Project on Concrete Mix Design for various grades of Concrete

1.

AIM: To design M50 without Fly ash using IS code

Concrete mix design for M50 grade concrete without Fly ash

Grade designation - M50

Type of cement - OPC 43

Maximum nominal size of aggregate - 20mm

Workability - 110mm

Exposure - Severe

Minimum cement content - 320Kg/m3

Maximum w/c ratio - 0.45

Minimum garde - M30

Method of placing - Chute

Maximum cement content - 450Kg/m3 (As per IS 456:2000, Cl 8.2.4.2 )

Chemical admixture - Super plasticizer

Test data

• Specific gravity

cement - 3.17

Fine aggregate - 2.64

Coarse aggregate - 2.75

Chemical admixtures - 1.10

Fine aggregate - table 9 , zone 2 IS 383

Target strength , f'ck=fck+1.65s

from table 2 of IS 10262:2019, S=5

f'ck=50+1.65*5= 58.25 N/mm2

or

f'ck=fck+X

from table1 X=6.5

= 50+6.5= 56.5 N/mm2

Approximate air content

From table 3 of IS 10262:2019, the approximate amount of entrapped air in normal concrete is 1% for 20mm aggregate

Selection of water cement ratio

from table 5 of IS 456, MAX W/C = .45

from as per IS 10262:2019 W/C = .34

0.34<0.45

W/C ratio =0.34

Selection of water content

form IS 10262:2019 table 4 , water content for 20mm size aggregate= 186Kg

for 110mm slump, water content = 186+(.072*186)=199.39 lit

Based on trial water content reduction of 23% is consired while using super plasticizer

Now water content= 199.39*.77= 153.53Kg/m3

Calculation of cement content

w/c ratio = 0.34

water content as per concrete = 153.53 Kg/m3

cement content = 153.53/0.34 = 451.558 Kg/m3

As per IS 456, min cement content is 320Kg/m3

Hence it is safe

Super plasticizer= 2% of weight of cement content = 0.02*451.558 =9.031 kg/m3

Proportioning of volume of coarse and fine aggregate

As per IS 10262:2019 TABLE 5

for zone 3, volume of coarse aggregate= 0.64

for w/c 0.5 = 0.64

fow w/c 0.34=?

x= (0.5-0.34)*0.01/0.05 = 0.032

Proportioning volume of coarse aggregate = 0.64+0.032 = 0.672

Proportioning of fine aggregate = 1-0.672 = 0.328

Mix calculation

Volume of concrete = 1m3

Volume of cement = weight of cement / sepcific gravity*1000 = 451.558/3.17*1000 = 0.142 m3

Volume of water = 153.53/1000 = 0.153m3

Volume of admixture = 9.031/1.10*1000 = 0.00821m3

Total vol of other material except aggregate = 0.142+.153+0.00821+0.01 = 0.313 m3

Volume of coarse and fine aggregate = 1-0.313 = 0.687 m3

Mass of coarse aggregate = 0.687*0.672*2.75*1000 = 1269.576 kg

Mass of fine aggregate = 0.687*0.328*2.64*1000 = 594.887 kg

Mix proportion

Cement = 451.558 kg/m3

Water = 153.53 kg/m3

Admixture = 9.031 kg/m3

Fine aggregate = 594.887 kg/m3

Coarse aggregate = 1269.576 kg/m3

w/c = 0.34

2.

AIM: To design M35 with Fly ash using IS code

Concrete mix design for M35 grade concrete with Fly ash

Grade designation - M35

Type of cement - Unknown

Mineral admixture: Fly ash

Maximum nominal size of aggregate - 40mm

Workability - 95mm

Exposure - Very Severe from IS 456:2000

Minimum cement content - 320Kg/m3

Maximum w/c ratio - 0.45

Minimum garde - M35

Method of placing - Chute

Maximum cement content - 450Kg/m3 (As per IS 456:2000, Cl 8.2.4.2 )

Chemical admixture - Super plasticizer

Test data

• Specific gravity

Cement - 3.2

Fly ash- 2.2

Fine aggregate - 2.64

Coarse aggregate - 2.75

Chemical admixtures - 1.10

Fine aggregate - table 9 , zone 2 IS 383

Target strength , f'ck=fck+1.65s

from table 2 of IS 10262:2019, S=5

f'ck=35+1.65*5= 43.25 N/mm2

or

f'ck=fck+X

from table1 X=6.5

= 35+6.5= 41.5 N/mm2

Approximate air content

From table 3 of IS 10262:2019, the approximate amount of entrapped air in normal concrete is 0.8% for 40mm aggregate

Selection of water cement ratio

from table 5 of IS 456, MAX W/C = .45

from as per IS 10262:2019 W/C = .37

0.37<0.45

W/C ratio =0.37

Selection of water content

form IS 10262:2019 table 4 , water content for 40mm size aggregate= 165Kg

for 95mm slump, water content = 165+(.054*165)=173.91 lit

Based on trial water content reduction of 23% is consired while using super plasticizer

Now water content= 173.91*.77= 133.91 Kg/m3

Calculation of cement content

w/c ratio = 0.37

water content as per concrete = 133.91 Kg/m3

Cementitious content = 133.91/0.37 = 361.91 Kg/m3

As per IS 456, min cement content is 340Kg/m3

Hence it is safe

Since fly ash is going to be replaced with cement, based on trials we need to add 10%

New Cementitious content= 361.91*1.10= 398.101kg/m3

New w/c=133.91/398.101 = 0.336

20% of cementitious is going to be replaced by fly ash

Fly ash = 398.101*0.2 = 79.62 kg/m3

Cement = 398.101-79.62 = 318.48 kg/m3

Superplasticizer = 1.7% of weight of cementitious content = 0.017*398.101 = 6.76 kg/m3

Proportioning of volume of coarse and fine aggregate

As per IS 10262:2019 TABLE 5

for zone 2, volume of coarse aggregate= 0.71

for w/c 0.5 = 0.71

for w/c 0.336=?

x= (0.5-0.336)*0.01/0.05 = 0.032

Proportioning volume of coarse aggregate = 0.71+0.032 = 0.742

Since the method of placing is pumping, volume of coarse aggregate should be reduced by 5%

New volume of coarse aggregate = 0.742*.95 = 0.704

Proportioning of fine aggregate = 1-0.704 = 0.296

Mix calculation

Volume of concrete = 1m3

Volume of cement = weight of cement / sepcific gravity*1000 = 318.48/3.2*1000 = 0.099 m3

Volume of fly ash = 79.62/2.2*1000 = 0.036 m3

Volume of water = 133.91/1000 = 0.133 m3

Volume of admixture = 6.76/1.10*1000 = 0.00614 m3

Total vol of other material except aggregate = 0.099+.036+0.133+0.00614+.01 = 0.284 m3

Volume of coarse and fine aggregate = 1-0.284 = 0.716 m3

Mass of coarse aggregate = 0.716*0.704*2.75*1000 = 1386.176 kg

Mass of fine aggregate = 0.716*0.296*2.64*1000 = 559.511 kg

Mix proportion

Cement = 318.48 kg/m3

Fly ash = 79.62 kg/m3

Water = 133.91 kg/m3

Admixture = 6.76 kg/m3

Fine aggregate = 559.511 kg/m3

Coarse aggregate = 1386.17 kg/m3

w/c = 0.336