Project on Concrete Mix Design for various grades of Concrete
AIM:
Calculation of Concrete mix design for M35 grade concrete with flyash as per IS10262:2009
1.DATA REQUIRED FOR CONCRETE MIX DESIGN:
a.Grade of designation:M35
b.Type of cement: opc 43 conforming to IS8112
c.Type of minerals: Flyash IS3812(part 1)
d.maximum nominal size of aggregate: 20mm
e.Minimum cement content: 320kg/m^3(from table 5 of 456:2000)
f.Maximum water/cement ratio:0.45 (from table 5 of IS456:2000)
g.Environmental exposure condition:Severe(for R.C.C)
h.Workability : 100mm(Slump for pumpable concrete)
i.Method of concrete pouring: Pumping
j. Degree of supervision: Good
k.Type of aggregate:Crushed angular aggregate
l.Chemical admixtures type:Super plasticizer
Step :2
Test data for materials
a. Cement used : OPC 43 grade confirming to IS 8112
b. Specific gravity of cement : 3.15
c. Fly ash : Conforming to IS 3812 part 1
d. Specific gravity of flyash : 2.2
e. Chemical admixture : Superplaticizer conforming to IS 9103
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. Seive analysis for coarse aggregate: conforming to table 2 of is382
j. sieve analysis for fine aggregate:conforming to grading zone 2 of is382.
3.Target strength of mix proportioning:
f'ck=fck+1.65s
=35+1.65*5=43.25N/MM^2.
Where fck= characteristic compressive strength
s= standard deviation.
4.Selection of water/cement ratio:
From table 5, IS456:2000 for severe exposure,maximum water/cement ratio=0.45
on experience water cement ratio=0.4
0.4<0.45, Hence o.k.
5.Selection of water content:
From table 2 of IS456:2009, the maximum water content fro 20mm aggregate=186litre(for 25 to 50mm slump range).
Estimated water content for 100mm slump= 186+(6/100*186)
= 197.16litre.
As super plasticizer is used the water content can be reduced upto 30%
Based on trials water content reduction of 29% is achieved with plasticizer. Hence the arrived water content=197.16*0.71=139.98=140litres.
6.CALCULATION OF CEMENT CONTENT:
Water/cement ratio=0.4
Cementious material(cement+flyash)= 140/0.4=350kg/m^3.
From table 5 of IS456 minimum cement content for severe exposure condition=320kg/m^3.
350kg/m^3>320kg/m^3.
Now to propotion a mix containing flyash the following steps are suggested:
a. The percentage of flyash needs to be decided based on projects requirement and quality of materials.
b. In some cases increase in cementious material can be warned. increase in cementious material content and its percentage may be based on experience and trails.
This example is with increase of 10% cementious material content
Cementious material content=350*1.10=385kg/m^3.
Water content=140kg/m^3.
so, Water/cement ratio=140/385=0.364
Fly ash @ 30% cementious material content=385*30%=115kg/m^3.
Cement(opc)= 385-115=270kg/m^3.
Saving of cement while using flyash= 350-270=80kg/m^3.
7.Proportion of volume of coarse aggregate and fine aggregate content
From table 3 of IS10262:2009, volume of coarse aggregate coresponding to 20mm size and fine aggregate(zone 1) for water cement ratio of 0.6
present water cement ratio=0.4
Therefore 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 incresed by 0.02.
Hence the corrected volume of coarse aggregate for water cement ratio is 0.40=0.64
For pumpable concrete these values are reduced by10%
volume of coarse aggregate= 0.64*0.9=0.576
volume of fine aggregtae =1-0.576=0.424.
8.MIX CALCULATION:
The mix calculation per unit volume of concret shall be as follows:
a. volume of concrete=1m^3
b.volume of cement= MASS OF CEMENT/SPECIFIC GRAVITY OF CEMENT*1/1000
=270/3.15*1/1000
=0.086M^3.
c.volume of flyash= mass of flyash/specific gravity of flyash*1/1000
=115/2.2*1/1000
=0.052m^3.
d.volume of water= mass of water/specific gravity of water*1/1000
=140/1*1/1000863.2kg/m^3
=0.140m^3.
e. volume of chemical admixtures=mass of chemical admixture/specific gravity of chemical admixture*1/1000
=7.6/1.14*1/1000
=0.006m^3.
f.volume of coarse and fine aggregate= (a- (b+c+d+e))
=(1-(0.086+0.052+0.14+0.006))
= 0.716m^3.
g.Mass of coarse aggregate= f*volume of coarse aggregate*specific gravity of coarse aggregate*1000
=0.716*0.576*2.74*1000
=1130kg/m^3.
e.Mass of fine aggregate= f*volume of fine aggregate*specific gravity of fine aggregate*1000
=0.716*0.44*2.74*1000
=863kg/m^3.
9.MIX PROPORTION:
Cement = 270 kg/m3
Fly ash = 115 kg/m3
Water = 140kg/m3
Fine aggregate = 863 kg/m3
Coarse aggregate = 1130 kg/m3
Chemical admixture = 7kg/m3
Water- cement ratio = 0.364
Mix ratio 1: 2.24: 2.94
Step : 10
The slump shall be measured and the water content and dosage of admixture shall be adjusted for achieving the required slump on trial . The mix proportion shall be reworked for the actual water content and checked for durability requirements.
Step :11
Two or more trials having variation of 10 % of water-cement ratio in Clause 10( Step 10) shall be carried out and a graph between three water -cement ratios and corresponding strengths shall be plotted to work out the mix proportions for the given target strength for feild trials .However durability shall be met.
RESULT:
The mix design for M35 Grade concrete with fly ash is 1:2.24:2.94.
MIX DESIGN FOR M50 GRADE CONCRETE
AIM:
Calculation of Concrete mix design for M50 grade concrete as per IS10262:2009
1.DATA REQUIRED FOR CONCRETE MIX DESIGN:
a.Grade of designation:M50
b.Type of cement: opc 43 conforming to IS8112
c.maximum nominal size of aggregate: 20mm
d.Minimum cement content: 320kg/m^3(from table 5 of 456:2000)
e.Maximum water/cement ratio:0.45 (from table 5 of IS456:2000)
f.Environmental exposure condition:Severe(for R.C.C)
g.Workability : 100mm(Slump for pumpable concrete)
h.Method of concrete pouring: Pumping
i. Degree of supervision: Good
j.Type of aggregate:Crushed angular aggregate
k.Chemical admixtures type:Super plasticizer
Step :2
Test data for materials
a. Cement used : OPC 43 grade confirming to IS 8112
b. Specific gravity of cement : 3.15
c. Specific gravity of flyash : 2.2
d. Chemical admixture : Superplaticizer conforming to IS 9103
e. Specific gravity of :
Coarse aggregate : 2.74
Fine aggregate : 2.74
f. Water absorption :
Coarse aggregate : 0.5%
Fine aggregate : 1%
g. Free surface moisture
Coarse aggregate : Nil
Fine aggregate : Nil
h. Seive analysis for coarse aggregate: conforming to table 2 of is382
i.sieve analysis for fine aggregate:conforming to grading zone 2 of is382.
3.Target strength of mix proportioning:
f'ck=fck+1.65s
=50+1.65*5=58.25N/MM^2.
Where fck= characteristic compressive strength
s= standard deviation.
4.Selection of water/cement ratio:
From table 5, IS456:2000 for severe exposure,maximum water/cement ratio=0.45
on experience water cement ratio=0.4
0.4<0.45, Hence o.k.
5.Selection of water content:
From table 2 of IS456:2009, the maximum water content from 20mm aggregate=186litre(for 25 to 50mm slump range).
Estimated water content for 100mm slump= 186+(6/100*186)
= 197.16litre.
As super plasticizer is used the water content can be reduced upto 30%
Based on trials water content reduction of 29% is achieved with plasticizer. Hence the arrived water content=197.16*0.71=139.98=140litres.
6.CALCULATION OF CEMENT CONTENT:
Water/cement ratio=0.4
Cement content= 140/0.4=350kg/m^3.
From table 5 of IS456 minimum cement content for severe exposure condition=320kg/m^3.
350kg/m^3>320kg/m^3.Hence o.k
7.Proportion of volume of coarse aggregate and fine aggregate content
From table 3 of IS10262:2009, volume of coarse aggregate coresponding to 20mm size and fine aggregate(zone 1) for water cement ratio of 0.6
present water cement ratio=0.4
Therefore 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 incresed by 0.02.
Hence the corrected volume of coarse aggregate for water cement ratio is 0.40=0.64
For pumpable concrete these values are reduced by10%
volume of coarse aggregate= 0.64*0.9=0.576
volume of fine aggregtae =1-0.576=0.424.
8.MIX CALCULATION:
The mix calculation per unit volume of concret shall be as follows:
a. volume of concrete=1m^3
b.volume of cement= MASS OF CEMENT/SPECIFIC GRAVITY OF CEMENT*1/1000
=350/3.15*1/1000
=0.111M^3.
c.volume of water= mass of water/specific gravity of water*1/1000
=140/1*1/1000
=0.140m^3.
d. volume of chemical admixtures=mass of chemical admixture/specific gravity of chemical admixture*1/1000
=7.6/1.14*1/1000
=0.006m^3.
e.volume of coarse and fine aggregate= (a- (b+c+d))
=(1-(0.111+0.140+0.006))
= 0.743m^3.
f.Mass of coarse aggregate= f*volume of coarse aggregate*specific gravity of coarse aggregate*1000
=0.743*0.576*2.74*1000
=1173kg/m^3.
e.Mass of fine aggregate= f*volume of fine aggregate*specific gravity of fine aggregate*1000
=0.743*0.424*2.74*1000
=863kg/m^3.
9.MIX PROPORTION:
Cement = 350 kg/m3
Water = 140kg/m3
Fine aggregate = 863 kg/m3
Coarse aggregate = 1173 kg/m3
Chemical admixture = 7kg/m3
Water- cement ratio = 0.4
Mix ratio 1: 2.46: 3.35
Step : 10
The slump shall be measured and the water content and dosage of admixture shall be adjusted for achieving the required slump on trial . The mix proportion shall be reworked for the actual water content and checked for durability requirements.
Step :11
Two or more trials having variation of 10 % of water-cement ratio in Clause 10( Step 10) shall be carried out and a graph between three water -cement ratios and corresponding strengths shall be plotted to work out the mix proportions for the given target strength for feild trials .However durability shall be met.
RESULT:
The mix design for M50 Grade concrete is 1:2.46:3.35.