Project on Concrete Mix Design for various grades of Concrete
Q1) CONCRETE MIX DESIGN FOR M35 GRADE CONCRETE WITH USE FLY ASH:
Answer:Stipulation for proportioning:
a)Grade of designation:M35.
b)Type of cement:OPC 53Grade.
c)Maximum size of aggregate:20mm.
d)Minimum cement content:320kg/m^3.(From table-5 of IS 456:2000)
e)Maximum water cement ratio:0.45(From table-5 of IS 456:2000)
f)Workability:100mm slump.(Slump value for pumpeable concrete)
g)Explosive condition:Severe(For reinforced concrete)
h)Method of concrete placing:pumping
i)Degree of supervision:Good
j)Type of aggregate:Crushed angular aggregate
k)Maximum cement content:450kg/m^3.
l)Chemical damixture:super plasticizer.
2)Test data for material:
Cement used:53 grade.
Specific gravity of cement:3.15
Specific gravity of fly ash:2.2
Specific gravity of coarse aggregate:2.74
Specific gravity of coarse aggregate:2.74
Water absorption of coarse aggregate:0.5%
Water absorption of fine aggregate:1%.
Sieve analysis for coarse aggregate:Conforming to table-2 of IS 383.
Sieve analysis for fine aggregate:Conforming to table-4 of grading zone-2 of IS 383.
3)Target strength of concrete:
f`ck=fck+1.65S. where:f`ck=Target compressive strength for 28days.
fck=Characteristics ofcompressive strength at 28 days,
S=Standard deviation.(From table-1 of IS 10262:2009)
f`ck=35+1.65(5)
=43.25N/mm^2.
4)Selection of water cement ratio:water cement ratio from table-5 of IS 456:2000.
The maximum water cement ratio is 0.45.
the w/c ratio not over than 0.45 then take 0.43. 0.43<0.45.
The water cement ratio=0.43
5)Selection of water content:It is taken from table-2 of IS 10262:2009,For 20mm aggregate.
186Liters for 25 to 50mm slump.
to increase the 3% for every extra 25%
the 75mm slump: 186+(186 X 3/100)
=191.58KG/M^3.
water content for 100mm slump
maximum water content is 186kg/m^3 for slump 25 to 50mm, to increase the slump value every 25% to increase the water content 3%.
for slump 100mm
water content=186+6 X 186/100
=197.16=197liters.
If the super plasticizers are used the water content can be reduced up to 20% and above
Water content=197 X 0.8=157.6=158Liters.
6)Selection of Cement and Fly ash content:water cement ratio=0.43
Cement content=water content/water cement ratio
=197/0.43
=458.139=458kg/m^3.
If super plasticizer is used the water content can be reduced of 20% and above.
=197 X 0.8=158
Cement content=158/0.43
=367.44=368kg/m^3.
The cementitious content has to be increased in order to attain good workability and strength.to increasing cementitious content by 10%.
Final cementitious content=368 X 1.10
=395KG.
The minimum cement content for table-5 IS 456:2000 is 340kg.
Hence 395>340kg/m^3.
The new water cement ratio=158/395
=0.4
Fly ash content is taken as 30% of total cement content=395 X 0.3
=118.5Kg/m^3.
Cement required=Final cement content - fly ash content
=395-118.5
=276.5kg/m^3.
7)Proportion of volume of coarse aggregate and fine aggregate content:From table-3 IS 10262:2009,
volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate for water cement ratio is 0.50.Is in the present case water cement ratio is 0.43.
The volume of coarse aggregate needs to be increased to decreases the fine aggregate content.
The proportion of volume of coarse aggregate is increased by 0.2(at the rate of -/+0.01 for every+or-0.05 change in water cement ratio.
For pumpeable concretevalues should bereduced upto 10%.
Volume of coarse aggregate=0.62 X 0.9=0.558
Volume of fine aggregate=1-0.558=0.442
8)Mix calculations:
a)Volume of concrete:1M^3
b)Volume of cement=Mass of cement/specific gravity of cement X 1/1000.
=276.5/3.15 X 0.001
=0.087M^3.
c)Volume of fly ash= mass of fly ash/specific gravity of fly ash X 1/1000.
=118.5/2.2 X 0.001
=0.053
d)Volume of water=Mass of water/specific gravity of water X 1/1000.
=158/1 X 0.001
=0.158M^3.
e)Volume of chemical admixture=mass of chemical admixture/specific gravity of admixture x 1/1000.
To add 2% of cementinuous material=(mass of cement X 2/100)
=(368 X 2/100)
=7.36
=7.36/1.145 X 0.001
=0.0064M^3.
f)Volume of aggregate(Coarse aggregate and Fine aggregate)=(a-(b+c+d+e))
=(1-(0.087+0.053+0.158+0.0064))
=(1-0.3044)
=0.6956m^3
g)Mass of coarse aggregate= f X volume of coarse aggregate X specific gravity of coarse aggregate X 1000.
=0.6956 X 0.558 X 2.74 X 1000
=1063.516kg/m^3.
h)Mass of fine aggregate= f X volume of fine aggregate X specific gravity of fine aggregate X 1000.
=0.6956 X 0.442 X 2.74 X 1000
=842.42kg/m^3.
9)Mix proportions:
Cement=276.5kg/m^3
Fly ash=118.5kg/m^3
coarse aggregate=1063.516kg/m^3
Fine aggregate=842.420kg/m^3
water=158kg/m^3
Chemical admixture=7.18kg/m^3
Water cement ratio=0.43
10)mix proportion =1:2.132:2.692.
Q2) CONCRETE MIX DESIGN M50 GRADE CONCRETE WITHOUT USE FLY ASH:
Answer:Stipulation for proportioning:
a)Grade of designation:M50.
b)Type of cement:OPC 53Grade.
c)Maximum size of aggregate:20mm.
d)Minimum cement content:320kg/m^3.(From table-5 of IS 456:2000)
e)Maximum water cement ratio:0.45(From table-5 of IS 456:2000)
f)Workability:100mm slump.(Slump value for pumpeable concrete)
g)Explosive condition:Severe(For reinforced concrete)
h)Method of concrete placing:pumping
i)Degree of supervision:Good
j)Type of aggregate:Crushed angular aggregate
k)Maximum cement content:450kg/m^3.
l)Chemical damixture:super plasticizer.
2)Test data for material:
Cement used:53 grade.
Specific gravity of cement:3.15
Specific gravity of coarse aggregate:2.74
Specific gravity of coarse aggregate:2.74
Water absorption of coarse aggregate:0.5%
Water absorption of fine aggregate:1%.
Sieve analysis for coarse aggregate:Conforming to table-2 of IS 383.
Sieve analysis for fine aggregate:Conforming to table-4 of grading zone-2 of IS 383.
3)Target strength of concrete:
f`ck=fck+1.65S. where:f`ck=Target compressive strength for 28days.
fck=Characteristics ofcompressive strength at 28 days,
S=Standard deviation.(From table-1 of IS 10262:2009)
f`ck=50+1.65(5)
=58.25n/mm^2.
4)Selection of water cement ratio:water cement ratio from table-5 of IS 456:2000.
the w/c ratio not over than 0.45 then take 0.43. 0.43<0.45.
The water cement ratio=0.43
5)Selection of water content:It is taken from table-2 of IS 10262:2009,For 20mm aggregate.
186Liters for 25 to 50mm slump.
to increase the 3% for every extra 25%
the 75mm slump: 186+(186 X 3/100)
=191.58KG/M^3.
water content for 100mm slump
maximum water content is 186kg/m^3 for slump 25 to 50mm, to increase the slump value every 25% to increase the water content 3%.
for slump 100mm
water content=186+6 X 186/100
=197.16=197liters.
If the super plasticizers are used the water content can be reduced up to 20% and above
Water content=197 X 0.8=157.6=158Liters.
6)Selection of cement content:water cement ratio=0.43
Cement content=water content/water cement ratio
=197/0.43
=458.139=458kg/m^3.
If super plasticizer is used the water content can be reduced of 20% and above.
197 X 0.8=158
Cement content=158/0.43
=367.44=368kg/m^3.
7)Proportion of volume of coarse aggregate and fine aggregate content:From table-3 IS 10262:2009,
volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate for water cement ratio is 0.50.Is in the present case water cement ratio is 0.43.
The volume of coarse aggregate needs to be increased to decreases the fine aggregate content.
The proportion of volume of coarse aggregate is increased by 0.2(at the rate of -/+0.01 for every+or-0.05 change in water cement ratio.
For pumpeable concretevalues should bereduced upto 10%.
Volume of coarse aggregate=0.62 X 0.9=0.558
Volume of fine aggregate=1-0.558=0.442
8)Mix calculations:
a)Volume of concrete:1M^3
b)Volume of cement=Mass of cement/specific gravity of cement X 1/1000.
=368/3.15 X 0.001
=0.116M^3.
c)Volume of water=Mass of water/specific gravity of water X 1/1000.
=158/1 X 0.001
=0.158M^3.
d)Volume of chemical admixture=mass of chemical admixture/specific gravity of admixture x 1/1000.
To add 2% of cementinuous material=(mass of cement X 2/100)
=(368 X 2/100)
=7.36
=7.36/1.145 X 0.001
=0.0064M^3.
e)Volume of aggregate(Coarse aggregate and Fine aggregate)=(a-(b+c+d))
=(1-(0.116+0.158+0.0064))
=(1-0.2804)
=0.7196m^3
f)Mass of coarse aggregate= e X volume of coarse aggregate X specific gravity of coarse aggregate X 1000.
=0.7196 X 0.558 X 2.74 X 1000
=1100.210kg/m^3.
g)Mass of fine aggregate= e X volume of fine aggregate X specific gravity of fine aggregate X 1000.
=0.7196 X 0.442 X 2.67X 1000
=849.228kg/m^3.
9)Mix proportions:
Cement=368kg/m^3
coarse aggregate=1100.210kg/m^3
Fine aggregate=849.228kg/m^3
water=158kg/m^3
Chemical admixture=7.18kg/m^3
Water cement ratio=0.43
10)mix proportion =1:2.307:2.989.