Project on Concrete Mix Design for various grades of Concrete
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I STIPULATIONS FOR PROPORTIONING
OF M35 GRADE CONCRETE:
A) Grade Designation : M35
B) Type of Cement: OPC 53
C) Type of Admixture: Fly ash
D) Maximum Nominal: Size of Aggregate
20mm
E) Minimum Cement Content: 340kg Table
5-IS456
F) Maximum Cement Content: 450kg As per
code
G) Partial replacement of cement by Fly ash:
30% as per requirement
H) Maximum W/C ratio: 0.45 Table 5-IS456
I)Workability: 100mm
j)Chemical Admixture: PCS Type
k) Exposure conditions: very severe(for
reinforced conctere)
l) Method of concrete placing : pumping
M) Degree of supervision: good
N) Type of aggregate: Crushed
angular aggregates.
O) Maximum cement
content: 450kg/m3
II. TEST DATA FOR MATERIALS:
A) Cement Used: OPC 53 Confirming to
IS8112
B) Specific Gravity of Cement: 3.15 Test - IS:
2720
C) Mineral Admixture Fly ash: Confirming to
IS12089
D) Specific Gravity of Fly ash: 2.90
E) Chemical Admixture a: Super plasticizer
0.6% IS9103
F) Specific Gravity of Test - IS 2386
Coarse Aggregate: 2.74
Fine Aggregate: 2.74
G) Water Absorption Test – IS 2386
Coarse aggregate: 0.5 %
Fine aggregate: 1%
H) Sieve Analysis Test - IS 2386
Coarse aggregate Confirming toTable 2-
IS383
Fine aggregate Zone Il Confirming to
Table 4-1S383
III. TARGET STRENGTH FOR MIX
PROPORTIONS OF M35 GRADE
CONCRETE:
Strength of the concrete may deviate
slightly depends on the quality of the
material, method of mixing and construction
practices. Hence target strength (Fck) should
be higher than the required strength of the
concrete (fck). Value of standard deviation(s)
for different grade of concrete is given in
Table 1 of IS456.
Fck = fck+1.65s "S" from Table1-IS10262
Fck = 35+1.65x5
Fck = 43.25 N/mm^2
IV. SELECTION OF WATER-CEMENT RATIO:
From the table the maximum water-
cement ratio for different grade of concrete is
given in Table 5-IS456. You can reduce the
water-cement ratio based on your
requirements. Water-cement ratio directly
affects the strength of the concrete.
Maximum W/C ratio =0.45 Table 5-IS456
Adopted W/C ratio =0.45
V. SELECTION OF WATER CONTENT
Maximum Water Content =186 L Table
2-IS10262
Above water-content is for 25 to 50mm
slump, but the slump we require is 100mm.
hence we need to increase the water content
to get the required slump for good workability. Clause 4.2 of IS1026 suggests an
increase of 3% of water content from its
original value for every increase of 25mm.
Here we have a 50mm increase in the water
content hence we have to increase the water
content by 6 %.
Water-content for 100mm Slump
=186+0.06*186)
=197.16 L
Since superplasticizers are used water
content can be reduced to get good strength
of concrete. Percentage of reduction of water
depends on the type of superplasticizers
used in the concrete.
Percentage of Reduction in water content
=20%
Water content requirement after SP =198 –
(0.20*198)
=157.73
Adopted Water Content =160 L
VI. CALCULATION OF CEMENT AND FLY
ASH CONTENT:
Water Cement Ratio =0.45
Total Cementitious (Cement +Fly ash)
requirement = Water Content/
WaterCement ratio:
=160/0.45
=355.55 kg
Since Fly ash is used the amount of
Cementitious content (Cement+Fly ash) shall
be increased to get good workability and
strength. the percentage of increase
depending on experience and research. Here
we increased the cementitious content by 1.1
%.
Final Cementitious :
Content (Cement+Fly ash) = 356*1.1
=391.6 kg
Minimum Cement Content:
required for 'very severe' exposure = 340kg
Table 5-1S 456
Adopted Cementious content =391.6 kg >
340kg
Fly ash content requirement = 391.6 * 0.30
30% replacement
= 117.48
Cement Content requirement =Cementious
content - Fly ash
=391.6-117.48
= 274.12
Calculation of Super Plasticiers @ 0.6 percent
to the mass of cementitious content
= 391.6*(0.6/100)
= 2.35 kg
VII COARSE AND FINE AGGREGATE:
Coarse Aggregate ratio = 0.62 Table3-
IS10262
(For W/C =0.5)
Coarse Aggregate ratio for 0.45 w/c ratio =
0.63 (adding 0.01 for every
decrease 0.05)
Final Fine Aggregate ratio = 0.37 (1-0.63) =
0.37
VIII MIX CALCULATIONS OF M35 GRADE
CONCRETE:
A) Volume of Concrete = 1 cu.m
B) Total Volume of Cement = Mass
ofCement/Specific gravityof cement*1/1000
= 275/(3.15*1000)
= 0.087 cu.m
C) Total Volume of Fly ash = Mass of fly
ash/Specific gravity of flyash*1/1000
= 118/(2.5*1000)
= 0.041 cu.m
D) Volume of Water =Mass of water/Specific
gravityofwater*1/1000
= 160/(1*1000)
= 0.160 cu.m
E) Volume of Superplasticizers =
Superplasticizers /(S.G*1000)
= 2.35/(1.12*1000)
= 0.002 cu.m
F) Total Aggregates requirement = A-
(B+C+D+E)
=1 -(0.087
+0.041+0.160+0.002)
=0.71 cu.m
G) Coarse Aggregate (C.A) = F *volume of C.A
* S.G * 1000
= 0.71*0.63 *2.74
*1000
= 1225.6 kg
1) Fine Aggregate (F.A) = F *volume of F.A*
S.G* 1000
= 0.71*0.37*2.74 *1000
=719.8 kg
Cement Flyash Sand Aggregate Water and
Superplasticizer needed for M35 grade
concrete
IX.MIX PROPORTIONS FOR TRIAL NUMBER
1. Cement:275 kg
2. Flyash: 118 kg
3. Fine Aggregate: 720 kg
4. Coarse Aggregate (20mm): 1226 kg
5. WATER:160 L
6. PCE based SuperPlasticizer: 2 L
Therefore Mix Ratio of M35 Grade
concrete by weight is Cement: Flyash: F.A:
C.A: Water = 1:0.4:2.6:4.46:0.58
X. The slumpshall be measured and the water
content and dosage of admixture shall be
adjusted for acheving the required slump
work on trial. The mix proportion shall be
reworked for the actual water content and
checked for durablity requiremets.
XI. Two more trials having variations of 10%
of water-cement ratio is clause X shall be
carried out a graph between the three water -
cement ratio and corresponding strength
shall be plotted to work out the mix
proportions for the given target strength for
the trials, and also durability is also shall be
met.
1. STIPULATIONS FOR
PROPORTIONING:
a). Grade Designation = M50
b). Type of cement = OPC 53 grade
conforming to IS 8112
c). Max nominal size of aggregates = 20MM
d). Minimum cement content = 320kg/m^3
(from table 5 IS 456:2000 exposure
condition)
e). Max water-cement ratio = 0.45 (from
table 5 IS 456:2000 exposure condition)
f).workability = 100mm (Slump value for
pumpable concrete)
g). Exposure condition = very severe (for
reinforced concrete)
h).Method pf concrete placing = Pumping
i). Degree of supervision = good
j). Type of aggregates = crushed angular
aggregates
k).Maximum cement content = 450kg/m^3
1) Chemical admixture = super plasticizer
I.TEST DATA FOR MATERIAL:
a). cement used = OPC 53 conforming to IS
8112
b).specific gravity of cement = 3.15
c).chemical admixture = super plasticizer
conforming to IS 9103
d).specific gravity of course aggregate = 2.74
specific gravity of fine aggregate= 2.74
e).water absorption of course aggregates =
0.5%,
water absorption of fine aggregate= 1.0%
f).Free surface moisture for course aggregate
NIL,
free surface moisture for fine aggregare = NIL
g).Sieve analysis- course aggregate
conforming to table 2 of IS 383
h) fine aggregate conforming to grading
zone 1 of table 4 of IS 383
III. TARGET MEAN STRENGTH FOR MIX
PROPORTIONING:
f'ck = fck +1.65S (from table 1 IS 10262:2009)
S=5N/mm2
= 50+1.65*5 = 58.25 N/mm^2
IV SELECTION OF WATER CEMENT
RATIO:
from table 5 IS 456:2000 max w/c ratio =
0.45
Based on experience adopt w/c ratio = 0.40
0.40 < 0.45, hence OK
V. SELECTION OF WATER CONTENT:
from table 2 of IS 10262:2009, water
content for for 20 mm aggregate = 186 litre,
for 25 to 50 mm slump range for the disered
workability oher than 50mm slump the water
required may increased or decreased by 3%
for each increase or decrease of 25mm
slump.
Hence,
Estimated water content for 100 mm slump
= 186+6/100 *186 = 197 litres
As super plasticizer is used, the water content
can be reduced by 30%
Based on water content reduction of 29% is
achived with plasticizer
Hence the arrived water content = 197* 0.71=
140 litres
VI. CALCULATION OF CEMENT CONTENT:
w/c ratio = 0.40
cementitious material (cement)= 140/0.40=
350kg/m^3
from table 5 of IS 456:2000 min cement
content for severe exposure condition =
320kg/m^3
350kg/m^3 >320kg/m3, Hence OK.
Proportion of volume of course aggregate
and fine aggregate.
VIL. PROPORTION OF VOLUME OF COARSE
AGGREGATE AND FINE AGGREGATE
CONTENT:
From table 3 of IS 10262:2009, volume of
course aggregate corresponding to 20mm
size aggregate and fine aggregate (Zone 1) w/c
ratio = 0.6
In present case w/c ratio = 0.40
Therefore, volume of course aggregate needs
to be increased to decreased fine aggregate
content
As w/c ratio is lower by 0.10, the proportion
of volume of course aggregate is increased by
0.02 at the water of -/+0.01 for every -
/+0.05 change in w/c ratio
Volume of course aggregate for w/c ratio of
0.4 =0.62
For pumpable concrete for these values are
reduced by 10%
volume of course aggregate=0.62*0.9=0.56
volume of aggregate content=1-0.56=0.44
VIL. MIX CALCULATION:
1. volume of concrete= 1m^3
2. volume of cement= mass of
cement/specific gravity of cement*1/1000
= 350/3.15*1/1000=0.111m^3
3. volume of water= mass of water/specific
gravity of water*1/1000
140/1*1/1000=0.140m^3
4. volume of chemical admixture = mass of
chemical admixture/specific gravity of
chemical admixture*1/1000
=7.6/1.145*1/1000=0.006m^3
5. volume of aggregate(Fine aggregate &
Course aggregate)=(a-(b+c+d))
= (1-(0.111+0.140+0.006))
= 0.743m^3
6. Mass of course aggregate= e*volume of
course aggregate * specific gravity of course
aggregate*1000
=
0.743*0.56*2.74*1000
= 1140kg/m^3
7.Mass of fine aggregates e*volume of fine
aggregate * specific gravity of fine
aggregate*1000
0.743*0.44*2.74*1000
= 896kg/m^3
IX. MIX PROPORTION:
1. cement= 350kg/m^3
2. water= 140kg/m^3
3. fine aggregate= 896kg/m^3
4.course aggregate= 1140kg/m^3
5. chemical admixture= 7kg/m^3
6. w/c ratio= 0.4
7.water-cement ratio = 0.4
Trial mix ratio= 1:2.5:3.3
X. The slump shall be used measured and
the watr content and dosage of admixture
shal be adjusted for achieving the required
slump on trial. The mix proportioning shall be
reworked for the water content of actual
value and checked for durability
requirements.
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