Project on Concrete Mix Design for various grades of Concrete

MIX DESIGN M35 GRADE CONCRETE

A) Stipulation for mix design:

1)Grade designation : M 35

2)Type of cement : OPC 43 grade confirming to IS 269

Type of mineral admixture : Fly ash conforming to IS 3812 (Part1)

3) Maximum nominal size of aggregate : 20 mm

4) Minimum cement content : 340 kg/m³

5) Maximum water-cement ratio : 0.45

6) Workability : 50-100 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 : Super Plasticizer

B)Test data for material

• Specific gravity of cement : 3.12
• Specific gravity of fly ash : 2.2
• Specific gravity of Coarse aggregate : 2.74
• Specific gravity of Fine aggregate : 2.56
• Chemical admixture : 1.145

Water absorption
1) Coarse aggregate : 0.5 percent
2) Fine aggregate : 1.0 percent

C) The coarse and fine aggregates are wet and their total moisture content is 2 percent and 5 percent
respectively. Therefore, the free moisture content in coarse and fine aggregate shall be as shown in (j)
below
Free (surface) moisture
1) Coarse aggregate : Free moisture = Total moisture content –Water absorption
= 2.0 – 0.5 = 1.5 percent
2) Fine aggregate : Free moisture = Total moisture content –Water absorption
= 5.0 – 1.0 = 4.0 percent

C) Target strength for mean proportion

f target = fck+1.65 x s

As per the table I of IS: 10262-2009 , standard deviation, s = 5.0 N/mm² Therefore, target strength = 35 + 1.65 x 5.0 =43.25N/mm2

D)Selection of water cement ratio

is 456table 5 w/c =0.45

E)Selection of water content

is 456table 2 maximum water content for = 186litr for 20mm aggregate

water content for 100mm slump =186+(6/100) x 186 =197 ltr

super plasticizer reduce 20% water content = = 197-[197 x (25/100)] = 147ltr

F)calculation of water content

Water-cement ratio =0.45

From Table 5 of IS 456, minimum cement content for very sever exposure condition =340kg/meter cube

G) volume of coarse and fine aggregate

From Table 3 of is 10262 volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone II) for a water-cement ratio of 0.50 = 0.62

the water-cement ratio is 0.45. Therefore, the volume of coarse aggregate is required to be increased to reduce the fine aggregate content.As the water-cement ratio is lower by 0.10, the proportion of the volume of coarse aggregate is increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in the water-cement ratio). Therefore. the corrected proportion of the volume of coarse aggregate for the water-cement ratio of 0.45 = 0.63

For pumpable concrete, these values should be reduced by 10 percent.

Therefore, volume of coarse aggregate = 0.63 x 0.9 = 0.567.

Volume of fine aggregate content =1 – 0.567 =0.43

H)Mix calculation

a) Volume of concrete = 1m³

b) Volume of cement = (Mass of cement/Specific Gravity of Cement) X (1/1000)

= (350/3.12) X (1/1000)

= 0.112 meter cube

c) Volume of fly ash =Mass of fly ash /Specificgravity of fly ash(1/1000)

= 142/2.2 x 1/1000 =0.0645 meter cube

d) Volume of water = (Mass of water/specific gravity of water) X (1/1000)

= (147/1) X (1/1000)

= 0.147 meter cube

e) Volume of superplasticizer = (Mass of superplasticizer / Specific gravity of admixture) X (1/1000)

= (7/1.145) X (1/1000)

= 0.006 m³

f) Volume of all aggregate = (a-(b+c+d))

= 1 – (0.112 + 0.147+0.006)

= 0.735 m³

g) Mass of coarse aggregate = Volume of all aggregate X volume of coarse aggregate X Specific gravity of coarse aggregate X 1000

= 0.735 x 0.567 x 2.74 x 1000

= 1141.88 kg

h)Mass of fine aggregate = Volume of all aggregate X volume of fine aggregate X Specific gravity of fine aggregate X 1000

= 0.735 x 0.433 x 2.56 x 1000

=814.7kg

I)mix proportion

Cement = 350 kg/m³

fly ash = 130 kg/m³

Water = 147 kg/m³

Super plasticizer = 7 kg/m³

Fine aggregates = 814.73 kg/m³

Coarse aggregate = 1141.88 kg/m³

W/c = 0.45

M30 MIX DESIGN WITHOUT FLUY ASH

Stipulations for Concrete Mix Design

• Grade designation : M 50
• Type of cement : OPC 53 grade confirming to IS 8112
• Maximum nominal size of aggregate : 20 mm
• Minimum cement content : 360 kg/m³
• Maximum water-cement ratio : 0.35
• Workability : 50-75 mm (slump)
• Exposure condition : Extreme (for reinforced concrete)
• Method of concrete placing : Pumping
• Degree of supervision : Good
• Type of aggregate : Crushed angular aggregate
• Maximum cement content : 450 kg/m³
• Chemical admixture type : Super Plasticizer

Test Data for Materials

The following data are collected by performing standard tests in a laboratory.

Specific gravity of cement : 3.12

Specific gravity of Coarse Aggregate : 2.74

Procedure for Concrete Mix Design of M 50 Concrete

1. Target Strength for Mix Proportioning

f_target = f_ck + 1.65 x s

f_target denotes the Target Average Compressive Strength at 28 days,

f_ck denotes the Characteristic Compressive Strength at 28 days,

‘s’ stands for Standard Deviation

According to the table 1 of IS 10262

standard deviation, s = 5.0 N/mm²

Therefore, target strength = 50 + 1.65 x 5.0 = 58.25 N/mm²

2. Selection of Water/Cement Ratio

From Table 5 of 1S 456

Maximum water-cement ratio = 0.35

3. Selection of Water Content

From Table 2 of IS 456 maximum water content =186 litres (for 25 to 50 mm slump range) for 20 mm aggregate.

Estimated water content for 100 mm slump =186+(6/100) x 186 =197 litres.

(Note: If Super plasticizer is used, the water content can be reduced up to 20% and above.)

Based on trials with Super plasticizer water content reduction of 27% has been achieved, Hence the arrived water content = 197 – [197 x (27/100)] = 143 litres.

4. Calculation of Cement Content

Water-cement ratio = 0.35

Cement content = 143/0.35 = 410 kg/m³

From Table 5 of IS 456, minimum cement content for ‘Extreme exposure’ condition = 360 kg/m³

410 kg/m³ > 360 kg/m³, hence, O.K.

5. Proportion of Volume of Coarse Aggregate and Fine Aggregate Content

From Table 3 of IS 10262 volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone II) for a water-cement ratio of 0.50 =0.62.

In the present case, the water-cement ratio is 0.35. Therefore. the volume of coarse aggregate is required to be increased to decrease the fine aggregate content. As the water-cement ratio is lower by 0.10. the proportion of the volume of coarse aggregate is increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in the water-cement ratio).

Therefore. the corrected proportion of the volume of coarse aggregate for the water-cement ratio of 0.35 = 0.65.

NOTE – In case the coarse aggregate is not angular one, then the volume of coarse aggregate may be increased by 10 percent based on experience.

For pumpable concrete, these values should be reduced by 10 percent.

Therefore, volume of coarse aggregate = 0.65 x 0.9 = 0.585.

Volume of fine aggregate content =1 – 0.585 =0.415

6. Mix Calculations

a) Volume of concrete = 1m³

b) Volume of cement = (Mass of Cement/ Its Specific Gravity ) X (1/1000)

= (410/3.12) X (1/1000)

= 0.131 m³

c) Volume of Water = (Mass of water/specific gravity of water) X (1/1000)

= (143/1) X (1/1000)

= 0.143 m³

d) Volume of Superplasticizer = (Mass of Superplasticizer / Specific gravity of admixture) X (1/1000)

= (8.2/1.145) X (1/1000)

= 0.007 m³

e) Volume of all aggregate = (a – (b + c + d))

= 1 – (0.131 + 0.143+0.007)

= 0.719 m³

e) Mass of coarse aggregate = Volume of All Aggregate X Volume of Coarse Aggregate X Specific Gravity of Coarse Aggregate X 1000

= 0.719 x 0.585 x 2.74 x 1000

= 1152.48 kg

f) Mass of fine aggregate = Volume of all aggregate X volume of fine aggregate X Specific gravity of fine aggregate X 1000

= 0.719 x 0.415 x 2.56 x 1000

= 763.86 kg

7. Concrete Mix Proportions

• Cement = 410 kg/m³
• Water = 143 kg/m³
• Super plasticizer = 7 kg/m³
• Fine aggregates = 763.86 kg/m³
• Coarse aggregate = 1152.48 kg/m³
• W/c = 0.35