Project on Concrete Mix Design for various grades of Concrete
Mix design for M35 grade concrete with fly ash
Aim:Mix design for M35 grade concrete with fly ash
propcedure:
step:1
stipulations for proportioning
a.Grade designation:M35
b.Type of cement:opc 43 grade confirming to IS 8112
c.Type of material admixture:fly ash confirming to IS 3812(part 1)
d.Maximum narmal size of aggregates:20mm
e.Minimum cement content:3420kg/m3(table:5 is 456-2000, based on exposure condition)
f.Maximum water cement ratio:0.45(table:5 IS 456-2000, based on exposure condition)
g.Workability:100mm slump value of pumpable concrete.
h.Exposure condition:severe(for rainforced concrete)
i.Method of concrete placing:pumping
j.Degree of supervision:Good
k.type of aggregate:crushed angular aggregate
l.maximum cement content:450kg/m3
m.Chemical admixture type:Superplasticizer.
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:Confirming to IS 3812 part 1
d.Specific gravity of fly ash:2.2
e.Chemical admixture:superplasticizer c
onforming to IS 9103
f.Specific gravity of:coarse aggregate:2.74
fine aggregate:2.74
g.Water obsorption:
coarse aggregate:0.5%
Fine aggregate:1%
h.Free surface moisture:
Coarse aggregate:Nil
Fine aggregate:Nill
i.Seive analysis
Coarse aggregate:
is | Analysis of | %of |
seive | coarse aggregate | different | Remark
size(mm) | fraction | fraction |confirming
____________________________________________________ | to Table 2 |of IS 383
I II I II Combined |
20 100 60 40 100 | 100
10 0 0 28.5 | 71.2 28.5 |
4.75 3.7 | 9.4 3.7 |
2.36 |
0 | | | | Fine aggregate:Conforming to grading zone1 of table 4 |
IS 383. | _________________________________________________________________________
step:3
To find target mean strength for mix proportioning:
Target mean strength f'ck=fck
+1.65s
=35+1.65*5
=43.25N/m.m2
fck-Characteristic compressive strength
s-Standard deviation
step:4
Selection of water -cement ratio:
Maximum water-cement ratio=0.45(for severe condition,
from table 5 of IS456-2000)
On experience water -cement ratio =0.4
0.4<0.45,Hence ok.
step 5:
calculation of water content
Maximum water content for 20mm aggregate=186 liters
(table 2 of IS 1026:2009)for 25mm to 50mm slump range
for 100mm slump=186+(6/100)*186=197 litres
As superplasticizer is used,the water content is reduced upto 30%
Based on trials waterr content reduction of 29% is achieved
with plasticizer
Hence arrived water content=197*0.71=140 litres
step:6
calculation of cement content
Water-cement ratio=0.4
cementatious material(cement+fly ash)=140/0.4=350k g/m3
In table 5 of IS 456-2000,the cement content for severe
exposure=320k g/m3
350k g/m3>320k g/m3
Hence ok,
To proportion the mix containing flyash the following steps are
suggested:
a.The percentage of flyash need to be decided based on
project requirment and quality of materials.
b.In some cases increase in cementatious materials can be warrned.
Increase in cementatious materials content and its percentage
may be based on experience and trial
in this increase of 10%
cementatious material content is cosidered.
Cementatious material content=
350*1.1=385k g/m3
water content=140k g/m3
so,water-cement ratio=140/385=0.364
Flyash at 30% total cementatious material content
=35-30%=115k g/m3
Cement(opc)=385-115=270k g/m3
Saving of cement while using flyash=350-270
=80k g/m3
fly ash being utilized=115k g/m3
step:7
proportion of volume of coarse aggregate and fine
aggregate and fine aggregate content
Feom table 3 of IS 1026:2009,volume
of coarse aggregate corresponding to 20 mm size aggregate
and fine aggregate(zone1) for water-cement ratio=0.6
In present case the water -cement ratiois 0.4
Therefore the volume of coarse aggregate needs
to be increased to decrease the fine aggregate content.
As the water-cement ratio is lowered by 0.1,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)
Hence the corrected value ofcoarse aggregate for the
water-cement ratio=0.64
(If coarse aggregate is not of angular type,then also
the volume of coarse aggregate may be required to be increased
suitably,based on experience)
For pumpable concrete,these are reduced by 10%
Volume of coarse aggregate=0.64*0.9=0.576
Volume of fine aggregate=1-0.576=0.424
step:8
mix calculation
Mix calculation per unit volume of concrete:
a.Volume of concrete=1m^3.
b.Volume of cement=(mass of cement/specific gravity
of cement)*/1000=
(270/3.15)*1/1000=0.086m3
c.Volume of flyash=(mass of flyash/specific gravityof fly ash)
*/1000=(115/2.2)*1/1000=
0.052m3
d.Volume of water=(mass of water/specific gravity of water)*/1000
(140/1)*1/1000=0.140m3
e.Volume of chemical admixture=(Mass of admixture/specific gravity
of admixture)*1/1000 =
(7.6/1.14)*1/1000=0.006m3
f.Volume of aggregate(Fine aggregate and coarse)=a-(b+c+d+e)
1-(0.086+0.052+0.140+0.006)=0.716m3
g.Mass of coarse aggregate=f*volume of coarse aggregate*specific
gravity of coarse aggegate *1000
=
0.716*0.567*2.74*1000=
1130k g/m3
h.Mass of fine aggregate=f*Volume of fine aggregate*specific
gravity of fine aggregate*1000=
0.716*0.424*2.74*1000=
831k g/m3
step :9
mix proportion
Cement=270k g/m3
Flyash=115k g/m3
water=140k g/m3
Fine aggregate=831k g/m3
Coarse aggregate=1130k g/m3
Chemical admixture=7k g/m3
Water-cement ratio=0.364
Mix ratio 1:2.15:2.94
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 rewarked 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 correspionding strengths shall be plotted to work out the
mix proportions for the given target strength for field trials.However durability
shall be met.
Result:The mix design for M35 grade of concrete with flyash is 1:2,15:2.94
Mix design of M50 grade concrete:
Aim :Mix design of M50 grade concrete
procedure:
step:1
stipulation for proportioning
a.Grade designation:M50
b.Type of cement:OPC grade 43 conforming to IS 8112
c.Maximum naminal size of aggregate:20mm
d.Minimum cement content:320k g/m3
e.Maximum -water cement ratio:0.45(table:5 IS 456-2000,
based on exposure condition)
f.Workability:100mm,slump value of pumpable concrete
g.Exposure condition:Severe(for reinforced concreter)
h.Metho of concrete placing:pumping
i.Degree of supervision:good
j.Type of aggregate:Crushed angular aggregate
k.Maximum cement content:450 kg/m^3.
l.Chemical admixture type:Superplasticizer.
step:2
Test data for materials
a.Cement used:OPC 43 grade confirming to IS 8112
b.Specific gravityof cement:3.15
c.Chemical admixture:Superplasticizer conforming to IS
9103
d.Specific gravity of:
Coarse aggregate:2.74
Fine aggregate:2.74
e.Water obsorption:
Coarse aggregate:0.5%
Fine aggregate:1%
f.Free surface moisture
Coarse aggregate:Nil
Fine aggregate:Nil
g.Seive analysis
Coarse aggregate:
IS Analysis %of |
Seive of coarse different | size aggregate fraction | Remarks
(mm) fraction |
I II I II Combined | conferming 20 100 60 40 100 | to
100 | table 2
10 0 0 28.5 | of
71.2 28.5 | IS 383
4.75 3.7 |
9.4 3.7 |
2.36 |
0 |
____________________________________________________|_______
Fine aggregate:Confirming to grading zone 1of table 4 IS 383 .
step:3
To find target mean strength for proportioninig:
Target mean strength,f'ck=fck+1.65s
=50+1.65*5
=58.25 N/m m2
fck=Characteristic strength
s=Standard deviation
step:4
Selection of water cement ratio
From table :5 of IS 456-2000,by exposure condition
Here severe condition is considared,
Maximum water -cement ratio=0.45
Based on experience water -cement ratio=0.4
0.4<0.45,hence ok.
step:5
Selection of water content
Maximum water content for 20mm aggregate
=186litres(table 2 of IS 1026:2009) for
25mm to 50mm slump range
For 100mm slump =186+(6/100)*186=197 litres
As superplasticizer is used,the water content is reduced
upto 30%
Based on trials water content reduction of 29% is achieved
with plasticizer
Hence arrived water content=197*0.71=140 litres
step:6
calculation of cement content
Water-cement ratio =0.4
Cementcontent=140/0.4=350 k g/m3
In table 5 of IS456-2000,the cement content
for severe exposure=320k g/m3
350k g/m3>320k g/m3
Hence ok.
step:7
proportion of volume of coarse aggregate and fine
aggregate content
corresponding to 20mm size aggregate and fine aggregate(Zone1)
for water-cement ratio is 0.6
In present case the water -cement ratio is 0.4
Therefore the volume of coarse aggregate needs to be increased
to decrease the fine aggregate content.
As the water-cement ratio is lowered by 0.1,the proportion of
volume of coarse aggregate is increased by 0.02(at the rate of +/-
0.01for every +/-0.05 change in water cement ratio)
Hence the corrected value of coarse aggregate for the
water cement ratio=0.64
(If coarse aggregate is not of angular type,then also
the volume of coarse aggregate may be required to be
increased suitably,based on experience)
For pumpable concrete,these are reduced by 10%
Volume of coarse aggregate=1-0.576
=0.424
step:8
Mix calculation
For unit volume of concrete
a.Volume of concrete=1m3
b.Volume of cement=(Mass of cement/Specific gravity of
cement)*1/1000
= (350/3.15)*1/1000=0.111m3
c.Volume of water=(Mass of water/Specific gravity of water)*1/1000
=(140/1)*1/1000
=0.140m3
d.Volume of chamical admixture=(Mass of admixture/Specific gravity of
admixture)*1/1000
=(7.6/1.145)*1/1000
=0.006m3
e.Volume of aggregate (fine adn coarse)=a-(b+c+d)
1-(0.111+0.140+0.006)=0.743m3
f.Mass of coarse aggregate=ex volume of coarse aggregate
x specific gravity of coarse aggregate x 1000
=0.743*0.576*2.74*1000=1173k g/m3
g.Mass of fine aggregate=e*volume of fine aggregate*
Specific gravity of fine aggregate*1000
=0.743*0.424*2.74*1000=863k g/m3
step:9
Mix proportion
Cement=350k g/m3
Water=140kg/m^3
Fine aggregate=863k g/m3
Coarse aggregate=1173k g/m3
Chemical admixture=7k g/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)shell 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 ratio for M50 grade concrete is1;2.2.46:3:35
Tables used are:
1.Table:8 of IS 10262
Grade Standard deviation(s)
N/mm^2
M 10 3.5
M 15 3.5
M 20 4
M 25 4
M 30 5
M 35 5
M40 5
M45 5
M50 5
+1N/mm^2 where there is deviation,when not periodically
checked for warkability and strength.
2.Table :5 of IS 456-2000
Base on exposure condition
plain concrete reinforced Concr
sl.no Exposure min max min min max min
cement water- grade cement free grade
content cement of concrete content w/c of
( k g/m3) ratio (k g/m3) ratio concrete
_________________________________________________________________________________
1. Mild 220 0.6 _ 300 0.55 M20
2. Modurate 240 0.6 M15 300 0.5 M25
3. severe 250 0.5 M20 320 0.45 M30
4. Very 260 0.45 M20 340 0.45 M35
severe
5. Extreme 280 0.4 M25 360 0.4 M40
3.Table :2 of IS 10262:2009
Sl.no Nominal Maximum
maximum size water
aggregate(mm) content(kg)
1. 10 208
2. 20 186
3. 40 165
4.Table :3 IS 1026:2009
Volume of coarse aggregate per unit volume of
total aggregate for different zones of fine aggregate
Nominal Zone Zone Zone Zone
Sl.No maximum size of IV III II I
aggregate
1. 10 0.5 0.48 0.46 0.44
2. 20 0.66 0.64 0.62 0.6
3. 40 0.75 0.73 0.71 0.69