Project on Concrete Mix Design for various grades of Concrete
Concrete Mix Design for M35 grade concrete
1. Stipulations for Mix Design Concrete
- Grade designation : M 35
- Type of cement : OPC 53 grade confirming to IS 8112
- Maximum nominal size of aggregate : 20 mm
- Minimum cement content : 340 kg/m3
- Maximum water-cement ratio : 0.45
- Workability : 50-100 mm (slump)
- Exposure condition : Very Severe (for reinforced concrete)
- Method of concrete placing : Pumping
- Degree of supervision : Good
- Type of aggregate : Crushed angular aggregate
- Maximum cement content : 450 kg/m3
- Chemical admixture type : Super Plasticizer
2. Test Data for Materials (to be determined in the laboratory)
- Specific gravity of cement : 3.12
- Specific gravity of Coarse aggregate : 2.74
- Specific gravity of Fine aggregate : 2.56
3. Target Strength for Mix Proportioning
ftarget = fck + 1.65 x S
Explanation of terms:
‘ftarget‘ is the target average compressive strength at 28 days,
‘fck‘ is the characteristic compressive strength at 28 days, and
‘s’ is the standard deviation
As per the table I of IS: 10262-2009 , standard deviation, s = 5.0 N/mm2
Therefore, target strength = 35 + 1.65 x 5.0 = 43.25 N/mm2
4. Selection of Water/Cement Ratio
From Table 5 of IS 456:2000,
Maximum water-cement ratio = 0.45
5. Selection of Water Content
From Table 2 of IS 456, maximum water content =186 litres (for 25 to 50 mm slump range) for 20 mm aggregate.
Estimated water content for 100 mm slump =186+(6/100) x 186 =197 liter.
(Note: If Super plasticizer is used, the water content can be reduced upto 20% and above.)
Based on trials with Super plasticizer water content reduction of 25% has been achieved, Hence the arrived water content = 197-[197 x (25/100)] = 147 litres.
6. Calculation of Cement Content
Water-cement ratio =0.45
Cement content = 147/0.45 = 350 kg/m3
From Table 5 of IS 456, minimum cement content for ‘Very Severe‘ exposure condition = 340 kg/m3
350 kg/m3 > 340 kg/m3, hence, Ok
7. The Proportion of the Volume of Coarse Aggregate and Fine Aggregate Content
From Table 3 of IS 10262, volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate for a water-cement ratio of 0.50 = 0.62.
In the present case, the water-cement ratio is 0.45. Therefore, the volume of coarse aggregate is required to be increased to reduce the fine aggregate content.
As the water-cement ratio is lower by 0.10, the proportion of the volume of coarse aggregate is increased by 0.02 . Therefore. the corrected proportion of the volume of coarse aggregate for the water-cement ratio of 0.45 = 0.63.
For pumpable concrete, these values should be reduced by 10 percent.
Therefore, volume of coarse aggregate = 0.63 x 0.9 = 0.567.
Volume of fine aggregate content =1 – 0.567 =0.433
8. Mix Calculations
a) Volume of concrete = 1m3
b) Volume of cement = (Mass of cement/Specific Gravity of Cement) X (1/1000)
= (350/3.12) X (1/1000)
= 0.112 m3
c) Volume of water = (Mass of water/specific gravity of water) X (1/1000)
= (147/1) X (1/1000)
= 0.147 m3
d) Volume of superplasticizer = (Mass of superplasticizer / Specific gravity of admixture) X (1/1000)
= (7/1.145) X (1/1000)
= 0.006 m3
e) Volume of all aggregate = (a-(b+c+d))
= 1 – (0.112 + 0.147+0.006)
= 0.735 m3
f) Mass of coarse aggregate = Volume of all aggregate X volume of coarse aggregate X Specific gravity of coarse aggregate X 1000
= 0.735 x 0.567 x 2.74 x 1000
= 1141.88 kg
g)Mass of fine aggregate = Volume of all aggregate X volume of fine aggregate X Specific gravity of fine aggregate X 1000
= 0.735 x 0.433 x 2.56 x 1000
= 814.73 kg
9. Concrete Mix Proportions
- Cement = 350 kg/m3
- Water = 147 kg/m3
- Super plasticizer = 7 kg/m3
- Fine aggregates = 814.73 kg/m3
- Coarse aggregate = 1141.88 kg/m3
- W/c = 0.45
oncrete Mix Ratio Obtained
The Mix Ratio of M35 as obtained is 1 : 2.32 : 3.26
This is the procedure for mx design calculation of M35 grade concrete .
Stipulations for Concrete Mix Design
- Grade designation : M 50
- Type of cement : OPC 53 grade confirming to IS 8112
- Maximum nominal size of aggregate : 20 mm
- Minimum cement content : 360 kg/m3
- Maximum water-cement ratio : 0.35
- Workability : 50-75 mm (slump)
- Exposure condition : Extreme (for reinforced concrete)
- Method of concrete placing : Pumping
- Degree of supervision : Good
- Type of aggregate : Crushed angular aggregate
- Maximum cement content : 450 kg/m3
- Chemical admixture type : Super Plasticizer
Test Data for Materials
The following data are collected by performing standard tests in a laboratory.
Specific gravity of cement : 3.12
Specific gravity of Coarse Aggregate : 2.74
Specific gravity of Fine Aggregate : 2.56
Procedure for Concrete Mix Design of M 50 Concrete
1. Target Strength for Mix Proportioning
ftarget = fck + 1.65 x s
ftarget denotes the Target Average Compressive Strength at 28 days,
fck denotes the Characteristic Compressive Strength at 28 days,
‘s’ stands for Standard Deviation
According to the table 1 of IS: 10262-2009 ,
standard deviation, s = 5.0 N/mm2
Therefore, target strength = 50 + 1.65 x 5.0 = 58.25 N/mm2
2. Selection of Water/Cement Ratio
From Table 5 of IS 456 : 2000,
Maximum water-cement ratio = 0.35
3. Selection of Water Content
From Table 2 of IS 456, maximum water content =186 litres (for 25 to 50 mm slump range) for 20 mm aggregate.
Estimated water content for 100 mm slump =186+(6/100) x 186 =197 litres.
(Note: If Super plasticizer is used, the water content can be reduced up to 20% and above.)
Based on trials with Super plasticizer water content reduction of 27% has been achieved, Hence the arrived water content = 197 – [197 x (27/100)] = 143 litres.
4. Calculation of Cement Content
Water-cement ratio = 0.35
Cement content = 143/0.35 = 410 kg/m3
From Table 5 of IS 456, minimum cement content for ‘Extreme exposure’ condition = 360 kg/m3
410 kg/m3 > 360 kg/m3, hence, O.K.
5. Proportion of Volume of Coarse Aggregate and Fine Aggregate Content
From Table 3 of IS 10262. volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone II) for a water-cement ratio of 0.50 =0.62.
In the present case, the water-cement ratio is 0.35. Therefore. the volume of coarse aggregate is required to be increased to decrease the fine aggregate content. As the water-cement ratio is lower by 0.10. the proportion of the volume of coarse aggregate is increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in the water-cement ratio).
Therefore. the corrected proportion of the volume of coarse aggregate for the water-cement ratio of 0.35 = 0.65.
For pumpable concrete, these values should be reduced by 10 percent.
Therefore, volume of coarse aggregate = 0.65 x 0.9 = 0.585.
Volume of fine aggregate content =1 – 0.585 =0.415
6. Mix Calculations
a) Volume of concrete = 1m3
b) Volume of cement = (Mass of Cement/ Its Specific Gravity ) X (1/1000)
= (410/3.12) X (1/1000)
= 0.131 m3
c) Volume of Water = (Mass of water/specific gravity of water) X (1/1000)
= (143/1) X (1/1000)
= 0.143 m3
d) Volume of Superplasticizer = (Mass of Superplasticizer / Specific gravity of admixture) X (1/1000)
= (8.2/1.145) X (1/1000)
= 0.007 m3
e) Volume of all aggregate = (a – (b + c + d))
= 1 – (0.131 + 0.143+0.007)
= 0.719 m3
e) Mass of coarse aggregate = Volume of All Aggregate X Volume of Coarse Aggregate X Specific Gravity of Coarse Aggregate X 1000
= 0.719 x 0.585 x 2.74 x 1000
= 1152.48 kg
f) Mass of fine aggregate = Volume of all aggregate X volume of fine aggregate X Specific gravity of fine aggregate X 1000
= 0.719 x 0.415 x 2.56 x 1000
= 763.86 kg
7. Concrete Mix Proportions
- Cement = 410 kg/m3
- Water = 143 kg/m3
- Super plasticizer = 7 kg/m3
- Fine aggregates = 763.86 kg/m3
- Coarse aggregate = 1152.48 kg/m3
- W/c = 0.35