Project on Concrete Mix Design for various grades of Concrete

Mix design for M35 With fly ash:

STIPULATIONS FOR PROPORTIONING:

• Grade of designation:M35
• Exposure condition: moderate(assuming)
• Assume type of cement: OPC43 (IS 8112)
• Max size of aggregate:20mm
• Minimum cement content:300 kg/m3 (from IS 456-2000 exposure Cond”)
• W/C ratio :0.5 (from IS 456-2000 exposure Cond”)
• Workability :50mm
• Method of concrete placing: pumping
• Degree of supervision: good
• Type of aggregate: crushed angular aggregate.
• Chemical admixture type: superplasticizer.

Test data for materials:

• Cement used: OPC 43
• Specific gravity of cement:3.15
• Chemical admixture type: superplasticizer. (IS 9103)

Sieve analysis:

• Fine aggregate: Conforming to grading zone-1 table-4 of IS 383
• Coarse aggregate: Conforming to table-2 of IS 383 (20mm) @w/c 0.5

Target strength for mix proportioning:

Target mean strength(ft) = fck+1.65 S

M35= fck =35 N/mm2

S=standard deviation=5 N/mm2 (from Table-8 IS 456-2000)

Ft=35+1.65*5

=43.25 N/mm2

I.W/C ratio from graph-1:

From table-5 IS 10262 2009

w/c ratio=0.36

II.W/C ratio from graph-2:

From graph-2 IS 10262-2009

Hence, we used curve line D

We assume w/c ratio=0.41

III.According to environment exposure condition:

Exposure condition: moderate

From IS 456-2000 table-5 clause 6.1.2,8.2.4.1 & 9.1.2

w/c ratio=0.5

Now compare above all three values the lower value is adopted as w/c ratio for design mix.

Hence w/c ratio for M35 is 0.36.

Selection of water content:

From IS 10262-2009, max water content for 20mm aggregate@25-50mm slump value is:186 lit

As superplasticizer used, the water content can be decreased up to 30%

Based on trails water content reduction of 29% is achieved with plasticizer.

Hence, the arrived water content=186*0.71

=132lit

Calculation of cement content:

w/c=0.36

132/0.36=c

C=336.66=337kgs >300 kg

Proportion of vol. of CA& FA content:

From table-3 IS 10262-2009 vol. of coarse aggregate = 0.6 (@w/c=0.5)

But actual w/c =0.39 it is lower by 0.11, the proportion of vol. increased by0.2

(@+/- 0.01 for every 0.05 change in w/c ratio)

Therefore, vol of coarse aggregate @0.5 W/C=0.62

For pumpable concrete these values are reduced by 10%

Therefore, vol of coarse aggregate=0.62*0.9=0.558=0.56

Vol of FA=1-0.56=0.44

Mix calculations:

• a) Vol of concrete:1m3
• b) Vol of cement= (mass of cement/sp, gravity of cement) x1/1000

=337/3.15*1/1000=0.1069m3

• c)Vol of water=132/1*1/1000=0.132m3
• d)Vol of chemical admixture:7.6/1.145*1/1000=0.006m3
• e) Vol of aggregates=(a-(b+c+d)) =0.7551
• Mass of CA=e*vol of CA*sp. Gravity of CA*1000

=0.755*0.56*2.74*1000=1158.472

• Mass of FA=e*vol of FA*sp. Gravity of FA*1000

=0.755*0.44*2.74*1000=910.228

Mix proportions:

• Cement:337kg/m3
• Water:132lit/m3
• FA:910kg/m3
• CA:1158.5kg/m3
• Chemical admixture:7 kg/m3
• w/c ratio:0.36

Trail mix:

Cement: FA: CA

1:2.7:3.43

----------------------------------------------------------------------------------------------------------------------------------

Mix design for M50:

STIPULATIONS FOR PROPORTIONING:

• Grade of designation:M50
• Exposure condition: severe(assuming)
• Assume type of cement: OPC53 (IS 8112)
• Max size of aggregate:20mm
• Minimum cement content:320 kg/m3 (from IS 456-2000 exposure Cond”)
• W/C ratio :0.5 (from IS 456-2000 exposure Cond”)
• Workability :100mm
• Method of concrete placing: pumping
• Degree of supervision: good
• Type of aggregate: crushed angular aggregate.
• Chemical admixture type: superplasticizer.

Test data for materials:

• Cement used: OPC 53
• Specific gravity of cement:3.15
• Chemical admixture type: superplasticizer. (IS 9103)

Sieve analysis:

• Fine aggregate: Conforming to grading zone-1 table-4 of IS 383
• Coarse aggregate: Conforming to table-2 of IS 383 (20mm) @w/c 0.5

Target strength for mix proportioning:

Target mean strength(ft) = fck+1.65 S

M50= fck =35 N/mm2

S=standard deviation=5 N/mm2 (from Table-8 IS 456-2000)

Ft=50+1.65*5

=58.25 N/mm2

I.W/C ratio from graph-1:

From table-5 IS 10262 2009

w/c ratio=0.35

II.W/C ratio from graph-2:

From graph-2 IS 10262-2009

Hence, we used curve line D

We assume w/c ratio=0.4

III.According to environment exposure condition:

Exposure condition: moderate

From IS 456-2000 table-5 clause 6.1.2,8.2.4.1 & 9.1.2

w/c ratio=0.45

Now compare above all three values the lower value is adopted as w/c ratio for design mix.

Hence w/c ratio for M50 is 0.35.

Selection of water content:

From IS 10262-2009, max water content for 20mm aggregate@25-50mm slump value is:186 lit

But slump here is 100mm therefore for every 25mm increase slump water content increased by 3%.

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

= 197.16 lit

=197 lit

Calculation of cement content:

w/c=0.35

197/0.35=c

C=562.85=563kgs >320 kg

Proportion of vol. of CA& FA content:

From table-3 IS 10262-2009 vol. of coarse aggregate = 0.6 (@w/c=0.5)

But actual w/c =0.35 it is lower by 0.15, the proportion of vol. increased by0.2

(@+/- 0.01 for every 0.05 change in w/c ratio)

Therefore, vol of coarse aggregate @0.5 W/C=0.63

For pumpable concrete these values are reduced by 10%

Therefore, vol of coarse aggregate=0.63*0.9=0.567=0.567

Vol of FA=1-0.567=0.433

Mix calculations:

• a) Vol of concrete:1m3
• b) Vol of cement= (mass of cement/sp, gravity of cement) x1/1000

=563/3.15*1/1000=0.17873m3

• c)Vol of water=197/1*1/1000=0.197m3
• d) Vol of aggregates=(a-(b+c)) =0.62427
• Mass of CA=e*vol of CA*sp. Gravity of CA*1000

=0.6242*0.567*2.74*1000=969.744

• Mass of FA=e*vol of FA*sp. Gravity of FA*1000

=0.6242*0.433*2.74*1000=740.5633

Mix proportions:

• Cement:563kg/m3
• Water:197lit/m3
• FA:740.56kg/m3
• CA:969.744kg/m3
• w/c ratio:0.35

Trail mix:

Cement: FA: CA

1:1.31:1.722

---------------------------------------------------------------------------------------------------------------------