### Cement Concrete Calculator | PCC Calculator | RCC ...

Strength of PCC is defined as compressive strength after 28 days, expressed as M15, M20, where M stands for Mix and 15 stands for 15 N/mm 2 (n/mm 2 must be read as 'Newton's per millimeter Cubic') compressive strength at 28 days. The proportions of materials (cement, sand, coarse aggregate) for nominal mix/design mix concrete that are normally used are 1:3:6 or â€¦