Project on Concrete Mix Design for various grades of Concrete
Concrete Mix Design for M35 grade concrete with fly ash
1.Stipulations for proportioning
| A | Grade Designation | M35 | |
| B | Type of Cement | OPC 53 | |
| C | Type of Admixture | Fly ash | |
| D | Maximum Nominal Size of Aggregate |
20mm | |
| E | Minimum Cement Content | 340kg | IS 456 |
| F | Maximum Cement Content | 450kg | As per code |
| G | Partial replacement of cement by Fly ash |
30% | as per requirement |
| H | Maximum W/C ratio | 0.45 | IS 456 |
| I | Workability | 100mm | |
| J | Chemical Admixture | PCS Type |
2.Test data for materials
| A | Cement Used | OPC 53 | Confirming to IS8112 |
| B | Specific Gravity of Cement | 3.15 | IS: 2720 |
| C | Mineral Admixture | Fly ash | Confirming to IS12089 |
| D | Specific Gravity of Fly ash | 2.90 | |
| E | Chemical Admixture | 0.6% | IS9103 |
| F | Specific Gravity of | IS 2386 | |
| Coarse Aggregate | 2.74 | ||
| Fine Aggregate | 2.74 | ||
| Admixture PCE based | 1.12 | ||
| G | Water Absorption | IS 2386 | |
| Coarse aggregate | 0.5 % | ||
| Fine aggregate | 1 % | ||
| H | Sieve Analysis | IS 2386 | |
| Coarse aggregate | Confirming to Table 2-IS383 |
||
| Fine aggregate | Zone II | Confirming to Table 4-IS383 |
3.Target strength for mix proportions
Fck= fck+1.65*S
Value of standard deviation(s) for different grade of concrete is taken from in Table 1 of IS456.
Fck =35+1.65*5=43.25 N/mm^2.
4.Selection of water ceement ratio
The maximum water-cement ratio for M35 grade of concrete is taken from in Table 5-IS456.
The maximum water cement ratio =0.45
Adopted water cement ratio =0.45.
5.Selection of water content.
Maximum water content = 186 litre.
Above water-content is for 25 to 50mm slump but the slump we require is 100mm. hence we need to increase the water content to get the required slump for good workability. Clause 4.2 of IS1026 suggests an increase of 3% of water content from its original value for every increase of 25mm. Here we have a 50mm increase in the water content hence we have to increase the water content by 6 %.
Water content for 100 mm slump
=186+(0.06*186)=197.16 litre.
Since superplasticizers are used water content can be reduced to get good strength of concrete.
Percentage of Reduction in water content = 20%=198 – (0.20*198)=157.73
Adopted water content =160 litre.
6.Calculation of cement and fly ash content.
Adopted water cement ratio =0.45
Total Cementitious (Cement +Fly ash) requirement
=Water Content / WaterCement ratio=160/0.45=355.55 kg.
Since Fly ash is used the amount of Cementitious content (Cement+Fly ash) shall be increased to get good workability and strength. the percentage of increase depending on experience and research. Here we increased the cementitious content by 1.1 %
Final Cementious Content (Cement+Fly ash)= 356*1.1=391.6 kg
Minimum Cement Content required for severe exposure is 340 kg
Adopted cement content =391.6 kg
391.6 kg > 340 kg ...Hence Ok.
Fly ash content ,30% replacement
391.6*0.30=117.48 ~118 kg
Cement Content requirement =Cementious content – Fly ash
= 391.6-117.48=274.12.
Calculation of Super Plasticiers 0.6 percent to the mass of cementitious content = = 391.6*(0.6/100) = 2.35 kg.
7.Coarse and Fine aggregate.
Coarse aggregate ratio = 0.62
Coarse Aggregate ratiofor 0.45 w/c ratiov = 0.63.
Final Fine Aggregate ratio = 1-0.63) = 0.37
8.Mix Calculations
Volume of concrete = 1 cu.m
Volume of Cement = Mass of Cement/(Specific Gravity*1000)
=275/(3.15*1000) =0.087 cu.m.
Total Volume of Fly ash = Flyash/(Specific Gravity*1000)
=118/(2.5*1000) = 0.041 cu.m.
Volume of Water =Water /(Specific Gravity*1000)
= 160/(1*1000)= 0.160 cu.m.
Volume of Superplasticizers = Superplasticizers /(Specific G*1000)
= 2.35/(1.12*1000)=0.002 cu.m.
Total Aggregates requirement= a – (b+c+d+e)
=1 -(0.087 +0.041+0.160+0.002)=0.71 cu.m.
Coarse Aggregate (C.A) = F * Coarse.Agg ratio *
Specific Gravity*1000
= 0.71*0.63 *2.74 *1000= 1225.6 kg
Fine Aggregate (F.A)=F * Fine Agg ratio * Specific Gravity * 1000
= 0.71*0.37*2.74 *1000=719.8 kg.
9.
| S.No. | Materials | Quantity |
| 1 | Cement | 275 kg/cu.m |
| 2 | Flyash | 118 kg/cu.m |
| 3 | Fine Aggregate | 720 kg/cu.m |
| 4 | Coarse Aggregate (20mm) | 1226 kg/cu.m |
| 5 | WATER | 160 L/cu.m |
| 6 | PCE based SuperPlasticizer | 2 L |
Therefore Mix Ratio of M35 Grade concrete by weight is Cement : Flyash: F.A : C.A : Water = 1:0.4:2.6:4.46:0.58.
2.Concrete Mix design for M50 grade concrete.
1.Stipulations for proportioning
| A | Grade Designation | M50 | |
| B | Type of Cement | OPC 53 | |
| C | Exposure Condition | Extreme | |
| D | Maximum Nominal Size of Aggregate |
20mm | |
| E | Minimum Cement Content | 360kg | IS 456 |
| F | Maximum Cement Content | 450kg | As per code |
| G | type of aggregate | Crushed angular aggregate. | as per requirement |
| H | Maximum W/C ratio | 0.35 | IS 456 |
| I | Workability | 50-75mm | |
| J | Chemical Admixture | Super Plasticizer |
2.Test data for materials
Specific gravity of cement : 3.12
Specific gravity of Coarse Aggregate : 2.74
Specific gravity of Fine Aggregate : 2.56
3.Target strength for mix proportions
Fck= fck+1.65*S
Value of standard deviation(s) for different grade of concrete is taken from in Table 1 of IS456.
Fck =45+1.65*5=58.25 N/mm^2.
4.Selection of water ceement ratio
From Table 5 of IS -456,
Maximum water-cement ratio = 0.35
Adopted water cement ratio =0.35.
5.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.
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.
6.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.
7.Coarse and Fine aggregate.
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.
8.Mix Calculations
Volume of concrete = 1m3
Volume of cement = (Mass of Cement/ Its Specific Gravity ) X (1/1000)
= (410/3.12) X (1/1000)
= 0.131 m3
Volume of Water = (Mass of water/specific gravity of water) X (1/1000)
= (143/1) X (1/1000)
= 0.143 m3
Volume of Superplasticizer = (Mass of Superplasticizer / Specific gravity of admixture) X (1/1000)
= (8.2/1.145) X (1/1000)
= 0.007 m3
Volume of all aggregate = (a – (b + c + d))
= 1 – (0.131 + 0.143+0.007)
= 0.719 m3
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
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
9.
| S.No. | Materials | Quantity |
| 1 | Cement | 410 kg/m^3 |
| 2 | Water | 143 L/m^3 |
| 3 | Fine Aggregate | 763.86 kg/m^3 |
| 4 | Coarse Aggregate (20mm) | 1152.48 kg/m^3 |
| 5 | Water Cement ratio | 0.35 |
| 6 | Super Plasticizer | 7 L |
Mix proportion by weight 1:2.30:4.60