Project on Concrete Mix Design for various grades of Concrete

Concrete Mix design of M35 Grade With Fly Ash:

1. Assumed data for M35 Grade:

1. Type of cement- OPC 53 Grade (Confirming to IS 8112)
2. Maximum Nominal size of aggregate- 20mm
3. Minimum Cement Content For- 340 kg/cu.m
4. Maximum w/c ratio- 0.45
5. Workability of concrete- 100mm
6. Exposure condition- Severe
7. Method of placing of concete- Pumping
8. Degree of supervision- Good
9. Types of Aggregate- Crushed Angular Aggregate
10. Maximum cement content-450 kg/cu.m
11. Chemical admixture- Super Plasticizers
12. Admixture- Fly Ash
13. Partial replaccement of cement by Fly ash=30%.

2. Test Data for material-

• Used cement- OPC 43 Grade Confirming to IS 8112
• Specific Gravity- 3.15
• Chemical admixture- Superplasticizer confirming to IS 9103
• Specific Gravity for coarse aggregate & Fine aggregate- 2.74
• Specific Gravity of Fly ash-2.9
• Water absorption for Coarse aggregate is 0.5% & Fine aggregate 1.0%
• Free surface moisture Coarse aggregate & Fine aggregate (Should be dry in Condition.)
• Sieve Analysis- Coarse aggregate (IS 383,Table-2) & Fine aggregate (IS 383, Table-4)

3. Target Mean Strength of mix concrete:

• f'ck=fck+1.65xS
• Where,
• f'ck= Target Avarage compressive strength at 28 days
• fck= characteristics mcompressive strength at 28 days
• S= Standard deviation (As per IS 10262:2009, Table No.8, Clause No. 9.2.4.2 & Table 11)
• f'ck=35+1.65x5.0
• f'ck=43.25 MPa

4. Selection of water cement ratio:

• As per IS 456:2000 Table No. 5
• w/c ratio- 0.45

5. Selection of water content:

• As per IS 10262:2009 Table no.2.
• Maximum water content for 20mm aggregate= 186 litre. (For 25mm to 50mm slump range)
• Estimated water content for 100mm slump= 186+(6/100)= 197.16 litre.
• As per plasticizers are used, the water content can be reduced upto 20%.
• Hence arrived water content= 197x0.8= 160 litres.

6. Calculation of cement:

• w/c ratio= 0.45
• Cement= 160/0.45= 356 kg/cu.m
• Since the cementitious content is used (Cement+Fly ash) shall be increased to get good workability & strength. We increase the cementitious content by 1.1%
• Final cementitious content(Cemen+fly ash)= 356x1.1=391.6 kg/cu.m
• As per IS 456:2000, Table No. 5, minimum cement content for severe exposure condition 320 kg/cu.m
• 356 >320 kg/cu.m_______Hence ok.
• Fly ash content requirement= 392x0.3=118 kg
• Cement content required=cementitious content-fly ash

= 392-118= 274kg/cu.m.

7. Volume of coarse aggregate & fine aggregate:

• As per IS 10262:2009, Table No.3, volume of coarse aggregate 7 corrosponding to 20mm size aggregate & fine aggregate (Zone I) for w/c rario=0.6.
• In present case w/c ratio is 0.4.
• Therefore, the volume of coarse aggregate needs to be increased to decrease the fine aggregate content.
• As per w/c 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 +_0.05 change in w/c ratio)
• Corrected volume of coarse aggregate for w/c ratio of 0.4=0.62.
• For pumpable concrete these values are reduced by 10%.
• Volume of Coarse aggregate=0.62x0.9=0.56.
• Volume of fine aggregate= 1-0.56=0.44.

8. Mix calculation:

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

a. Volume of concrete=1 cu.m

b. Volume of cement= (Mass of cement/ Specific gravity)x(1/1000)

= (274/3.15)x(1/1000)

= 0.087 cu.m

c. Volume of water= (Mass of water/Specific Gravity of water)x(1/1000)

= (160/1)x(1/1000)

= 0.16 cu.m

d. Volume of chemical admixture= ( Mass of chemical admixture/ specific gravity of Chemical admixture)x(1/1000)

= (7.6/1.145)x(1/1000)

= 0.0066 cu.m

e. Volume of aggregate (Coarse & Fine aggregate)= (a-(b+c+d))

= (1-(0.087+0.16+0.0066))

= 0.7464 cu.m

f. Mass of Coarse aggregate= e x Volume of coarse aggregate x Specific gravity of Coarse aggregate x 1000

= 0.7464x0.56x2.74x1000

= 1146 kg/cu.m

g. Mass of Fine aggregate= e x Volume of fine aggregate x Specific Gravity of Fine aggregate x 1000

= 0.7464x0.44x2.74x1000

= 890 kg/cu.m

h. Mix proportion for trial

Cement= 356 kg/cu.m

Water= 160 kg/cu.m

Fine Aggregate= 890 kg/cu.m

Coarse aggregate= 1146 kg/cu.m

Chemical Admixture= 7 kg/cu.m

w/c ratio= 0.4

Trial ratio= 1:2.56:3.26.

Calculation of Mix design For M50 Grade of concrete without Fly ash:

1. Assumed Data for m50 Grade:

1. Type of cement- OPC 43 Grade
2. Minimum nominal size of aggregate- 20mm
3. Maximum cement content-320 kg/cu.m
4. Maximum water cement ratio- 0.45
5. Workability of concrete= 100mm
6. Exposure condition- Moderate
7. Method of placing concrete- Pumping
8. degree of supervision-Good
9. Types of aggregate- Crushed Angular aggregate
10. Maximum cement content- 450 kg/cu.m
11. chemical admixture- Superplasticizer

2. Test data for material:

a. Used cement- 43 Grade (Confirming to IS 8112)

b. Specific gravity- 3.15

c. Chemical admixture- Superplasticiser (Confirming to IS 9103)

d. Specific Gravity for Coarse aggregate & Fine Aggregate- 2.74

e. Water Absorption for Coarse aggregate 0.5% & fine aggregate 1.0%.

f. Free surface moisture (Should be dry in condition)

g. Seive analysis Coarse aggregate (IS 383,Table No.2) & Fine aggregate (IS 383, Table No.4)

3. Target strength of mix concrtete:

• f'ck=fck+1.65xs
• Where,
• f'ck= Target avarage strength of compressive strength at 28 days
• fck= Characteristics compressive strength at 28 days
• s= Standard deviation (As per Is 10262:2009, Table No.2)
• f'ck=50+1.65x5.0

= 58.25 MPa

4. Selection of water cement ratio:

• As per IS 456:2000, Table No.5
• w/c ratio= 0.45
• Based on experience adopted w/c ratio is 0.4.
• 0.4<0.45 _______Hence Ok.

5. Selection of water content:

• As per IS 10262:2009, Table No. 2.
• Maximum water for 20mm size aggregate= 186 litres.
• Estimated water content for 100mm slump= 186+(6/100)x186

= 197 litres.

• As per plasticiser are used water content reduced by 20%.
• Hence final water content= 197x0.8=158 litres.

6. Calculation of cement content:

• w/c ratio=0.4
• Cement= 158/0.4=396 kg/cu.m
• As per IS 456:2000, Table no.5, minimum cement content for moderate exposure condition is 300kg/cu.m
• 396 > 300 Kg/cu.m

7. volume of coarse & fine aggregate:

• As per IS 10262:2009, Table No.3, Volume of coarse aggregate & corrosponding to 20mm aggregate size & fine aggregate (Zone I) for w/c ratio=0.6.
• In present case w/c ratio is 0.4.
• The volume of coarse aggregate needs to be increased to decrease the Fine aggregate content.
• As the w/c ratio is lower by 0.1, the proportion of volume of coarse aggregate is lowered by 0.02 (at the rate of -/+ 0,01 for every +_0.05 change in w/c ratio)
• corrected volume of w/c ratio of 0.4= 0.62
• For pumpable concrete these value is reduced by 10%.
• Volume of Coarse aggregate= 0.62x0.9=0.56
• Volume of Fine aggregate= 1-0.56=0.44

8. Mix calculation:

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

a.Volume of concrete= 1 cu.m

b.volume of cement= (Mass of cement/ specific gravity of cement)x(1/1000)

= (396/3.15)x(1/1000)=0.126 cu.m

c. Volume of water= (Mass of water/Specific Gravity of water)x(1/1000)

= (158/1)x(1/1000)=0.158 cu.m

d. Volume of chemical admixture=(Mass of chemical admixture/specific gravity of chemical admixture)x(1/1000)

= (7.6/1.145)x(1/1000)

= 0.0066 cu.m

e. Volume of Coarse aggregate & fine aggregate=(a-(b+c+d))

= (1-(0.126+0.158+0.0066))=0.71 cu.m

f. Mass of coarse aggregate= e x Volume of coarse aggregate x Specific gravity of coarse aggregate x 1000

= 0.71x0.56x2.74x1000

= 1090 kg/cu.m

g, Mass of coarse aggregate= e x Volume of fine aggregate x specific gravity of fime aggregate x 1000

= 0.71x0.44x2.74x1000

= 750 kg/cu.m

h. Mix proportion for Trial no. 1

Cement=396 kg/cu.m

Water=158 kg/cu.m

Fine Aggregate=750 kg/cu.m

Coarse aggregate= 1090 kg/cu.m

Chemical admixture= 7 kg/cu.m

w/c ratio= 0.4.