Project on Concrete Mix Design for various grades of Concrete

1. Mix design for M35 grade concrete by using Fly ash

• Stipulations for proportioning:

• Grade designation: M35
• Types of cement: OPC 43 grade conforming to IS8112
• Type of mineral admixture: Fly ash conforming to IS 3812 (part 1)
• Maximum nominal size of aggregates: 20mm
• minimum cement content: 320 kg/m^3
• maximum w/c ratio: 0.45
• Workability: 100 mm (Slump)
• Exposure condition: very Severe
• Method of concrete placing: pumping
• Degree of supervision: Good
• Type of aggregate: Crushed angular aggregates
• Maximum cement content: 450 kg/m^3
• Chemical admixture type: Superplasticizer

• Test data for material:

• cement used: OPC 43 grade conforming to IS 8112
• the specific gravity of cement: 3.15
• Fly ash: Conforming to IS 3812
• Chemical admixture: superplasticizer conforming to IS 9103

S.G of C.A is: 2.74

• S.G of F.A: 2.74
• Water absorption: 0.5%
• Water absorption: 1.0%
• Free moisture of C.A: nill
• Free moisture of F.A: nill

• Target strength for Mix proportioning

• f'ck = fck+1.65s
• where fck=35N/mm^2
• s= 5.0
• f'ck=35+1.65*5=43.25N/mm^2

• Selection of water-cement ratio:

• maximum water-cement ratio=0.45
• based on experience adopt water-cement ratio as 0.40

• Selecting of water content

• maximum water content for 20mm aggregates=186litre(for 25 to 50 mm slump range)
• Estimated water content for 100 mm slump= 186+(6/100)*186=197litre
• Based on trials with superplasticizer water content reduction of 29% has been achieved. Hence, the arrived water content= 197*0.71= 140litres

• Calculation of cement and fly ash content:

• w/c = 0.4
• Cementitious material (cement+fly ash) content = 140/0.4 = 350 kg/m^3
• minimum cement content for very severe exposure condition = 320 kg/m^3
• 3650 kg/m^3 > 320 kg/m^3, hence ok.
• cementitiousmaterial content = 350*1.10= 385 kg/m^3
• water content = 140 kg/m^3
• so,w/c ratio = 140/385= 0.364
• Fly ash @30% of total cementitious material content = 385*30%=115 kg/m^3
• cement = 385-115=270 kg/m^3
• saving of cement while using fly ash = 350-270= 80kg/m^3
• fly ash being utilized= 115kg/m^3

• proportion of volume of coarse aggregate and fine aggregates content

• volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate(zone1) for water-cement ratio of 0.50=0.60
• Therefore, corrected proportion of volume of coarse aggregates for the water-cement ratio of 0.40=0.62.
• for pumpable concrete these values should be reduced by 10%
• Therefore, volume of coarse aggregate=0.62*0.9=0.56.
• volume of fine aggregate content=1-0.56=0.44

• Mix calculations

• Volume of concrete=1m^3
• Volume of cement =(270/3.154)*(1/1000)= 0.086m^3
• volume of fly ash =(115/1)*(1/1000)=0.052m^3
• Volume of water =(140/1)*(1/1000)=0.140m^3
• volume of chemical admixture =(7/1.145)*(1/1000)=0.007m^3
• volume of all aggregates =[1-(0.086+0.052+0.140+0.007)]=0.715m^3
• mass of coarse aggregates = 0.715*0.56*2.74*1000= 1097 kg
• mass of fine aggregates = 0.715*0.44*2.74*1000=862 kg

• Mix proportions

• cement = 270 kg/m^3
• fly ash = 115 kg/m^3
• water = 140 kg/m^3
• fine aggregates = 862 kg/m^3
• coarse aggregates= 1097kg/m^3
• chemical admixture= 7.7 kg/m^3

Mix ratio = 1:3.19:4.06

2. Mix design for M35 grade concrete by using Fly ash

• Stipulations for proportioning:

• Grade designation: M50
• Types of cement: OPC 43 grade conforming to IS8112
• Maximum nominal size of aggregates: 20mm
• minimum cement content: 320 kg/m^3
• maximum w/c ratio: 0.45
• Workability: 100 mm (Slump)
• Exposure condition: Severe
• Method of concrete placing: pumping
• Degree of supervision: Good
• Type of aggregate: Crushed angular aggregates
• Maximum cement content: 450 kg/m^3
• Chemical admixture type: Superplasticizer

• Test data for material:

• cement used: OPC 43 grade conforming to IS 8112
• the specific gravity of cement: 3.15
• Chemical admixture: superplasticizer conforming to IS 9103
• S.G of C.A is: 2.7
• S.G of F.A: 2.74
• Water absorption: 0.5%
• Water absorption: 1.0%
• Free moisture of C.A: nill
• Free moisture of F.A: nill

• Target strength for Mix proportioning

• f'ck = fck+1.65s
• where fck=50N/mm^2
• s= 5.0
• f'ck=35+1.65*5=58.25N/mm^2

• Selection of water-cement ratio:

• maximum water-cement ratio=0.45
• based on experience adopt water-cement ratio as 0.40

• Selecting of water content

• maximum water content for 20mm aggregates=186litre(for 25 to 50 mm slump range)
• Estimated water content for 100 mm slump= 186+(6/100)*186=197litre
• Based on trials with superplasticizer water content reduction of 29% has been achieved. Hence, the arrived water content= 197*0.71= 140litres

• Calculation of cement and fly ash content:

• w/c = 0.4
• Cementitious material (cement+fly ash) content = 140/0.4 = 350 kg/m^3
• minimum cement content for very severe exposure condition = 320 kg/m^3
• 3650 kg/m^3 > 320 kg/m^3, hence ok.
• cementitiousmaterial content = 350*1.10= 385 kg/m^3
• water content = 140 kg/m^3
• so,w/c ratio = 140/385= 0.364
• cement = 350kg/m^3

• proportion of volume of coarse aggregate and fine aggregates content

• volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate(zone1) for water-cement ratio of 0.50=0.60
• Therefore, corrected proportion of volume of coarse aggregates for the water-cement ratio of 0.40=0.62.
• for pumpable concrete these values should be reduced by 10%
• Therefore, volume of coarse aggregate=0.62*0.9=0.56.
• volume of fine aggregate content=1-0.56=0.44

• Mix calculations

• Volume of concrete=1m^3
• Volume of cement =(350/3.154)*(1/1000)= 0.111m^3
• Volume of water =(140/1)*(1/1000)=0.140m^3
• volume of chemical admixture =(7/1.145)*(1/1000)=0.006m^3
• volume of all aggregates =[1-(0.086+0.052+0.140+0.006)]=0.713m^3
• mass of coarse aggregates = 0.713*0.56*2.74*1000= 1140 kg
• mass of fine aggregates = 0.713*0.44*2.74*1000=896 kg

• Mix proportions

• cement = 350 kg/m^3
• water = 140 kg/m^3
• fine aggregates = 896kg/m^3
• coarse aggregates= 1140kg/m^3
• chemical admixture= 7 kg/m^3

Mix ratio = 1:2.56:3.25