Project on Concrete Mix Design for various grades of Concrete
AIM: To calculate the concrete mix design for M35 concrete with fly ash. And concrete mix design of M50 concrete mix without fly ash.
EQUATIONS: Target main strength Fck = fck + 1.65
PROCEDURE AND CALCULATION :
1. TARGET MEAAN STRENGTH
f'ck = fck = 1.65
fck = 35 n/mm2 (M35 concrete)
s = 5 N/mm2
fck = 35 + (1.65 x 5) = 43.25 n/mm2
2. SELECTION OF WATER CEMENT RATIO
M35 concrete
extreme = w/c ratio = 0.40
M35 = w/c ratio = 0.45
lower water content for better workability 0.40<0>
water cement ratio = 0.40
minimum cement content = 360 kg/m3
3. SELECTION OF WATER CONTENT
NOMINAL SIZE OF AGGREGATES = 20mm
minimum water content = 186 litres
slump ranges feom 25mm to 50mm
as superplasticizers (20% reduced) = 186 x 80/100 =148.8 so the water content is 149 litres
4. CALCULATON OF CEMENTITIOUS CONTENT
W/C ration = 0.40
water content= W =149 kg
cementitious content= c=149/0.40= 372.5 = 370 kg/m3
minimum cement content = 360 kg/m3, 360<370>
370 x 0.10 + 370 = 407 kg/m3
W = 149 kg
w/c ratio = 149/407 = 0.366
fly ash at 30% total cementitious material content = 407 x 30/100 = 122 kg/m3
saving of cement while using fly ash = 370 - 285 = 85kg/m3
fly ash = 122kg/m3
5. VOLUME OF COARSE AND FINE AGGREGATES
coarse aggregates are seived according to table 2 IS 383
fine aggregates are seived according to table 2 IS 383
therefore nominal size of coarse aggregate is 20mm and fine aggregate should be zone 1
and the volume of coarse aggregate = 0.60
w/c ratio = 0.4 (=/- 0.01 for every +/- 0.005)
so the volume of coarse aggregate is 0.62
volume of fine aggregate = 1 - 0.62 = 0.38
6. MIX CALCULATION
VOLUME OF CONCRETE = 1m3
volume of cement = (285/3.15) x 1/1000 = 0.090 m3
volume of fly ash = (122/2.2)x(1x1000) = 0.055m3
volume of water = (149/1)x1/1000 = 0.149 m3
volume of admixture = (7.6/1.145)x1/1000 = 0.006 m3
volume of coarse and fine aggregate = a - (b + c + d +e ) = 1 - ( 0.090 + 0.149 + 0.006) + 0.7 m3
mass of coarse aggregate = 1189.16 kg/m3
mass of fine aggregate = 728 kg/m3
RESULT AND CONCLUSION:
cement = 285 kg/m3
fly ash = 122 kg/m3
water = 149 kg/m3
coarse aggregate = 1189 kg/m3
fine aggregate = 728 kg/m3
chemical admixture = 7.6 kg/m3
w/c ratio = 0.366
trial mix ratio : 285:728:1189 = 1:2.55:4.17(C:FA:CA)