Project on Concrete Mix Design for various grades of Concrete

Topic1: – Concrete Mix Design for M35 Grade of Concrete with Fly Ash-

To Calculate the mix design of M35 Grade of Concrete for stipulation for proportioning-

• Grade of concrete –M35
• Type of cement – OPC 43 grade
• Type mineral admixture – Fly ash
• Maximum nominal Size of aggregate -20mm
• Workability-100mm
• Exposure condition – severe for reinforced concrete
• Method of concrete placing –pumping
• Chemical admixture- Super plasticizer
• Minimum cement content- 320kg/m3
• Maximum cement content – 450 kg/m3
• Specific gravity of cement – 3.15
• Specific gravity of fly ash- 2.2
• Specific gravity of coarse & fine aggregate - 2.74

Procedure-

1. Target strength for mix proportion

f’ck = fck + 1.65s

Where,

F’ck =Target avg compressive strength at 28 days.

Fck = characteristics compressive strength at 28 days

S = Standard deviations

From Table 1 – IS 10262-2009, Standard deviations, S=5N/mm2

Target strength =35+ (1.65 X 5) = 43.25 N/mm2

2. Selection of Water-Cement Ratio-

From Table 5- IS456-2000, Maximum W/C ratio for severe Condition =0.45

From Graph, Target means strength v/s water cement ratio

W/C ratio =0.36

From graph 28 Days Compressive strength v/s water cement ratio

W/C ratio =0.41

Therefore, the lower value of the above three vale is adopted as w/c ratio for mix design

so, W/C ratio =0.36

3. Selection of Water Content -

From Table 2, maximum water content for 20mm aggregate =186 litre for 25-50mm slump

Estimated Water content for 100mm slump =186 + ((6/100)X186)=197litre

As super plasticizer is used, the water content reduced up to 30%

Based on trial with Superplasticizer water content reduction of 29% has been achieved

=197 X 0.71 = 140 litre

4. Calculation of cement and Fly ash Content -

W/C ratio=0.36

Cementationous material (cement + flyash) content =140/0.36=389 kg

From table 5 of IS 456, minimum cement content for severe exposure 389kg/m3

fly ash its perrcentage decide on the basis of project requirements and quality materisals

For find the fly ash we have to consider 10% of cementationous material

Cementationous cement =389*1.10= 458.84

W/C ratio =140/458.84= 0.30

Fly ash @30% of total cementationous material =458.84X30%=137.65 kg/m3

cement=458.84-137.65=321.19kg/m3

saving of cement while using fly ash =389-321.19= 67.81 kg/m3

5. Proportion of volume of coarse & Fine Aggregate content -

from Table 3, volume of coarse aggregate corresponding to 20mm size of aggregate and fine aggregate for water cement ratio of 0.50-0.60

in the present water cement ratio is 0.36, therefore the volume of coarse aggregate is required to be increased to decrease the fine aggregate content

As water cement ratio is lower 0.14, the proportion of volume of coarse aggregate is increased by 0.03

There fore corrected proportion of volume of coarse aggregate for the water cement ratio 0.36=0.63

For pumpable concrete these value should be reduced by 10%

There fore the volume of coarse aggregate =0.63*0.9 =0.57

Volume of fine aggregate content =1-0.57= 0.43

6. Mix Calculation -

a) Volume of concrete = 1m3

b) volume of cement = (mass of cement / Sp. gravity of cement)X(1/1000)

= (321.19/3.15)X (1/1000)

= 0.102 m3

c) Volume of fly ash=(mass of fly ash/sp. gravity of fly ash) X (1/1000)

=(137.19/2.2) X (1/1000)

= 0.062 m3

d) volume of water = (mass of water /sp. gravity of water) X (1/1000)

= (140/1) X (1/1000)

=0.140 m3

e) Volume of admixture @ 2% by mass of cementationous material =( mass of admixture / sp. gravity of admixture ) X (1/1000)

= (9.17/1.145)X (1/1000)

= 0.008m3

f) volume of all aggregate =((a-(b+c+d+e))

= ((1-(0.102+0.062+0.140+0.008))

= 0.69

g) mass of coarse aggregate = (f X volume of coarse aggregate X sp. gravity X 1000)

= 0.69 X 0.57 X 2.74X 1000= 1077.64kg

h) mass of fine aggregate = (f X volume of coarse aggregate X sp. gravity X 1000)

= 0.69x0.43x2.74 x1000= 812.958kg

7. Mix Proportion for M35 -

Cement =321.19 kg/m3

fly ash = 116 kg/m3

water = 140 kg/m3

Fine Aggregate = 812.96 kg/m3

Coarse aggregate =1077.64 kg/m3

Chemical Admixture = 9.17 kg/m3

W/C ratio = 0.30

Result - The mix ratio for M35 grade of concrete with fly ash will - 1:2.53:3.35

Topic2: – Concrete Mix Design for M50 Grade of Concrete without Fly Ash-

To Calculate the mix design of M35 Grade of Concrete for stipulation for proportioning-

• Grade of concrete –M50
• Type of cement – OPC 43 grade
• Maximum nominal Size of aggregate -20mm
• Workability-100mm
• Exposure condition – severe for reinforced concrete
• Method of concrete placing –pumping
• Chemical admixture- Super plasticizer
• Minimum cement content- 320kg/m3
• Maximum cement content – 450 kg/m3
• Specific gravity of cement – 3.15
• Specific gravity of coarse & fine aggregate - 2.74

Procedure-

1. Target strength for mix proportion

f’ck = fck + 1.65s

Where,

F’ck =Target avg compressive strength at 28 days.

Fck = characteristics compressive strength at 28 days

S = Standard deviations

From Table 1 – IS 10262-2009, Standard deviations, S=5N/mm2

Target strength =50+ (1.65 X 5) = 58.25 N/mm2

2. Selection of Water-Cement Ratio-

From Table 5- IS456-2000, Maximum W/C ratio for severe Condition =0.45

From graph 28 Days Compressive strength v/s water cement ratio

W/C ratio =0.34

Therefore, the lower value of the above three vale is adopted as w/c ratio for mix design

so, W/C ratio =0.34

3. Selection of Water Content -

From Table 2, maximum water content for 20mm aggregate =186 litre for 25-50mm slump

Estimated Water content for 100mm slump =186 + ((6/100)X186)=197litre

As super plasticizer is used, the water content reduced up to 30%

Based on trial with Superplasticizer water content reduction of 29% has been achieved

=197 X 0.71 = 140 litre

4. Calculation of cement Content -

W/C ratio=0.34

Cementationous material (cement + flyash) content =140/0.34=411.76 kg = 412 kg

From table 5 of IS 456, minimum cement content for severe exposure 412kg/m3

412> 320 kg

5. Proportion of volume of coarse & Fine Aggregate content -

from Table 3, volume of coarse aggregate corresponding to 20mm size of aggregate and fine aggregate for water cement ratio of 0.50-0.60

in the present water cement ratio is 0.36, therefore the volume of coarse aggregate is required to be increased to decrease the fine aggregate content

As water cement ratio is lower 0.16, the proportion of volume of coarse aggregate is increased by 0.03

There fore corrected proportion of volume of coarse aggregate for the water cement ratio 0.34=0.63

For pumpable concrete these value should be reduced by 10%

There fore the volume of coarse aggregate =0.63*0.9 =0.57

Volume of fine aggregate content =1-0.57= 0.43

6. Mix Calculation -

a) Volume of concrete = 1m3

b) volume of cement = (mass of cement / Sp. gravity of cement)X(1/1000)

= (412/3.15)X (1/1000)

= 0.130 m3

c) volume of water = (mass of water /sp. gravity of water) X (1/1000)

= (140/1) X (1/1000)

=0.140 m3

d) Volume of admixture @ 2% by mass of cementationous material =( mass of admixture / sp. gravity of admixture ) X (1/1000)

= (8.24/1.145)X (1/1000)

= 0.007m3

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

= ((1-(0.130+0.140+0.007))

= 0.723

f) mass of coarse aggregate = (f X volume of coarse aggregate X sp. gravity X 1000)

= 0.723 X 0.57 X 2.74X 1000= 1129.18kg

g) mass of fine aggregate = (f X volume of coarse aggregate X sp. gravity X 1000)

= 0.723x0.43x2.74 x1000= 851.84kg

7. Mix Proportion for M35 -

Cement =412 kg/m3

water = 140 kg/m3

Fine Aggregate = 851.84 kg/m3

Coarse aggregate =1129.18 kg/m3

Chemical Admixture = 8.24 kg/m3

W/C ratio = 0.34

Result - The mix ratio for M50 grade of concrete without fly ash will - 1:2.06:2.74