Project on Concrete Mix Design for various grades of Concrete
Concrete Mix Design for M35 grade concrete with fly ash
Aim:- Concrete mix design for M35 grade concrete with flyash.
Procedure:-
1. Details of proportion
- Grade destination- M35
- Type of cement- OPC43 (IS8112).
- Type of mineral admixture- flyash (IS3812).
- Max. nominal size of aggregate -20mm
- Minimum cement content- 320kg/cum (based on exposure condition Table -5 IS456:2000)
- max. W/c ratio -0.45 (IS456 2000 table-5)
- Workability-100mm slump
- Exposure condition- severe (for reinforced concrete)
- Method of concret placing-Pumping
- Type of aggregate- crushed angular aggregate
- max. cement content- 450kg/cum
- chemical admixture- superplasticizer
2. Test data of material
- Cement used- OPC43
- Specific gravity of cement -3.15
- Specific gravity of flyash -2.2
- specific gravity of coarse aggregate- 2.74
- specific gravity of fine aggregate-2.74
- water absorption of coarse aggregate-0.5%
- water absorption of fine aggregate-1%
- Free surface moisture of fine aggregate- nill
- Free surface moisture of Coarse aggregate- nill
3. Calculation of traget mean strength of concrete
Target mean strength =f'ck
f'ck= fck+1.5s
f'ck=35+1.5 x 5
f'ck=43.25 N/sqm
fck= characterstic compressive strength
s = standard deviation
4. Selection of water cement ratio
W/C ratio=0.45 (based on exposer condition IS 456: 2000)
On observation experienced w/c ratio=0.4
then 0.4<0>
5. Calculation of water content
From Table 2, maximum water content for 20mm aggregate =186 litre for 25-50mm slump
Estimated Water content for 100mm slump =186 + ((6/100)X186)=197litre
As super plasticizer is used, the water content reduced up to 30%
Based on trial with Superplasticizer water content reduction of 29% has been achieved
=197 X 0.71 = 140 litre
6. Calculation of cement and Fly ash Content -
W/C ratio=0.36
Cementationous material (cement + flyash) content =140/0.36=389 kg
From table 5 of IS 456, minimum cement content for severe exposure 389kg/m3
fly ash its perrcentage decide on the basis of project requirements and quality materisals
For find the fly ash we have to consider 10% of cementationous material
Cementationous cement =389*1.10= 458.84
W/C ratio =140/458.84= 0.30
Fly ash @30% of total cementationous material =458.84X30%=137.65 kg/m3
cement=458.84-137.65=321.19kg/m3
saving of cement while using fly ash =389-321.19= 67.81 kg/m3
7. Proportion of volume of coarse & Fine Aggregate content -
from Table 3, volume of coarse aggregate corresponding to 20mm size of aggregate and fine aggregate for water cement ratio of 0.50-0.60
in the present water cement ratio is 0.36, therefore the volume of coarse aggregate is required to be increased to decrease the fine aggregate content
As water cement ratio is lower 0.14, the proportion of volume of coarse aggregate is increased by 0.03
There fore corrected proportion of volume of coarse aggregate for the water cement ratio 0.36=0.63
For pumpable concrete these value should be reduced by 10%
There fore the volume of coarse aggregate =0.63*0.9 =0.57
Volume of fine aggregate content =1-0.57= 0.43
8. Mix Calculation -
a) Volume of concrete = 1m3
b) volume of cement = (mass of cement / Sp. gravity of cement)X(1/1000)
= (321.19/3.15)X (1/1000)
= 0.102 m3
c) Volume of fly ash=(mass of fly ash/sp. gravity of fly ash) X (1/1000)
=(137.19/2.2) X (1/1000)
= 0.062 m3
d) volume of water = (mass of water /sp. gravity of water) X (1/1000)
= (140/1) X (1/1000)
=0.140 m3
e) Volume of admixture @ 2% by mass of cementationous material =( mass of admixture / sp. gravity of admixture ) X (1/1000)
= (9.17/1.145)X (1/1000)
= 0.008m3
f) volume of all aggregate =((a-(b+c+d+e))
= ((1-(0.102+0.062+0.140+0.008))
= 0.69
g) mass of coarse aggregate = (f X volume of coarse aggregate X sp. gravity X 1000)
= 0.69 X 0.57 X 2.74X 1000= 1077.64kg
h) mass of fine aggregate = (f X volume of coarse aggregate X sp. gravity X 1000)
= 0.69x0.43x2.74 x1000= 812.958kg
9. Mix Proportion for M35 -
Cement =321.19 kg/m3
fly ash = 116 kg/m3
water = 140 kg/m3
Fine Aggregate = 812.96 kg/m3
Coarse aggregate =1077.64 kg/m3
Chemical Admixture = 9.17 kg/m3
W/C ratio = 0.30
Result - The mix ratio for M35 grade of concrete with fly ash will - 1:2.53:3.35
Concrete Mix Design for M50 Grade of Concrete without Fly Ash
Aim- Concrete Mix Design for M50 Grade of Concrete without Fly Ash-
To Calculate the mix design of M35 Grade of Concrete for stipulation for proportioning-
- Grade of concrete –M50
- Type of cement – OPC 43 grade
- Maximum nominal Size of aggregate -20mm
- Workability-100mm
- Exposure condition – severe for reinforced concrete
- Method of concrete placing –pumping
- Chemical admixture- Super plasticizer
- Minimum cement content- 320kg/m3
- Maximum cement content – 450 kg/m3
- Specific gravity of cement – 3.15
- Specific gravity of coarse & fine aggregate - 2.74
Procedure-
1. Target strength for mix proportion
f’ck = fck + 1.65s
Where,
F’ck =Target avg compressive strength at 28 days.
Fck = characteristics compressive strength at 28 days
S = Standard deviations
From Table 1 – IS 10262-2009, Standard deviations, S=5N/mm2
Target strength =50+ (1.65 X 5) = 58.25 N/mm2
2. Selection of Water-Cement Ratio-
From Table 5- IS456-2000, Maximum W/C ratio for severe Condition =0.45
From graph 28 Days Compressive strength v/s water cement ratio
W/C ratio =0.34
Therefore, the lower value of the above three vale is adopted as w/c ratio for mix design
so, W/C ratio =0.34
3. Selection of Water Content -
From Table 2, maximum water content for 20mm aggregate =186 litre for 25-50mm slump
Estimated Water content for 100mm slump =186 + ((6/100)X186)=197litre
As super plasticizer is used, the water content reduced up to 30%
Based on trial with Superplasticizer water content reduction of 29% has been achieved
=197 X 0.71 = 140 litre
4. Calculation of cement Content -
W/C ratio=0.34
Cementationous material (cement + flyash) content =140/0.34=411.76 kg = 412 kg
From table 5 of IS 456, minimum cement content for severe exposure 412kg/m3
412> 320 kg
5. Proportion of volume of coarse & Fine Aggregate content -
from Table 3, volume of coarse aggregate corresponding to 20mm size of aggregate and fine aggregate for water cement ratio of 0.50-0.60
in the present water cement ratio is 0.36, therefore the volume of coarse aggregate is required to be increased to decrease the fine aggregate content
As water cement ratio is lower 0.16, the proportion of volume of coarse aggregate is increased by 0.03
There fore corrected proportion of volume of coarse aggregate for the water cement ratio 0.34=0.63
For pumpable concrete these value should be reduced by 10%
There fore the volume of coarse aggregate =0.63*0.9 =0.57
Volume of fine aggregate content =1-0.57= 0.43
6. Mix Calculation -
a) Volume of concrete = 1m3
b) volume of cement = (mass of cement / Sp. gravity of cement)X(1/1000)
= (412/3.15)X (1/1000)
= 0.130 m3
c) volume of water = (mass of water /sp. gravity of water) X (1/1000)
= (140/1) X (1/1000)
=0.140 m3
d) Volume of admixture @ 2% by mass of cementationous material =( mass of admixture / sp. gravity of admixture ) X (1/1000)
= (8.24/1.145)X (1/1000)
= 0.007m3
e) volume of all aggregate =((a-(b+c+d))
= ((1-(0.130+0.140+0.007))
= 0.723
f) mass of coarse aggregate = (f X volume of coarse aggregate X sp. gravity X 1000)
= 0.723 X 0.57 X 2.74X 1000= 1129.18kg
g) mass of fine aggregate = (f X volume of coarse aggregate X sp. gravity X 1000)
= 0.723x0.43x2.74 x1000= 851.84kg
7. Mix Proportion for M35 -
Cement =412 kg/m3
water = 140 kg/m3
Fine Aggregate = 851.84 kg/m3
Coarse aggregate =1129.18 kg/m3
Chemical Admixture = 8.24 kg/m3
W/C ratio = 0.34
Result - The mix ratio for M50 grade of concrete without fly ash will - 1:2.06:2.74