CHECKLIST FOR STRENGTH REQUIREMENTS FOR CONCRETE
a) MAINTAIN A WATER/ CEMENT RATIO OF 0.5, i.e. use 25 lts of water per bag of cement.
b) Testing of cube moulds of 150 x 150 x 150 mm
STRENGTHS IN Kg/cm2
Concrete
Grade
Target Strength of
150 mm cube at
3 days in Kg/cm2.
(60 % strength)
Target Strength of
150 mm cube at
7 days in Kg/cm2.
( 77 % strength)
Target Strength of
150 mm cube at
28 days in Kg/cm2.
( 100% strength)
M20
170
218
283
M25
200
256
333
STRENGTHS IN N/mm2
Concrete
Grade
Target Strength of
150 mm cube at
3 days in N/mm2.
(60 % strength)
Target Strength of
150 mm cube at
7 days in N/mm2.
( 77 % strength)
Target Strength of
150 mm cube at
28 days in N/mm2.
( 100% strength)
M20
17.0
21.8
28.3
M25
20.0
25.6
33.3
All the testing cubes should be cast from a single concrete mix batch. (load).
Concrete Strength
Ration of Nominal Mix
Theoretical Consumption per
Minimum Cement Content per cum.
Strength Required in Kg/ cm2 by
3 days
7 days
28 days
M20
1:1.5:3
8.20 bags
6.40 bags
170
218
283
M15
1:2:4
6.40 bags
6.00 bags
140
179
233
M10
1:3:6
4.40 bags
4.40 bags
M7.5
1:4:8
3.40 bags
3.40 bags
Note: Cement bags of 50 kg
Item of work
Type
Ratio of Mix
Theoretical consumption
Masonry
Laterite (All Sizes)
1:5
1.90 Bags / Cum
Masonry
Brick 230 thk. and above
1:5
1.46 Bags/ Cum
Masonry
Brick 115 thk. And below
1:5
1.46 Bags/ Cum
Masonry
Concrete Block 200 thk.
1:5
0.60 Bags/ Cum
Masonry
Concrete Block 150 thk.
1:5
0.60 Bags/ Cum
Masonry
Concrete Blocks 100 thk.
1:5
0.60 Bags/ Cum
Plaster for brick masonry
18mm thk. In double coat
1:3 & 1:4
0.255 Bags/ Sqm
--Do--
12mm thk in single coat
1:4
0.155 Bags/ Sqm
For ceilings
8mm thk in single coat
1:3
0.144 Bags/ Sqm
Plaster for Laterite Masonry
18mm thk. In double coat
1:3 & 1:4
0.311 Bags/ Sqm
-- Do--
12 mm thk. in single coat
1:4
0.188 Bags/ Sqm
Drip moulds/ band
Per cum of work
1:4
7.650 Bags/ Cum
Flooring
IPS 50mm thk. Incl. Plaster and neat cement slurry
1:2:4
0.450 Bags/ Sqm
Note: Cement bag of 50 kg.
