Project on Concrete Mix Design for various grades of Concrete

1. Stipulations:
2. Grade – M35
3. Type of cement- OPC43 Grade confirming IS8112
4. Mineral Admixture- Fly ash confirming to IS 3812
5. Maximum size of nominal aggregate: 20mm
6. Minimum cement content: 320 kg/m³ (As per table-5 of IS 456)
7. Maximum W/C = 0.45 (As per table-5 of IS 456)
8. Workability =100mm (slump value for pumpable concrete)
9. Exposure conditions = Severe
10. Degree of Supervision = Good
11. Maximum cement content= 450 kg/m³
12. Chemical Admixture = Superplasticiser

Test Data:

1. Cement = OPC43 Grade confirming IS8112
2. Specific gravity = 3.15
3. Specific gravity of fly ash = 2.2
4. Chemical Admixture- Super Plasticisers
5. Specific gravity of coarse aggregate/ fine aggregate =2.74
6. Water absorption= 0.5% CA & 1% FA
7. Free surface Moisture = Nil
8. Sieve analysis of CA & FA should confirm to grading Zone 1 Table 4 of IS 383

Target mean strength = 35+1.65*5 = 43.25 N/mm²

Selection of W/C:

W/C as per IS 456 Table-5 = 0.45, However as per experience may be taken as 0.40

As 0.40<0.45 hence ok

Selection of Water Content:

From Table 2 of IS10262:2009, Maximum Water content for 20 mm aggregates = 186 litre (For 25mm to 50mm Slump)

Estimated Water Content for 100 mm slump = 186+(186*6%) =197 litre

If Super Plasticisers are used water content is reduced by 30%

Water content arrived = 197*0.71 = 140 litres

Cement content = 140/0.4 = 350Kg/m3

As per Table-5 of IS 456 min. cement content for severe exposure condition = 320 kg/m³

Hence 350Kg/m3 > 320 kg/m³ (OK)

With addition of fly ash Cementous material content is to be increased by 10%

Cementous material content = 350*1.10 = 385kg/m³

Water content = 140 Kg/m³

Water/Cement = 0.364

Flyash@30% total Cementous material content = 385*30% =115 Kg/m³

OPC = 385-115 = 270kg/m³

Saving of cement = 80 Kg/m³

Fly ash used = 115Kg/m³

Volume of CA corresponding to 20 mm size aggregate and fine aggregate of W/C of 0.5 is 0.6

As the current W/C ratio is 0.4.

Therefore, corrected volume of CA to FA for W/C 0.4 is 0.62

Due to Pumpable concrete these values are reduced by 10%. Therefore, volume of CA = 0.62*0.9=0.56

Volume of FA = 0.44

Volume of Concrete = 1m³

Volume of Cement = 270/3150 = 0.086m³

Volume of fly ash = 115/2200 = 0.052m3

Volume of water = 140/1000 = 0.14m3

Volume of Chemical admixture = (2% * 385)/1145 =0.006 m3

Volume of FA&CA = 1-(0.006+0.14+0.052+0.086) =0.716 m3

Mass of CA = 0.716*0.56*2.74*1000 = 1098kg/m3

Mass of FA = 0.716*0.44*2.74*1000 = 863 kg/m3

Cement = 270Kg/m3

Fly ash = 115 kg/m3

Trial ratio = 1:2.24:2.85

2. Stipulations:
3. Grade – M50
4. Type of cement- OPC43 Grade confirming IS8112
5. Maximum size of nominal aggregate: 20mm
6. Minimum cement content: 320 kg/m³ (As per table-5 of IS 456)
7. Maximum W/C = 0.45 (As per table-5 of IS 456)
8. Workability =100mm (slump value for pumpable concrete)
9. Exposure conditions = Severe
10. Degree of Supervision = Good
11. Maximum cement content= 450 kg/m³
12. Chemical Admixture = Superplasticiser

Test Data:

1. Cement = OPC43 Grade confirming IS8112
2. Specific gravity = 3.15
3. Specific gravity of fly ash = 2.2
4. Chemical Admixture- Super Plasticisers
5. Specific gravity of coarse aggregate/ fine aggregate =2.74
6. Water absorption= 0.5% CA & 1% FA
7. Free surface Moisture = Nil
8. Sieve analysis of CA & FA should confirm to grading Zone 1 Table 4 of IS 383

Target mean strength = 50+1.65*5 = 58.25 N/mm²

Selection of W/C:

W/C as per IS 456 Table-5 = 0.45, However as per experience may be taken as 0.40

As 0.40<0.45 hence ok

Selection of Water Content:

From Table 2 of IS 10262:2009, Maximum Water content for 20 mm aggregates = 186 litre (For 25mm to 50mm Slump)

Estimated Water Content for 100 mm slump = 186+(186*6%) =197 litre

If Super Plasticisers are used water content is reduced by 30%

Based on trials water content can be reduced by 29%

Water content arrived = 197*0.71 = 140 litres

Cement content = 140/0.4 = 350Kg/m3

Proportion of volume of CA and FA content:

From table-3 of IS 10262:2009, Volume of CA corresponding to 20 mm size aggregate & FA for Water/Cement = 0.6

In the present case the water cement ratio = 0.4

Therefore, the volume of CA needs to be increased to decrease the fine aggregate content

As the water cement ratio is lower by 0.10, the proportion of volume of CA increased by 0.02

Corrected Volume of CA for Water cement ratio 0.4 = 0.62

Due to pumpable concrete the volume of CA to total aggregates are reduced by 10%

Volume of CA = 0.62*0.9 = 0.56

Volume of Fine aggregate = 0.44

Volume of Concrete = 1m³

Volume of cement = 0.111 m³

Volume of Water = 140/1000 = 0.14 m³

Volume of chemical admixture = 7/1145 =0.006 m³

Volume of FA & CA = 1-(0.006+0.14+0.111) = 0.743 m³

Mass of CA = 0.743* 2.74*1000*0.56 = 1140 Kg/ m³

Mass of FA = 0.44*0.743*2.74*1000 = 896 Kg/ m³

Cement = 350 Kg/ m³

Water = 140 Kg/ m³

FA = 896 Kg/ m³

CA = 1140 Kg/ m³

Trial mix = 1:2.56:3.26