Answer by Arafat Basheer:
Differs from level to level and type of member. I worked in a project of G+27 and we used concrete mixes ranging from M50 to M30 in columns and beams, and M35 to M25 in slabs higher mixes in lower levels and lower mixes in upper levels. Column reinforcements ranged from 32mm to 12mm depending again on location and level of structure. Shear walls had dense and higher dia bars, so did outer skeltal columns. Inner skeltal columns had lower dia as compared to outer columns.