Project on Concrete Mix Design for various grades of Concrete

Calculate the Concrete Mix Design for M35 grade concrete with fly ash & M50 grade concrete without Fly ash

Data required for mix design of M35 grade of concrete with fly ash.

1. Grade designation : M35
2. Type of cement : OPC 43 grade
3. Type of admixture : Fly ash
4. Maximum nominal size of aggregate : 20mm
5. Minimum cement content : 300Kg/m
6. Maximum water cement ratio : 50
7. Workability : 100mm (slump)
8. Exposure condition : Moderate (for reinforced concrete)
9. Method of concrete placing : Pumping
10. Degree of supervision : Good
11. Type of aggregate : Crushed angular aggregate
12. Maximum cement content : 450 Kg/m³
13. Chemical admixture type : Super plasticizer

Test data for materials

1. Cement used : OPC 43 grade conforming to IS 8112
2. Specific gravity of cement : 3.15
3. Fly ash : Confirming to IS 3812 Part 1
4. Specific gravity of fly ash : 2
5. Chemical admixture : Super plasticizer
6. Specific gravity of coarse aggregate : 2.74
7. Specific gravity of fine aggregate : 2.74
8. Sieve analysis coarse aggregate : 20 mm
9. Fine aggregate : Corresponds to zone 1 of IS 10262

Target mean strength

f_t = f_ck + 1.65 s

f_ck = 35 N/mm²

s = Assumed Standard deviation as per IS 10262 2009 Table 1

5 N/mm²

f_t = 35 + 1.65 * 5

= 43.25 N/mm²

Selection of water cement ratio

From table 5 of IS 456 the water cement ratio for moderate weather condition is = 0.50

Based on experience adopted w/c is 0.45

0.45 < 0.50, hence ok.

Selection of water content

From Table 2 of IS 10262 2009 the maximum water content

for 20mm coarse aggregate is = 186 lit (Slump 25mm t to 50mm )

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

Maximum water content = 197.16 lit

Since Super plasticizer is used as chemical admixture the maximum water content is reduced by 30%.

Maximum water content = 197.16 * 0.70 = 138 lit

Calculation of cement and fly ash content

Water cement ratio = 0.45

Water content = 138 lit

Cement content = `138/.45`

= 307 Kg/m³

As per IS 456 Table 5,

Minimum cement content for Moderate exposure condition is = 300 Kg/m³

307Kg/m³ > 300 Kg/m³ Hence ok.

Mix containing fly ash following steps to be considered,

The percentage of fly ash content is based on quality of material and project requirement.

Increase in cementitious material is done based on experience and trails. A increase of 10% of cementitious material is used.

Cementitious material content = 307 * 1.10 = 338 Kg/m³

Water content = 138 lit

Water cement ratio = 138 / 338

= 0.40

Fly ash @ 30% of cementitious material

Fly ash = 338 * .30 = 101 Kg/m³

Cement content = 338 – 101 = 237 Kg/m³

Proportion of Volume of coarse aggregate and fine aggregate

As per IS 10262 2009 Table 3,

The volume of coarse aggregate for 20 mm size and fine aggregate corresponding to Zone 1 for water cement ratio 0.50 = 0.60

Here we have water cement ratio of 0.45 for every 0.05 change in water cement ratio there is a increase I coarse aggregate content of 0.01. Hence for 0.45 water cement ratio increase coarse aggregate content of 0.01.

Thus volume of coarse aggregate for water cement ratio 0.45 = 0.61

For pumping 10%of the value should be reduced

Volume of coarse aggregate = 0.61 * 0.90 = 0.55

Volume of fine aggregate = 1 – 0.55 = 0.45

Mix calculations

1. Volume of concrete = 1 m3
2. Volume of cement = Mass of cement / Specific gravity of cement * ( 1 / 1000)

= ( `237/3.15 *1/1000`)

= 0.075 m³

3. Volume of fly ash = Mass of fly ash / Specific gravity of fly ash * (1/1000)

= 101 / 2.2 (1/1000)

= 0.045

4. Volume of water =Mass of water / Specific gravity of water * ( 1/1000 ) = ( `138/1 * 1/1000`)

= 0.138 m³

5. Volume of Chemical admixture = Mass of chemical admixture / Specific gravity of chemical admixture * ( 1/1000)

= ( `7/1.145 * 1/1000`)

= 0.006 m³

6. Volume of total aggregate = 1 – (2+3+4+5)

= 1 – (0.075 + 0.045 + 0.138+0.006)

= 0.736 m³

7. Mass of coarse aggregate = 6 * volume of coarse aggregate * Specific gravity of coarse aggregate * 1000

= 0.736 * 0.55 * 2.74 * 1000

= 1109 Kg

8. Mass of fine aggregate = 6 * Volume of fine aggregate * Specific gravity of fine aggregate * 1000

= 0.736 * 0.45 * 2.74 * 1000

= 907 Kg

Mix proportion

Cement = 237 Kg

Fly ash = 101 Kg

Water = 138 lit

Fine aggregate = 907 Kg

Coarse aggregate = 1109 Kg

Chemical admixture = 7 Kg/m³

Water cement ratio = 0.40

Data required for mix design of M30 grade of concrete.

1. Grade designation : M50
2. Type of cement : OPC 43 grade
3. Maximum nominal size of aggregate : 20mm
4. Minimum cement content : 340Kg/m
5. Maximum water cement ratio : 45
6. Workability : 50 mm (slump)
7. Exposure condition : Very Severe (for reinforced concrete)
8. Method of concrete placing : Pumping
9. Degree of supervision : Good
10. Type of aggregate : Crushed angular aggregate
11. Maximum cement content : 450 Kg/m³
12. Chemical admixture type : Nil

Test data for materials

13.Cement used : OPC 43 grade conforming to IS 8112

14.Specific gravity of cement : 3.15

15.Chemical admixture : Nil

16.Specific gravity of coarse aggregate : 2.74

17.Specific gravity of fine aggregate : 2.74

18.Sieve analysis coarse aggregate : 20 mm

19.Fine aggregate : Corresponds to zone 2 of IS 10262

Target mean strength

f_t = f_ck + 1.65 s

f_ck = 50 N/mm²

s = Assumed Standard deviation as per IS 10262 2009 Table 1

5 N/mm²

f_t = 50 + 1.65 * 5

= 58.25 N/mm²

Selection of water cement ratio

From table 5 of IS 456 the water cement ratio for Very severe weather condition is = 0.45

Based on experience adopted w/c is 0.40

0.40 < 0.45, hence ok.

Selection of water content

From table 2 of Is 10262 2009 the maximum water content

for 20mm coarse aggregate is = 186 lit (Slump 25mm to 50mm

For 50 mm slump = 186

Maximum water content = 186 lit

Calculation of cement content

Water cement ratio = 0.40

Water content = 186 lit

Cement content = ( `186/0.40`)

= 465 Kg/m³

As per IS 456 Table 5,

Maximum cement content for Very Severe exposure condition is = 450 Kg/m³

465Kg/m³ > 450 Kg/m³ Since maximum cement content is lower than the designed cement content, redesign the water cement ratio.

From Table 5 of IS 456 the water cement ratio for very severe weather condition is 0.45.

Water cement ratio = 0.45

Water content = 186 lit

Cement content = ( `186/0.45`)

= 413 Kg/m³

As per IS 456 Table 5,

Maximum cement content for Very Severe exposure condition is = 450 Kg/m³

413Kg/m³ < 450 Kg/m³, Hence ok.

Proportion of Volume of coarse aggregate and fine aggregate

As per IS 10262 2009 Table 3,

The volume of coarse aggregate for 20 mm size and fine aggregate corresponding to Zone 2 for water cement ratio 0.50 = 0.62

Here we have water cement ratio of 0.45 for every 0.05 change in water cement ratio there is a increase in coarse aggregate content of 0.01. Hence for 0.45 water cement ratio increase coarse aggregate content of 0.01.

Thus volume of coarse aggregate for water cement ratio 0.45 = 0.63

For pumping 10%of the value should be reduced

Volume of coarse aggregate = 0.63 * 0.90 = 0.57

Volume of fine aggregate = 1 – 0.57 = 0.43

Mix calculations

1. Volume of concrete = 1 m3
2. Volume of cement = Mass of cement / Specific gravity of cement * ( 1/1000 )

= (`413/3.15 *1/1000`) = 0.131 m³

3. Volume of water = Mass of water / Specific gravity of water * ( 1/1000 )

= ( `186/1*1/1000`)

= 0.186 m³

4. Volume of total aggregate = 1 – (2+3)

= 1 – (0.131 + 0.186 )

= 0.683 m³

5. Mass of coarse aggregate = 4 * volume of coarse aggregate * Specific gravity of coarse aggregate * 1000

= 0.683 * 0.57 * 2.74 * 1000

= 1067 Kg

6. Mass of fine aggregate = 4 * Volume of fine aggregate * Specific gravity of fine aggregate * 1000

= 0.683 * 0.43 * 2.74 * 1000

= 805 Kg

Mix proportion

Cement = 413 Kg

Water = 186 Kg

Fine aggregate = 805 Kg

Coarse aggregate = 1067 Kg

Water cement ratio = 0.45