Construction Technology_Concrete Mix Design_Project 1
MIX DESIGN for M35 GRADE CONCRETE USING FLYASH
i)
a. Grade designation : M35
b. Type of cement :OPC 43 grade conforming to IS 8112
c. Type of mineral admixture:Flyash conforming to IS3812 (part 1)
d.Maximum nominal size of aggregate : 20mm
e.Minimum cement content : 320 kg/mm^3 (from table of IS456:2000-exposure)
f. Maximum water-cement ratio : 0.45 (From table 5 of IS 456:2000-exposure condition)
g.Workability: 100mm (slump value for pumpable concrete)
h.exposure condition : severe (for reinforced concrete)
i.method of concrete placing: pumping
j. degree of supervision: Good
k.Type of aggregate: Crushed angular aggregate
l.Maximum cement content : 450kg/m^3
m.Chemical admixture type: Superplasticizer conforming to IS 9103
ii)
*Specific gravity of:
coarse aggregate: 2.74
fine aggregate: 2.74
*Water absorption:
coarse aggregate: 0.5%
fine aggregate: 1.0%
*Free surface moisture:
coarse aggregate: nil
fine aggregate: nil
*Sieve analysis
coarse aggregate: Conforming to table 2 of IS 383
fine aggregate: Conforming to grading zone 1 of table 4 of IS 383
iii) Target strength for mix proportioning:
f'ck=fck+1.65xS
from Table 1 of IS 10262:2009, standard deviation ,S=5N/mm^2
Therefore,Target strength= 35+1.65x5=43.25N/mm^2
f'ck= Target average compressive strength at 28days
f ck= characteristic compressive strength at 28days
iv) selection of water cement ratio:
from table 5 of is IS456:2000 for severe exposure,maximum water-cement ratio=0.45
Based on experience,adopted water cement ratio is 0.40
0.40<0.45,hence O.K
v) selection of Water content
from table 2 of IS 10262:2009,maximum water content for 20mm aggregate=186litre(for 25mm to 50mm slump range)
estimated water content for 100mm slump=186+6/100*186=197litre.
As superplasticizer is used,the water content can be reduced up to 20% and above
Based on the trails water content can be reduced upto 29% is achieved with plasticizer.
Hence the water content = 197*0.71=140 litre
vi) calculation of cement content
Water cement ratio =0.4
cement content= 140/0.4=350kg/m^3
from the table 5 of IS 456 minimum cement content for severe exposure condition=320kg/m^3
350kg/m^3>320kg/m^3,hence ok
vii)Now to proportion a mix containing flyash the following steps are suggested
a. The % of flyash needs to be decided based on project requirement and quality of materials
b. In some cases increase in cementitious materials can be warranted.increase in cementitious content and its percentage based on experience and trail (This example with increase of 10% cementitious material)
Cementitious material content = 350 * 1.10= 385kg/m^3
water content = 140 kg/m^3
so, water cement ratio = 140/385= 0.364
FLYASH @ 30% total cementitious 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
flyash being utilized= 115kg/m^3
viii) Proportion of volume of coarse aggregate and fine aggregate
From table 3 of IS 10262:2009, Volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (zone 1) for water cement ratio = 0.6
water cement ratio is 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 is increased by 0.02
corrected volume of coarse aggregate for water cement ratio of 0.40=0.62
For pumpable concrete these values are reduced by 10%
therefore,volume of coarse aggregate= 0.62x0.9=0.56
volume of fine aggregate=1-0.56=0.44
viii) mix calculations:
a. volume of concrete= 1m^3
b. volume of cement =
(mass of cement/specific gravity of cement)x(1/1000)=(270/3.15)x1/1000=0.086m^3
c. volume of flyash =
(mass of flyash/specific gravity of flyash)x(1/1000)=(115/2.2)x1/1000=0.052m^3
d. volume of water =
(mass of water/specific gravity of water)x(1/1000)=140/1x1/1000=0.140m^3
e. volume of chemical admixture =
(mass of chemical admixture/specific gravity of admixture)x(1/1000)=7.6/1.145x1/1000=0.006m^3
f.volume of aggregates(F.A & C.A)= (a-(b+c+d+e))=(1-(0.086+0.052+0.140+0.006))=0.716m^3
f. mass of coarse aggregate= e x (volume of coarse aggregate) x (specific gravity of coarse aggregate)x1000= 0.716x0.56x2.74x1000=1098kg/m^3
g. mass of fine aggregate= e x (volume of fine aggregate) x (specific gravity of fine aggregate)x1000
= 0.743x0.44x2.74x1000=863kg/m^3
ix) Mix proportions for trail number 1:
cement = 270kg/m^3
Flyash = 115kg/m^3
Water = 140kg/m^3
fine aggregate = 863kg/m^3
coarse aggregate = 1098kg/m^3
chemical admixture = 7kg/m^3
water cement ratio = 0.364
Trail mix ratio = 1:2.24:2.85
MIX DESIGN for M50 GRADE CONCRETE
i)
a. Grade designation : M50
b. Type of cement :OPC 53 grade conforming to IS 8112
c. Maximum nominal size of aggregate : 20mm
d. Minimum cement content : 320 kg/mm^3 (from table of IS456:2000-exposure)
e. Maximum water-cement ratio : 0.45 (From table 5 of IS 456:2000-exposure condition)
f. Workability: 100mm (slump value for pumpable concrete)
g. exposure condition : extreme (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 admixture type: Superplasticizer conforming to IS 9103
ii)
*Specific gravity of:
coarse aggregate: 2.74
fine aggregate: 2.74
*Water absorption:
coarse aggregate: 0.5%
fine aggregate: 1.0%
*Free surface moisture:
coarse aggregate: nil
fine aggregate: nil
*Sieve analysis
coarse aggregate: Conforming to table 2 of IS 383
fine aggregate: Conforming to grading zone 1 of table 4 of IS 383
iii) Target strength for mix proportioning:
f'ck=fck+1.65xS
from Table 1 of IS 10262:2009, standard deviation ,S=5N/mm^2
Therefore,Target strength= 50+1.65x5=58.25N/mm^2
iv) selection of water cement ratio:
from table 5 of is IS456:2000 for severe exposure,maximum water-cement ratio=0.45
Based on experience,adopted water cement ratio is 0.40
0.40<0.45,hence O.K
v) selection of Water content
from table 2 of IS 10262:2009,maximum water content for 20mm aggregate=186litre(for 25mm to 50mm slump range)
estimated water content for 100mm slump=186+6/100*186=197litre.
As superplasticizer is used,the water content can be reduced up to 20% and above
Based on the trails water content can be reduced upto 29% is achieved with plasticizer.
Hence the water content = 197*0.71=140 litre
vi) calculation of cement content
Water cement ratio =0.4
cement content= 140/0.4=350kg/m^3
from the table 5 of IS 456 minimum cement content for severe exposure condition=320kg/m^3
350kg/m^3>320kg/m^3,hence ok
vii) Proportion of volume of coarse aggregate and fine aggregate
From table 3 of IS 10262:2009, Volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (zone 1) for water cement ratio = 0.6
water cement ratio is 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 is increased by 0.02
corrected volume of coarse aggregate for water cement ratio of 0.40= 0.62
For pumpable concrete these values are reduced by 10%
therefore,volume of coarse aggregate= 0.62x0.9= 0.56
volume of fine aggregate=1-0.56= 0.44
viii) mix calculations:
a. volume of concrete= 1m^3
b. volume of cement =
(mass of cement/specific gravity of cement)x(1/1000)=350/3.15x1/1000=0.111m^3
c. volume of water =
(mass of water/specific gravity of water)x(1/1000)=140/1x1/1000=0.140m^3
d. volume of chemical admixture =
(mass of chemical admixture/specific gravity of admixture)x(1/1000)=7.6/1.145x1/1000=0.006m^3
e. volume of aggregates(F.A & C.A)= (a-(b+c+d))=(1-(0.111+0.140+0.006))=0.743m^3
f. mass of coarse aggregate= e x (volume of coarse aggregate) x (specific gravity of coarse aggregate)x1000=0.743x0.56x2.74x1000=1140kg/m^3
g. mass of fine aggregate= e x (volume of fine aggregate) x (specific gravity of fine aggregate)x1000
=0.743x0.44x2.74x1000=896kg/m^3
ix) Mix proportions for trail number 1:
cement = 350kg/m^3
water = 140kg/m^3
fine aggregate = 896kg/m^3
coarse aggregate = 1140kg/m^3
chemical admixture = 7kg/m^3
water cement ratio = 0.4
trail mix ratio = 1:2.56:3.26
tHANk yOU