Project on Concrete Mix Design for various grades of Concrete
Mix Design for M35 Grade Concrete with Fly ash
1) Stipulations for Proportioning
a) Grade designation : M35
b) Type of cement : OPC 53 grade conforming to IS-12269-1987
c) Type of mineral admixture : Fly ash conforming to IS 38I2 (Part I)
d) Maximum nominal size of aggregate : 20mm
e) Minimum cement content : 320 kg/m'
f) Maximum water-cement ratio : 0.45
g) Workability : 50-75 mm (Slump)
h) Exposure condition : Severe (for reinforced concrete)
i) Method of concrete placing : Pumping
j) Degree of supervision : Good
k) Type of aggregate : Crushed angular aggregate
l) Maximum cement (OPC) content : 450 kg/m3
m) Chemical admixture type : Super plasticizer confirming to IS-9103
2) Test Data of materials:
a) Cement used : OPC 43 grade conforming to IS 8112
b) Specific gravity of cement : 3.15
c) Fly ash : conforming to IS 38I2 (Part I)
d) Specific gravity of fly ash : 2.2
e) Chemical admixture : Super plasticizer conforming to IS 9103
f) Specific gravity of
I) Coarse aggregate : 2.74
2) Fine aggregate : 2.74
g) Water absorption
1) Course aggregate : 0.5%
2) Fine aggregate : 1.0%
h) Free (surface) moisture
1) Coarse aggregate : Nil (absorbed moisture also nil)
2) Fine aggregate : Nill
j) Sieve analysis
1) Coarse aggregate : Confirming to Table 2 IS383
2) Fine aggregate : Conforming to grading Zone I of Table 4 of IS 383
3) Target Strength For Mix Proportioning
Fck = fck+1.65s
Fck = target average compressive strength at 28 days
fck = characteristics compressive strength at 28 days
s = standard deviation.
S = 5 N/mm2 (From IS 10262-2009 table 1- page 2)
=35 + (1.65*5)
Fck = 43.25 N/mm2
4) Selection of Water – Cement Ratio
Check in IS 456:2000 for severe condition = 0.45
Based on experience we adopt water-cement ratio as 0.40.
⸫ Maximum water-cement ratio > Adopted water-cement ratio
0.45>0.40
5) Selection of Water Content
From Table 2 IS 10262:2009, maximum water content for 20 mm aggregate = 186 Liters (25-50 mm slump range)
The water content above is for a slump of 25 to 50 mm, but according to the specification our concrete requires a slump of 75 mm. Therefore, to get the desired slump, the water content must be increased. Clause 4.2 of IS1026 recommends increasing the water content by 3% to obtain an additional 25 mm slump. Therefore, to obtain a slump of 25mm in addition to our concrete, the water content must be increased by 3%.
Estimated Water content for 50-75 mm Slump = 186 + {(3/100)*186} = 191.58 liter
As super plasticizer is used, the water content can be reduced up 30%.
Based on trials with super plasticizer water content reduction of 29% has been achieved. Hence the arrived water content = 192 * 0.71 = 136.32 Liters
⸫ Water content = 137 liter
6) Calculation of Cement and Fly ash Content
Adopted Water Cement ratio = 0.40
Total Cementitious (Cement +Fly ash) content = 137/0.40 = 342.5 kg/m3
From Table 5 of IS 456, minimum cement content for 'severe' exposure conditions = 320kg/m3
Since flying ash is used, the amount of cementitious content (cement + fly ash) should be increased to get good performance and strength. The percentage of increasing cementitious content depends on experience and research. Here we have increased the cementitious content by 10%.
=342.5*1.10 = 376.75 kg/m3
376.75 kg/m3> 320kg/m3
Fly ash @ 30% of total cementitious material content = 376.75 * (30/100) = 113.025 kg/m3 ≈ 114kg/m3
Cement content = total cementitious content – Fly ash content
= 376.75 – 113.025 = 263.725 kg/m3 ≈ 264 kg/m3
Calculation of Super Plasticizers @ 2.0 percent to the mass of cementitious content =376.75*(2/100) = 7.5 kg/m3
Saving of cement while using fly ash = 342.5 – 263.725 = 78.775kg/m3
Fly ash being utilized = 113.025kg/m3
7) Proportion of Volume of Coarse Aggregate and Fine Aggregate Content
From Table-3 volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone I) for water-cement ratio of 0.50 =0.60.
In the present case water-cement ratio is 0.40. Therefore, volume of coarse aggregate is required t0 be increased to decrease the fine aggregate content. As the water-cement ratio is lower by 0.10 the proportion of volume of coarse aggregate is increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in water-cement ratio). Therefore, corrected proportion of volume of coarse aggregate for the water-cement ratio of 0.40 = 0.62
For Pumpable concrete these values should be reduced by 10%.
Volume of Coarse aggregate = 0.62 X 0.9 = 0.56
Volume of Fine aggregate = 1 - 0.56 = 0.44
8) Mix Calculations
The mix calculations per unit volume of concrete shall be as follows:
a) Volume of Concrete = 1 m3
b) Volume of Cement = (Mass of cement / Spg of cement)*(1/1000)
= (263.725/3.15)*(1/1000) = 0.084m3
c) Volume of Fly ash = (Mass of Fly ash / Spg of Fly ash)*(1/1000)
= (113.025/2.2)*(1/1000) = 0.051m3
d) Volume of Water = (Mass of Water / Spg of Water)*(1/1000)
= (137/1)*(1/1000) = 0.137m3
e) Volume of Chemical Admixture = (Mass of Admixture / Spg of Admixture)*(1/1000) = (7.5/1.145)*(1/1000) = 0.0065m3
f) Volume of all aggregate = a-(b + c + d + e)
= 1 – (0.084 + 0.051 + 0.137 + 0.0065) = 0.7215 m3
g) Mass of Coarse aggregate = f * Volume of Coarse aggregate * Specific gravity of coarse aggregate * 1000
= 0.7215*0.56*2.74*1000 = 1107.06kg ≈ 1108 kg
h) Mass of Fine aggregate = f * Volume of Fine aggregate * Specific gravity of Fine aggregate * 1000
= 0.7215*0.44*2.74*1000 = 869.84 kg ≈ 870 kg
9) Mix Proportions for Trial Number 1
Cement = 264 kg/m3
Fly ash = 114 kg/m3
Fine aggregate = 870 kg/m3
Coarse aggregate = 1108 kg/m3
Water = 0.137 kg/m3
Chemical admixture= 0.0065 kg/m3
Water cement ratio = 137/376.75 = 0.36
To find the design mix ratio, divide the calculated value of all materials by the weight of cement. Therefore Mix Ratio of M35 Grade concrete by weight is
Cement: Fly ash: F.A : C.A : Water
= 1 : 0.43 : 3.3 : 4.20 : 0.51
Mix design for M50 grade concrete.
1) Stipulations for Proportioning:
a) Grade designation : M50
b) Type of cement : OPC 53 grade conforming to IS-12269-1987
c) Type of mineral admixture : Nill
d) Maximum nominal size of aggregate : 20mm
e) Minimum cement content : 320 kg/m3
f) Maximum water-cement ratio : 0.45
g) Workability : 50-75 mm (Slump)
h) Exposure condition : Severe (for reinforced concrete)
i) Method of concrete placing : Pumping
j) Degree of supervision : Good
k) Type of aggregate : Crushed angular aggregate
l) Maximum cement (OPC) content : 450 kg/m3
m) Chemical admixture type : Super plasticizer Confirming to IS-9103
2) Test Data of materials:
a) Cement used : OPC 43 grade conforming to IS 8112
b) Specific gravity of cement : 3.15
c) Chemical admixture : Super plasticizer conforming to IS 9103
d) Specific gravity of
1) Coarse aggregate : 2.74
2) Fine aggregate : 2.74
e) Water absorption
1) Course aggregate : 0.5%
2) Fine aggregate : 1.0%
f) Free (surface) moisture
1) Coarse aggregate : Nil (absorbed moisture also nil)
2) Fine aggregate : Nill
g) Sieve analysis
1) Coarse aggregate : Confirming to Table 2 IS383
2) Fine aggregate : Conforming to grading Zone I of Table 4 of IS 383
3) Target Strength For Mix Proportioning
Fck = fck+1.65s
Where,
Fck = target average compressive strength at 28 days
fck = characteristics compressive strength at 28 days
s = standard deviation.
S = 5 N/mm2 (From IS 10262-2009 table 1- page 2)
=50 + (1.65*5)
Fck = 58.25 N/mm2
4) Selection of Water – Cement Ratio
Check in IS 456:2000 for severe condition = 0.45
Based on experience we adopt water-cement ratio as 0.40.
⸫ Maximum water-cement ratio > Adopted water-cement ratio (0.45 > 0.40)
5) Selection of Water Content
From Table 2 IS 10262:2009, maximum water content for 20 mm aggregate = 186 Liters (25-50 mm slump range)
The water content above is for a slump of 25 to 50 mm, but according to the specification our concrete requires a slump of 75 mm. Therefore, to get the desired slump, the water content must be increased. Clause 4.2 of IS1026 recommends increasing the water content by 3% to obtain an additional 25 mm slump. Therefore, to obtain a slump of 25mm in addition to our concrete, the water content must be increased by 3%.
Estimated Water content for 50-75 mm Slump = 186 + {(3/100)*186} = 191.58 liter
As super plasticizer is used, the water content can be reduced up 30%.
Based on trials with super plasticizer water content reduction of 29 percent has been achieved,
Hence the arrived water content = 192 * 0.71 = 136.32 Liters
⸫ Water content = 137 liters
6) Calculation of Cement Content.
Adopted Water Cement ratio = 0.40
Cement content = 137/0.40 = 342.5 kg/m3
From Table 5 of IS 456, minimum cement content for 'severe' exposure conditions = 320kg/m3
342.5 kg/m3> 320kg/m3 (Say 343kg/m3 )
Calculation of Super Plasticizers @ 2.0 percent to the mass of cementitious content =342.5*(2/100) = 6.85 kg/m3
7) Proportion of Volume of Coarse Aggregate and Fine Aggregate Content
From Table-3 volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone I) for water-cement ratio of 0.50 =0.60.
In the present case water-cement ratio is 0.40. Therefore, volume of coarse aggregate is required t0 be increased to decrease the fine aggregate content. As the water-cement ratio is lower by 0.10 the proportion of volume of coarse aggregate is increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in water-cement ratio). Therefore, corrected proportion of volume of coarse aggregate for the water-cement ratio of 0.40 = 0.62
For Pumpable concrete these values should be reduced by 10%.
Volume of Coarse aggregate = 0.62 X 0.9 = 0.56
Volume of Fine aggregate = 1 - 0.56 = 0.44
8) Mix Calculations
a) Volume of Concrete = 1 m3
b) Volume of Cement = (Mass of cement / Spg of cement)*(1/1000)
= (342.5/3.15)*(1/1000) = 0.109m3
c) Volume of Water = (Mass of Water / Spg of Water)*(1/1000)
= (137/1)*(1/1000) = 0.137m3
d) Volume of Chemical Admixture = (Mass of Admixture / Spg of Admixture)*(1/1000) = (6.85/1.145)*(1/1000) = 0060m3
e) Volume of all aggregate = a-(b + c + d )
= 1 – (0.109 + 0.137 + 0.0060) = 0.748 m3
g) Mass of Coarse aggregate = e * Volume of Coarse aggregate * Specific gravity of coarse aggregate * 1000
= 0.748*0.56*2.74*1000 = 1147.73kg ≈ 1148 kg
h) Mass of Fine aggregate = e * Volume of Fine aggregate * Specific gravity of Fine aggregate * 1000
= 0.748*0.44*2.74*1000 = 901.78 kg ≈ 902 kg
9) Mix Proportions for Trial Number 1
Cement = 343 kg/m3
Fine aggregate = 902 kg/m3
Coarse aggregate = 1148 kg/m3
Water = 0.137 kg/m3
Chemical admixture = 0.0060 kg/m3
Water cement ratio = 137/342.5 = 0.40
To find the design mix ratio, divide the calculated value of all materials by the weight of cement. Therefore Mix Ratio of M35 Grade concrete with Fly ash by weight is Cement: Fly ash: F.A : C.A : Water
= 1 : 2.63 : 3.35 : 0.40