by Page Contents
1. Mix stipulation for ingredients of concrete
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- Grade of Concrete : M40
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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 : 380Kg/cum
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- Maximum Water- Cement Ratio : 0.4
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- Workability : 150 ± 25 mm (slump)
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- Exposure Condition : Moderate
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- Method of Concrete Placing : Pumping/Bucket
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- Degree of Supervision : Good
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- Type of Aggregate : Crushed angular Aggregate, Crushed Stone Sand
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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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- Chemical Admixture : BASF Master Glenium Sky 8511
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- Specific Gravity of Admixture : 1.07
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- Specific Gravity
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Coarse aggregate
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20mm : 2.65
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12.5mm : 2.63
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Fine aggregate : Crushed stone aggregate : 2.59
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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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20 mm : 0.37%
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12.5 mm : 0.54%
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Fine aggregate
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Crushed Stone Aggregate : 2.35%
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Free Surface Moisture
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Sieve Analysis :
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Coarse aggregate :
IS Seive Sizes % Passing IS Requirement as per IS 383 Table 2 Ratio Confirming to IS 383 table 2 Single Sized Graded 40% 60% 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 38.00 60 98.00 12.5 0 99.15 – 85-100 90-100 0.00 59.49 59.49 10 2.54 51.07 0-20 0 – 45 40 – 85 1.02 30.64 31.66 4.75 0.88 0.42 0-5 0-10 0 – 10 0.35 0.25 0.60 PAN 0 0 – – – 0 0 0 -
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 permissible limit on 150 micron IS sieve is increased to 20%.
IS Seive Sizes
% Passing Ratio River Sand:Msand A Combined Passing A B 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 -
All in Aggregate :
IS Seive Sizes 22.8% 34.2% 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 98.86% 4.75 0.88 0.42 100 30-50 43.34% 0.6 0 0 38.87 10-35 16.71% 0.15 0 0 9.74 0-6 4.19% 3. Stipulation of Target Mean Strength and Mix Proportioning as per MORTH
Target Mean Strength for M-40 Grade =52Mpa
4. Calculation for water/Cement Ratio (W/C)
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As per technical specification max Water/Cement + Binder= 0.4
5.Calculation for Water content
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Ref Tab 2 , IS 10262 , Maximum water content per cum for 20mm Aggregate = 186 litre for 50 mm slump 186 + (0.09 * 186) (add 3% for every 25 mm increase) =203 lit
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Based on trials with super plasticizers, water content reduced by 29%, hence the arrived water content = 139.89 Let us add water 140lit
6. Calculation for Cementious content
Water-Cementitious Ratio = 0.36 Cementious content (Cement OPC 53 + GGBFS) = 389 Say Cementitious = 390 ,
Cement =390 kg/m3
Based on experience and lab trials, super plasticizer= 0.48 %
7.Calculation for arriving Aggregate content
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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
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Adjust for W/c ratio: Add @ 0.01 for every decrease in 0.05 = 0.028
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Therefore, corrected proportion= 0.648
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Adjust for pumpability, i.e. decrease by 10% = 0.58 %
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Based on experience Considering Volume of coarse aggregate=0.57
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Therefore, Volume of Fine aggregate =0.43
8.Mix volume Calculation per cubic meter
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a)Volume of concrete = 1 m3
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b) Volume of cement = Mass of cement specific gravity of cement × 1000 = 0.1238 m3
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c)Volume of water = Mass of water x specific gravity of water× 1000 = 0.140 m3
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d)Volume of admixture = Mass of admixture x specific gravity of admixture× 1000 = 0.00175 m3
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e) Volume of all in aggregate = [a-(b+c+d)] = 0.73 m3
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f) Mass of coarse aggregate
1) 20 mm = e × volume of CA × sp. gravity × % of 20mm × 1000
= 0.73*0.57*2.65*0.5*1000
= 443.75 kg/m3
Say 444 kg/m3
2) 12 mm = e× volume of CA × sp. gravity × % of 12mm × 1000
= 0.73*0.57*2.63*0.5*1000
= 660.60 kg/m3
Say 661 kg/m3-
g) Mass of Fine aggregate = e × volume of FA × sp. gravity × 1000
= 0.73*0.43*2.59*1000
= 817.95 kg/m3
Say 818 kg/m3
9.Mix Details
cement = 390 kg
20mm = 444 kg
12mm = 661 kg
Crushed stone sand = 818 kg
Chemical admixture = 1.87 kg
Free Water = 140 kg
Water-Cement Ratio = 0.36
Concrete density = 2454 kg/m3 -
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