by -
- Grade of Concrete : M20
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- Type of Cement : OPC 53 grade confirming to IS 269
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- Maximum Nominal Size Aggregate : 20 mm
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- Minimum Cement content : 240Kg/cum
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- Maximum Water- Cement Ratio : 0.6
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- Workability : 100 ± 25 mm (slump)
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- Exposure Condition : Moderate
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- Method of Concrete Placing : Pumping or Bucket
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- Degree of Supervision : Good
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- Type of Aggregate : Crushed angular Aggregate
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- Chemical admixture type : Super plasticizers Confirming IS 9103:1999
2. Material Properties
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- Cement : Ultratech OPC 53 grade confirming to IS 269
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- Specific Gravity of cement : 3.15
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- Cement : Ultratech OPC 53 grade confirming to IS 269
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- Chemical Admixture : BASF Master Glenium Sky 8511
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- Specific Gravity of Admixture : 1.07
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- Chemical Admixture : BASF Master Glenium Sky 8511
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- Specific Gravity
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- Coarse aggregate
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- 20mm : 2.69
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- 12.5mm : 2.67
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- Ratio of aggregate: 20mm-50% & 12.5mm-50%
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- Coarse aggregate
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- Fine aggregate
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- Crushed stone aggregate : 2.57
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- Fine aggregate
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- Water: 1
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- Specific Gravity
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- Water Absorption
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- Coarse aggregate
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- 20mm : 0.37%
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- 12.5mm : 0.54%
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- Coarse aggregate
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- Fine aggregate
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- Crushed stone aggregate : 2.35%
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- Fine aggregate
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- Free Surface Moisture
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- Fine aggregate : Nil
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- Coarse aggregate: Nil
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- Free Surface Moisture
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- Sieve Analysis
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- Coarse aggregate:
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- Sieve Analysis
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- Water Absorption
| IS Seive Sizes | % Passing | IS Requirement as per IS 383 Table 2 | Ratio | Confirming to IS 383 table 2 | |||||||
| Single Sized | Graded | 50% | 50% | ||||||||
| 20 mm | 12.5 mm | 20 mm | 12.5 mm | 20 mm | 12.5 mm | Combined 100% | |||||
| 20 | 95.01 | 100 | 85-100 | 100 | 100 | 47.505 | 50 | 97.51 | |||
| 12.5 | 0 | 99.15 | – | 85-100 | 90-100 | 0.00 | 49.575 | 49.58 | |||
| 10 | 2.54 | 51.07 | 0-20 | 0 – 45 | 40 – 85 | 1.27 | 25.535 | 26.81 | |||
| 4.75 | 0.88 | 0.42 | 0-5 | 0-10 | 0 – 10 | 0.44 | 0.21 | 0.65 | |||
| PAN | 0 | 0 | – | – | – | 0 | 0 | 0 | |||
Sieve Analysis of Coarse Aggregate, M20 grade concrete
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- Fine Aggregate: Confirming to grading Zone II of table 4 of IS 383 Note:- as per field trials for pumpable concrete fine aggregate should pass zone II; According to IS 383 clause No. 31.2.2 allows to use crushed stone sand as fine aggregate for concrete .According to IS 383-2016 for crushed stone sand, the permeassible limit on 150 micron IS sieve is increased to20%.
| IS Seive Sizes | % Passing | Ratio RS:Msand | Specification | Combined Passing | |||||
| 0 | 1 | IS 383 Zone II | |||||||
| R Sand | M Sand | R Sand | M Sand | ||||||
| 4.75 | 0 | 100 | 0 | 100 | 90-100 | 100 | |||
| 2.36 | 0 | 85.88 | 0 | 85.88 | 75-100 | 85.88 | |||
| 1.18 | 0 | 58.95 | 0 | 58.95 | 55-90 | 58.95 | |||
| 600 | 0 | 38.87 | 0 | 38.87 | 35-59 | 38.87 | |||
| 300 | 0 | 21.47 | 0 | 21.47 | 8-30 | 21.47 | |||
| 150 | 0 | 9.74 | 0 | 9.74 | 0-10 | 9.74 | |||
Sieve Analysis of Fine Aggregate, M20 grade concrete
All in aggregate:
| IS Seive Sizes | 28.5% | 28.5% | 43% | Specification | Combined Passing | |||
| 20mm | 12.5mm | c sand | min-max | |||||
| 40 | 100 | 100 | 100 | 100-100 | 100.00% | |||
| 20 | 95.01 | 100 | 100 | 95-100 | 98.58% | |||
| 4.75 | 0.88 | 0.42 | 100 | 30-50 | 43.37% | |||
| 0.6 | 0 | 0 | 38.87 | 10-35 | 16.71% | |||
| 0.15 | 0 | 0 | 9.74 | 0-6 | 4.19% | |||
Sieve Analysis of All in Aggregate, M20 grade concrete
3. Target Mean Strength
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- As per MORTH the Target Mean Strength for M-20 Grade = 30Mpa
4. Selection of water/Cement Ratio (W/C)
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- As per the specification max Water/Cement + Binder = 0.6
5. Water content Calculation
Ref Tab 2 , IS 10262 , Maximum water content per cum for 20mm Aggregate = 186 litre for 50 mm slump
= 186 + (0.06 * 186) (add 3% for every 25 mm increase )
= 197 lit
Based on trials with super plasticizers, water content reduced by 27%,hence the arrived water content = 141.96lit, So Let us add water 142 lit
6. Cementious content Calculation
Water-Cementitious Ratio = 0.6
Cementious content (Cement OPC 53 ) = 237
Say Cementitious content = 240 kg/m3
Cement = 240 kg/m3
Based on experience and lab trials, Based on experience and lab trials, super plasticizer = 0.8 %
7. Aggregate content Calculation
Ref Tab 3 of IS 10262 , for Sand Zone II , volume of coarse aggregate
per unit vol of total aggregate for 0.5 water-cement ratio = 0.62
Adjust for W/c ratio : Add @ 0.01 for every decrease in 0.05= -0.02
Therefore , corrected proportion = 0.6
Adjust for pumpability , i.e decrese by 10% = 0.54 %
Based on experience Considering Volume of coarse aggregate = 0.57
Therefore, Volume of Fine aggregate = 0.43
8. Mix volume Calculation per cubic meter of concrete
a) Volume of concrete = 1 m3
b) Volume of cement = (Mass of cement /specific gravity of cement) × 1000 =240/(3.15×1000)= 0.0762 m3
c) Volume of water = (Mass of water /specific gravity of water)× 1000 = 0.142 m3
d) Volume of admixture = (Mass of admixture /specific gravity of admixture)× 1000 = (240×0.8)/(100×1.07×1000)=0.00179 m3
e) Volume of all in aggregate =[a-(b+c+d)] =1-(0.0762+0.142+0.00179)=0.78
f) Mass of coarse aggregate(CA)
1) 20 mm = e × volume of CA × sp. gravity × % of 20mm × 1000 = 0.78*0.57*2.69*0.5*1000= 598kg/m3, Say 598 kg/m3
2) 12 mm = e× volume of CA × sp. gravity × % of 12mm × 1000 = 0.78*0.57*2.67*0.5*1000 = 593.55 kg/m3 Say 594 kg/m3
g) Mass of Fine aggregate = e× volume of FA × sp. gravity × 1000 =0.78*0.43*2.57*1000= 861.99kg/m3 Say 862 kg/m3
9. Details of Mix Design
- cement = 240 kg
- 20mm = 598 kg
- 12mm = 594 kg
- Crushed stone sand = 862 kg
- Chemical admixture = 1.92 kg
- Free Water = 142 kg
- Water-Cement Ratio = 0.6
- Concrete density = 2437 kg/m3
