Project on Concrete Mix Design for various grades of Concrete
Calculation of mix design for M35 grade with fly ash :-
I) Stipulation for proportioning :-
a) Grade designation = M35
b) Type of cement = OPC 43 grade conforming to IS8112.
c) Type of mineral admixture = Fly ash conforming to IS3812(part 1)
d) Maximum nominal size of aggregate = 20mm
e) Minimum cement content = 320kg/m^3 (From table 5 of IS 456:2000-exposure condition)
f) Maximum water cement ratio = 0.45 (From table 5 of IS 456:2000-exposure condition)
g) Workability = 100mm (Slump value for pumpable concrete)
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 content = 450kg/m^3
m) Chemical admixtures type = Super plasticizer
II) Test data for materials :-
a) Cement used = OPC 43 grade conforming to IS 8112
b) Specific gravity of cement = 3.15
c) Fly ash = conforming to IS3812(part 1)
d) Specific gravity of fly ash = 2.2
e) Chemical admixture = Superplasticizer conforming to IS9103
f) Specific gravity of
*Coarse aggregate = 2.74
*Fine aggregate = 2.74
g) Water absorption
*Coarse aggregate = 0.5%
*Fine aggregate = 1%
h) Free surface moisture
*Coarse aggregate = Nil
*Fine aggregate = Nil
i) Sieve analysis
*Coarse aggregate
*Fine aggregate = Conforming to grading zone I of table 4 of IS383
III) Target strength for mixproportioning :-
F'ck = Fck+1.65S
Where, F'ck = Target average compressive strength at 28days
Fck = Characteristic compressive strength at 28days
S = Standard deviation
From table 1 of IS 10262:2009, Standard deviation
S = 5N/mm^2
There fore, the target strength = 35 + 1.65*5
= 43.25N/mm^2
IV) Selection of water cement ratio :-
From table 5 of IS 456:2000 for severe exposure condition,
Maximum Water cement ratio =0.45
Based on experiance, adopt water cement ratio as 0.4
0.4<0.45,Hence OK
V) Selection of water content :-
From table 2 of IS10262:2009, Maximum water content for 20mm
aggregate = 186litres(for 25mm to 50mm slump range)
Estimate water content for 100mm slump = 186+(0.06*186)
= 197litre
As super plasticizer is used, the water content canbe reduced.
Based on trail water content reduction of 23% is acheived with plasticizer.
Hence the arrived water content = 197*0.77
= 151.96litres
= 152litres.
VI) Calculation of cement content :-
Water cement ratio = 0.4
Cementaneous material (cement + flyash) content
= 152/0.4
= 380kg/m^3
From table 5 of IS456 minimum cement content for "severe" exposure
condition = 320kg/m^3
380kg/m^3 > 320kg/m^3,Hence OK
Now, to proportion a mix containing fly ash the following steps are suggested
a) The percentage of flyash need tobe decided based on project requirement and quality of materials.
b) In some cases increase in cementaneous material canbe warranted.
Increase in cementaneous material contant and its percentage maybebased on experiance and trail(This example is with increase of 10% cementaneous material content).
Cementaneous material content = 380*1.1
= 418kg/m^3
Water content = 152llitres
So, Water cement ratio = 152/418
= 0.364
Fly ash at 30% total cementaneous material
content = 418*0.30
= 125.4kg/m^3
Cement (OPC) = 418-125.4
= 292.6kg/m^3
= 293kg/m^3
Saving of cement while using
fly ash = 380-293
= 87 kg/m^3
Flyash cance utilized = 125.4 kg/m^3
VII) Proportion of volumeof coarse aggregate andfine aggregate content :-
From table 3 of IS 10262:2009,volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (zone I) for water cement ratio of 0.5 is 0.6
In the present case the water cement ratio is 0.40
*Therefore, the volume of coarse aggregate needs tobe increased to decrease the fine aggregate content.
*As water cement ratio is lower by 0.10,the proportion of volume of coarse aggregate is increased by 0.02.
(at rate of +/-0.01 for every +/-0.05 change inwater cement ratio)
Therefore the corrected volume of coarseaggregate for water cement ratio of 0.40 is 0.62.
(Note:- If coarse aggregate is not angular type, then also the volume of coarse aggregate maybe required tobe increased suitably,Based on experience).
For pumpable concrete these values are reduced by 10%.
Therefore, volume of coarse
aggregate = 0.62*0.90
= 0.56
Volume of fine aggregate
content = 1-0.56
= 0.44
VIII) Mix proportion :-
The mix calculation per unit volume of concrete shall be follows
a) Volume of conccrete = 1m^3
b) Volume of cement = (Mass of cement/specific gravity of cement)*(1/1000)
= (293/3.15)*(1/1000)
= 0.093 m^3
c) Volume of fly ash = (Mass of fly ash/specific gravity of fly ash)*(1/1000)
= (125.4/2.2)*(1/1000)
= 0.057 m^3
d) Volume of water = (Mass of water/specific gravity of water)*(1/1000)
= (152/1)*(1/1000)
= 0.152 m^3
e) Volume of chemical admixture
= (Mass of chemical admixture/specific gravity of chemical admixture)*(1/1000)
= (8.4/1.145)*(1/1000)
= 0.00733 m^3
Mass of chemical admixture = 2% of cementaneous material
= (418*0.02)
= 8.4
f) volume of aggregate(FA and CA)
= (a-(b+c+d+e))
= (1-(0.093+0.057+0.152+0.00733))
= 0.69 m^3
g) Mass of coarse aggregate
= f*volume of coarse aggregate*specific gravity of coarse aggregate*1000
= 0.69*0.56*2.74*1000
= 1059 kg/m^3
h) Mass of fine aggregate = f*volume of fine aggregate*specific gravity of fine aggregate*1000
= 0.69*0.44*2.74*1000
= 832 kg/m^3
IX) Mix proportion :-
Cement = 293 kg/m^3
Fly ash = 125.4 kg/m^3
Water = 152 kg/m^3
Fine aggregate = 832 kg/m^3
Coarse aggregate = 1059 kg/m^3
Chemical admixture = 7.3kg/m^3
Water cement ratio = 0.364
Mix ratio = 1:2:2.63
Concrete mix design for M50 grade concrete :-
1) stipulation for proportioning :-
a) Grade designation = M50
b) Type of cement = OPC43 grade conforming to IS 8112
c) Maximum nominal size of aggregate = 20mm
d) Minimum cement content = 320kg/m^3(from table 5 of IS 456:2000 - Exposure condition)
e) Maximum water cement ratio = 0.45(from table 5 of IS 456:2000 - Exposure condition)
f) Workability = 100mm (slump value for pumpable concrete)
g) Exposure condition = Severe(for reinforced concrete)
h) Method of concrete placing = pumping
i) Degree of super vision = good
j) Type of aggregate = crushed angular aggregate
k) Maximum cement content = 450kg/m^3
l) Chemical admixtures type = Super plasticizer.
2) Test data for materials :-
a) Cement used = OPC 43 grade confirming to IS 8112
b) Specific gravity of cement = 3.15
c) Chemical admixtures = super plasticizer conforming to IS 9103
d) Specific gravity of
Coarse aggregate = 2.74
Fine aggregate = 2.74
e) Water absorption
Coarse aggregate = 0.5%
Fine aggregate = 1%
f) Free surface moisture
Coarse aggregate = Nil
Fine aggregate = Nil
g) Seive analysis
Coarse aggregate =
Fine aggregate = Conforming to grading zone 1 of table 4 of IS 383.
3) Target strength of mix proportioning :-
F'ck = Fck + 1.65S
Where, F'ck = Target average compressive strength at 28days,
Fck = Characteristic compressive strength at 28days,
S = Standard deviation.
From table 1 of IS 10262:2009, Standard deviation,S = 5N/mm^2(for M30)
Therefore,Target strength = 50 + 1.65*5 = 58.25MPa
4) Selection of water cement ratio :-
From table5 of IS 456:2000 for severe exposure,maximum water cement ratio = 0.45
Based on experience,adopted water-cement ratio is 0.40
0.40<0.45,hence OK.
5) Selection of water content :-
From table 2 of IS10262:2009, Maximum water content for 20mm aggregate = 186litres(for 25mm to 50mm slump range)
Estimated water content for 100mm slump = 186 + (6/100)*186
= 197litres.
As superplasticizer is used, the water content can be reduced up to 20% and above Based on trial water content reduction of 29% is acheived with plasticizer.
Hence the acheived water content = 197 - (0.2*197)
= 157.6litres.
6) Calculation of cement content :-
Water cement ratio = 0.40
Cement content = 157.6/0.4 = 394kg/m^3
From table 5 of IS 456 minimum cement content for severe exposure
condition = 320 kg/m^3
394kg/m^3 > 320kg/m^3, Hence OK.
7) Proportion of volume of coarse aggregate and fine aggregate content :-
From table 3 of IS 10262:2009, Volume of coarse aggregate corresponding to 20mm size aggregate(zone I) for water cement ratio of 0.5 is 0.6.
In the present case the water cement ratio is 0.40.
* Therefore, the volume of coarse aggregate needs to be increased to decrease the fine aggregate content.
* As water-cement ratio is lower by 0.10, the proportion of volume of coarse aggregate is increased by 0.02(at the of +/-0.01 for every +/- 0.05 change in water cement ratio).
Therefore, corrected volume of coarse aggregate for the water-cement ratio of 0.40 = 0.62
For pumpable concrete these volume are reduced by 10%.
Therefore, volume of coarse aggregate = 0.62*0.9 = 0.56
Volume of fine aggregate content = 1-0.56 = 0.44.
8) Mix calculations :-
The mix calculation per unit volume of concrete shall be follows
a) Volume of concrete = 1m^3
b) Volume of cement = (Mass of cement/Specific gravity of cement)*(1/1000)
= (394/3.15)*(1/1000)
= 0.125m^3.
c) Volume of water = (Mass of water/Specific gravity of water)*(1/1000)
= (157.6/1)*(1/1000)
= 0.158m^3
d) Volume of chemical admixture
= (Mass of chemical admixture/Specific gravity of admixture)*(1/1000)
= (7.88/1.145)*(1/1000)
= 0.0069m^3
Mass of chemical admixture = 2% of cementanious material
= (394*0.02)
= 7.88
e) Volume of aggregate(FA and CA)
= (a-(b+c+d))
= (1-(0.125+0.158+0.0069))
= 0.7101m^3
f) Mass of coarse aggregate
= e * Volume of coarse aggregate * specific gravity * 1000
= 0.7101*0.56*2.74*1000
= 1089.424kg/m^3
g) Mass of fine aggregate = e * Volume of fine aggregate * Specific gravity of fine aggregate * 1000
= 0.7101*0.44*2.74*1000
= 855kg/m^3.
9) Mix proportion :-
Cement = 394kg/m^3
Water = 157.6kg/m^3
Fine aggregate = 855kg/m^3
Coarse aggregate = 1089.424kg/m^3
Chemical admixture = 7.88kg/m^3
Water cement ratio = 0.4
Mix design ratio = 1:2.17:2.76.
Concrete mix design for M30 = 1:2.17:2.76.