Project on Concrete Mix Design for various grades of Concrete

1) In this case we develop the mix design for M35 grade concrete with fly ash. For this we consider following conditions;

1. Grade of Concrete : M35
2. Cement - OPC 43 grade
   
3. Maximum size of aggregate: 20mm
4. exposure condition : Severe
5. Slump : 75mm
6. aggregate : Angular
7. Admixture : Super Plasticizer (specific gravity = 1.145)
   
8. water content : Nill
9. Reinforced Concrete
10. Fine aggregate : Zone-II
11. Process of Concrete Pouring : Pump
12. specific gravity for Fly ash = 2.2

• Target mean strength: F'ck = Fck+1.65xS

for M35 grade concrete Standard deviation (S) = 5

therefore, F'ck = 35+(1.65x5)

F'ck = 43.25 N/mm²

• water cement ratio as per table-5 of IS 456:2000 for severe condition is 0.45

but,as per the graph the water cement ratio for M35 concrete was 0.40, hence W/C is considered as 0.40.

• Maximum water content as per table-2 of IS 10262:2009 for 20mm aggregate with 25 to 50mm slump is 186 Lts.

but, we have considered slump as 75mm, as 3% is added for every 25mm slump beyond 50mm, 3% is added to 186Lts

i.e 186+(186*3%) = 191.58 Lts approximately = 192 Lts

As super plasticizer is used water content can be reduced 20 to 30%, hence 29% is reduced.

i.e 192 X 0.71 = 136.22 ~137 Lts.

• we have considered water cement ratio W/C = 0.40

i.e 144/C = 0.40

C = 137/0.40 = 342.5 ~ 343 Kg

343 > 320 (From table5 of IS456:2000)

Hence, OK

Admixture = 2% of Cement = 343 X 2% = 6.86 Kg

• For Fly ash Quantity

Cement material increase by 10%

i.e 343 X 10% ~ 378 Kg

Hence, W/C = 137/378 = 0.362

Fly ash = 30% of Cement quantity = 378 X 30% = 113.40 ~ 114 Kgs

Cement = 378-114 = 264 Kgs

• Volume of Coarse aggregate as per table 3 of IS 10262:2009 for Zone-II is 0.62 Kg/M³

as the concrete is poured by pump 10% of CA is reduced, i.e 0.62 X 0.90 = 0.56 Kg/M³

Fine aggregate = 1 - 0.56 = 0.44 Kg/M³

• Mix Calculations

Cement = 264/3.15X 1/1000 = 0.084 Kg/M³

Fly Ash = 114/2.22X 1/1000 = 0.052 Kg/M³

Water = 137/1X 1/1000 = 0.137 Kg/M³

Admixture = 6.86/1.145X 1/1000 = 0.006 Kg/M³

Total Aggregate = 1-(0.109+0.192+0.006) = 0.693 Kg/M³

Coarse Aggregate = 0.693 X 0.56 X 2.74 X 1000 = 1064 Kg

Fine Aggregate = 0.693 X 0.44 X 2.74 X 1000 = 836 Kg

• Mix Proportion

1: 2.21 : 2.81

2) In this case we develop the mix design for M50 grade concrete without fly ash. For this we consider following conditions;

1. Grade of Concrete : M50
2. Cement - OPC 43 grade
   
3. Maximum size of aggregate: 20mm
4. exposure condition : Severe
5. Slump : 75mm
6. aggregate : Angular
7. Admixture : Super Plasticizer (specific gravity = 1.145)
   
8. water content : Nill
9. Reinforced Concrete
10. Fine aggregate : Zone-II
11. Process of Concrete Pouring : Pump
    

• Target mean strength: F'ck = Fck+1.65xS

for M35 grade concrete Standard deviation (S) = 5

therefore, F'ck = 50+(1.65x5)

F'ck = 58.25 N/mm²

• water cement ratio as per table-5 of IS 456:2000 for severe condition is 0.45

but,as per the graph the water cement ratio for M35 concrete was 0.40, hence W/C is considered as 0.30.

• Maximum water content as per table-2 of IS 10262:2009 for 20mm aggregate with 25 to 50mm slump is 186 Lts.

but, we have considered slump as 75mm, as 3% is added for every 25mm slump beyond 50mm, 3% is added to 186Lts

i.e 186+(186*3%) = 191.58 Lts approximately = 192 Lts

As super plasticizer is used water content can be reduced 20 to 30%, hence 29% is reduced.

i.e 192 X 0.71 = 136.22 ~137 Lts.

• we have considered water cement ratio W/C = 0.30

i.e 144/C = 0.30

C = 137/0.30 = 456.66 ~ 457 Kg

457 > 320 (From table5 of IS456:2000)

Hence, OK

Admixture = 2% of Cement = 457 X 2% = 9.14 Kg

• Volume of Coarse aggregate as per table 3 of IS 10262:2009 for Zone-II is 0.62 Kg/M³

as the concrete is poured by pump 10% of CA is reduced, i.e 0.62 X 0.90 = 0.56 Kg/M³

Fine aggregate = 1 - 0.56 = 0.44 Kg/M³

• Mix Calculations

Cement = 457/3.15X 1/1000 = 0.145 Kg/M³

Water = 137/1X 1/1000 = 0.137 Kg/M³

Admixture = 9.14/1.145X 1/1000 = 0.008 Kg/M³

Total Aggregate = 1-(0.145+0.137+0.008) = 0.71 Kg/M³

Coarse Aggregate = 0.71 X 0.56 X 2.74 X 1000 = 1089.42 ~ 1090 Kg

Fine Aggregate = 0.71 X 0.44 X 2.74 X 1000 = 855.98 ~ 856 Kg

• Mix Proportion

1: 1.87 : 2.39