Project on Concrete Mix Design for various grades of Concrete
Disign Mix for M35 with fly ash
let us consider the data for designing M35 grade concrete mix,
1) Data collection:
- Grade Designation: M35
- Type of cement: 43 grade
- Maximum nominal size of aggregate: 20mm
- Minimum cement content: 320kg/m3 (from table 5 of IS 456:2000 - Exposure condition)
- Maximum water-cement ratio: 0.45 (From table 5 of IS 456:2000-Expoure condition)
- Workability : 100mm (slump value for pumpable concrete)
- Exposure condition : Severe (for RCC)
- Maximum cement content : 450 Kg/m3
- Specific gravity of cement: 3.15
- Specific gravity of Fly ash: 2.2
- Zone of fine aggregate : (zone-I)
- Specific gravity of corse agregate : 2.74
- Specific gravity of fine aggregate : 2.74
- Moisture content of FA and CA : Nill
- Chemical Admixture : super plastisizer
- Specific gravity of super plastisizer : 1.145
2) Target strength for mixing proportion:
fck'=fck+1.65 S
Where S=standard deviation = 5 (From table Is 10262:2009)
fck'=35+(1.65x5)
= 43.25 N/mm2
Therefore Target mean strength=43.25 pa.
3) Selection of water cement ratio:
- From above graph for fck'=43.25pa w/c ratio is 0.35
- from above graph For 43.25 pa curve E is considered, therefore, W/C =0.41
- From table 5 of IS 456:2000 for severe exposure, maximum water cement ratio=0.45, based on experiance let us consider W/C=0.4<0.45, hence ok.
Therefore consider 0.4 as w/c ratio.
4) Selection of Water content:
From table 2 of IS 10262:2009, maximum water content for 20mm aggregate=186 litre(for slump 25-50mm)
Therefore, for slump 100mm
Estimated water content for 100mm slump=186+(6/100)*186
= 197.16 litres.
As superplastisizer is used, thus water content be reduced to 30% but from trails let us consider 29% reduction,
Therefore: 197.16x0.71=140Litres.
5. Calculation of Cement content:
Water cement ratio = 0.4
Cementatious material(Cement+Fly ash)=140/0.4 =350 kg/m3
From table 5 of IS 456:2000 minimum cement content for Severe exposure condition=320kg/m3
350 kg/m3 > 320kg/m3 hence Ok,
For adding fly ash some consideration has to be taken.
- 10% of cementatious material is increse in order to use fly ash Therefore, 350+1.10 =385 kg/m3
- New water cement ratio =140/385 = 0.364
- Fly ash @30% of total cementatious material = 385x30% = 115.5 kg/m3
- Therefore for Cement Content = 385-115.5 = 269.5 kg/m3
6. calculation of Volume of coarse aggregate:
From table 3 of IS 10262:2009, volume of aggregate corresponding to 20mm size aggregate and fie aggregate (zone I) for water cement ratio of 0.5 is 0.60
Therefore for w/c ratio of 0.4 the volume changes to 0.62
(from the clause given in table 3, i.e.,As Water ceent ratio is lowered by 0.10, the proportion of volume of coarse aggregate is increased by 0.02 (at the rate of -/+ 0.01 for every +/-0.05 change in water cement ratio.)
for pumpable concrete these values are reduced by 10%
Therefore , volume of coarse aggregate =0.62x0.9 = 0.558 =0.56
Volume of fine aggregate =1-0.56=0.44
7. Mix Calculation:
a) Volume of Concrete =1 m3
b) Volume of Cement = (Mass of cement/specific gravity of cement) x(1/1000)
=(269.5/3.15)*(1/1000)
=0.0855 m3
c) Volume of Fly ash = (Mass of Fly ash/specific gravity of Fly ash) x(1/1000)
=(115.5/2.2)*(1/1000)
=0.0525 m3
d) Volume of Water = (Mass of water/specific gravity of water) x(1/1000)
= 140/1x0.001
=0.140 m3
e) Volume of super plastisizer =(Mass of plastisizer/specific gravity of plastisixer) x(1/1000)
= (7.7/1.145)x0.001
=0.0067m3
f) Volume of aggregate( CA &FA) ={a-(b+c+d+e)}
={1-(0.0588+0.0525+0.140+0.0067)}
=0.742m3
g) Mass of Coarse aggregate =fxvolume of coarse aggregatex specific gravity of coarse aggregatex1000
=0.742x0.56x2.74x1000
=1138.5 kg/m3
h) Mass of Fine aggregate =f x volume of Fine aggregate x specific gravity of Fine aggregate x 1000
=0.742 x 0.44 x 2.74x1000
=894.5 kg/m3
8. Mix Proportions
- Cement = 269.5 kg/m3
- Fly ash = 115.5 kg/m3
- Water = 140 kg/m3
- Chemical Admixture = 7.7 kg/m3
- Fine aggregate = 894.5 kg/m3
- coarse aggregate = 1138.5 kg/m3
- W/C ratio = 0.364
Design Mix for M35 with Fly Ash
1 : 2.32 : 2.95
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Disign Mix for M50
let us consider the data for designing M35 grade concrete mix,
1) Data collection:
- Grade Designation: M50
- Type of cement: 43 grade
- Maximum nominal size of aggregate: 20mm
- Minimum cement content: 320kg/m3 (from table 5 of IS 456:2000 - Exposure condition)
- Maximum water-cement ratio: 0.45 (From table 5 of IS 456:2000-Expoure condition)
- Workability : 100mm (slump value for pumpable concrete)
- Exposure condition : Extreem (for RCC)
- Maximum cement content : 450 Kg/m3
- Zone of fine aggregate : (zone-I)
- Specific gravity of cement: 3.15
- Specific gravity of corse agregate : 2.74
- Specific gravity of fine aggregate : 2.74
- Moisture content of FA and CA : Nill
- Chemical Admixture : super plastisizer
- Specific gravity of super plastisizer : 1.145
2) Target strength for mixing proportion:
fck'=fck+1.65 S
Where S=standard deviation = 5 (From table Is 10262:2009)
fck'=50+(1.65x5)
= 58.25 N/mm2
Therefore Target mean strength=58.25 pa.
3) Selection of water cement ratio:
- From above graph for fck'=58.25 pa w/c ratio cannot be identified.
- from above graph also w/c ratio cannot be identified.
- From table 5 of IS 456:2000 for extreem exposure, maximum water cement ratio=0.40, based on experiance let us consider W/C=0.35<0.40, hence ok.
Therefore consider 0.35 as w/c ratio.
4) Selection of Water content:
From table 2 of IS 10262:2009, maximum water content for 20mm aggregate=186 litre(for slump 25-50mm)
Therefore, for slump 100mm
Estimated water content for 100mm slump=186+(6/100)*186
= 197 litres.
As superplastisizer is used, thus water content be reduced to 30% but from trails let us consider 29% reduction,
Therefore: 197x0.71=140Litres.
5. Calculation of Cement content:
Water cement ratio = 0.35
Cementatious material i.e., Cement=140/0.35 =400 kg/m3
From table 5 of IS 456:2000 minimum cement content for Extreem exposure condition=360kg/m3
400 kg/m3 > 360kg/m3 hence Ok,
6. calculation of Volume of coarse aggregate:
From table 3 of IS 10262:2009, volume of aggregate corresponding to 20mm size aggregate and fine aggregate (zone I) for water cement ratio of 0.5 is 0.60
Therefore for w/c ratio of 0.35 the volume changes to 0.63
(from the clause given in table 3, i.e.,As Water ceent ratio is lowered by 0.15, the proportion of volume of coarse aggregate is increased by 0.03 (at the rate of -/+ 0.01 for every +/-0.05 change in water cement ratio.)
for pumpable concrete these values are reduced by 10%
Therefore , volume of coarse aggregate =0.63x0.9 = 0.567 =0.57
Volume of fine aggregate =1-0.57=0.43
7. Mix Calculation:
a) Volume of Concrete =1 m3
b) Volume of Cement = (Mass of cement/specific gravity of cement) x(1/1000)
=(400/3.15)*(1/1000)
=0.1269 m3
c) Volume of Water = (Mass of water/specific gravity of water) x(1/1000)
= 140/1x0.001
=0.140 m3
d) Volume of super plastisizer =(Mass of plastisizer/specific gravity of plastisixer) x(1/1000)
= (8/1.145)x0.001
=0.0069m3
e) Volume of aggregate( CA &FA) ={a-(b+c+d)}
={1-(0.1269+0.140+0.0069)}
=0.726m3
f) Mass of Coarse aggregate =e x volume of coarse aggregatex specific gravity of coarse aggregatex1000
=0.726x0.57x2.74x1000
=1133.8 kg/m3
g) Mass of Fine aggregate =e x volume of Fine aggregate x specific gravity of Fine aggregate x 1000
=0.726 x 0.43 x 2.74x1000
=855.37 kg/m3
8. Mix Proportions
- Cement = 400 kg/m3
- Water = 140 kg/m3
- Chemical Admixture = 8 kg/m3
- Fine aggregate = 855.37 kg/m3
- coarse aggregate = 1133.8 kg/m3
- W/C ratio = 0.35
Design Mix for M50 without Fly Ash
1 : 2.14 : 2.84