Project on Concrete Mix Design for various grades of Concrete
Concrete Mix Design for M35 grade concrete with fly ash
1 Target strength of mix proportion
f'ck= fck+1.65S
= 35+1.65*5
=43.25N/mm^2
From table 1 IS 10262:2009 S= 5N/mm^2
2 Selection of w/c ratio
From Table 5 of IS 456:2000 for severe exposure
W/c ratio=0.45
Based on experience adopted w/c =0.40
0.40 less than 0.45 hence OK
3 Selection of water content
From Table 2 of IS10262:20009 max water content for 20mm aggreate= 186lit (for 25-50 mm Slump value)
For 100 mm Slump=186+(6*186/100)
=197 lit
As super-plasticizers is used w.c can be reduced to 29%
Water content=197*71/100
=140lit
4 Calculation of cement content
w/c ratio=0.4
Cementitous material (Cement+fly ash)=140/0.4
=350N/mm2 grater than 320N/mm2
Hence OK
The percentage of fly ash need to be decided based on Project requirements and quality of material
In some cases increase in cementitous material can be warranted.Increase in cementitous material content check percentage may be based on experience and trail
Cementitous material content=350*1.1=385kg/m3
Water content=140kg/m3
w/c ratio=140/385= 0.364
Fly ash@30% total cementitous material content=385*30/100
=115.5kg/m3
Cement=385-115.5
=269.5kg/m3
Saving Cement while using fly ash=350-269.5
=80kg/m3
Fly ash being utilized=115.5kg/m3
5 Proportioning volume of coarse aggregate and fine aggreate content
From Table 3 of IS 10262:2009 volume of CA corresponding to 20mm aggreate and fine aggreate (zone1) for w/c ratio=0.5=0.6
In present case w/c ratio=0.4
Volume of coarse aggreate need to increase to decrease the fine aggreate content
As w/c ratio is lower by 0.1 proportion of volume of CA is increased by 0.02 rate of +-0.001 for every+_0.005 change in w/c ratio
Corrected volume of CA for w/c ratio=0.4~0.62
For pumpable concrete these value reduced by 10%
Volume of CA= 0.62*30/100
= 0.56
Volume of FA= 1-0.56
= 0.44
6) Mix calculation
a)Volume of concrete=1m3
b) Volume of cement= Mass of concrete/(Specific gravity of cement*1000)
= 269.5/(3.15*1000)
= 0.085 m3
c) Volume of fly ash= Mass of fly ash/(Specific gravity of fly ash* 1000)
=115.5/(2.2*1000)
= 0.0525 m3
d) Volume of water= Mass of water/(Specific gravity of water* 1000)
= 140/(1*1000)
=0.140 m3
e) Volume of chemical admixtures= Mass of admixtures/(Specific gravity of admixtures* 1000)
=7.6/(1.145*1000)
= 0.006 m3
f) Volume of FA and CA
={a-(b+c+d+e)}
={1-(0.085+0.0525+0.140+0.006)}
=0.7165 m3
g)Mass of coarse aggreate
= f* volume of CA* sp.gr*1000
=0.7165*0.56*2.74*1000
=1099.39 kg/m3
h) Mass of fine aggreate
= f* volume of FA * sp. gr* 1000
= 0.7165*0.44*2.74*1000
= 863.81 kg/m3
7) Mix proportion
Cement= 269.5 kg/m3
Fly ash= 115.5 kg/m3
Water=140 kg/m3
Fine aggreate= 863.81 kg/m3
Coarse aggregate= 1099.39 kg/m3
Chemical admixture= 7 kg/m3
w/c ratio= 0.364
Concrete mix design for M50 grade without fly ash
1) Target strength of mix proportion
f'ck= f'ck+1.65 *S
f'ck= 50+1.65*5
From Table 1 IS 10262:2009 S= 5 N/mm2
f'ck= 58.25 N/mm2
2) Selection of w/c ratio
From Table 5 of IS 456:2000 severe exposure maximum w/c ratio= 0.45 Based on experience adopted w/c ratio=0.4
0.4<0.45 hence OK
3) Selection of water content
From Table 2 IS 10262 : 2009 maximum water content for 20 mm aggreate=180 lit ( For 25-50 mm Slump value)
For 100mm slump= 186+(186*6/100)
= 197 lit
As super-plasticizers is used water content can be reduced upto 30%
hence arrived water content= 197*71/100=140 lit
4) Calculation of cement content
w/c =0.4
Cement content= 140/0.4
= 350 kg/m3
From IS 456:2000 minimum Cement content for severe exposure condition 320 kg/m3
350<320 kg/m3 Hence OK
5) Proportion of volume of CA and FA content
From Table 3 of IS 10262-2009 volume of CA corresponding to 20 mm size of aggreate and FA ( zone1) for w/c ratio of 0.5=0.6
In present case w/c ratio=0.4
Volume of CA needs to increase to decrease FA content
As w/c ratio is lower by 0.1 . The proportion of volume of CA is increased by 0.02(@ rate of+- 0.01 for every+-0.05 change in w/c ratio)
Corrected volume of CA for w/c ratio 0.4=0.62
For pumpable concrete these value reduced to 10 %
Volume of CA = 0.62*0.9= 0.56
Volume of FA= 1-0.56=0.44
6) Mix calculation
a) Volume of concrete= 1m3
b) Volume of cement= Mass of cement/(Specific gravity of cement*1000)
= 350/(3.15*1000)
=0.111 m3
c) Volume of water= Mass of water/(Specific gravity of water*1000)
= 140/(1*1000)
=0.0140 m3
d) Volume of chemical admixture=Mass of admixture/(Specific gravity of admixture*1000)
= 7/(1.145*1000)
= 0.006 m3
e) Volume of aggreate CA and FA
={a-(b+c+d)}
={1-(0.111+0.0140+0.006)}
=0.743 m3
f) Mass of coarse aggreate
= e* volume of CA* Sp.gr*1000
=0.743*0.56*2.74*1000
=1140 kg/m3
g) Mass of fine aggreate
= e* volume of FA* Sp.gr*1000
= 0.743*0.44*2.74*1000
=896 kg/m3
7) Mix proportion
Cement= 350kg/m3
Water=140 kg/m3
Fine aggreate= 896 kg/m3
Coarse aggreate= 1140 kg/m3
Chemical admixture= 7 kg/m3
w/c ratio=0.4
Mix ratio= 1:2.56:3.26