Project on Concrete Mix Design for various grades of Concrete
CHALLENGE - 5 (PROJECT)
Calculate the Concrete Mix Design for M35 grade concrete with fly ash & M50 grade concrete without Fly ash.
The project attempts to calculate the mix design for M35 grade concrete with fly ash and M50 grade concrete without fly ash respectively. The mix design has been done using IS:10262:2009 and IS:456-2000 respectively. Grade and properties of Cement, Aggregates and mineral admixture (Fly ash) has been assumed. Volumetric Proportions of Cement, Sand, Coarse Aggregate, Water and Admixture has been calculated per kg of Concrete and expressed as mix design.
- Mix design for M35 grade concrete with fly ash
Stipulations for proportioning:
Grade = M35
Cement type = OPC 43 conforming to IS:8112
Mineral admixture = Fly ash conforming to IS:3812(Part1)
Maximum nominal aggregate size = 20 mm
Minimum cement content = 320 kg/m3 (From Table 5 of IS:456-2000)
Exposure condition = Severe (From Table 5 of IS:456-2000)
Maximum w/c ratio = 0.45
Workability = 100mm (For pumpable concrete)
Method of concrete placing = Pumping
Degree of supervision = Good
Type of aggregate = Crushed angular aggregate
Maximum Cement content = 450 kg/m3
Chemical admixture type = Super plasticizer
Percentage of fly ash = 30 percent
Test data for materials:
Cement used = OPC 43 grade conforming to IS:8112
Specific gravity of cement = 3.15
Fly ash = Conforming to IS:3812 (Part 1)
Specific gravity of fly ash = 2.2
Chemical admixture = Superplasticizer conforming to IS:9103
Specific gravity of coarse aggregate = 2.74
Specific gravity of fine aggregate = 2.74
Water absorption of coarse aggregate = 0.5%
Water absorption of fine aggregate = 1.0%
Free surface moisture coarse
aggregate = Nil
Free surface moisture fine
aggregate = Nil
Fine aggregate grading = Zone I (Table 4 of IS:383)
Target mean strength for mix proportioning
ft = fck + 1.65S
From Table 1 of IS:10262-2009, Standard deviation, S = 5 N/mm2
Ft = 35 + 1.65 x 5 = 43.25 N/mm2.
Selection of water cement ratio
From Table 5 of IS:456-2000, for ‘severe’ exposure condition,
Maximum water-cement ratio = 0.45 (irrespective of the concrete grade)
From graph 1 of IS:10262-2009,
w/c ratio = 0.35
From graph 2 of IS:10262-2009,
w/c ratio = 0.425
w/c ratio adopted
(Minimum of the three) = 0.350
Selection of water content
From Table 2 of IS:10262-2009, for nominal maximum size of aggregate 20mm
Maximum water content = 186 kg
(for 20 to 50mm slump)
Water content for 100mm slump = 186 x 1.06 = 197.16 kg
As super-plasticizer is used, assuming water content can be reduced by 20 percent.
Water content = 0.80 x 197.16 = 157.73 kg
= 158 litres
Calculation of Cement content
Water-cement ratio = 0.35
Cementitious material = 158/0.35 = 451.42 kg/m3
(Cement + fly ash)
Minimum cement content = 320 kg/m3
452 kg/m3 > 320 kg/m3. Hence ok.
Cementitious material can be increased by 10 percent.
Cementitious material = 451.42x1.1 = 496.562
= 497 kg/m3
Water content = 158 litres
Hence w/c ratio (actual) = 158/497 = 0.317
For 30 percent fly-ash percent,
Fly ash = 0.30 x 497 = 150 kg/m3
Cement = 497 - 150 = 347 kg/m3
Saving of cement = 452 - 347 = 105 kg/m3
Proportioning of volume of coarse aggregate and fine aggregate
From table 3 of IS:10262-2009, for nominal maximum size of aggregate 20mm and corresponding to w/c ratio of 0.50
Volume of coarse aggregate per unit volume of total aggregate for Zone 1
= 0.60 kg/m3
W/c ratio = 0.32
(Volume of coarse aggregate has to be increased at the rate of -/+ 0.01 for every ± 0.05 change in water-cement ratio)
Modified volume of coarse aggregate per unit volume of total aggregate
= 0.6 + 0.036
= 0.636 kg/m3
For pumpable concrete, these values are reduced by 10 percent.
Modified volume of coarse aggregate per unit volume of total aggregate
= 0.636 x 0.9
= 0.58 kg/m3
Volume of fine aggregate = 1 - 0.5724
= 0.43 kg/m3
Mix calculation
Volume of Concrete = 1 m3
Volume of Cement = Mass of Cement/Specific gravity of Cement x 1/1000
= 347/3.15 x 1/1000 = 0.111 m3
Volume of Fly ash = Mass of Fly ash/Specific gravity of Fly ash x 1/1000
= 150/2.2 x 1/1000 = 0.068 m3
Volume of Water = Mass of Water/Specific gravity of Water x 1/1000
= 158/1 x 1/1000 = 0.158 m3
Volume of Chemical admixture = Mass of Chemical admixture/Specific gravity of Chemical admixture x 1/1000
Mass of Chemical admixture = 2 percentage by mass of cementitious material
= 0.02 x 497 = 10 kg/m3
Volume of Chemical admixture = 10/1.145 x 1/1000
= 0.008 m3
Total volume of aggregate per m3 of concrete
(FA+CA) = 1 - (0.111+0.068+0.158+0.008)
= 0.655 m3
Mass of Coarse aggregate and Fine aggregate in 1 m3 of concrete:
Mass of coarse aggregate = Total volume of aggregate per m3 of concrete x Volume of coarse aggregate x Specific gravity of coarse aggregate x 1000
= 0.655 x 0.58 x 2.74 x 1000
= 1041 kg
Mass of fine aggregate = Total volume of aggregate per m3 of concrete x Volume of fine aggregate x Specific gravity of fine aggregate x 1000
= 0.655 x 0.43 x 2.74 x 1000
= 772 kg
Mix ratio
Cement = 347 kg/m3
Fly Ash = 150 kg/m3
Water = 158 kg/m3
Fine aggregate = 772 kg/m3
Coarse aggregate = 1041 kg/m3
Chemical admixture = 10 kg/m3
Water-Cement ratio = 0.320
Mix ratio = 347: 772 :1041
= 1:2.22:3
(1 part of Cement to 2.22 parts of Fine aggregate to 3 parts of Coarse aggregate)
- Mix design for M50 grade concrete without fly ash
Stipulations for proportioning:
Grade = M50
Cement type = OPC 43 conforming to IS:8112
Maximum nominal aggregate size = 20 mm
Minimum cement content = 320 kg/m3 (From Table 5 of IS:456-2000)
Exposure condition = Severe (From Table 5 of IS:456-2000)
Maximum w/c ratio = 0.45
Workability = 100mm (For pumpable concrete)
Method of concrete placing = Pumping
Degree of supervision = Good
Type of aggregate = Crushed angular aggregate
Maximum Cement content = 450 kg/m3
Chemical admixture type = Super plasticizer
Test data for materials:
Cement used = OPC 43 grade conforming to IS:8112
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 of coarse aggregate = 0.5%
Water absorption of fine aggregate = 1.0%
Free surface moisture coarse
aggregate = Nil
Free surface moisture fine
aggregate = Nil
Fine aggregate grading = Zone I (Table 4 of IS:383)
Target mean strength for mix proportioning
ft = fck + 1.65S
From Table 1 of IS:10262-2009, Standard deviation, S = 5 N/mm2
Ft = 50 + 1.65 x 5 = 58.25 N/mm2.
Selection of water cement ratio
From Table 5 of IS:456-2000, for ‘severe’ exposure condition,
Maximum water-cement ratio = 0.45 (irrespective of the concrete grade)
w/c ratio adopted = 0.45
Selection of water content
From Table 2 of IS:10262-2009, for nominal maximum size of aggregate 20mm
Maximum water content = 186 kg
(for 20 to 50mm slump)
Water content for 100mm slump = 186 x 1.06 = 197.16 kg
As super-plasticizer is used, assuming water content can be reduced by 20 percent.
Water content = 0.80 x 197.16 = 157.73 kg
= 158 litres.
Calculation of Cement content
Water-cement ratio = 0.45
Cement content = 158/0.45 = 352 kg/m3
Minimum cement content = 320 kg/m3
352 kg/m3 > 320 kg/m3. Hence ok.
Proportioning of volume of coarse aggregate and fine aggregate
From table 3 of IS:10262-2009, for nominal maximum size of aggregate 20mm and corresponding to w/c ratio of 0.50
Volume of coarse aggregate per unit volume of total aggregate for Zone 1
= 0.60 kg/m3
W/c ratio = 0.45
(Volume of coarse aggregate has to be increased at the rate of -/+ 0.01 for every ± 0.05 change in water-cement ratio)
Modified volume of coarse aggregate per unit volume of total aggregate
= 0.60 + 0.01
= 0.61 kg/m3
For pumpable concrete, these values are reduced by 10 percent.
Modified volume of coarse aggregate per unit volume of total aggregate
= 0.61 x 0.9
= 0.55 kg/m3
Volume of fine aggregate = 1 - 0.55
= 0.45 kg/m3
Mix calculation
Volume of Concrete = 1 m3
Volume of Cement = Mass of Cement/Specific gravity of Cement x 1/1000
= 352/3.15 x 1/1000 = 0.111 m3
Volume of Water = Mass of Water/Specific gravity of Water x 1/1000
= 158/1 x 1/1000 = 0.158 m3
Volume of Chemical admixture = Mass of Chemical admixture/Specific gravity of Chemical admixture x 1/1000
Mass of Chemical admixture = 2 percentage by mass of cementitious material
= 0.02 x 352 = 7.04 kg/m3
Volume of Chemical admixture = 10/1.145 x 1/1000
= 0.008 m3
Total volume of aggregate per m3 of concrete
(FA+CA) = 1 - (0.111+0.158+0.008)
= 0.723 m3
Mass of Coarse aggregate and Fine aggregate in 1 m3 of concrete:
Mass of coarse aggregate = Total volume of aggregate per m3 of concrete x Volume of coarse aggregate x Specific gravity of coarse aggregate x 1000
= 0.723 x 0.55 x 2.74 x 1000
= 1090 kg
Mass of fine aggregate = Total volume of aggregate per m3 of concrete x Volume of fine aggregate x Specific gravity of fine aggregate x 1000
= 0.723 x 0.45 x 2.74 x 1000
= 892 kg
Mix ratio
Cement = 352 kg/m3
Water = 158 kg/m3
Fine aggregate = 892 kg/m3
Coarse aggregate = 1090 kg/m3
Chemical admixture = 7.04 kg/m3
Water-Cement ratio = 0.450
Mix ratio = 352: 892 :1090
= 1:2.53:3.1
(1 part of Cement to 2.53 parts of Fine aggregate to 3.1 parts of Coarse aggregate)