Project on Concrete Mix Design for various grades of Concrete
AIM OF THE PROJECT:
concrete mix design for M35 grade concrete with fly ash and M50 without flyash
CONCRETE MIX DESIGN FOR M35 GRADE CONCRETE WITH FLY ASH:
1. STIPULATIONS FOR MIX DESIGN :
grade designation - M35
Type of cement - OPC grade 53 conforming to IS 8112
maximum nominal size of aggregate - 20mm
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 - 450kg/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 fine aggregate - 2.56
specific gravity of coarse aggregate - 2.74
3. TARGET STRENGTH FOR MIX PROPORTIONING :
ftarget = fck + 1.65 * S
where ftarget = target average compressive strength at 28 days
fck = charecteristic compressive strength at 28 days
'S' is the standard deviation
as per table I of IS 10262-2009 , standard deviation S = 5.0
ftarget = 35+ 1.65 * 5.0 = 43.25 N/mm⊃2;
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 = 187 lit ( for 25 to 50mm slump ) for 20mm aggregate
estimated water content for 100mm slump = 186+(6/100)*186 = 197 lit
(note : if super plasticizer is used , the water content may be reduced to 20% and above )
based on trials , water cement content is achieved by 25 % , hence arrived water content = 197-( 25/100 ) * 197 = 147 lit
6. CALCULATION OF CEMENT CONTENT :
water cement ratio = 0.45
cement content = 147/0.45 = 350 kg/m3
from table 5 IS 456 , minimum cement content for very severe condtion = 340kg/m3
350 kg/m3 > 340 kg/m3 , hence OK
7. THE PROPORTION OF VOLUME OF COARSE AND FINE AGGREGATE:
from table 3 of IS 10262, volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate for a (zone II) for a water cement ratio of 0.50=0.62
in present case , water cement is ratio is 0.45 , therefore the volume of coarse aggregate is required to be increased to reduce the fine aggregate content.As the water cemnt ratio is lowered 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 0.45=0.63.
Then 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 %
Therefore , volume of coarse aggregate = 0.63*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 )
= 0.147m3
d) volume of superplasticizer = (mass of super plasticizer/ specific gravity of admixture) x ( 1/1000 )
= ( 7/1.145 ) x ( 1/1000 )
= 0.006m3
e) volume of all aggregate = (a-(b+c+d))
= 1-(0.112+0.147+0.006)
= 0.735m3
f) Mass of coarse aggregate = volume of all aggregate x volume of coarse aggregate x specific gravity of coarse aggregate x 1000
= 0.735x0.567x2.74x1000
= 1141.88 kg
g) Mass of fine aggregate = volume of all aggregate x volume of fine agregate x specific gravity of fine aggregate x 1000
= 0.735x0.433x2.56x1000
= 814.73 kg
9. CONCRETE MIX PROPORTIONS:
cement = 350 kg/m3
Water = 147 kg/m3
Super plasticizer = 7 kg/m3
Fine aggregate = 814.53kg/m3
coarse aggregate = 1141.88 kg/m3
w/c ratio = 0.45
II CONCRETE MIX DESIGN FOR M50 GRADE WITHOUT FLYASH:
STIPULATIONS FOR MIX DESIGN:
grade of cement = M50
Type of cement = OPC 53 grade conforming to IS 8112
Maximum nominal size of aggregate = 20mm
Minimum cement content = 360 kg/m3
Maximum water-cement ratio = 0.35
Workability = 50-75mm 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 = Super plasticizer
TEST DATA FOR MATERIALS:
The following data are collected based on a standard test from 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:
1. TARGET STRENGTH FOR MIX PROPORTIONING:
ftarget = fck+1.65*s
According to IS 10262 : 2009
standard deviation s = 5.0 N/mm2
Therefore Target strength = 50+1.65*5 = 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 = 187 lit ( for 25 to 50mm slump ) for 20mm aggregate
estimated water content for 100mm slump = 186+(6/100)*186 = 197 lit
(note : if super plasticizer is used , the water content may be reduced to 20% and above )
based on trials , water cement content is achieved by 27 % , hence arrived water content = 197-( 27/100 ) * 197 = 143 lit
4. CALCULATION OF CEMENT CONTENT :
water cement ratio = 0.35
cement content = 143/0.35 = 410 kg/m3
from table 5 IS 456 , minimum cement content for very severe condtion = 340kg/m3
410 kg/m3 > 340 kg/m3 , hence OK
5. THE PROPORTION OF VOLUME OF COARSE AND FINE AGGREGATE:
from table 3 of IS 10262, volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate for a (zone II) for a water cement ratio of 0.50=0.62
in present case , water cement is ratio is 0.45 , therefore the volume of coarse aggregate is required to be increased to reduce the fine aggregate content.As the water cemnt ratio is lowered 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 0.45=0.63.
Then 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 %
Therefore , volume of coarse aggregate = 0.65*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 / specific gravity of cement ) 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 )
= 0.143m3
d) volume of superplasticizer = (mass of super plasticizer/ specific gravity of admixture) x ( 1/1000 )
= ( 8.2/1.145 ) x ( 1/1000 )
= 0.007m3
e) volume of all aggregate = (a-(b+c+d))
= 1-(0.131+0.143+0.007)
= 0.719m3
f) Mass of coarse aggregate = volume of all aggregate x volume of coarse aggregate x specific gravity of coarse aggregate x 1000
= 0.719x0.585x2.74x1000
= 1152.48 kg
g) Mass of fine aggregate = volume of all aggregate x volume of fine agregate x specific gravity of fine aggregate x 1000
= 0.719x0.415x2.56x1000
= 763.86 kg
7. CONCRETE MIX PROPORTIONS:
cement = 410 kg/m3
Water = 143 kg/m3
Super plasticizer = 7 kg/m3
Fine aggregate = 763.86kg/m3
coarse aggregate = 1152.48 kg/m3
w/c ratio = 0.35.