Project on Concrete Mix Design for various grades of Concrete

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1)The mix design for m35 grade concrete 

Step(1):

•  Target mean strength ft =fck +1.65*S
• From table 1 of IS 10262:2009

      Standard deviation S =5N/mm2

       ft=35+1.65*5=43.25N/mm2

Step(2):

• Selection of water cement ratio -From table -5 of IS 456:2000,it can be taken depending upon the exposure condition.
• Max.water cement ratio is 0.45
• Based on experience adopted water cement ratio is 0.40
• 0.40<0.45 hence ok.

Step(3):

• Selection of water content -From table 2 of IS 10262-2009
• The max .water cement for 20mm to 50mm slump is 186kg =186litres
• Estimate water content for 100 mm slump
• 186+6/100*186=197 litres

  As superplasticizers is used .The water content is reduced up to 20% and above 

 Hence the arrived water content =197*0.74=140 litres

Step(4):

• Selection of cement content -it can be calculated from water cement ratio
• Min.cement content is taken from table -5 of IS456:2000
• W=140 litres
• C=140/0.4=350kg

Step(5):

• Mix calculations

A) vol. of concrete=1m3

B)vol.of Fly Ash =mass of fly ash /specific gravity of fly ash *1/1000=115/2.2*1/1000=0.052m3

C)volume of cement =mass of cement /specific gravity of cement *1/1000

     =350/3.15*1/1000

    =0.111m3

D) volume of water=mass of water/specific gravity of water *1/1000

  = 140/1*1/1000

    =0.140m3

E) vol. of chemical admixtures= mass of chemical admixers/specific gravity of chemical admixtures *1/1000

     =2.5/1.145*1/1000

     =0.006m3

F) volume of aggregates =(a-(b+c+d))

        =(1-(0.111+0.140+0.006))

     =0.743m3

G) mass of coarse aggregates =e*voluime if coarse aggregate*specific gravity of coarse aggregate*1000

     =0.743*056*2.74*1000

    =1140kg/m3

H) mass of fine aggregate =e*vol of fine aggregate

   *specific gravity of fine aggregate *1000

     0.743*0.44*2.74*1000=896kg/m3.

• Cement=350kg/m3
• Water=140kg/m3
• Fly Ash =0.052kg/m3
• Fine aggregate=896kg/m3
• Coarse aggregate =1140 kg /m3
• Chemical admixtures =0.006 kg/m3
• Water cement ratio= 0.4kg/m3

The mix ratio =1:2:56:3.26.

 And   M50 grade concrete without fly ash 

  Step(1):

• Target mean strength ft =fck+1.65*S

       ft =50+1.65*5=58.25N/mm2

Step(2):

• As per table % water cement ratio is 0.40
• 0.40<0.45 hence ok

Step(3):

• For 20mm slump water cement ratio is 186litres
• Estimated water content for 100mm slump is  =186+6/100*186=197litrs
• Hence superplasticizers are used then 30% water content is reduced then 197*0.7=140litres

Step(4): 

   Cement content is 

   W/C =0.4=140/0.4=350kg/m3

Step(5):

 Mix calculations:-

A) volume of concrete =1m3

B) vol. of cement= 350/3.15*1/1000=0.111m

C)volume of water =140/1*1/1000

    =0.140 m3

D) volume of chemical admixtures =2.5/1.145*1/1000=0.006kg/m3

E) volume of aggregate =(a-(b+c+d))

       =(1-(0.111+0.145+0.006))

      =0.743kg/m3

F) mass of coarse aggregate =e*volume of coarse aggregate *specific gravity of coarse aggregate *1000

       =0.743*0.56*2.74*1000=1140kg/m3

G) mass of fine aggregate

 =0.743*0.44*2.74*1000=896kg/m3

  Mix proportions

• Cement =360kg/m3
• Water=140kg/m3
• Fine aggregater=896kg/m3
• Coarse aggregate =1140kg/m3
• chemical admixtures=0.006kg/m3
• Water cement ratio=0.4kg/m3

 The mix ratio= 1:2:56:3.26.