Why steel is provided in Reinforced Cement Concrete?
It is concrete in which reinforcement is embedded in it. Embedded steel makes the reinforced concrete Strong and it provides strength. whereas concrete is good in compressive strength and weak in tensile strength. Due to which the structure without providing steel may failure due to brittle and there is no ductility. For that reason, steel is provided with concrete to contributes tensile strength because of it it doesn’t fail as brittle, it is ductile failure. Ductile failure because it gives prior warning before failing.
Different Grades of Concrete (IS 456:2000)
Ordinary Concrete (M10-M20):
It is used for general RCC work. Grade designation of the concrete is M10-M20. As we know, where M denoted Mix and the number denotes it compressive strength.
Standard Concrete (M25-M60):
It is used for Prestressed Concrete work. Grade designation of the concrete is M25-M60. As we know, where M denoted Mix and the number denotes it compressive strength.
High Strength Concrete (M65-M100):
It is used for High Strength RCC work. Grade designation of the concrete is M65-M100. As we know, where M denoted Mix and the number denotes it compressive strength.
Note : Characteristics Compressive strength is at age of 28 days. (Unit: N/mm2 )
Note : For the grade above M60, Specifications of IS 456 are not valid and these concrete specialised literature or experiments are to be referred .
Note : Minimum grade of concrete depends upon the exposure conditions in anticipated life of concrete structure which governs its durability as follows:
Min grade of concrete as per IS456 [RCC : M20]
Min grade of concrete as per IS456 [PCC : M15]
As per IS456, Minimum grade of concrete is M20 but as IS 13920, suggests as minimum grade of concrete M25
As per NBC, building higher than 12m, M25 is taken.
For concrete of grade M30 & above rate of gain of compressive structure is performing experiment.
