Project on Concrete Mix Design for various grades of Concrete

AIM  : To calculate the concrete mix design for M35 grade concrete with fly ash 

introduction: Mix design calculate procedure is the same when either GGBS or fly ash is used , the only change will be specific gravity of the admixture. the specific gravity of the fly ash ranges from 2.1 to 3  whereas the specific ggravity of GGBS is 2.85 superplasticizers are required for all high strength concrete to get good workability and good strength in concrete.

EQUATIONS: Traget mean strength f'ck= fck+1.65s , f 'ck = traget mean strength . fck = compressive strength at 28 days of concrete s = standard deviation 

•      volume of cement =     mass of cement/ specific gravity of cement * 1/1000
•      volume of water=      mass of water / specific gravity of water *1/1000
•      volume of chemichal admixture=     mass of chemical admixture  /specific gravity of chemical admixture *1/1000
• volume of fly ash = mass of fly ash/specific gravity *1/1000
• volume of concrete = 1m^3
• volume of aggrgate = [ vol.of concrete - vol.of cement +vol.of fly ash +vol.of water+vol.of admixture]
• volume of coarse agrregate = vol.of aggregate *vol.of coarse aggregate *specific gravity of coarse aggregate*1000
• mass of fine  aggregate = vol.of aggregate *vol.of fine aggregate *specific gravity of fine aggregate *1000

 CODES FOR CONCRETE MIX DESIGN :

•     IS 10262:2009
• IS 456:2000
• IS 8112
• IS 9103 
• IS 3812 (part -1)

  OBJECTIVES : 

•     The main objective is to produce concrete  as economically as possible 
• to achieve desired workability durability and minimum strength of M35 grade concrete

PROCEDURE & CALCULATION:

1.  Target mean strength :   F' ck = f ck+1.65 

          fck = 35N/mm^(m35)  

        table -1 IS 10262 :2009

      s= 5N/mm^2  f'ck= 35+(1.65 *5) =43.25N/mm2 

 2. SELECTION OF WATER CEMENT RATIO:

      given, M35 

         assume : Exposure condition : extreme

      table -5  - IS 456 :2000

  therefore, Extreme = w/c ratio =0.40

   M35 = w/c ratio = 0.45 lower the water cement ratio better the workability 0.40 <0.45 

   water cement ratio=0.45 

   minimum cement content = 360kg /mm^2

3. SELECTION OF WATER CONTENT :

             assume ; nominal size of aggregare = 20mm table 2 - IS 10262:2009 

      minimum water content = 186litrs slump ranges from 25 to 50 mm as superplasticizers (20% reduces)

      186*80*100=148.8 

          ( 100-20=80) water content =149 liters

4. CALCULATION OF CEMENTITIOUS (CEMENT + FLY ASH)

                water cement ratio= w/c = 0.40

            water content = w= 149kg 

           cementitious content = c= 149/0.40 = 372.5 

           =370kg/m^3 

          minimum cement =360kg/m^3 360 < 370/m^3 increase by 10% 370 *0.10 +370 = 407kg /m^3 

        w = 149kg 

      water cement ratio=149/407= 0.366

   Fly ash at 30%total  cementitiuos material content = 407*30/100 = 122kg/m^3

cement cordinary portland cement =407 -122 = 285kg/m 

 saving of cement while using fly ash = 370 -285 =85  kg/m^3 

                 fly ash = 122kg/m^3 

5.VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE :

 fine aggregate are sieved accroding to zone 1 of table 4 IS383 

    coarse aggregate are sieved accroding to table 2 IS 383 accroding table 3 IS 10262:2009 Norminal size of aggregates=20m

  fine aggregate (zone 1)

therofore, volume of coarse aggregate = 0.60 

 water cement ratio = 0.4 

   so, volume of coarse aggate = 0.62

   vol.of fine aggregate = 1-0.62=0.38

6. MIX CALCULATION: 

 1.vol.of concrete =1m^3

 2.vol.of cement = 285/3.15*1/1000  = 0.090m^3

 3. vol.of fly ash = 122/2.2*1/1000 = 0.055m^3

 4. vol.of water =149/1*1/1000 = 0.149m^3

 5. vol.of admixture = 7.6/1.145*1/1000 = 0.006m^3

 6. vol.of coarse aggregate and fine aggregate = a- (b+c+d+e) = 1 -(0.090+0.55+0.149+0.006) = 0.7m^3 

 7. mass of coarse aggregate = 0.7*0.62*2.74*1000 = 1189.16kg/m^3

 8. Mass of fine aggate = 0.7*0.38*2.74*1000 = 728kg /m^3 

RESULT AND CONCLUSION:

TRIAL MIX: 

 cement = 285 kg/m^3

 Fly ash = 122kg /m^3 

  water = 149kg /m^3

  coarse aggregate = 1189kg/m^3 

  fine aggregate = 728kg/m^3 

  chemical admixture = 7.6kg/m^3

  water cement ratio= 0.366

  trail mix ratio: 285:728:1189 = 1:2.5:4.17    (C:FA:CA)

conclusion:   1. This trailmix ratios should match the durabitlity , minimum strength of M35grade concrete

                 2.if ti dones not statisfiy the above criteria two or more trails for increase of 10% should be done 

 AIM: To calculate   M 50  grade   without fly ash

Equations : 

raget mean strength f'ck= fck+1.65s , f 'ck = traget mean strength . fck = compressive strength at 28 days of concrete s = standard deviation 

•      volume of cement =     mass of cement/ specific gravity of cement * 1/1000
•      volume of water=      mass of water / specific gravity of water *1/1000
•      volume of chemichal admixture=     mass of chemical admixture  /specific gravity of chemical admixture *1/1000
• volume of fly ash = mass of fly ash/specific gravity *1/1000
• volume of concrete = 1m^3
• volume of aggrgate = [ vol.of concrete - vol.of cement +vol.of fly ash +vol.of water+vol.of admixture]
• volume of coarse agrregate = vol.of aggregate *vol.of coarse aggregate *specific gravity of coarse aggregate*1000
• mass of fine  aggregate = vol.of aggregate *vol.of fine aggregate *specific gravity of fine aggregate *1000

 CODES FOR CONCRETE MIX DESIGN :

•     IS 10262:2009
• IS 456:2000
• IS 8112
• IS 9103 
• IS 3812 (part -1)

Objectives: 1. the main objective is to produce concrete as economically as possible 

                 2. to achieve desired workability durability and minimum strength of M50 grade concrete

PROCEDURE & CALCULATION:

1.  Target mean strength :   F' ck = f ck+1.65 

          fck = 35N/mm^(m35)  

        table -1 IS 10262 :2009

      s= 5N/mm^2  f'ck= 50+(1.65 *5) =58.28N/mm2 

 2. SELECTION OF WATER CEMENT RATIO:

      given, M50

         assume : Exposure condition : extreme

      table -5  - IS 456 :2000

  therefore, Extreme = w/c ratio =0.40

   M35 = w/c ratio = 0.45 lower the water cement ratio better the workability 0.40 <0.45 

   water cement ratio=0.45 

   minimum cement content = 360kg /mm^2

3. SELECTION OF WATER CONTENT :

             assume ; nominal size of aggregare = 20mm table 2 - IS 10262:2009 

       minimum water content = 186litrs slump ranges from 25 to 50 mm as superplasticizers (20% reduces)

      186*80*100=148.8 

          ( 100-20=80) water content =149 liters

4. CALCULATION OF CEMENTITIOUS (CEMENT + FLY ASH)

                water cement ratio= w/c = 0.40

            water content = w= 149kg 

           cementitious content = c= 149/0.40 = 372.5 

           =370kg/m^3  (hence ok)

5.VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE :

 fine aggregate are sieved accroding to zone 1 of table 4 IS383 

    coarse aggregate are sieved accroding to table 2 IS 383 accroding table 3 IS 10262:2009 Norminal size of aggregates=20m

  fine aggregate (zone 1)

therofore, volume of coarse aggregate = 0.60 

 water cement ratio = 0.4 

   so, volume of coarse aggate = 0.62

   vol.of fine aggregate = 1-0.62=0.38

 6. MIX CALCULATION: 

 1.vol.of concrete =1m^3

 2.vol.of cement = 373/3.15*1/1000  = 0.118m^3

 3.vol.of water =149/1*1/1000 = 0.149m^3

 4. vol.of admixture = 7.6/1.145*1/1000 = 0.006m^3

5. vol.of coarse aggregate and fine aggregate = a- (b+c+d+e) = 1 -(0.118+0.149+0.006) = 0.727m^3 

 6. mass of coarse aggregate = 0.727*0.38*2.74*1000 = 1235.02kg/m^3

 7. Mass of fine aggate = 0.727*0.38*2.74*1000 = 756.9kg /m^3 

RESULT AND CONCLUSION:

TRIAL MIX: 

  cement = 285 kg/m^3

  water = 149kg /m^3

  coarse aggregate = 1235.02kg/m^3 

  fine aggregate = 756.9kg/m^3 

  chemical admixture = 7.6kg/m^3

  water cement ratio= 0.40

  trial mix ratio: 373:756.9:1235.02 = 1:2.02:3.31  (C:FA:CA)

conclusion: 

                  1. This trial mix ratio should match the workability , durability minimum strength of M50 grade concrete 

                 2. if it does not satifiy the above criteria two or more trials for increase  of 10% should be done