Project on Concrete Mix Design for various grades of Concrete

MIX DESIGN FOR M35 GRADE OF CONCRETE WITH FLY ASH -

Aim - Mix proportioning of concrete using fly ash as a part of replacement of OPC

1) Stipulations for proportioning -

1. a) Grade designation - M35
2. b) Type of cement - OPC 43 grade conforming to IS 8112
3. c) Type of mineral admixture - Fly ash conforming to IS 3812 (part 1)
4. d) Maximum nominal size of aggregate - 20mm
5. e) Minimum cement content - 340kg/m^3 (from table 5 of IS 456:2000- Exposure condition)
6. f) Maximum water-cement ratio - 0.45 (from table 5 of IS 456:2000 -Exposure condition)
7. g) Workability - 100mm (slump value for pumpable concrete)
8. h) Exposure condition - Severe ( for Reinforced concrete)
9. i) Method of concrete placing - pumping
10. j) Degree of supervision - Good
11. k) Type of aggregate - Crushed angular aggregate
12. l) Maximum cement content - 450 kg/m^3
13. m) Chemical admixture type - Superplasticizers

2) Test date for material -

1. a) cement used - OPC 43 grade conforming to IS 8112
2. b) specific gravity of cement - 3.15
3. c) Fly ash - Conforming to IS 3812 (part 1)
4. d) Specific gravity of fly ash - 2.2
5. e) Chemical admixture - Superplasticizers conforming to IS 9103
6. f) Specific gravity of - coarse aggregate - 2.74

- Fine aggregate - 2.74

1. g) Water absorption of - coarse aggregate - 0.5%

- Fine aggregate - 1.0%

1. h) Free surface moisture of - coarse aggregate - nil

- Fine aggregate - nil

1. i) Sieve analysis-

Coarse aggregate - According to zone

Fine aggregate - Conforming to grading zone 1 of table 4 of IS 383

3) Target strength for mix proportioning -

F'ck = fck + 1.65S

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 S = 35 + 1.65*5 = 43.25 n/mm^2

4) Selection of water cement ratio-

from table 5 of IS 456:2000 for severe exposure condition

Water-cement ratio = 0.45

Adopted W/c ratio = 0.40

0.40 is less than 0.45 hence,OK.

5) Selection of water content-

from table 2 of IS 10262:2009,Maximum water content for 20mm aggregate = 186 lit (for 25-50mm slump)

Water content for 100mm slump = 186 +6/100 *186 = 197 lit

As superplasticizers is used,the water content is reduced by 30%

On trial basis, it is reduced by 29%

hence, (100-29=71)

Water content = 197*0.71 = 140 lit

6)Calculation of cement content-

Water- cement ratio= 0.40

Cementitious material(cement and fly ash) = 140/0.40 = 350kg/m^3

from table 5 of IS 456 Minimum cement content for severe exposure condition = 340 kg/m^3

350 kg/m^3 is greater than 340 kg/m^3 hence,OK.

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

a)The percentage of fly ash to be decided based on project requirement.

1. b) Cementitious material is increased by 10%

Cementitious material content = 350*1.10 = 385 kg/m^3

Water content = 140kg/m^3

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

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

Cement (OPC) = 385-115= 270kg/m^3

Saving of cement while using fly ash = 350-270 = 80 kg/m^3

Fly ash used = 115 kg/m^3

7) proportion of volume of coarse aggregate and fine aggregate-

from table 3 of IS 10262 : 2009,volume of coarse aggregate corresponding to 20mm size of aggregate and fine aggregate

(zone 1) for W/c ratio = 0.60

In present case, Water cement ratio = 0.40

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

As water-cement ratio is lowered by 0.10 , the proportion of volume of coarse aggregate is increased by 0.02

Therefore, Corrected volume of coarse aggregate for W/c ratio 0.40 = 0.62

for pumpable concrete,the value is reduced by 10%

Volume of coarse aggregate = 0.62*0.9 = 0.56

Volume of fine aggregate = 1-0.56 = 0.44

8) Mix calculations-

1. a) Volume of concrete = 1 m^3
2. b) Volume of cement = mass of cement/specific gravity of cement * 1/1000

= 270/3.15 * 1/1000 = 0.086 m^3

c)Volume of fly ash = mass of fly ash/specific gravity of fly ash * 1/1000

= 115/2.2 * 1/1000 = 0.052 m^3

1. 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 chemical admixture/specific gravity of chemical admixture * 1/1000

= 7.6/1.145 * 1/1000 = 0.006 m^3

1. f) Volume of aggregate (FA and CA)= (volume of concrete-(volume of cement+volume of fly ash+volume of water+volume of

chemical admixture))

= (1-(0.086+0.052+0.140+0.006)) = 0.716 m^3

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

= 0.716*0.56*2.74*1000 = 1098 kg/m^3

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

= 0.716*0.44*2.74*1000 = 863 kg/m^3

9) Mix proportion for trial 1-

Cement = 270 kg/m^3

Fly ash = 115 kg/m^3

Water = 140 kg/m^3

Fine aggregate = 863 kg/m^3

Coarse aggregate = 1098 kg/m^3

Chemical admixture = 7 kg/m^3

W/c ratio = 0.364

RESULT - TRIAL MIX RATIO = 1 : 2.24 : 2.85

1 % of cement,2.24% of sand and 2.85% of coarse aggregate.

MIX DESIGN FOR M50 GRADE OF CONCRETE WITHOUT FLY ASH

Aim - Mix proportioning of concrete without fly ash

1) Stipulation for proportioning -

1. a) Grade designation - M50
2. b) Type of cement - OPC 43 grade conforming to IS 8112
3. c) Maximum nominal size of aggregate - 20mm
4. d) Minimum cement content - 320 kg/m^3 (from table 5 of IS 456:2000-Exposure condition)
5. e) maximum water-cement ratio - 0.45 (from table 5 of IS 456:2000-Exposure condition)
6. f) Workability - 100mm slump (Pumpable concrete)
7. g) Exposure condition - Severe (for reinforced concrete)
8. h) Method of concrete placing - Pumping
9. i) Degree of supervision - Good
10. j) Type of aggregate - Crushed angular aggregate
11. k) Maximum cement content - 450 kg/m^3
12. l) Chemical admixture type - Superplasticizers

2) Test data for material -

1. a) cement used - OPC 43 grade conforming to IS 8112
2. b) Specific gravity of cement - 3.15
3. c) chemical admixture - Superplasticizers conforming to IS 9103
4. d) Specific gravity of - Coarse aggregate - 2.74

- Fine aggregate - 2.74

1. e) Water absorption of - Coarse aggregaete - 0.5%

- Fine aggregate - 1.0%

1. f) Free surface moisture - coarse aggregate - nil

- Fine aggragate - nil

1. g) Sieve analysis - coarse aggregate - According to zone

- Fine aggregate - Conforming to grading Zone 1 of table 4 of IS 383

3) Target strength for mix proportioning -

F'ck = fck + 1.65S

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*5 = 58.25 n/mm^2

4)Selection of water cement ratio -

from table 5 of IS 456:2000 for severe exposure condition

Maximum water-cement ratio = 0.45

Adopted water-cement ratio = 0.40

0.40 is less than 0.45 hence,OK.

5) Selection of water content -

from table 2 of IS 10262:2009, Maximum water content for 20mm aggregate = 186 lit (for 25mm-50mm slump)

Water content for 100mm slump = 186 + 6/100 * 186 = 197 lit

As superplasticizers is used,the water content can be reduced to 29 %

(100-29 = 71)

Water content = 197*0.71 = 140 lit

6) Calculation of cement content -

water-cement ratio = 0.40

Cement content = 140/0.40 = 350 kg/m^3

from table 5 of IS 456,Minimum cement content for severe exposure condition = 320 kg/m^3

350 kg/m^3 is greater than 320 kg/m^3 hence, OK.

7) Proportion of volume of coarse aggregate and fine aggregate -

from table 3 of IS 10262:2009, volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (zone

1) for water-cement ratio = 0.6

In present case, water-cement ratio = 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

Corrected volume of coarse aggregate for water-cement ratio 0.40 = 0.62

for pumpable concrete, the value is reduced by 10%

Volume of coarse aggregate = 0.62*0.9 = 0.56

Volume of fine aggregate = 1-0.56 = 0.44

8) Mix calculations -

1. a) Volume of concrete = 1 m^3
2. b) Volume of cement = mass of cement/specific gravity of cement * 1/1000

= 350/3.15 * 1/1000 = 0.111 m^3

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

= 140/1 * 1/1000 = 0.14 m^3

1. d) Volume of chemical admixture = mass of chemical admixture/specific gravity of chemical admixture * 1/1000

= 7.6/1.145 * 1/1000 = 0.006 m^3

1. e) Volume of aggregate (FA and CA) = (volume of concrete- (volume of cement+volume of water+volume of chemical

admixture))

= (1-(0.111+0.140+0.006)) = 0.743 m^3

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

= 0.743*0.56*2.74*1000 = 1140 kg/m^3

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

= 0.743*0.44*2.74*1000 = 896 kg/m^3

9) Mix proportion for trial 1 -

Cement = 350 kg/m^3

Water = 140 kg/m^3

Fine aggregate = 896 kg/m^3

Coarse aggregate = 1140 kg/m^3

Chemical admixture = 7 kg/m^3

Water-cement ratio = 0.40

RESULT - TRIAL MIX RATIO IS - 1 : 2.56 : 3.26

1% of cement,2.56% of sand and 3.26% of coarse aggregate.