Project on Concrete Mix Design for various grades of Concrete

1) Concrete Mix Design for M35 grade concrete with fly ash

I. Stipulations for proportioning:

a) Grade designation : M35

b) Type of cement: OPC 43 grade conforming to IS 8112

c) Type of mineral admixture : Fly ash conforming to IS 3812 (Part 1)

d) Maximum nominal size of aggregate: 20 mm

e) Minimum cement content : 320 kg/m^3 (From Table 5 of IS 456: 2000-Exposure condition)

f) Maximum water-cement ratio : 0.45 (From Table 5 of IS 456: 2000- Exposure condition)

g) Workability : 100 mm (slump value for pumpable concrete)

h) Exposure condition: Severe (for reinforced concrete)

i)Method of concrete placing: Pumping

j) Degree of supervision : Good

k) Type of aggregate : Crushed angular aggregate

l) Maximum cement content: 450 kg/m3

m) Chemical admixture type: Superplasticizer

2. Test data for materials:

a) Cement used: OPC 43 grade conforming to lIS 8112

b)Specific gravity of cement :3.15

c) Fly ash: Conforming to IS 3812 (Part 1)

d) Specific gravity of fly ash: 2.2

e) Chemical admixture: Superplasticizer conforming to IS 9103

f) Specific gravity of

• Coarse aggregate:2.74
• Fine aggregate:2.74

e) Water absorption

• Coarse aggregate: 0.5%
• Fine aggregate : 1.0%

f) Free Surface moisture:

• Coarse aggregate: Nil
• Fine aggregate: Nil

d) Sieve Analysis

• Fine aggregate :Conforming to grading zone l of Table 4 of IS 383

3. Target Strength for Mix proportioning

f'ck = fck + 1.65 S

Where, f'ck = Target average compressive strength at 28 days

fck = Characteristic compressive strength at 28 days

S =Standard deviation

From Table 1 of IS 10262: 2009, standard deviation,

S = 5 N/mm^2

Target strength = 35+1.65 x5

= 43.25 N/mm 2

4. Selection of Water-cement ratio

• From Table 5 of IS 456: 2000 for severe exposure, maximum water-cement ratio = 0.45
• Based on experience, adopt water-cement ratio as 0.40

0.40<0.45, Hence O.K

5. Selection of Water content

• From Table 2 of IS 10262: 2009, maximum water content for 20mm aggregate = 186 litre (for 25mm to 50mm slump range)
• Estimated water content =186+ 6/100 x 186

= 197 ltr

• As superplasticizer is used the wae content can be reduced up to 30% Based on trials wateri content reguction.of 29% is achieved with plasticizer

Hence the arrived water content is =197xO.71 = 140 litre

6. Calculation of Cement content:

• Water-cement ratio= 0.4
• Cementitious material (cement +fly ash) content = 140/0.4 = 350 kg/m3
• From Table 5 of IS 456 minimum cement content for 'severe" exposure condition = 320 kg/m^3

350 kg/m^3 > 320 kg/m^3, Hence OK

Now, to proportion a mix containing fly ash the following steps are suggested:

• a) The percentage of fly ash neesi to be decided based on project requirement and quality of materials
• b) In some cases increase in cementitious material can be warranted. Increase in cementitious material content and its percentage may be based on experience and trial (This example is with inerease of 10% cementitious material conte

Cementitious material content = 350 x 1.10 = 385 Kg/m^3

Water content = 140 Kg/m^3

So, Water-cement ratio = 140/385 = 0.364

Fly ash @ 30% total cementitious material content = 385 x 30% = 115 Kg/m^3

cement (opc) = 385-115 = 270 Kg/m^3
saving a cement using fly ash = 350-270 = 80 Kg/m^3 and

Fly ash being utilized =115 Kg/m^3

7. Proportion of Volume of coarse aggregate and Fine ageregate content:

• From Table 3 of Is 10262: 2009, Volume of coarse aggregate corresponding to 20 mm size aggregate and fine

aggregate (Zone l) for water-cement ratio = 0.6

• In the present case the water cement ratio is = 0.40

Therefore, the volume of coarse aggregate needs to be increased to decrease the fine aggregate content. As water-cement ratio is lower by 0.10, the proportion of volume of coarse aggregate is increased by 0.02. (at the rate of -/+ 0.01 for every t 0.05 change in water-cement ratio). Therefore, corrected volume of coarse aggregate for the water-cement ratio of 0.40 = 0.62

• For pumpable concrete these values are reduced by 10%
• Therefore, volume of coarse aggregate = 0.62*0.9 = 0.56
• Volume of fine aggregate content = 1-0.56 = 0.44

8. Mix Calculations:

The mix calculation per unit volume of concrete shall be as follows

• a) Volume of Concrete = 1 m^3

• b) Volume of Cement= Mass of cement/ Specific gravity of cement x 1/1000

= 270/3.15x 1/1000

= 0.086 m3

• c) Volume of Fly ash= Mass of fly ashy/Specific gravity of fly ash x 1/1000

= 115/2.2 x 1/1000

= 0.052 m3

• d) volume of water = Mass of water /Specific gravity of water x 1/1000

  = 140/1x1/100

  = 0.140m3

• e) Volume of chemical admikture = mass of addmixture / Secific gravity of admixture x 1/1000

  = 7.6/1.145 x 1/1000

  = 0.006 m3

• f) Volume of ageregate (FA & CA) = (a-(b+c+d+e))

  = (1-(0.086+0.052+0.140+0.006))

= 0.716 m3

• g) Mass of Coarse aggregate = f x Volume of coarse aggregate x Specific gravity of coarse aggregate X 1000

=0.716 x 0.56 x 2.74 x 1000

= 1098 Kg/m^3

• h) Mass of fine aggregate = f X Volume of fine aggregate x Specific gravity of fine aggregate X1000

= 0.716 X 0.44 x 2.74x 1000

= 863 Kg/m3

9. Mix proportions for Trial Number 1:

• Cement= 270 Kg/m3
• Fly ash= 115 Kg/m3
• Water = 140 Kg/m13
• Fine aggregate= 863 Kg/m^3
• Coarse aggregate =1098 Kg/m^3
• Chemical admixture =7 Kg/m3
• Water-cement ratio =0.364

2)Mix Design for M50 grade concrete :

I. Stipulations for proportioning:

a) Grade designation : M50

b) Type of cement: OPC 53 grade conforming to IS 8112

c) Maximum nominal size of aggregate: 20 mm

d) Minimum cement content : 320 kg/m^3 (From Table 5 of IS 456: 2000-Exposure condition)

e) Maximum water-cement ratio : 0.45 (From Table 5 of IS 456: 2000- Exposure condition)

f) Workability : 100 mm (slump value for pumpable concrete)

g) Exposure condition: Severe (for reinforced concrete)

h)Method of concrete placing: Pumping

i) Degree of supervision : Good

j) Type of aggregate : Crushed angular aggregate

k) Maximum cement content: 450 kg/m3

l) Chemical admixture type: Superplasticizer

2. Test data for materials:

a) Cement used: OPC 53 grade conforming to IS 3812

b)Specific gravity of cement :3.15

c) Specific gravity of fly ash: 2.2

d) Chemical admixture: Superplasticizer conforming to IS 9103

e) Specific gravity of

• Coarse aggregate:2.74
• Fine aggregate:2.74

e) Water absorption

• Coarse aggregate: 0.6%
• Fine aggregate : 1.3%

f) Free Surface moisture:

• Coarse aggregate: Nil
• Fine aggregate: Nil

d) Sieve Analysis

• Fine aggregate :Conforming to grading zone l of Table 4 of IS 383

3. Target Strength for Mix proportioning

f'ck = fck + 1.65 S

Where, f'ck = Target average compressive strength at 28 days

fck = Characteristic compressive strength at 28 days

S =Standard deviation

From Table 1 of IS 10262: 2009, standard deviation,

S = 5 N/mm^2

Target strength = 50+1.65 x5

= 58.25 N/mm 2

4. Selection of Water-cement ratio

• From Table 5 of IS 456: 2000 for severe exposure, maximum water-cement ratio = 0.45
• Based on experience, adopt water-cement ratio as 0.42

0.42<0.45, Hence O.K

5. Selection of Water content

• From Table 2 of IS 10262: 2009, maximum water content for 20mm aggregate = 186 litre (for 25mm to 50mm slump range)
• Estimated water content =186+ 6/100 x 186

= 197 ltr

• As superplasticizer is used the wae content can be reduced up to 30% Based on trials wateri content reguction.of 29% is achieved with plasticizer

Hence the arrived water content is =197xO.71 = 140 litre

6. Calculation of Cement content:

• Water-cement ratio= 0.42
• From Table 5 of IS 456 minimum cement content for 'severe" exposure condition = 320 kg/m^3

=140/0.42= 333.3

333.3 kg/m^3 > 320 kg/m^3, Hence OK

7. Proportion of Volume of coarse aggregate and Fine ageregate content:

• From Table 3 of Is 10262: 2009, Volume of coarse aggregate corresponding to 20 mm size aggregate and fine

aggregate (Zone l) for water-cement ratio = 0.6

• In the present case the water cement ratio is = 0.42

Therefore, the volume of coarse aggregate needs to be increased to decrease the fine aggregate content. As water-cement ratio is lower by 0.10, the proportion of volume of coarse aggregate is increased by 0.02. (at the rate of -/+ 0.01 for every t 0.05 change in water-cement ratio). Therefore, corrected volume of coarse aggregate for the

water-cement ratio of 0.42 = 0.62

• For pumpable concrete these values are reduced by 10%
• Therefore, volume of coarse aggregate = 0.62*0.9 = 0.56
• Volume of fine aggregate content = 1-0.56 = 0.44

8. Mix Calculations:

The mix calculation per unit volume of concrete shall be as follows

• a) Volume of Concrete = 1 m^3

• b) Volume of Cement= Mass of cement/ Specific gravity of cement x 1/1000

= 333.3/3.15x 1/1000

= 0.105 m3

• c) volume of water = Mass of water /Specific gravity of water x 1/1000

  = 140/1x1/100

  = 0.140m3

• d) Volume of chemical admikture = mass of addmixture / Secific gravity of admixture x 1/1000

  = 7.6/1.145 x 1/1000

  = 0.006 m3

• e) Volume of ageregate (FA & CA) = (a-(b+c+d))

  = (1-(0.105+0.140+0.006))

= 0.749 m3

• g) Mass of Coarse aggregate = e x Volume of coarse aggregate x Specific gravity of coarse aggregate X 1000

=0.749 x 0.56 x 2.74 x 1000

= 1149 Kg/m^3

• h) Mass of fine aggregate = f X Volume of fine aggregate x Specific gravity of fine aggregate X1000

= 0.749 X 0.44 x 2.74x 1000

= 896 Kg/m3

9. Mix proportions for Trial Number 1:

• Cement= 333.3 Kg/m3
• Water = 140 Kg/m13
• Fine aggregate= 896 Kg/m^3
• Coarse aggregate =1149 Kg/m^3
• Chemical admixture =7 Kg/m3
• Water-cement ratio =0.42