Hi, To solve this query first you must have to know what is a composite structure and RCC structure.
Composite structure building exists when the two different materials are bound together by any means in a very strong manner so that they can act as a single component give a structural point of view.
Reinforced cement concrete buildings is a composite material but having low tensile strength and ductility which are encountered by the inclusion of reinforcement having higher tensile strength and ductility. Indian forced cement concrete structures reinforcement abound with cement concrete and both the members are really strong and compression and tension.
So if I concluded for G+ 12 types of painting reinforced cement concrete structures is used because it has very high tensile and ductility property and gives a high resistance against competition and tension also.
Hope you get the concept.