Project on Concrete Mix Design for various grades of Concrete
MIX DESIGN FOR M35 GRADE CONCRETE WITH FLY ASH
1. TARGET MEAN STRENGTH
F'ck= fck +1.65x s
s = 5 N/mm2 from table 1 IS 10262:2009, standard deviation, s
fck = 35N/mm2
F'ck = 35 +1.65 x5 =43.5N/mm2
2. WATER CEMENT RATIO
assume atmospheric condition = extreme
tabel 5 - IS456 2000
at extreme the w/c ratio=0.40
M35= w/c ratio =0.45
since 0.40 is lesser than 0.45, the w/c ratio with better workability is 0.40
3. MINIMUM CEMENT CONTENT
360kg/m3 for 0.40 w/c ratio
water content = nominal size of aggregates = 20mm
table IS10262 2009
minimum water content = 186kg
slump ranges from 25 to 50mm
As superplasticizers(20% reduced= 100-20= 80%)
186x80%= 148.8 ~ water content , W= 149L
4. CEMENT + FLYASH
w/c ratio =0.40
W = 149kg
Cement + flyash =149/0.40 =372.5~ 370kg/m3
minimum cement content = 360kg/m3
360<370 , hence okay
increase by 10% = 370x0.10 +370 = 407kg/m3
W = 149kg,
water cement ratio =149/407= 0.366
flyash at 30%, total cementitious material content
= 407x30/100 = 122Kg/m3
cement = 407-122= 285kg/m3
saving for cement using fly ash= 370 -285 = 85kg/m3
fly ash =122kg/m3
5. VOLUME OF FINE AND COARSE AGGREGATES(FA AND CA)
FA -> ZONE 1 TABLE 4, IS383
CA -> TABLE 2 IS 383
nominal size of aggregates= 20mm
Fine aggregates Zone 1, therefore
Volume of coarse aggregates = 0.60
water cement ratio = 0.4(+/-0.01 for every +/- 0.005)
so volume of CA =0.62
volume of FA = 1-0.62 =0.38
6. VOLUME OF CONCRETE =1m3
VOLUME OF CEMENT =285/3.15 X 1/1000 =0.090m3
VOLUME OF FLYASH =122/2.2 X 1/1000=0.055m3
VOLUME OF WATER =149/1 X 1/1000 =0.149m3
VOLUME OF ADMIXTURE =7.6/1.145 X 1/1000=0.006m3
VOLUME OF CA AND FA = a -(b+c+d+e)=1-(0.090+0.055+0.149+0.006)=0.7m3
MASS OF COARSE AGGREGATE =0.7X0.62X2.74X1000= 1189.16kg/m3
MASS OF FINE AGGREGATE =0.7X0.38X2.74X1000 =728 kg/m3
7. RESULTS
CEMENT =785kg/m3
FLYASH =122kg/m2
WATER =149 kg
COARSE AGGREGATE =1189 kg/m3
FINE AGGREGATE = 728 kg/m3
CHEMICAL ADMIXTURE = 7.6kg/m3
WATER CEMENT RATIO = 0.366
TRIAL MIX RATIO = 285 :728:1189 = 1:2.55:4.17 =C:FA:CA
trial mix ratio should match the workability , durability and minimum working strength of M35 grade concrete , if not further trials should be done.
CONCRETE MIX DESIGN FOR M50 WITHOUT FLYASH
- TARGET MEAN STRENGTH
F’ck = fck + 1.65 x S …………………….. S= standard deviation from the table 1 IS10262:2009 = 5
= 50 +1.65 X 5 =58.25 N/mm2
- WATER CEMENT RATIO
TABLE 5 IS456:2000
Extreme exposure condition ; W/C RATIO = 0.40
M50 ; W/C =0.40
Lower the ratio better the workability, there the w/c ratio = 0.40
MINIMUM CEMENT CONTENT
FOR M 50 -> 360 kg/m3
- WATER CONTENT
Nominal size of aggregates = 20mm
Minimum water content W= 186 L
Slump ranges from 25 – 50mm
As superplasticisers used , 20% reduced
100-20 =80%
186x80% =148.8 ~ water content = 149L
- CEMENT CONTENT
Water cement ratio = 0.4
W = 149L
CEMENT CONTENT =C = 149/0.40 =372.5 ~ 375 kg/m3
Minimum cemnt content = 360kg/m3
Since 360 <370, hence okay.
- VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE
COARSE AGGREGATE = ZONE 1 TABLE 4 IS383
FINE AGGREGATE = TABLE 2 IS383
According to table 3 IS10262 :2009
Nominal Size of aggregates =20mm
Fine aggregates , Zone 1 ;
Volume of coarse aggregate =0.60
Water cement ratio = 0.40
(+/-0.01 for every +/-0.005)
Volume of coarse aggregate = 0.62
Volume of fine aggregate =1-0.62 =0.38
- MIX CALCULATION
VOLUME OF CONCRETE =1m3
VOLUME OF CEMENT =375/3.15 X 1/1000 =0.118m3
VOLUME OF WATER =149/1 X 1/1000 =0.149m3
VOLUME OF ADMIXTURE =7.6/1.145 X 1/1000=0.006m3
VOLUME OF CA AND FA = a -(b+c+d+e)=1-(0.118+0.149+0.006)=0.727m3
MASS OF COARSE AGGREGATE =0.727X0.62X2.74X1000= 1235.02kg/m3
MASS OF FINE AGGREGATE =0.727X0.38X2.74X1000 =756.9 kg/m3
- RESULT
CEMENT =375 kg/m3
WATER =149 kg
COARSE AGGREGATE =1235 kg/m3
FINE AGGREGATE = 756.9kg/m3
CHEMICAL ADMIXTURE = 7.6kg/m3
WATER CEMENT RATIO = 0.40
TRIAL MIX RATIO = 375:757:1235= 1:2.01: 3.29=C:FA:CA
trial mix ratio should match the workability , durability and minimum working strength of M50 grade concrete , if not further trials should be done.