Project on Concrete Mix Design for various grades of Concrete
Aim :
To estimate the Mix design for M35 grade concrete with fly ash is used a part of replacement for OPC by assuming the suitable data.
Introduction :
For Design mix of M35 grade concrete 20% Fly ash is partial replacement in the place of OPC.
For preperation of design mix following guideline or IS code are used.
IS code 10262 : 2019 for Mix design.
Is code 456 : 2000 for Exposure condition, minimum cement content and maximum water cement ratio.
IS code 4031 : 1968 water cement ratio for 7 days strength.
Procedure :
Mix proportioning of concrete using 20% fly ash is replacement for OPC
I. Stipulations for proportioning
a) Grade designation : M35
B) Type of cement : OPC 43 grade conforming to IS 8112
C) Type of mineral admixture : Fly ash conforming to IS 3812 part(1)
D)Maximum nominal size of aggregate : 20 mm
E)Minimum cement content : 340 kg/m3 (from table 5 of IS 456: 2000 Exposure condition)
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 : very 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 : 450 kg/m3
M)Chemical admixture type : Superplasticizer
II. Test data for materials:
a)Cement used for : OPC 43 grade conforming to IS 8112
b) Specific gravity of cement : 3.15
c)Fly ash : Conforming to IS 3812(part 1)
d) specific gravity of fly ash : 2.2
e)Chemical admixture : Superplaticizer conforming to IS 9103
f) Specific gravity of coarse aggregate : 2.74
Specific gravity of fine aggregate : 2.74
g)Water absorption
Coarse aggregate : 0.5%
Fine aggregate : 1.0%
h) free surface moisture
Coarse aggregate : NILL
Fine aggregate : NILL
i) Sieve analysis
Coarse aggregate : Zone 1 as per IS 383
Fine aggregate :Zone 1 as per IS 383
III. Target strength for Mix proportion
F'ck=Fck+1.65*S
from table 1 of IS 10262 : 2019 standard deviation S=5N/mm2
F'ck= 35+1.65*5
=43.25 N/mm2
IV. selection of water cement ratio
From table 5 of IS 456 : 2000 for ver sereve condition exposure, Maximum water cement ratio = 0.45
From IS 10262 : 2019 Free water cement ratio curve, maximum water cement ratio = 0.38
From IS 4031 : 1968 water cement ratio for 7 day strength, maximum water cement ratio =0.5
0.38<0.45 hence ok
Water cement ratio = 0.38
V. From table 2 of IS 10262 : 2019, maximum water content for 20 mm aggregate = 186 kg or lit ( 25 to 50 mm slump)
Estimate water content for 100mm slump = (186*6/100)+186
= 197 kg or lit
As superplasticizer is used, the water content can be reduce up to 30%
Based on trails water content reduce 29% ia achieved with plasticizer
Hence arrived water content = 197*0.71
=140 lit or kg
VI. Calculation of cement content
water cement ratio = 0.38
Cemntitious material (cement+fly ash content)=140/0.38
= 368 kg/m3
From table 5 of IS 456 minimum cement content for very severe exposure condition=340 kg/m3
368>340 kg
Hence ok
Now, to proportion a mix containing fly ash
a) The percentage of fly ash need to be quality of materials
b) In some case increase in cementitious material can be warranted. Increase in cementitious material content and it's percentage may be based on experience and trials ( In this design mix increase of 10% cementitious material)
Cementitious material content=368×1.10
= 405 kg/m3
Water content= 140 kg
So, water cement ratio= 140/405
= 0.346
Fly ash @ 20% total cementitious material content= 405×20%
=81 kg/m3
Cement OPC = 405-81
=324 kg/m3
Saving of cement while using fly ash= 368-324
=44 kg/m3
Fly ash being utilised=81kg/m3
VII. Proportion of volume of coarse agfregate and fine aggregate content:
Fro table 3 0f IS 10262 : 2019, volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (zone 1) for water cement ratio of 0.5=0.6
Therefore, corrected volume of coarse aggregate for water cement ratio of 0.38= 0.62
For pumpable concrete these values are reduced by 10%
therefore, volume of coarse aggregate = 0.62*0.9
= 0.56
volume of fine aggregate = 1- 0.56
= 0.44
VIII. Mix calculation
The mix calculation per unit volume of concrete as follows;
a) volume of concrete = 1 m3
b) volume of cement = ( Mass of cement/ Specific gravity of cement)*(1/1000)
=( 324/3.15)*(1/1000)
= 0.1 m3
c) volume of fly ash = ( Mass of fly ash/ Specific gravity of fly ash)*(1/1000)
=( 81/2.2)*(1/1000)
= 0.036 m3
d) volume of water = ( Mass of water/ Specific gravity of water)*(1/1000)
=( 140/1)*(1/1000)
= 0.14 m3
e) volume of chemical admixture= ( Mass ofchemical admixture/ Specific gravity of chemical admixture)*(1/1000)
=( 7.6/1.145)*(1/1000)
= 0.006 m3
f) Volume of aggregate (fine and coarse aggregate) = (a-(b+c+d+e))
= (1-(0.1+0.036+0.14+0.006))
= (1-0.282)
= 0.718 m3
g) Mass of coarse aggregate = f*volume of coarse aggregate *specific gravity of coarse aggregate* 1000
= 0.718*0.56*2.74*1000
=1101 kg/m3
Mass of coarse aggregate = f*volume of coarse aggregate *specific gravity of coarse aggregate* 1000
= 0.718*0.44*2.74*1000
= 866 kg/m3
Result :
Mix proportion
Cement =324 kg/m3
Fly ash =81 kg/m3
water = 140 kg or lit
Fine aggregate =866 kg/m3
coarseaggregate=1101 kg/m3
chemical admixture= 7 kg/m3
water cement ratio = 0.38
Mix ratio = 1 : 2.14 : 2.72
Aim :
To estimate the Mix design for M50 grade concrete by assuming the suitable data.
Introduction :
For Design mix of M50 grade concrete by using the OPC.
For preperation of design mix following guideline or IS code are used.
IS code 10262 : 2019 for Mix design.
Is code 456 : 2000 for Exposure condition, minimum cement content and maximum water cement ratio.
IS code 4031 : 1968 water cement ratio for 7 days strength.
Procedure :
Mix design for M50 grade concrete without fly ash
I. Stipulations for proportioning
a) Grade designation : M50
B) Type of cement : OPC 43 grade conforming to IS 8112
C) Type of mineral admixture : Fly ash conforming to IS 3812 part(1)
D)Maximum nominal size of aggregate : 20 mm
E)Workability : 100mm (slump value for pumpable concrete)
F)Exposure condition : very severe ( for reinforced concrete)
G)Method of concrete placing :Pumping
H)Degree of supervision : Good
I)Type of aggregate : crushed angular aggregate
J)Maximum cement content : 450 kg/m3
K)Chemical admixture type : Superplasticizer
II. Test data for materials:
a)Cement used for : OPC 43 grade conforming to IS 8112
b) Specific gravity of cement : 3.15
c)Chemical admixture : Superplaticizer conforming to IS 9103
d) Specific gravity of coarse aggregate : 2.74
Specific gravity of fine aggregate : 2.74
e)Water absorption
Coarse aggregate : 0.5%
Fine aggregate : 1.0%
f) free surface moisture
Coarse aggregate : NILL
Fine aggregate : NILL
g) Sieve analysis
Coarse aggregate : Zone 1 as per IS 383
Fine aggregate :Zone 1 as per IS 383
III. Target strength for Mix proportion
F'ck=Fck+1.65*S
from table 1 of IS 10262 : 2019 standard deviation S=5N/mm2
F'ck= 50+1.65*5
=58.25 N/mm2
IV. selection of water cement ratio
From IS 10262 : 2019 Free water cement ratio curve, maximum water cement ratio = 0.33
From IS 4031 : 1968 water cement ratio for 7 day strength, maximum water cement ratio =0.42
0.33<0.42 hence ok
Water cement ratio = 0.33
V. From table 2 of IS 10262 : 2019, maximum water content for 20 mm aggregate = 186 kg or lit ( 25 to 50 mm slump)
Estimate water content for 100mm slump = (186*6/100)+186
= 197 kg or lit
As superplasticizer is used, the water content can be reduce up to 30%
Based on trails water content reduce 29% ia achieved with plasticizer
Hence arrived water content = 197*0.71
=140 lit or kg
VI. Calculation of cement content
water cement ratio = 0.33
Cemntitious material (cement+fly ash content)=140/0.33
= 425 kg/m3
Therefoere 450 > 425 kg/m3 Hence ok
VII. Proportion of volume of coarse agfregate and fine aggregate content:
Fro table 3 0f IS 10262 : 2019, volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (zone 1) for water cement ratio of 0.5=0.6
Therefore, corrected volume of coarse aggregate for water cement ratio of 0.33= 0.63
For pumpable concrete these values are reduced by 10%
therefore, volume of coarse aggregate = 0.63*0.9
= 0.57
volume of fine aggregate = 1- 0.57
= 0.43
VIII. Mix calculation
The mix calculation per unit volume of concrete as follows;
a) volume of concrete = 1 m3
b) volume of cement = ( Mass of cement/ Specific gravity of cement)*(1/1000)
=( 425/3.15)*(1/1000)
= 0.13 m3
c) volume of water = ( Mass of water/ Specific gravity of water)*(1/1000)
=( 140/1)*(1/1000)
= 0.14 m3
d) volume of chemical admixture= ( Mass ofchemical admixture/ Specific gravity of chemical admixture)*(1/1000)
=( 7.6/1.145)*(1/1000)
= 0.006 m3
e) Volume of aggregate (fine and coarse aggregate) = (a-(b+c+d+))
= (1-(0.13+0.14+0.006))
= (1-0.276)
= 0.724 m3
f) Mass of coarse aggregate = f*volume of coarse aggregate *specific gravity of coarse aggregate* 1000
= 0.724*0.57*2.74*1000
=1130 kg/m3
Mass of coarse aggregate = f*volume of coarse aggregate *specific gravity of coarse aggregate* 1000
= 0.724*0.43*2.74*1000
= 1000 kg/m3
Result :
Mix proportion
Cement =425 kg/m3
water = 140 kg or lit
Fine aggregate =1000 kg/m3
coarseaggregate=1130 kg/m3
chemical admixture= 7 kg/m3
water cement ratio = 0.33
Mix ratio = 1 : 2.35 : 2.66