Strength of RCC is defined as compressive strength after 28 days, expressed as M15, M20,
where M stands for Mix and 15 stands for 15 N/mm2
(n/mm2 must be read as 'Newton’s per
millimeter Cubed) 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 1:4:8.
As strength. 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.
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 |
M10 or 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 |