About Lesson
Concrete mixed design
- The method of concrete mixed design consists of optimum proportion of cement, sand, coarse aggregate and water to produce a concrete of specified property.
- The most usually specified properties are comprehensive strength at specified age, workability and durability.
|
Grade |
Specified characteristics |
Mix proportion |
Cement / m3 of |
Water/ 50 kg |
|
|
|
comprehensive strength |
|
|
concrete quintal |
cement- liter |
|
|
at 28 days N/m-m2 |
|
|
|
|
|
M25 |
25 |
1 |
:1: 2 |
6.1 |
27 |
|
M20 |
20 |
1:1½:3 |
4 |
30 |
|
|
M15 |
15 |
1 |
:2:4 |
3.20 |
32 |
|
M12 |
12 |
1 |
:3:6 |
2.20 |
34 |
|
M10 |
10 |
1 |
:4:8 |
1.70 |
45 |
|
M7 |
7 |
1:5:6 |
1.30 |
60 |
|
NOTE:
- M7 and M5 are used for lean concrete bases and simple foundation for masonary wall. More than M15 are used for RCC.
- More than M30 are used for prestrested concret work.