Project on Concrete Mix Design for various grades of Concrete
1)
Aim:
To calculate the concrete Mix Design for M35 grade concrete with fly ash
Codes used:
- IS 10262:2009
- IS 456 : 2000
- IS 9013
- IS 8112
- IS 3812
Objective:
To produce concrete as economical as possible with desired workability, durability, and minimum strength of M35 grade concrete.
Test data material ( obtained from lab ):
- Specific gravity of cement : 3.12
- Specific gravity of Coarse aggregate : 2.74
- Specific gravity of Fine aggregate : 2.56
Stipulation
- 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 : Extreme
- Method of concrete placing : Pumping
- Degree of supervision : Good
- Type of aggregate : Crushed angular aggregate
- Maximum cement content : 450 kg/m3
Procedure
1.Target mean strength;
f'ck = fck + 1.65 x S
where,
‘f'ck‘ 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
2.Selection of Water-cement ratio;
Assume the exposure condition is Extreme. Hence from Table 5 - IS 456 : 2000
Extreme = w/c = 0.40
M35 = w/c = 0.45
For achieveing better workability the water cement ratio should be low
therefore, water cement ratio = 0.40
3.Selection of water content;
From Table 2 of IS456, 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.
4.Calculation of cement content;
W/C ratio = 0.40
Water content = 147 litres
Cement content = 147 / 0.40 kg/m3
= 367.5 ~ 368 kg/m3 < 370 kg m3 ( hence okay )
Increase by 10%
368 x 10% + 368 = 404.8 ~ 405 kg/m3
New w/c = 147 / 405
= 0.363
Fly ash at 30% total cement content = 405 x 30%
= 121.5 kg/m3 ~ 122 kg/m3
therefore, Ordinary Portland cement = 405 - 122
= 283 kg/m3
Cement saved = 368 - 283
= 85 kg/m3
5.Volume of Coarse and Fine aggregate;
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 0.45. 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 (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 0.45 = 0.63.
Note : In case the coarse aggregate is not angular one. then also the volume of coarse aggregate may be required 10 be increased suitably, based on experience.
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
6. Mix Calculation ;
a) Volume of concrete = 1 m3
b) Volume of cement = ( Mass of cement / Specific gravity of cement ) x ( 1/1000)
= ( 368 / 3.12 ) ( 1 /1000 )
= 0.118 m3
c) Volume of water = ( mass of water / Specific gravity if water ) x ( 1/1000 )
= (147/1)(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
7. Concrete Mix proportions;
- Cement = 368 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 = 0.40
Mix Ratio obtained:
The Mix Ratio of M35 as obtained is 1 : 2.32 : 3.26 (Cement : Fine aggregate : Coarse aggregate)
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2)
Aim:
To calculate the concrete Mix Design for M50 grade concrete without fly ash
Codes used:
- IS 10262:2009
- IS 456 : 2000
- IS 9013
- IS 8112
- IS 3812
Objective:
To produce concrete as economical as possible with desired workability, durability, and minimum strength of M5o grade concrete.
Test data material ( obtained from lab ):
- Specific gravity of cement : 3.12
- Specific gravity of Coarse aggregate : 2.74
- Specific gravity of Fine aggregate : 2.56
Stipulation
- 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 : Extreme
- Method of concrete placing : Pumping
- Degree of supervision : Good
- Type of aggregate : Crushed angular aggregate
- Maximum cement content : 450 kg/m3
Procedure
1.Target mean strength;
f'ck = fck + 1.65 x S
where,
‘f'ck‘ 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 = 50 + 1.65 x 5.0 = 58.35 N/mm2
2.Selection of Water-cement ratio;
Assume the exposure condition is Extreme. Hence from Table 5 - IS 456 : 2000
Extreme = w/c = 0.40
M35 = w/c = 0.45
For achieveing better workability the water cement ratio should be low
therefore, water cement ratio = 0.40
3.Selection of water content;
From Table 2 of IS456, 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 20% has been achieved, Hence the arrived water content = 197-[197 x (20/100)] = 149 litres.
4.Calculation of cement content;
W/C ratio = 0.40
Water content = 149 litres
Cement content = 149 / 0.40 kg/m3
= 372.5 ~ 373 kg/m3 > 370 kg m3 ( hence okay )
5.Volume of Coarse and Fine aggregate;
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 0.45. 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 (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 0.45 = 0.63.
Note : In case the coarse aggregate is not angular one. then also the volume of coarse aggregate may be required 10 be increased suitably, based on experience.
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
6. Mix Calculation ;
a) Volume of concrete = 1 m3
b) Volume of cement = ( Mass of cement / Specific gravity of cement ) x ( 1/1000)
= ( 373 / 3.12 ) ( 1 /1000 )
= 0.119 m3
c) Volume of water = ( mass of water / Specific gravity if water ) x ( 1/1000 )
= (149/1)(1/1000)
= 0.149 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 – (0.118 + 0.149 +0.006)
= 0.727 m3
f) Mass of coarse aggregate = Volume of all aggregate X volume of coarse aggregate X Specific gravity of coarse aggregate X 1000
= 0.727 x 0.62 x 2.74 x 1000
= 1235.02 kg
g)Mass of fine aggregate = Volume of all aggregate X volume of fine aggregate X Specific gravity of fine aggregate X 1000
= 0.727 x 0.38 x 2.74 x 1000
= 756.9 kg
7. Concrete Mix proportions;
- Cement = 373 kg/m3
- Water = 149 kg/m3
- Super plasticizer = 7 kg/m3
- Fine aggregates = 814.73 kg/m3
- Coarse aggregate = 1141.88 kg/m3
- W/c = 0.40
Mix Ratio obtained:
The Mix Ratio of M35 as obtained is 1 : 2.02 : 3.32 (Cement : Fine aggregate : Coarse aggregate)
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