CONCRETE MIX DESIGN AND QUANTITY CALCULATION
Concrete Mix design and Quantity Calculation
Concrete is a composite mixture of Cement Sand & Aggregate.
We use concrete in structure because of its load bearing ability. Here the term
Concrete Mix design introduced. It is the process where we find the mixing
ratio of concrete ingredient to achieve desire strength. Here strength is
compressive in nature.
As per IS-456:2000 different grade of concrete and desire compressive strength are mention bellow.
SL
NO
|
GRADES
OF CONCRETE
|
RATIO
OF CONCRETE (CEMENT : SAND :AGGREGATE)
|
CHARACTERISTIC COMPRESSIVE STRENGTH OF 150MM CUBE AFTER
28DAYS OF CURING
|
1
|
M5
|
1:5:10
|
5 N/ mm2
|
2
|
M7.5
|
1:4:8
|
7.5 N/ mm2
|
3
|
M10
|
1:3:6
|
10 N/ mm2
|
4
|
M15
|
1:2:4
|
15 N/ mm2
|
5
|
M20
|
1:1.5:3
|
20 N/ mm2
|
6
|
M25
|
1:1:2
|
25 N/ mm2
|
7
|
M30
|
1:0.75:1.5
|
30 N/ mm2
|
8
|
M35
|
1:0.5:1
|
35 N/ mm2
|
9
|
M40
|
1:0.25:0.5
|
40 N/ mm2
|
Here “M” stands for Mix and the “number” stands for Characteristic Compressive strength of the concrete in N/mm2 of 150 mm cube (150mmx150mmx150mm) after 28 days.
Now we calculate the quantity of Cement, Sand & Aggregate in
general ways for 1cum volume of Concrete.
Let, Ratio of graded
concrete given- C: S: A
Wet volume of concrete
given 1cum, but we continue our calculation to multiply dry volume factor to
given wet volume. For concrete we consider dry volume factor 1.54-1.57.
So, now our volume is 1cum x 1.54 = 1.54cum
For Cement – 1.54 x C/(C+S+A) cum
For Sand - 1.54
x S/(C+S+A) cum
For Aggregate - 1.54 x A/(C+S+A) cum
For example, we
calculate the quantity of Cement, Sand & Aggregate in M15 grade concrete.
Ratio of M15 - C: S: A = 1:2:4
For Cement – 1.54 x 1/(1+2+4) cum
=1.54 x 1/7 cum
= 0.22 cum
We know Volume of 1bag
cement is 0.035 cum.
Now required cement in Bags
= 0.22/0.035 = 6.28, Say 6 Bags
For Sand – 1.54 x 2/(1+2+4) cum
=1.54 x 2/7 cum
= 0.44 cum
For Aggregate – 1.54 x 2/(1+2+4) cum
=1.54 x 4/7 cum
= 0.88 cum
Quantities of Cement, Sand & Aggregate of
different grade of Concrete at a glance
SL NO
|
GRADE OF CONCRETE
|
UNIT
|
MATERIALS
|
QUANTITY OF MATERIALS
|
UNIT
|
1
|
M5 (1:5:10)
|
cum
|
1. Cement
2. Sand
3. Stone
Chips (6- 20mm)
|
1. 0.096
2. 0.48
3. 0.96
|
cum
|
2
|
M7.5
(1:4:8)
|
cum
|
1. Cement
2. Sand
3. Stone
Chips (6- 20mm)
|
1. 0.12
2. 0.48
3. 0.96
|
cum
|
3
|
M10(1:3:6)
|
cum
|
1. Cement
2. Sand
3. Stone
Chips (6- 20mm)
|
1. 0.156
2. 0.47
3. 0.94
|
cum
|
4
|
M15(1:2:4)
|
cum
|
1. Cement
2. Sand
3. Stone
Chips (6- 20mm)
|
1. 0.22
2. 0.44
3. 0.88
|
cum
|
5
|
M20(1:1.5:3)
|
cum
|
1. Cement
2. Sand
3. Stone
Chips (6- 20mm)
|
1. 0.286
2. 0.43
3. 0.86
|
cum
|
6
|
M25(1:1:2)
|
cum
|
1. Cement
2. Sand
3. Stone
Chips (6- 20mm)
|
1. 0.385
2. 0.385
3. 0.77
|
cum
|
Nice
ReplyDelete