Project on Concrete Mix Design for various grades of Concrete
*Concrete mix design for M35 concrete with fly ash
•Target mean strength : f’ck= fck +1.65 • f’ck = target mean strength
•fck= compressive strength at 28 days of concre
s = standard deviation ( IS 10262:2009 , table -1) volume of cement : (mass of cement /specfic gravity of cement )x1 /1000
Volume of water : ( mass of water /specific gravity of water ) x1 /1000
volume of chemical admixtures : ( mass of chemical admixture / specific gravity of chemical admixture )x 1/1000
Volume of fly ash : (mass of fly ash/specific gravity of fly ash )x 1/1000
Volume of concrete: 1 m^3
volume of aggregates : ( volume of concrete -( volume of cement +volume of fly ash + volume of water + volume of admixture )
Mass of coarse aggregates: volume of aggregate x volume of coarse aggregate x specific gravity of coarse aggregate x1000
Mass of fine aggregate : volume of aggregate x volume of fine aggregate x specific gravity of fine aggregate x1000
*Procedure and calculation
1.Target mean strength
F'ck=fck+1.65*S
=35+1.65*5=45N/mm^2
2.Selection of water cement ratio
Given M35, Assume: exposure condition: extreme (for reinforced concrete)
Extreme=w/c ratio=0.40
M35=w/c ratio=0.45
Lower the water cement ratio better the workability
0.40<0.45
Water cement ratio=0.40
Minimum cement content=360kg/m^3
3.Selection of water content
Assume nominal size of aggregate=20mm
Slump ranges from 25 to 50mm
As superplasticizers (20% reduced)
186*80/100=148.8 (100-20=80)
Water content=149 litres
4.Calculation of cementitious content (cement+fly ash)
Water cement ratio=w/c=0.40
Water content=w=149kg
Cementitious content=c=149/0.40=372.5=370kg/m^3
360<370kg/m^3. (hence okay)
Increase by 10%
370*0.10+370=407kg/m^3
W=149kg
Water cement ratio=149/407=0.366
Fly ash at 30% total cementitious content
407*30/100=122kg/m^3
Cement (ordinary Portland cement)
=407-122=285kg/m^3
Saving of cement while using fly ash
=370-285=85kg/m^3
Fly ash=122kg/m^3
5.Volume of Coarse aggregate and fine aggregate
Table 3 IS 10262:2009
Nominal size of aggregate=20mm
Fine aggregate (zone 1)
Vol of Coarse aggregate=0.60
Water cement ratio=0.4
(+/-0.01 for every +/- 0.005)
Volume of Coarse aggregate=0.62
Volume of fine aggregate=0.38
6.Mix calculation
1.volume of concrete=1m^3
2.volume of cement=(285/3.15)*1/1000=0.090m^3
3.volume of fly ash=(122/2.2)*1/1000=0.055m^3
4.volume of water=(149/1)*1/1000=0.149m^3
5.volume of admixture=(7.6/1.145)*1/1000=0.006m^3
6.volume of Coarse aggregate and fine aggregate
=a-(b+c+d+e)
=1-(0.090+0.055+0.149+0.006)
= 0.7m^3
7.mass of coarse aggregate=0.7*0.62*2.74*1000
=1189.16kg/m^3
8.mass of fine aggregate=0.7*0.38*2.74*1000
=728kg/m^3
7.mix proportion
Cement=285kg/m^3
Fly ash=122kg/m^3
Water=149
C.A=1189kg/m^3
F.A=728kg/m^3
Chemical admixture=7.6kg/m^3
Water cement ratio=0.366
Mix proportion by weight=1:2.55:417
*Concrete mix design for M50 grade concrete without fly ashT
•Target mean strength : f’ck= fck +1.65 s
•f'ck = target mean strength
•fck= compressive strength at 28 days of concrete
s=standard deviation ( IS 10262:2009 , table -1)
•Volume of cement : (mass of cement /specific gravity of cement )x1/1000
•Volume of water : ( mass of water/specific gravity of water ) x1 /1000
•Volume of chemical admixtures : ( mass of chemical admixture/ specific gravity of chemical admixture )x 1/1000
•Volume of concrete: 1 m^3
•Volume of aggregates : ( volume of concrete -( volume of cement + volume of water+volume of chemical admixture) )
•Mass of coarse aggregates: volume of aggregate x volume of coarse aggregate x specific gravity of coarse aggregate x1000
•Mass of fine aggregate : volume of aggregate x volume of fine aggregate x specific gravity of fine aggregate x1000
*Procedure and calculation
1. Target mean strength
F'ck=fck+1.65*S
=50+1.65*5=58.25N/mm^2
2.Selection of water cement ratio
Given M50 assume: exposure condition: extreme (for reinforced concrete)
Table 5- IS 10456:2000
Extreme=w/c ratio=0.40
M50=w/c ratio=0.40
Lower the water cement ratio better the workability
0.40
Water cement ratio=0.40
Minimum cement content=360kg/m^3
3.Selection of water content
Assume nominal size of aggregate=20mm
Slump ranges from 25 to 50mm
As superplasticizers (20% reduced)
186*80/100=148.8 (100-20=80)
Water content=149 litres
4.Calculation of cement content
Water cement ratio=w/c=0.40
Water content=w=149kg
Cement content=c=149/0.40=372.5=373kg/m^3.
Minimum cement content=360kg/m^3
360<370kg/m^3. (hence okay)
5.Volume of Coarse aggregate and fine aggregate
Table 3 IS 10262:2009
Nominal size of aggregate=20mm
Fine aggregate (zone 1)
Vol of Coarse aggregate=0.60
Water cement ratio=0.4
(+/-0.01 for every +/- 0.005)
Volume of Coarse aggregate=0.62
Volume of fine aggregate=1-0.62=0.38
6.Mix calculation
1.volume of concrete=1m^3
2.volume of cement=(373/3.15)*1/1000=0.118m^3
3.volume of water=(149/1)*1/1000=0.149m^3
5.volume of admixture=(7.6/1.145)*1/1000=0.006m^3
6.volume of Coarse aggregate and fine aggregate
=a-(b+c+d)
=1-(0.118+0.149+0.006)
= 0.727m^3
7.mass of coarse aggregate=0.727*0.62*2.74*1000
=1235.02kg/m^3
8.mass of fine aggregate=0.727*0.38*2.74*1000
=756kg/m^3
7.mix proportion
Cement=373kg/m^3
Water=149kg
C.A=1235.02kg/m^3
F.A=756kg/m^3
Chemical admixture=7.6kg/m^3
Water cement ratio=0.40
Mix proportion by weight=1:2.02:3.31