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

^Aim:

^{To calculate the concrete mix design for M35 grade of concrete with fly ash.}

^{Introduction:}

^{Concrete mix design is the method of finding the precise of cement, sand and aggregates for concrete to achieve the target strength in structures, therefore concrete mix in terms of cement:sand:aggregates. The design is done according to the requirements of concrete strength. So, we can achieve the desirable properties of concrete either it is in fresh stage or in hardened stage. The fresh concrete properties like workability, setting time, and hardened concrete properties like compressive strength, durability etc., are attained surely by this method. this project consists of the design of m35 grade cement with fly ash.}

^{Equation used :}

^{A) Target mean strength}

^{f'ck = fck + 1.65s}

^{f'ck - Largest average compressive strength at 28days.}

^{fck - Characteristics compressive strength at 28days}

^{s - standard deviation (IS 10262:2009, table-1)}

^{B) Cement content}

^{Cement content = water content / water-cement ratio}

^{C) Volume of calculation}

1. Volume of concrete = 1 m³
2. Volume of concrete = (Mass of cement / specific gravity of cement) X (1 / 1000)
3. Volume of water = (Mass of water / specific gravity of water) X (1 / 1000)
4. Volume of chemical admixture = (Mass of chemical admixture / specific gravity of chemical admixture) X (1 / 1000)
5. Volume of fly ash = (Mass of fly ash / specific gravity of fly ash) X (1 / 1000)
6. Volume of all in aggregates = (a-(b+c+d+e))
7. Mass of coarse aggregate = f X volume of coarse aggregate X specific gravity of coarse aggregate X 1000
8. Mass of fine aggregate = f X volume of coarse aggregate X specific gravity of coarse aggregate X 1000

Codes for concrete mix design

IS 10262:2009

IS 456:2000

IS 8112

IS 9103

IS 3812 (Part-I)

Procedure

Step-1

Stipulation for proportioning

1. Grade Designation M35
2. Type of cement OPC 43 grade conforming to IS 8112
3. Type of Mineral admixture Fly ash conforming to IS 3812 (Part-1)
4. Maximum nominal size of aggregates 20mm
5. Minimum cement content 320 kg/m³ (Table 5 IS 456:2000 Based on Exposure condition)
6. Maximum Water-cement ratio 0.45(Table:5 IS 456:2000 Based on Exposure condition)
7. Workability 100 slump value of pump able concrete
8. Exposure condition Severe (For reinforcement concrete)
9. Method of concrete placing pumping
10. Degree of supervision Good
11. Type of aggregates Crushed angular aggregates
12. Maximum cement content 450 kg/m³
13. Chemical admixture content Superplasticizer

Step-2

Test data for material

1. Cement used OPC 43 grade conforming to IS 8112
2. Specific gravity of cement 3.15
3. Fly ash Conforming to IS 3812 (PArt-1)
4. Specific gravity of Fly ash 2.2
5. Chemical admixture Superplasticizer Conforming to IS 9103
6. Specific gravity of Coarse aggregates 2.74
7. Specific gravity of Coarse aggregates 2.74
8. Water Absorption of Coarse aggregates 0.5%
9. Water Absorption of Fine aggregates 1.0%
10. Free surface of Coarse aggregates Nil
11. Free Surface of Fine aggregates Nil
12. Sieve analysis of Coarse aggregates Conforming to Table 2 of IS 383
13. Sieve analysis of Fine aggregates Conforming to Grading zone II of Table 4 of IS 383

Step-3

To Find Target Mean Strength for Mix Proportioning

^{f'ck = fck + 1.65s}

= 35 + 1.65 X 5

f'ck = 43.25 N/mm²

Step-4

Selection of Water-cement rati0 = 0.45

Maximum water/cement ratio = 0.45 (For severe condition from table 5 of IS 456:2000)

On experinece w/c ratio = 0.4

04<0.45 hence OK.

Step-5

Calculation of Water content

Maximum water content for 20mm aggregates = 186 liters(Table 2 of IS 10262:2009)for 25mmto50mm slump range

For 100 slump = 186+(6/100) X 186 = 197 litres

As Superplasticizer is used, the water content is reduced upto 30%

Based on trials water content reduction of 29% is achieved with plasticizer

Hence arrived water content = 197 X 0.71 = 140 litres

Step-6

Calculation of Cement content

Water/cement ratio = 0.4

Cementitious material (Cement fly ash) = 140/0.4 = 350kg/m³

In table 5 of IS 456:2000, the cement content for severe exposure = 320 kg/m³

350kg/m3 > 320kg/m3 hence OK.

To proportion the mix containing fly ash the following Steps are suggested

1. The percentage of fly ash need to be decided based on project requirements and quality material.
2. In some case increase in cementitious material can be warned. Increase in cementitious material content and its percentage may be based on experience and trial.

In this increase of 10% cementitious material content is consisdered

Cementitious material content = 350 X 1.1 = 385 kg/m³

Water content = 140 kg/m³

So, Water/cement ratio = 140/385 = 0.364

Fly ash at 30% total cementitious material content = 35-30% = 115kg/m³

Cement (OPC) = 385-115 = 270kg/m³

Saving of cement while using fly ash = 350-270 = 80kg/m³

Fly ash being utilized = 115kg/m³

Step-7

Proportion of volume of Coarse aggregates and Fine aggregates

From table 3 of IS 10262:2009 volume of coarse aggregates

Corresponding to 20mm size aggregates and Fine aggregates (Zone-2) of w/c ratio of 0.50 is 0.62

In the present case w/c ratio is 0.44.

Therefore, volume of Coarse aggregates is required to be increased to decrease the Fine aggregates content. As the water-cement ratio is lowered by 0.06.

The proportion of volume of coarse aggregates is increased by 0.02 (at the rate of -/+ 0.01 for every +/- 0.05 change in w/c ratio)

Therefore, corrected proportion of volume of coarse aggregates for the w/c ratio of 0.44

For pumpable concrete, these value should be reduced upto 10% =0.632 x 0.9 =0.568

Therefore, volume of coarse aggregates = 0.568

volume of Fine aggregates = 1-0.568 = 0.431

Step-8

Mix calculation

The mix Calculation as per unit volume of concrete

1. Volume of concrete = 1 m³
2. Volume of concrete = (Mass of cement / specific gravity of cement) X (1 / 1000) =(277/3.15) X (1/1000) =0.087 m³
3. Volume of water = (Mass of water / specific gravity of water) X (1 / 1000) =(118/2.2) X (1/1000) =0.053 m³
4. Volume of chemical admixture = (Mass of chemical admixture / specific gravity of chemical admixture) X (1 / 1000) =(158/1) X (1/1000) =0.158 m³
5. Volume of fly ash = (Mass of fly ash / specific gravity of fly ash) X (1 / 1000) (7.6/1.145) X (1/1000) =0.006 m³
6. Volume of all in aggregates = (a-(b+c+d+e)) = (1-(0.087+0.053+0.158+0.006)) = 0.696 m³
7. Mass of coarse aggregate = f X volume of coarse aggregate X specific gravity of coarse aggregate X 1000 = 0.696 X 0.568 x 2.74 X 10 1077 kg/m³
8. Mass of fine aggregate = f X volume of coarse aggregate X specific gravity of coarse aggregate X 1000 = 0.696 X 0.431 x 2.74 X 1000 822 kg/m³

Step-9

Mix proportion

Cement 277 kg/m3

Fly ash 118 kg/m3

Water 158 kg/m3

Fine aggregates 822 kg/m3

Coarse aggregates 20mm 1077 kg/m3

Chemical admixture 7.18 kg/m3

W/c ratio (lowest w/c ratio is selected) 0.4

Mix proportion by weight 1:2.08:2.72

Step-10

The slump shall be measured, the water content and dosage of admixture shall be adjusted for achieving the required slump on trial. The mix proportion shall be worked for the actual water content and checked for durability requirements.

Step-11

Two moe trials having variation of 10% w/c ratio shall be carried out and a graph between w/c ratio and corresponding strength shall be plotted to work out the mix proportion for the given target to field trials.

Result:

The mix design for M35 Grade of concrete with fly ash 1:2.08:2.72

Mix design for M50 Grade of concrete without fly ash

^Aim:

^{To calculate the concrete mix design for M50 grade of concrete without fly ash.}

^{Introduction:}

^{Concrete mix design is the method of finding the precise of cement, sand and aggregates for concrete to achieve the target strength in structures, therefore concrete mix in terms of cement:sand:aggregates. The design is done according to the requirements of concrete strength. So, we can achieve the desirable properties of concrete either it is in fresh stage or in hardened stage. The fresh concrete properties like workability, setting time, and hardened concrete properties like compressive strength, durability etc., are attained surely by this method. this project consists of the design of m50 grade cement without fly ash.}

^{Equation used :}

^{A) Target mean strength}

^{f'ck = fck + 1.65s}

^{f'ck - Largest average compressive strength at 28days.}

^{fck - Characteristics compressive strength at 28days}

^{s - standard deviation (IS 10262:2009, table-1)}

^{B) Cement content}

^{Cement content = water content / water-cement ratio}

^{C) Volume of calculation}

1. Volume of concrete = 1 m³
2. Volume of concrete = (Mass of cement / specific gravity of cement) X (1 / 1000)
3. Volume of water = (Mass of water / specific gravity of water) X (1 / 1000)
4. Volume of chemical admixture = (Mass of chemical admixture / specific gravity of chemical admixture) X (1 / 1000)
5. Volume of all in aggregates = (a-(b+c+d))
6. Mass of coarse aggregate = f X volume of coarse aggregate X specific gravity of coarse aggregate X 1000
7. Mass of fine aggregate = f X volume of coarse aggregate X specific gravity of coarse aggregate X 1000

Codes for concrete mix design

IS 10262:2009

IS 456:2000

IS 8112

IS 9103

IS 3812 (Part-I)

Procedure

Step-1

Stipulation for proportioning

1. Grade Designation M50
2. Type of cement OPC 43 grade conforming to IS 8112
3. Maximum nominal size of aggregates 20mm
4. Minimum cement content 320 kg/m³ (Table 5 IS 456:2000 Based on Exposure condition)
5. Maximum Water-cement ratio 0.45(Table:5 IS 456:2000 Based on Exposure condition)
6. Workability 100 slump value of pump able concrete
7. Exposure condition Severe (For reinforcement concrete)
8. Method of concrete placing pumping
9. Degree of supervision Good
10. Type of aggregates Crushed angular aggregates
11. Maximum cement content 450 kg/m³
12. Chemical admixture content Superplasticizer

Step-2

Test data for material

1. Cement used OPC 43 grade conforming to IS 8112
2. Specific gravity of cement 3.15
3. Chemical admixture Superplasticizer Conforming to IS 9103
4. Specific gravity of Coarse aggregates 2.74
5. Specific gravity of Coarse aggregates 2.74
6. Water Absorption of Coarse aggregates 0.5%
7. Water Absorption of Fine aggregates 1.0%
8. Free surface of Coarse aggregates Nil
9. Free Surface of Fine aggregates Nil
10. Sieve analysis of Coarse aggregates Conforming to Table 2 of IS 383
11. Sieve analysis of Fine aggregates Conforming to Grading zone II of Table 4 of IS 383

Step-3

To Find Target Mean Strength for Mix Proportioning

^{f'ck = fck + 1.65s}

= 50 + 1.65 X 5

f'ck = 58.25 N/mm²

Step-4

Selection of Water-cement rati0 = 0.45

Maximum water/cement ratio = 0.45 (For severe condition from table 5 of IS 456:2000)

On experinece w/c ratio = 0.4

04<0.45 hence OK.

Step-5

Calculation of Water content

Maximum water content for 20mm aggregates = 186 liters(Table 2 of IS 10262:2009)for 25mmto50mm slump range

For 100 slump = 186+(6/100) X 186 = 197 litres

As Superplasticizer is used, the water content is reduced upto 30%

Based on trials water content reduction of 29% is achieved with plasticizer

Hence arrived water content = 197 X 0.71 = 140 litres

Step-6

Calculation of Cement content

Water/cement ratio = 0.4

Cementitious material (Cement fly ash) = 140/0.4 = 350kg/m³

In table 5 of IS 456:2000, the cement content for severe exposure = 320 kg/m³

350kg/m3 > 320kg/m3 hence OK.

Step-7

Proportion of volume of Coarse aggregates and Fine aggregates

From table 3 of IS 10262:2009 volume of coarse aggregates

Corresponding to 20mm size aggregates and Fine aggregates (Zone-2) of w/c ratio of 0.50 is 0.62

In the present case w/c ratio is 0.44.

Therefore, volume of Coarse aggregates is required to be increased to decrease the Fine aggregates content. As the water-cement ratio is lowered by 0.06.

The proportion of volume of coarse aggregates is increased by 0.02 (at the rate of -/+ 0.01 for every +/- 0.05 change in w/c ratio)

Therefore, corrected proportion of volume of coarse aggregates for the w/c ratio of 0.44

For pumpable concrete, these value should be reduced upto 10% =0.64 x 0.9 =0.576

Therefore, volume of coarse aggregates = 0.568

volume of Fine aggregates = 1-0.576 = 0.424

Step-8

Mix calculation

The mix Calculation as per unit volume of concrete

1. Volume of concrete = 1 m³
2. Volume of concrete = (Mass of cement / specific gravity of cement) X (1 / 1000) =(350/3.15) X (1/1000) =0.111 m³
3. Volume of water = (Mass of water / specific gravity of water) X (1 / 1000) =(140/2.2) X (1/1000) =0.140 m³
4. Volume of chemical admixture = (Mass of chemical admixture / specific gravity of chemical admixture) X (1 / 1000) =(7.65/1) X (1/1000) =0.006 m³
5. Volume of all in aggregates = (a-(b+c+d)) = (1-(0.111+0.140+0.006)) = 0.743 m³
6. Mass of coarse aggregate = f X volume of coarse aggregate X specific gravity of coarse aggregate X 1000 = 0.743 X 0.576 x 2.74 X 1000 1173 kg/m³
7. Mass of fine aggregate = f X volume of coarse aggregate X specific gravity of coarse aggregate X 1000 = 0.743 X 0.424 x 2.74 X 1000 863 kg/m³

Step-9

Mix proportion

Cement 350 kg/m3

Water 140 kg/m3

Fine aggregates 863 kg/m3

Coarse aggregates 20mm 1173 kg/m3

Chemical admixture 7 kg/m3

W/c ratio (lowest w/c ratio is selected) 0.4

Mix proportion by weight 1:2.46:3.34

Step-10

The slump shall be measured, the water content and dosage of admixture shall be adjusted for achieving the required slump on trial. The mix proportion shall be worked for the actual water content and checked for durability requirements.

Step-11

Two moe trials having variation of 10% w/c ratio shall be carried out and a graph between w/c ratio and corresponding strength shall be plotted to work out the mix proportion for the given target to field trials.

Result:

The mix design for M50 Grade of concrete without fly ash 1:2.46:3.34

Tables are used:

1. Table-1 IS 10262:2009

2. Table-2 IS 10262:2009

3. Table-3 IS 10262:2009

4. Table-5 IS 456:2000