beam||1:2:4|
Architects refer the following concrete code table in drawing. Knowing this table will help you in deciding the proportion of cement, sand and gravel in RCC.
Concrete code and concrete ratio:
|Concrete Grade||Proportion of Cement : Sand : Stone pieces||Expected Compressive Strength at 28 days|
|M100||1 : 3 : 6||10 N/mm2 or 100 Kg/cm2|
|M15 or M150||1 : 2 : 4||15 N/mm2 or 150 Kg/cm2|
|M20 or M200||1 : 1.5 : 3||20 N/mm2 or 200 Kg/cm2|
|M25 or M250||1 : 1 : 2||25 N/mm2 or 250 Kg/cm2|
Let us learn a simple RCC work: how to prepare a column: (ppt)
RCC or Reinforced Cement Concrete is strengthening of Cement concrete by adding mild steel bars in it. There are two types of steel bar; round and torsion. The various elements of RCC construction are foundation, beam, column and slab. These can be prepared by mixing a right proportion of cement, sand, gravel with water and steel bars.
Prepare a RCC column of 8’’ X 8’’ and length 3 ft.