Project on Concrete Mix Design for various grades of Concrete

Aim- To determine the mix-design of the concrete for the grade M35 with Fly ash and M50 concrete without Fly ash using IS code Method

Introduction:

We design concrete mix-design when our grade of concrete is above M30 using IS code 10262-2019, Is456 all guidelines we have to follow as per IS codes

• M35 using fly ash
• Stipulation for proportioning

1. Grade of designation –M35
2. Type of cement -OPC 53 Grade IS8112
3. Type of mineral admixture - fly ash IS3812 Part-1
4. Maximum nominal size of aggregate - 20mm
5. Exposure condition – severe
6. Workability - 50-75mm slump
7. Method of concrete - pumping
8. Types of aggregate - Crush angular
9. Maximum cement content - As per IS456
10. Chemical admixture - Super-plasticizer

• Test data for material

1. Cement used – OPC53
2. SG of cement - 3.15
3. Fly ash - IS 3812,1
4. SG of Fly ash – 2.2
5. Chemical admixture- super-plasticizer conforming IS 9103
6. SG of

1) Course aggregate - 2.74

2) fine aggregate – 2.65

3) chemical admixture - 1.145

1. g) water absorption

1)coarse aggregate – 0.5 percent

2)fine aggregate – 1 percent

3) Target mean strength

f’_ck =f_ck+1.65 S

f’_ck =target average compressive strength

f_ck=characteristics compressive strength at 28 days

S= standard deviation

:. =35+1.65x5=43.25N/mm²

• selection of water cement ratio

using IS 456 table-5

the permissible w/c ratio is 0.45

• selection of water content

from table-2 IS456

Maximum water content for slump is 186lit

Estimate for slump75mm

186x1.03=191.58lit

Based on trials for super-plasticizer 153lit

• calculation of cement content and Fly ash

w/c ratio-0.45

cement content-

153/0.45=340.58 Kg/m3 >320 ok is456 table-5

Cementations material used 340.58x1.1=375kg/m3

Water content =153lit

Fly ash 30%

375x0.3=112.5kg/m3

Cement=375-112.5=262.5kg/m3

• proportion of volume of coarse aggregate and fine aggregate

from table-5 volume of coarse aggregate corresponding to 20mm size of aggregate and fine aggregate Zone ll for w/c ratio 0.5=0.62

the corrected proportion of volume of coarse aggregate for w/c ratio 0.45=0.63

for plumpable concrete the value reduce by 10%

0.63x0.9=0.567

Volume of fine aggregate content 1-0.567=0.433

• mix calculation

1. total volume=1m3
2. volume of cement=

=mass of cement/SG of cement x1/1000

=262.5/3.15 x 1/1000

=0.083m3

Volume of fly ash 112.5/2.2 x 1/1000

=0.005m3

1. volume of water

=mass of water/SG of water x 1/1000

=153/1 x 1/1000

=0.153m3

1. volume of admixture

1% of mass of cement

=mass of admixture/SG of admixture x 1/1000

=2.62/1.145 x 1/1000

=0.0022m3

1. volume of all in aggregate

=1-(0.112+0.083+0.153+0.0022)

=0.65m3

1. mass of coarse aggregate

=0.65x0.567x2.74x1000

=1010Kg

1. mass of fine aggregate

=0.65x0.433x2.67x1000

=746.26Kg

• concrete mix proportion

Cement – 265.5 Kg/m3

Fly ash – 112.5 Kg/m3

Water – 153Kg/m3

Super-plasticizer - 2.62Kg/m3

Fine aggregate – 746Kg/m3

Coarse aggregate – 1010Kg/m3

W/C - 0.40

• Result

Mix proportion arrived =1:1.97:2.67

• M50 grade of concrete
• Stipulation for proportioning

1. Grade of designation –M50
2. Type of cement -OPC 53 Grade IS8112
3. Maximum nominal size of aggregate - 20mm
4. Exposure condition – severe
5. Workability - 50-75mm slump
6. Method of concrete - pumping
7. Types of aggregate - Crush angular
8. Maximum cement content - As per IS456
9. Chemical admixture - Super-plasticizer

• Test data for material

1. Cement used – OPC53
2. SG of cement - 3.15
3. Chemical admixture- super-plasticizer conforming IS 9103
4. SG of

1) Course aggregate - 2.74

2) fine aggregate – 2.65

3) chemical admixture - 1.145

1. g) water absorption

1)coarse aggregate – 0.5 percent

2)fine aggregate – 1 percent

3) Target mean strength

f’_ck =f_ck+1.65 S

f’_ck =target average compressive strength

f_ck=characteristics compressive strength at 28 days

S= standard deviation

:. =50+1.65x5=58.25N/mm²

• selection of water cement ratio

using IS 456 table-5

the permissible w/c ratio is 0.45

Assume water cement ratio =0.35

• selection of water content

from table-2 IS456

Maximum water content for slump is 186lit

Estimate for slump75mm

186x1.03=191.58lit

Based on trials for super-plasticizer 153lit

• calculation of cement content and Fly ash

w/c ratio-0.35

cement content-

153/0.35=437 Kg/m3 >320 ok is456 table-5

• proportion of volume of coarse aggregate and fine aggregate

from table-5 volume of coarse aggregate corresponding to 20mm size of aggregate and fine aggregate Zone ll for w/c ratio 0.5=0.62

the corrected proportion of volume of coarse aggregate for w/c ratio 0.35=0.65

for plumpable concrete the value reduce by 10%

0.65x0.9=0.585

Volume of fine aggregate content 1-0.585=0.415

• mix calculation

1. total volume=1m3
2. volume of cement=

=mass of cement/SG of cement x1/1000

=437/3.15 x 1/1000

=0.139m3

1. volume of water

=mass of water/SG of water x 1/1000

=153/1 x 1/1000

=0.153m3

1. volume of admixture

1% of mass of cement

=mass of admixture/SG of admixture x 1/1000

=4.37/1.145 x 1/1000

=0.0038m3

1. volume of all in aggregate

=1-(0.139+0.153+0.0038)

=0.704m3

1. mass of coarse aggregate

=0.704x0.585x2.74x1000

=1128Kg

1. mass of fine aggregate

=0.704x0.415x2.67x1000

=780Kg

• concrete mix proportion

Cement – 437 Kg/m3

Water – 153Kg/m3

Super-plasticizer - 4.37Kg/m3

Fine aggregate – 780Kg/m3

Coarse aggregate – 1128Kg/m3

W/C - 0.35

• Result

Mix proportion arrived =1:1.78:2.58