Project on Concrete Mix Design for various grades of Concrete
Aim: To prepare Concrete Mix Design for M-35 Grade of Concrete with flyash.
Introduction: The detailed procedure and calculation for preparing the Concrete Mix Design for M-35 Grade Concrete using flyash taking references from the Indian Standard Codes such as IS 456:2000 and IS 10262:2009.The assumptions based on the Indian Standard Codes for the calculation of Design Mix are as under:
- Grade Designation: M-35
- Type of Cement: OPC 53 conforming to IS 12269:1987
- Type of Mineral Admixture: Fly-ash Conforming to IS 3812 (Part 1)
- Maximum Nominal Size of Aggregate: 20 mm
- Minimum Cement Content: 320 kg/`m^3` (Table 5 of IS 456:2000 based on exposure condition)
- Maximum Water Cement Ratio: 0.45 (Table 5 of IS 456:2000 based on exposure condition)
- Workability: 100 mm slump value for pumpable concrete
- Exposure Condition: Severe (for reinforced concrete)
- Method of Concrete Placing: Pumping
- Degree of Supervision:Good
- Type of Aggregate: Crushed Angular Aggregate
- Maximum Cement Content: 450 kg/`m^3`
- Chemical Admixture Type: Superplasticizer Conforming to IS 9103
Procedure: The procedure for Design Mix for the M-35 Grade of Concrete with flyash is as under:
Step 1: Test Data for Material
- Cement Used: OPC 53 conforming to IS 12269:1987
- Specific Gravity of Cement: 3.15
- Chemical Admixture: Superplasticizer conforming to IS 9103
- Specific Gravity of Coarse Aggregate: 2.74
- Specific Gravity of Fine Aggregate: 2.74
- Water Absorption for Coarse Aggregate: 0.5 percent
- Water Absorption for Fine Aggregate: 1.0 percent
- Free (surface) Moisture for Coarse Aggregate: Nil
- Free (surface) Moisture for Fine Aggregate: Nil
- Sieve Analysis
1. Coarse Aggregates
| IS Sieve Sizes (in mm) | Analysis of Coarse Aggregates Fraction | Percentage of Different Fractions | Remarks |
| I II |
I II Combined 60% 40% 100% |
Conforming to Table 2 of IS 383 | |
| 20 | 100 100 | 60% 40% 100% | |
| 10 | 0 71.20 | 0.00 28.5 28.5 | |
| 4.75 | 9.40 | 3.7 3.7 | |
| 2.36 | 0.00 |
2. Fine Aggregates : Conforming to Grading Zone 1 of Table 4 of IS 383.
Step 2: Target Strength for Mix Proportion
f'ck= fck + 1.65 x s
where,
f'ck= Target average compressive strength at 28 days,
fck = characterstics compressive strength at 28 days, and
s = standard deviation
From Table 1 of IS 10262:2009 standard deviation s=5
f'ck= 35 +1.65 x 5= 43.25 N/`mm^2`
Step 3: Select Water Cement Ratio
From Table 5 of the IS 456:2000, maximum water-cement rastio =0.45 (for severe condition),
Based on experience, adopt water cement ratio as 0.40
0.4<0.45, hence O.K.
Step 4: Selction of Water Content
From Table 2 of IS 10262:2009, maximum water content for 20 mm aggregates= 186 Litre
Estimated Water Content for 100 mm slump = 186+6/100x 186= 197 Litre
As superplasticizer is used, the water content can be reduced up to 20% and above.
Based on trials with superplasticizers water content reduction 29 percent has been achieved. Hence, the arrived water content = 197*0.71= 140 litre
Step 5: Calculation of Cement Content
Cement Content = 140/0.40 = 350 kg/`m^3`
From Table 5 of IS 456:2000, minimum cement content for "severe" exposure condtition= 320 kg/`m^3`
350 kg/`m^3` > 320 kg/`m^3`, hence O.K.
For proportiong the mix containing flyash the following steps are suggested
1. Decide the percentage of flyash to be used based on project requirement and the quality of materials.
2. In certain situation increase in cementitous material content may be warranted. The decision on increase in cementitious matrerial content and its percentage may be based on experience and trial.
In this case 10% increase of cementitous content has been considered.
Cementitous Material Content = 350 x 1.10 = 385 kg/`m^3`
Water Content = 140 kg/`m^3`
So, water cement ratio= 140/385 = 0.364
Flyash @ 30 percent of total cementitous content = 385x 30%= 115 kg/`m^3`
Cement (OPC)= 385-115= 270kg/`m^3`
Saving of Cement while using Flyash = 350-270 = 80 kg/`m^3`
Fly ash to be used = 115 kg/`m^3`
Step 6 Proportion of Volume of Coarse Aggregate and Fine Aggregate Content
From Table 3 of IS 10262:2009, volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone 1) for water cement ration of 0.50 = 0.60
In this present case water cement ratio is 0.40. Therefore, 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 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, corrected proportion of volume of coarse aggregate for the water cement ratio of 0.4= 0.62.
In this case the coarse aggregate is not angular one, then also volume of coarse aggregate may be required to be increased suitably as per the experience.
Fort pumpable concrete these values should be reduced by 10 per cent
Therefore, volume of coarse aggregate = 0.62 x 0.9 = 0.576
Volume of fine aggregate content = 1-0.576= 0.424
Step 7: Mix Calculation
1. Volume of Concrete (a)= 1`m^3`
2. Volume of Cement (b) = (Mass of Cement/Specific Gravity of Cement) x 1/1000
= (270/3.15) x (1/1000) = 0.086 `m^3`
3. Volume of Flyash (c)= (Mass of Flyash/Specific Gravity of Flyash) x 1/1000
= (115/2.2) x (1/1000)= 0.052`m^3`
4. Volume of water (d) = (Mass of Water/Specific Gravity of Water) x (1/1000)
= (140/1) x (1/1000) = 0.140`m^3`
5. Volume of Chemical Admixture (e) = (Mass of Chemical Admixture/Specific Gravity of Chemical Admixture) x (1/1000)
= (7.6/1.14) x (1/1000) = 0.006 `m^3`
6. Volume of Aggregate (f) = (Fine +Coarse) = a- (b+c+d+e)
= 1- (0.086+0.052+0.140+0.006)= 0.716 `m^3`
7. Mass of Coarse Aggregate = f x Volume of Aggregate x Specific gravity of Coarse aggregate x 1000
= 0.716 x 0.576 x 2.74 x 1000 = 1130 kg/`m^3`
8. Mass of Fine Aggregate = f x Volume of Aggregate x Specific Gravity of Fine Aggregate x 1000
= 0.716 x 0.424 x 2.74 x 1000 = 831 kg/`m^3`
Step 8: Mix proportion
Cement = 270 kg/`m^3`
Fly ash = 115 kg/`m^3`
Water = 140 kg/`m^3`
Fine Aggregate = 831 kg/`m^3`
Coarse Aggregate = 1130 kg/`m^3`
Chemical Admixture = 7 kg/`m^3`
Water Cement Ratio = 0.364
Mix Ratio = 1:2.15:2.94
Step 9: The slump shall be measured and the water content and dosage of admixture shall be adjusted for achieving the required slump on trial. The mixed proportion shall be reworked for the actual water content and checked for durability requirement.
Step 10: Two or more trials having variations of 10% of water cement ratio as per step 09 shall be carried and a graph between three water cement ratios corresponding to the strength shall be plotted to work out the mix proportion for the given target strength for the field trials. However the durability must be met.
Result: The Mix Design for the M-35 Grade Concrete using flyash with the following mix proportion has been prepared following the gudelines from IS 10262:2009 and IS456:2000:
- Cement = 270 kg/`m^3`
- Fly ash = 115 kg/`m^3`
- Water = 140 kg/`m^3`
- Fine Aggregate = 831 kg/`m^3`
- Coarse Aggregate = 1130 kg/`m^3`
- Chemical Admixture = 7 kg/`m^3`
- Water Cement Ratio = 0.364
- Mix Ratio = 1:2.15:2.94
Aim: To prepare Concrete Mix Design for M-50 Grade of Concrete without flyash.
Introduction: The detailed procedure and calculation for preparing the Concrete Mix Design for M-50 Grade Concrete without using flyash taking references from the Indian Standard Codes such as IS 456:2000 and IS 10262:2009.The assumptions based on the Indian Standard Codes for the calculation of Design Mix are as under:
- Grade Designation: M- 50
- Type of Cement: OPC 53 conforming to IS 12269:1987
- Maximum Nominal Size of Aggregate: 20 mm
- Minimum Cement Content: 320 kg/`m^3` (Table 5 of IS 456:2000 based on exposure condition)
- Maximum Water Cement Ratio: 0.45 (Table 5 of IS 456:2000 based on exposure condition)
- Workability: 100 mm slump value for pumpable concrete
- Exposure Condition: Severe (for reinforced concrete)
- Method of Concrete Placing: Pumping
- Degree of Supervision:Good
- Type of Aggregate: Crushed Angular Aggregate
- Maximum Cement Content: 450 kg/`m^3`
- Chemical Admixture Type: Superplasticizer Conforming to IS 9103
Procedure: The procedure for Design Mix for the M-50 Grade of Concrete without using flyash is as under:
Step 1: Test Data for Material
- Cement Used: OPC 53 conforming to IS 12269:1987
- Specific Gravity of Cement: 3.15
- Chemical Admixture: Superplasticizer conforming to IS 9103
- Specific Gravity of Coarse Aggregate: 2.74
- Specific Gravity of Fine Aggregate: 2.74
- Water Absorption for Coarse Aggregate: 0.5 percent
- Water Absorption for Fine Aggregate: 1.0 percent
- Free (surface) Moisture for Coarse Aggregate: Nil
- Free (surface) Moisture for Fine Aggregate: Nil
- Sieve Analysis
1. Coarse Aggregates
| IS Sieve Sizes (in mm) | Analysis of Coarse Aggregates Fraction | Percentage of Different Fractions | Remarks |
| I II |
I II Combined 60% 40% 100% |
Conforming to Table 2 of IS 383 | |
| 20 | 100 100 | 60% 40% 100% | |
| 10 | 0 71.20 | 0.00 28.5 28.5 | |
| 4.75 | 9.40 | 3.7 3.7 | |
| 2.36 | 0.00 |
2. Fine Aggregates : Conforming to Grading Zone 1 of Table 4 of IS 383.
Step 2: Target Strength for Mix Proportion
f'ck= fck + 1.65 x s
where,
f'ck= Target average compressive strength at 28 days,
fck = characterstics compressive strength at 28 days, and
s = standard deviation
From Table 1 of IS 10262:2009 standard deviation s=5
f'ck= 50 +1.65 x 5= 58.25 N/`mm^2`
Step 3: Select Water Cement Ratio
From Table 5 of the IS 456:2000, maximum water-cement rastio =0.45 (for severe condition),
Based on experience, adopt water cement ratio as 0.40
0.4<0.45, hence O.K.
Step 4: Selction of Water Content
From Table 2 of IS 10262:2009, maximum water content for 20 mm aggregates= 186 Litre
Estimated Water Content for 100 mm slump = 186+6/100x 186= 197 Litre
As superplasticizer is used, the water content can be reduced up to 20% and above.
Based on trials with superplasticizers water content reduction 29 percent has been achieved. Hence, the arrived water content = 197*0.71= 140 litre.
Step 5: Calculation of Cement Content
Cement Content = 140/0.40 = 350 kg/`m^3`
From Table 5 of IS 456:2000, minimum cement content for "severe" exposure condtition= 320 kg/`m^3`
350 kg/`m^3` > 320 kg/`m^3`, hence O.K.
Step 6 Proportion of Volume of Coarse Aggregate and Fine Aggregate Content
From Table 3 of IS 10262:2009, volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone 1) for water cement ration of 0.50 = 0.60
In this present case water cement ratio is 0.40. Therefore, 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 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, corrected proportion of volume of coarse aggregate for the water cement ratio of 0.4= 0.62.
In this case the coarse aggregate is not angular one, then also volume of coarse aggregate may be required to be increased suitably as per the experience.
Fort pumpable concrete these values should be reduced by 10 per cent
Therefore, volume of coarse aggregate = 0.62 x 0.9 = 0.576
Volume of fine aggregate content = 1-0.576= 0.424
Step 7: Mix Calculation
1. Volume of Concrete (a)= 1`m^3`
2. Volume of Cement (b) = (Mass of Cement/Specific Gravity of Cement) x 1/1000
= (350/3.15) x (1/1000) = 0.111 `m^3`
3. Volume of water (c) = (Mass of Water/Specific Gravity of Water) x (1/1000)
= (140/1) x (1/1000) = 0.140`m^3`
4. Volume of Chemical Admixture (d) = (Mass of Chemical Admixture/Specific Gravity of Chemical Admixture) x (1/1000)
= (7.6/1.14) x (1/1000) = 0.006 `m^3`
5. Volume of Aggregate (e) = (Fine +Coarse) = a- (b+c+d)
= 1- (0.111+0.140+0.006)= 0.743 `m^3`
6. Mass of Coarse Aggregate = e x Volume of Aggregate x Specific gravity of Coarse aggregate x 1000
= 0.743 x 0.576 x 2.74 x 1000 = 1173 kg/`m^3`
7. Mass of Fine Aggregate = f x Volume of Aggregate x Specific Gravity of Fine Aggregate x 1000
= 0.743 x 0.424 x 2.74 x 1000 = 863 kg/`m^3`
Step 8: Mix proportion
Cement = 350 kg/`m^3`
Water = 140 kg/`m^3`
Fine Aggregate = 863 kg/`m^3`
Coarse Aggregate = 1173 kg/`m^3`
Chemical Admixture = 7 kg/`m^3`
Water Cement Ratio = 0.364
Mix Ratio = 1:2.46:3.35
Step 9: The slump shall be measured and the water content and dosage of admixture shall be adjusted for achieving the required slump on trial. The mixed proportion shall be reworked for the actual water content and checked for durability requirement.
Step 10: Two or more trials having variations of 10% of water cement ratio as per step 09 shall be carried and a graph between three water cement ratios corresponding to the strength shall be plotted to work out the mix proportion for the given target strength for the field trials. However the durability must be met.
Result: The Mix Design for the M-50 Grade Concrete without using flyash with the following mix proportion has been prepared following the gudelines from IS 10262:2009 and IS 456:2000:
- Cement = 350 kg/`m^3`
- Water = 140 kg/`m^3`
- Fine Aggregate = 863 kg/`m^3`
- Coarse Aggregate = 1173 kg/`m^3`
- Chemical Admixture = 7 kg/`m^3`
- Water Cement Ratio = 0.364
- Mix Ratio = 1:2.46:3.35