Project on Concrete Mix Design for various grades of Concrete

A)Calculate the Concrete Mix Design for M35 grade concrete with fly ash

I. Stipulation for proportioning

• Grade designation: M35
• Type of cement: OPC 43 grade conforming to IS8112
• Type of mineral admixture: Fly ash confirming ro IS 3812 (part1)
• Maximum nominal size of aggregate : 20mm
• Minimum cement content: 320 kg/m3(from table 5 of IS 456-2000 depending upon exposure condition)
• Maximum w/c ratio : 0.45 (table 5 of IS 456-2000 depending upon exposure condition)
• Workability : 100mm (slump value for pumpable concrete)
• Exposure condition: severe (for reinforced concrete)
• method of concrete placing :Pumping
• Degree of supervision : Good
• Type of aggregate : Crushed angular aggregate
• Max cement content : 450 kg/m3
• Chemical admixture type: Superplasticizer

II. Test data for materials:

• Cement used: OPC 43 grade confirming to IS 8112
• specific gravity of cement: 3.15
• Fly ash: confirming to IS 3812 part 1
• Chemical admixture : Superplasticizer conforming to IS 9103
• Specific gravity of:

-Coarse aggregate : 2.74

-Fine aggregate:2.74

• Water absorption

-coarse aggregate:0.5%

-fine aggregate:1%

• Free surface moisture:

-coarse aggregate: Nil

-fine aggregate: Nil

• Sieve analysis:

-Coarse aggregate: conforming to all in aggregate of table 2 of IS 383

-Fine aggregate: Conforming to grading zone I of table 4 IS 383

III. Target strength for Mix proportioning

f'ck=fck+1.65s

f'ck=target average compressive strength at 28days

fck= characteristic compressive strength at 28 days

s= standard deviation

from table 1 of IS 10262 2009

s=5N/mm2

therefore,

f'ck=35+1.65*5

=43.25N/mm2

IV. Selection of w/c ratio

from table 5 of IS 456-2000 severe exposure

Max w/c ratio= 0.45

adopted w/c ratio is 0.44

0.44<0.45 hence ok.

V. Selection of water content

table 2 of IS 10262:2009

max water content for 20mm aggregate=186liter(for 20mm to 50mm slump range)

estimated water content for 100mm slump=186+6/100*186

=197liter

As superplasticizer is used the water content can be reduced up to 30% and above

Based on the trials with superplasticizer water content reduction of 29% has been achieved, Hence the arrived water content=197-[197*(29/100)]=140liters

VI. Calculation of cement content

Adopted w/c ratio=0.4

Cement content =140/0.4=350kg/m3

from table 5 of IS 456-2000 , Minimum cement content for severe exposure condition 320kg/m3

350kg/m3>320kg/m3 hence ok.

To proportion the mix containing flyash the following steps are suggested:

a. The percentage of flyash need to be decided based on project requirement and quality of materials

b. In some cases increase in cementatious materials can be warned. Increase in cementatious material content and its percentage may be based on experience and trial.

In this increase of 10% cementatious material content is considered.

Cementatious material content: 350*1.1=385 kg/m3

Water content = 140 kg/m3

So, water-cement ratio= 140/385 = 0.364

Fly ash at 30% total cementatious material content = 385*.3= 115 kg/m3

Cement(OPC) = 385-115 = 270 kg/m3

Saving of cement while using flyash = 350-270= 80 kg/m3

Fly ash beign utilized= 115 kg/m3

VII. Proportioning of volume of coarse aggregate and fine aggregate content

From table 3 (IS 10262:2009) volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate(Zone I) for w/c ratio of =0.6

In the present case w/c ratio is 0.4

Therefore, volume of CA is required to be increased to decrease the FA content. AS the w/c ratio is lower by 0.1

Therefore, corrected proportion of volume of CA for the w/c ratio of =0.64

For pumpable concrete these values should be reduced up to 10%

Therefore, volume of coarse aggregate=0.64*0.9=0.576

volume of fine aggregate content=1-0.576=0.424

VIII. Mix calculation

• Volume of concrete=1m3
• volume of cement={[mass of cement]/[specific gravity of cement]}*{(1/1000)}

=(270/3.15)*(1/1000)

= 0.086m3

• Volume of flyash= {[mass of flyash]/[specific gravity of flyash]}*{(1/1000)}

=(115/2.2)*(1/1000)

0.052 m3

• volume of water={[mass of water]/[specific gravity of water]}*{(1/1000)}

=(140/1)*(1/1000)

= 0.140m3

• volume of chemical admixture=[mass of chemical admixture/specific gravity of admixture]*[1/1000]

=(7.6/1.14) * (1/1000)

=0.006m3

• volume of all in aggregate=[a-(b+c+d+e)]

=[1-(0.086+0.0.052+0.140+0.006)]

=0.716kg/m3

• mass of coarse aggregate= e*volume of coarse agg*specific gravity of coarse agg*1000

=0.716*0.576*2.74*1000

= 1130 kg/m3

• mass of fine aggregate= e*volume of fine2 agg*specific gravity of fine agg*1000

  =0.716*0.576*2.74*1000

  = 831 kg/m3

IX. Mix proportions

Cement=270kg/m3

Fly ash = 115 kg/m3

water=140 liter/m3

Fine aggregate=831kg/m3

Coarse aggregate=1130 kg/m3

Chemical admixture = 7 kg/m3

Water cement ratio= 0.364

Trial mix ratio= 1:2.15:2.94

X. The slump shall be measured and the water content and dosage of admixture shall be adjusted for achieving the required slump based on trial, if required. The mix proportions shall be worked for the actual water content and checked for durability requirements.

XI. Two more trials having variation of + or - 10% of w/c ratio in X shall be carried out and a graph between 3 w/c ratios and their corresponding strength shall be plotted to work out the mix proportions for the given target strength for field trials. However, durability requirement shall be met.

A) Calculate the Concrete Mix Design for M50 grade concrete without fly ash

I. Stipulation for proportioning

• Grade designation: M50
• Type of cement: OPC 43 grade conforming to IS8112
• Maximum nominal size of aggregate : 20mm
• Minimum cement content: 320 kg/m3(from table 5 of IS 456-2000 depending upon exposure condition)
• Maximum w/c ratio : 0.45 (table 5 of IS 456-2000 depending upon exposure condition)
• Workability : 100mm (slump value for pumpable concrete)
• Exposure condition: severe (for reinforced concrete)
• method of concrete placing :Pumping
• Degree of supervision : Good
• Type of aggregate : Crushed angular aggregate
• Max cement content : 450 kg/m3
• Chemical admixture type: Superplasticizer

II. Test data for materials:

• Cement used: OPC 43 grade
• specific gravity of cement: 3.15
• Chemical admixture : Superplasticizer conforming to IS 9103
• Specific gravity of:

-Coarse aggregate : 2.74

-Fine aggregate:2.74

• Water absorption

-coarse aggregate:0.5%

-fine aggregate:1%

• Free surface moisture:

-coarse aggregate: Nil

-fine aggregate: Nil

• Sieve analysis:

-Coarse aggregate: conforming to all in aggregate of table 2 of IS 383

-Fine aggregate: Conforming to grading zone I of table 4 IS 383

III. Target strength for Mix proportioning

f'ck=fck+1.65s

f'ck=target average compressive strength at 28days

fck= characteristic compressive strength at 28 days

s= standard deviation

From table 1 of IS 10262 2009

s=5N/mm2

therefore,

f'ck=50+1.65*5

=58.25N/mm2

IV. Selection of w/c ratio

from table 5 of IS 456-2000 severe exposure

Max w/c ratio= 0.45

adopted w/c ratio is 0.4

0.4<0.45 hence ok.

V. Selection of water content

table 2 of IS 10262:2009

max water content for 20mm aggregate=186liter(for 20mm to 50mm slump range)

estimated water content for 100mm slump=186+6/100*186

=197liter

As superplasticizer is used the water content can be reduced up to 30% and above

Based on the trials with superplasticizer water content reduction of 29% has been achieved, Hence the arrived water content=197-[197*(29/100)]=140 liter

VI. Calculation of cement content

Adopted w/c ratio=0.4

Cement content =140/0.4=350kg/m3

from table 5 of IS 456-2000 , Minimum cement content for severe exposure condition 320kg/m3

350kg/m3>340kg/m3 hence ok.

VII. Proportioning of volume of coarse aggregate and fine aggregate content

From table 3 (IS 10262:2009) volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate(Zone II) for w/c ratio of=0.6

In the present case w/c ratio is 0.4

Therefore, volume of CA is required to be increased to decrease the FA content. AS the w/c ratio is lower by 0.1.

Therefore, corrected proportion of volume of CA for the w/c ratio of =0.64

For pumpable concrete these values should be reduced up to 10%

Therefore, volume of coarse aggregate=0.64*0.9=0.576

volume of fine aggregate content=1-0.576=0.424

VIII. Mix calculation

• Volume of concrete=1m3
• volume of cement={[mass of cement]/[specific gravity of cement]}*{(1/1000)}

=(350/3.15)*(1/1000)

= 0.1114m3

• volume of water={[mass of water]/[specific gravity of water]}*{(1/1000)}

=(140/1)*(1/1000)

= 0.140m3

• volume of chemical admixture=[mass of chemical admixture/specific gravity of admixture]*[1/1000]

=(7.6/1.145)*(1/1000)

=0.006m3

• volume of all in aggregate=[a-(b+c+d)]

=[1-(0.111+0.140+0.006)]

=0.743kg/m3

• mass of coarse aggregate= e*volume of coarse agg*specific gravity of coarse agg*1000

=0.743*0.576*2.74*1000

= 1173kg/m3

• mass of fine aggregate= e*volume of fine2 agg*specific gravity of fine agg*1000

  =0.743*0.576*2.74*1000

  = 863kg/m3

IX. Mix proportions

Cement=350kg/m3

water=140 liter/m3

Fine aggregate= 863kg/m3

Coarse aggregate=1173kg/m3

Water cement ratio= 0.4

Trial mix ratio= 1:2.46:3.35

X. The slump shall be measured and the water content and dosage of admixture shall be adjusted for achieving the required slump based on trial, if required. The mix proportions shall be worked for the actual water content and checked for durability requirements.

XI. Two more trials having variation of + or - 10% of w/c ratio in X shall be carried out and a graph between 3 w/c ratios and their corresponding strength shall be plotted to work out the mix proportions for the given target strength for field trials. However, durability requirement shall be met.