Project on Concrete Mix Design for various grades of Concrete
CONCRETE MIX FOR M35 GRADE WITH FLYASH
a) Grade designation : M35
b) Type of cement: OPC 43 grade conforming to IS 8112
C) Maximum nominal size of aggregate : 20mm
d) Minimum cement content: 320 kg/m^3 (From Table 5 of IS 456: 2000 Exposure condition)
e) Maximum water-cement ratio : 0.45 (From Table 5 of IS 456: 2000 Exposure condition)
f) Workability: 100 mm (slump value for pumpable concrete)
g) Exposure condition: Severe (for reinforced concrete)
h) Method of concrete placing: Pumping
i) Degree of supervision: Good
Type of aggregate: Crushed angular aggregate
(k) Maximum cement content: 450 kg/m^3
(K)FLYASH CONFORMING TO IS 3812 PART1
Chemical admixture type: Superplasticizer
II. Test data for materials:
a) Cement used: OPC 43 grade conforming to IS 8112
b) Specific gravity of cement: 3.15
c) Chemical admixture: Superplasticizer conforming to IS 9103
Construction Materials/Concrete Mix Design
d) Specific gravity of:
Coarse aggregate-2.74
Fine aggregate-2.74
e) Water absorption:
Coarse aggregate-0.5%
Fine aggregate-1.0%
Free Surface moisture:
Coarse aggregate : Nil
Fine aggregate:Nil
III. Target Strength for Mix proportioning:
f'ck = fck+1.65 S
Where, fick=Target average compressive strength at 28 days
fck = Characteristic compressive strength at 28 days
S = Standard deviation
From Table 1 of IS 10262: 2009, standard deviation, S = 5 N/mm^2
Therefore, Target strength = 35 + 1.65 X 5 = 43.25 N/mm^2
IV. Selection of Water-cement ratio:
From Table 5 of IS 456: 2000 for severe exposure, maximum water-cement ratio = 0.45
As per Is 10262 2019 fig 1 water-cement ratio is 0.40
0.40<45, hence O.K
V. Selection of Water content
From Table 2 of IS 10262: 2009, maximum water content for 20mm aggregate = 186 litre (for
25mm to 50mm slump range)
Estimated water content for 100 mm slump = 186 + 6/100 *186
= 197 litre
As superplasticizer is used, the water content can be reduced up to 20% and above
Based on trials water content reduction of 29% is achieved with plasticizer.
Hence the arrived water content = 197*0.71 = 140 litre
VI. Calculation of Cement Content:
Water-content = 0.4
Cementitious material(cement+flyash)= 140/0.4 = 350 kg/m^3
From Table 5 of IS 456 minimum cement content for 'severe' exposure condition = 320 kg/m^3
350 kg/m^3> 320 kg/m^3, Hence OK
NMOW TO PROPORTION A MIX CONTAINING FLYASH FOLLOWING STEPS ARE SUGGESTED
a)the percentage of fly ash need to be decided based on project requirement. and quality of material
b)increase in cementitious material content and its percentage may be based on experience and trial(we take increase of 10% cementitious material)
cementitious material=350x1.1=385kg/m3
water content =140kg/m3
w/c ratio=140/385=0.364
fly ash @ 30% of total cementitious material content=385*30%=115kg/m3
cement(opc)=350-115=270kg/m3
saving of cement=80kg/m3
VII. Proportion of Volume of coarse aggregate and Fine aggregate content:
From Table 3 of IS 10262: 2009, Volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (Zone I) for water-cement ratio = 0.6
In the present case the water cement ratio is 0.40
Therefore, the volume of coarse aggregate needs to be increased to decrease the fine aggregate content.
As water-cement ratio is lower by 0.10, the proportion of volume of coarse aggregate is Therefore, corrected volume of coarse aggregate for the water-cement ratio of 0.40 = 0.62 Note: If coarse aggregate is not of angular type, then also the volume of coarse aggregate may be required to be increased suitably, based on experience) For pumpable concrete these values are reduced by 10%
increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in water-cement ratio).
Therefore, volume of coarse aggregate = 0.62 X 0.9 = 0.56 Volume of fine aggregate content = 1-0.56 = 0.44
vii Mix calculation
a)volume of concrete=1m3
b)volume of cement=mass of cement/(specific gravity of cement*1000)
=270/3.15*1/1000
=0.086m3
volume of flyash=mass of fly ash/(specific gravity of fly ash * 1000)
=115/2.2x1/1000
=0.052m3
c)volume of water=mass of water/(specific gravity of water*1000)
=140/1*1/1000
=0.14m3
d)volume of admixture= mass of chemical admixture/(specific gravity of admixture*1000)
=7.6/1.145*1/1000
=0.006m3
e)volume of aggregate(fa&ca) =(a-(b+c+d)
=(1-(0.086+0.052+0.14+0.006)
=0.716m3
f)mass of coarse aggregate=e*volume of coarse aggregate*specific gravity of coarse aggregate*1000
=0.716*0.56*2.74*1000
=1098g/m3
g)mass of fine aggregate=e*volume of fine aggregate*specific gravity of fine aggregate*1000
=0.716*0.44*2.74*1000
=863kg/m3
ix)mix proportion for trial no.1
cement-270kg/m3
flyash-115kg/m3
water-140kg/m3
fine aggregate-863kg/m3
coarse aggregate-1093kg/m3
chemical admixture-7kg/m3
w/c ratio-0.364
trial mix ratio=1:2.24:2.85
CONCRETE MIX FOR M50 GRADE WITHOUT FLYASH
a) Grade designation : M30
b) Type of cement: OPC 43 grade conforming to IS 8112
C) Maximum nominal size of aggregate : 20mm
d) Minimum cement content: 320 kg/m^3 (From Table 5 of IS 456: 2000 Exposure condition)
e) Maximum water-cement ratio : 0.45 (From Table 5 of IS 456: 2000 Exposure condition)
f) Workability: 100 mm (slump value for pumpable concrete)
g) Exposure condition: Severe (for reinforced concrete)
h) Method of concrete placing: Pumping
i) Degree of supervision: Good
Type of aggregate: Crushed angular aggregate
(k) Maximum cement content: 450 kg/m^3
Chemical admixture type: Superplasticizer
- Test data for materials:
- a) Cement used: OPC 43 grade conforming to IS 8112
- b) Specific gravity of cement: 3.15
- c) Chemical admixture: Superplasticizer conforming to IS 9103
Construction Materials/Concrete Mix Design
- d) Specific gravity of:
Coarse aggregate-2.74
Fine aggregate-2.74
- e) Water absorption:
Coarse aggregate-0.5%
Fine aggregate-1.0%
Free Surface moisture:
Coarse aggregate : Nil
Fine aggregate:Nil
III. Target Strength for Mix proportioning:
f'ck = fck+1.65 S
Where, fick=Target average compressive strength at 28 days
fck = Characteristic compressive strength at 28 days
S = Standard deviation
From Table 1 of IS 10262: 2009, standard deviation, S = 5 N/mm^2
Therefore, Target strength = 50 + 1.65 X 5 = 58.25 N/mm^2
- Selection of Water-cement ratio:
From Table 5 of IS 456: 2000 for severe exposure, maximum water-cement ratio = 0.45
As per Is 10262 2019 fig 1 water-cement ratio is 0.34(~0.35)
0.35<0.45, hence O.K
- Selection of Water content
From Table 2 of IS 10262: 2009, maximum water content for 20mm aggregate = 186 litre (for 25mm to 50mm slump range)
Estimated water content for 100 mm slump = 186 + 6/100 *186
= 197 litre
As superplasticizer is used, the water content can be reduced up to 20% and above
Based on trials water content reduction of 29% is achieved with plasticizer.
Hence the arrived water content = 197*0.71 = 140 litre
- Calculation of Cement Content:
Water- content = 0.35
Cement content= 140/0.35 = 400kg/m^3
From Table 5 of IS 456 minimum cement content for 'severe' exposure condition = 320 kg/m^3
400kg/m^3> 320 kg/m^3, Hence OK.
VII. Proportion of Volume of coarse aggregate and Fine aggregate content:
From Table 3 of IS 10262: 2009, Volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (Zone I) for water-cement ratio = 0.6
In the present case the water cement ratio is 0.35
Therefore, the volume of coarse aggregate needs to be increased to decrease the fine aggregate content.
As water-cement ratio is lower by 0.10, the proportion of volume of coarse aggregate is Therefore, corrected volume of coarse aggregate for the water-cement ratio of 0.35 = 0.63 Note: If coarse aggregate is not of angular type, then also the volume of coarse aggregate may be required to be increased suitably, based on experience) For pumpable concrete these values are reduced by 10%
increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in water-cement ratio).
Therefore, volume of coarse aggregate = 0.63 X 0.9 = 0.56 Volume of fine aggregate content = 1-0.56 = 0.44
vii Mix calculation
a)volume of concrete=1m3
b)volume of cement=mass of cement/(specific gravity of cement*1000)
=400/3.15*1/1000
=0.126m3
c)volume of water=mass of water/(specific gravity of water*1000)
=140/1*1/1000
=0.14m3
d)volume of admixture= mass of chemical admixture/(specific gravity of admixture*1000)
=7.6/1.145*1/1000
=0.006m3
e)volume of aggregate(fa&ca) =(a-(b+c+d)
=(1-(0.126+0.140+0.006)
=0.728m3
f)mass of coarse aggregate=e*volume of coarse aggregate*specific gravity of coarse aggregate*1000
=0.728*0.56*2.74*1000
=1117.04kg/m3
g)mass of fine aggregate=e*volume of fine aggregate*specific gravity of fine aggregate*1000
=0.728*0.44*2.74*1000
=877.6kg/m3
ix)mix proportion for trial no.1
cement-400kg/m3
water-140kg/m3
fine aggregate-877.6kg/m3
coarse aggregate-1117.04kg/m3
chemical admixture-7.6kg/m3
w/c ratio-0.35
trial mix ratio=1:2.19:2.79