Project on Concrete Mix Design for various grades of Concrete

Concrete Mix design for M35 grade concrete with fly ash.

STEP 1-

• Stipulation for proportion :

1. Grade of design - M35
2. Type of cement - OPC 43 taken from the IS 8112
3. Type of mineral admixture - Fly Ash Conforming to IS 3812(Part 1)
4. Maximum nonimal size of aggregate - 20 MM
5. Minimum cement content - 320 kg/m^3 from IS 456-2000 (Table no 5).
6. Maximum water cement ratio - 0.45 from (table no 5 IS 456-2000) due to exposure condition
7. Workability - 100 mm (slump value of pumpable concrete)
8. Exposure condition - Severe (for reinforcement concrete)
9. Type of aggregate - crushed aggregate
10. Maximum cement content - 450 kg/m^3
11. Chemical admixture type - superplasticizer
12. Method of concrete placing - pumping

• Test Data For Material :

1. Cement used - 43 grade. From IS 8112
2. Specific gravity of cement - 3.15
3. Fly ash - conforming IS 3812 (Part 1)
4. Specific gravity of fly ash - 2.2
5. Chemical admixture - super plasticizer taken IS 9103
6. Specific gravity of course aggregate - 2.74.
7. Specific gravity of fine aggregate - 2.74
8. Water Absorption - Coarse aggregate - 0.5% Fine aggregate. - 1%
9. free surface moisture - Nil

STEP 2-

• From Table 1 Of 10262:2009, Standard deviation, S=5 N/mm^2.

To find the target mean strength for mix proportion

⸫ ft = fck + 1.65*S

= 35 + 1.65* 5

= 43.25 N/mm^2 where fck - Characteristic Compressive strength S - denotes the Standard deviation

STEP 3-

• Selection of water cement ratio -

from Table 5 of IS 456- 2000 For severe Exposure condition.

⸫ Maximum water cement ratio - 0.45

W/C ratio - 0.4 < 0.45. hence it is ok

STEP 4-

• Calculation of water content -

From Table 2 of IS 10262:2009

Maximum Water content for 20 mm aggregate = 186 liter .....(for 25mm and 50mm slump range.)

For 100mm slump = 186+(6/100)*186.

= 197 liters

As superplasticizer is used , the water content reduced upto 30 % and trial water content reduction of 29% is achieved with plastercizer

Water content = 197*0.71

= 140 liters

STEP 5-

• Calculation of cement content -

Water cement ratio - 0.4

Cementanious material ( cement + fly ash ) = 140/0.4

= 350kg/mm^3

From IS 456-2000 Table No 5 severe exposure = 320kg.mm^3 , hence it is ok

• Percentage of fly ash depends on project requirement and quality of material.

• In this increase 10% of cementitious material content

Cementitious material content - 140 kg.mm^3

water cement ratio = 140/385 = 0.364.

• fly ash at 30 % total cementitious material content 35-30% = 385 - 115 = 270.kg/m^3

• With uses of fly ash the cement get utlized. 350- 270 = 80kg.mm^3

• Fly ash beign utilzed = 115 kg.mm^3

STEP 6-

• Calculate the volume of coarse aggregate and fine aggregate -

From IS 1026-2009 the volume of coarse aggregate for 20mm size3 of aggregate and fine aggregate zone 1 for water cement ratio is 0.6

But, this case we have water cement ratio is 0.4

Therefore the volume of coarse aggregate needs to be increased to decrease fine aggregate content.

If water cement ratio is lowered by 0.1 then volume of coarse aggregate gets increased by 0.02

Hence correct value of coarse aggregate water cement rati is 0.64 .

But for pumpable concrete it reduced by 10%

Volume of coarse aggregate -

0.64*0.9 = 0.576

Volume of fine aggregate -

1 - 0.576 = 0.42

STEP 7-

• MIX CALCULATION -

a.For per unit volume of concrete is 1m^3

b. volume of cement = mass of cement / specific gravity of cement * 1/1000

= 270/3.15 *1/1000

= 0.086m^3

c. volume of Fly ash - Mass of fly ash / specific gravity of flyash *1/1000

= 115/2.2*1/1000

= 0.052 m^3

d. volume of water = mass of water / specific gravity of water *1/1000

= 140/1*1/1000

= 0.140 m^3

e. volume of chemical admixture - mass of admixture / specific gravity of admixture * 1/1000

= 7.6/1.14*1/1000 = 0.006m^3

f. Volume of aggregate fine and coarse aggregate -

a-(b+c+d+e) = 1-(0.086+0.052+0.140+0.006)

= 0.716 m^3

g. Mass of coarse aggregate = F* volume of coarse aggregate * specific gravity of coarse aggregate *1000

= 0.716*0.576*2.74*1000

= 1130 kg.m^3

h. Mass of fine aggregate = F* volume of fine aggregate *specific gravity of fine aggregate *1000

= 0.716*0.424*2.74*1000

= 831kg.m^3

STEP 8-

1 cement - 270 kg/m^3

2 fly ash - 115 kg/m^3

3 water - 140 kg/m^3

4 fine aggregate - 831 kg/m^3

5 coarse aggregate - 1130 kg/m^3

6 chemical admixture - 7 kg/m^3

7 water cement ratio - 0.364

STEP 9-

The slump shall be measured and water content and admixture shall be adjusted for required slump.

STEP 10-

Variation of 10% of wc ratio is carried by out a using two graph between the water cement ratio.

• RESULT

Mix design for M35 grade of concrete with fly ash is 1: 2.15 : 2.94

Concrete Mix design for M50 grade concrete without fly Ash

STEP 1-

• Stipulation for proportion :

1. Grade of design - M50
2. Type of cement - OPC 43 taken from the IS 8112
3. Maximum nonimal size of aggregate - 20 MM
4. Minimum cement content - 320 kg/m^3 from IS 456-2000 (Table no 5).
5. Maximum water cement ratio - 0.45 from (table no 5 IS 456-2000) due to exposure condition
6. Workability - 100 mm (slump value of pumpable concrete)
7. Exposure condition - Severe (for reinforcement concrete)
8. Type of aggregate - crushed aggregate
9. Maximum cement content - 450 kg/m^3
10. Chemical admixture type - superplasticizer
11. Method of concrete placing - pumping

• Test Data For Material :

1. Cement used - 43 grade. From IS 8112
2. Specific gravity of cement - 3.15
3. Chemical admixture - super plasticizer taken IS 9103
4. Specific gravity of course aggregate - 2.74.
5. Specific gravity of fine aggregate - 2.74
6. Water Absorption - Coarse aggregate - 0.5% Fine aggregate. - 1%
7. free surface moisture - Nil

STEP 2-

• From Table 1 Of 10262:2009, Standard deviation, S=5 N/mm^2.

To find the target mean strength for mix proportion

⸫ ft = fck + 1.65*S

= 50 + 1.65* 5

= 58.25 N/mm^2 where fck - Characteristic Compressive strength S - denotes the Standard deviation

STEP 3-

• Selection of water cement ratio -

from Table 5 of IS 456- 2000 For severe Exposure condition.

⸫ Maximum water cement ratio - 0.45

W/C ratio - 0.4 < 0.45 hence it is ok

STEP 4-

• Calculation of water content -

From Table 2 of IS 10262:2009

Maximum Water content for 20 mm aggregate = 186 liter .....(for 25mm and 50mm slump range.)

For 100mm slump = 186+(6/100)*186.

= 197 liters

As superplasticizer is used , the water content reduced upto 30 % and trial water content reduction of 29% is achieved. With plastercizer

Water content = 197*0.71

= 140 liters

STEP 5-

• Calculation of cement content -

Water cement ratio - 0.4

cement content = 140/0.4

= 350kg/mm^3

From IS 456-2000 Table No 5 severe exposure = 320kg.mm^3 , hence it is ok

STEP 6-

• Calculate the volume of coarse aggregate and fine aggregate -

From IS 1026-2009 the volume of coarse aggregate for 20mm size3 of aggregate and fine aggregate zone 1 for water cement ratio is 0.6

But, this case we have water cement ratio is 0.4

Therefore the volume of coarse aggregate needs to be increased to decrease fine aggregate content.

If water cement ratio is lowered by 0.1 then volume of coarse aggregate gets increased by 0.02

Hence correct value of coarse aggregate water cement ratio is 0.62 .

But for pumpable concrete it reduced by 10%

Volume of coarse aggregate -

0.62*0.9 = 0.558

Volume of fine aggregate -

1 - 0.558 = 0.442

STEP 7-

• MIX CALCULATION -

a.For per unit volume of concrete is 1m^3

b. volume of cement = mass of cement / specific gravity of cement * 1/1000

= 350/3.15 *1/1000

= 0.111m^3

c. volume of water = mass of water / specific gravity of water *1/1000

= 140/1*1/1000

= 0.140 m^3

d. volume of chemical admixture - mass of admixture / specific gravity of admixture * 1/1000

= 7/1.145*1/1000 = 0.006m^3

e. Volume of aggregate fine and coarse aggregate -

a-(b+c+d) = 1-(0.111+0.140+0.006)

= 0.743 m^3

f. Mass of coarse aggregate = e* volume of coarse aggregate * specific gravity of coarse aggregate *1000

= 0.743*0.56*2.74*1000

= 1140 kg.m^3

g. Mass of fine aggregate = e* volume of fine aggregate *specific gravity of fine aggregate *1000

= 0.743*0.424*2.74*1000

= 863kg.m^3

STEP 8-

1 cement - 350 kg/m^3

2 water - 140 kg/m^3

3 fine aggregate - 863 kg/m^3

4 coarse aggregate - 1140 kg/m^3

5 chemical admixture - 7 kg/m^3

6 water cement ratio - 0.4

STEP 9 -

Variation of 10% of wc ratio is carried by out a using two graph between the water cement ratio.

• RESULT

Mix design for M50 grade of concrete without fly ash is 1 : 2.56 : 3.26