BlogFor BusinessTalk to a counsellor
CoursesIIT ProgramsPlacementsLog in
BlogFor Business
Talk to a counsellor
Challenge

Project on Concrete Mix Design for various grades of Concrete

AAnand Pj20 Sept 2022

Calculate the Concrete Mix Design for M35 grade concrete with fly ash & M50 grade concrete without Fly ash

  1. I.Concrete Mix Design for M35 grade concrete with fly ash

STIPULATIONS FOR PROPORTIONING

  1. a) Grade designation: M35
  2. b) Type of cement : OPC 43 grade conforming to IS 8112
  3. c) Type of mineral admixture: Fly ash conforming to IS 38I2 (Part I)
  4. d) Maximum nominal size of aggregate: 20mm
  5. e) Minimum cement content: 320 kg/m3
  6. f) Maximum water-cement ratio: 0.45
  7. g) Workability: 100 mm (slump)
  8. h) Exposure condition : Severe (for reinforced concrete)
  9. i) Method of concrete placing : Pumping
  10. j) Degree of supervision : Good
  11. k) Type of aggregate : Crushed angular aggregate
  12. l) Maximum cement (OPC) content: 450 kg/m3
  13. m) Chemical admixture: Superplasticizer

TEST DATA FOR MATERIALS

  1. a) Cement used : OPC 43 grade conforming to IS 8112
  2. b) Specific gravity of cement : 3.15
  3. c) Fly ash : Conforming to IS 3812 (Part I)
  4. d) Specific gravity of fly ash: 2.2
  5. e) Chemical admixture : Superplasticizer conforming to IS 9103
  6. f) Specific gravity of:
  7. Coarse aggregate: 2.74
  8. Fine aggregate :2.74
  9. g) Water absorption:
  10. Coarse aggregate: 0.5 percent
  11. Fine aggregate: 1.0 percent
  12. h) Free (surface) moisture:
  13. Coarse aggregate: Nil (absorbed moisture also nil)
  14. Fine aggregate: Nil

Step 1: TARGET STRENGTH FOR MIX PROPORTIONING

As per IS 10262: 2009,

f'ck =fck + 1.65 s

where,

f'ck = target average compressive strength at 28 days,

fck = characteristic compressive strength at 28 days, and

s = standard deviation.

From Table 1 IS 10262:2009, standard deviation, s =5 N/mm2

Therefore, target strength =35 + 1.65 x 5 = 43.25 N/mm2

Step 2: SELECTION OF WATER-CEMENT RATIO

From Table 5 of IS 456, maximum water-cement ratio = 0.45 (severe).

As per Graph of generalized relation between free water cement ratio and compressive strength of concrete of Page 7, IS 10262 : 2009 , the w/c ratio is 0.36

Whereas, as per graph of relation between free water cement ratio and concrete strength for different cement strengths, the water cement ratio is 0.34

Therefore, 0.34 (lowest) is adopted.

Step 3: SELECTION OF WATER CONTENT

From Table 2, maximum water content =186 litre (for 25 to 50 mm slump range)

for 20 mm aggregate

Estimated water content for 100 mm slump =186+ (6/100) x186=197 litre

As superplasticizer is used, the water content can be reduced up 30 percent.

Based on trials with superplasticizer water content reduction of 29 percent has been achieved. Hence, the arrived water content =197 x 0.71 =140 litre

Step 4: CALCULATION OF CEMENT AND FLYASH CONTENT

Water-cement ratio =0.34

Cementitious (cement + fly ash) content= 140/0.34=411.76 kg/m^3

From Table 5 of IS 456, minimum cementitious content for 'severe' exposure condition = 320 kg/m3

411.76 kg/m3 > 320 kg/m3, hence, O.K.

NOTE - This illustrative example is with increase of 10 percent cementitious material content. Cementitious material content= 411.76 x 1.10 = 452.94 kg/m3

Water Content = 140 kg/m3

So. water-cement ratio = 140/452.94 = 0.309

Fly ash @ 30% of total cementitious material content= 452.94 x 30% =135.88 kg/m3

Cement (OPC) = 452.94 – 135.88 =317.06 kg/m3

Saving of cement while using fly ash = 411.76 – 317.06 = 94.7 kg/m3, and

Fly ash being utilized = 135.88 kg/m3

Step 5 : PROPORTION OF VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE CONTENT

From Table 3. volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone I) the water-cement ratio 0.5 =0.60.

In the present case water-cement ratio is 0.34. Therefore. volume of coarse aggregate is required to be increased to decrease the fine aggregate content. As the water-cement ratio is lower by 0.10. the proportion of volume of coarse aggregate is increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in water-cement ratio).

Therefore. corrected proportion of volume of coarse aggregate for the water-cement ratio of 0.35 = 0.63.

NOTE - In case the coarse aggregate is non angular one. then also volume of coarse aggregate may be required 10 be increased suitably , based on experience.

For pumpable concrete these values should be reduced by 10 percent.

Therefore, volume of coarse aggregate = 0.63 x 0.9 = 0.567.

Volume of fine aggregate content = 1- 0.567 =0.433

  1. Volume of concrete = 1m3
  2. Volume of cement = Mass of cement x 1

Specific gravity of cement 1000

=(317.06/3.15) x(1/1000)= 0.1006 m^3

  1. Volume of fly ash = Mass of fly ash x 1

Specific gravity of cement 1000

=(135.88/2.2)x(1/1000)= 0.062 m^3

  1. Volume of water = Mass of water x 1

Specific gravity of water 1000

=(140/1) x(1/1000) = 0.140 m^3

  1. Volume of admixture = Mass of admixture x 1

Specific gravity of admixture 1000

=(7/1.145) x(1/1000) = 0.006m^3

  1. Volume of all in aggregate = (a-(b+c+d+e)) = 0.691 m^3
  2. Mass of coarse aggregate = f x volume of coarse aggregate x sp. gr. of CA x 1000

=0.691 x 0.567 x 2.7 x 1000 = 1057.85 kg

  1. Mass of fine aggregate = f x volume of fine aggregate x sp. gr. of FA x 1000

= 0.691 x 0.433 x 2.7 x 1000 = 807.85 kg

MIX PROPORTION FOR TRIAL NUMBER 1

Cement= 317.06 kg/m^3

Flyash = 135.88

Fine aggregate=807.85 kg/m^3

Coarse aggregate = 1057.85 kg/m^3

Chemical Admixture=7.7 kg/m^3

Water=140 kg/m^3

Water cement ratio = 0.34

  1. Concrete Mix Design for M50 grade concrete without fly ash

STIPULATIONS FOR PROPORTIONING

  1. a) Grade designation: M50
  2. b) Type of cement: OPC 43 grade conforming to IS 8112
  3. c) Maximum nominal size of aggregate: 20mm
  4. d) Minimum cement content: 320 kg/m3
  5. e) Maximum water-cement ratio: 0.45
  6. f) Workability: 100 mm (slump)
  7. g) Exposure condition: Severe (for reinforced concrete)
  8. h) Method of concrete placing: Pumping
  9. i) Degree of supervision: Good
  10. j) Type of aggregate: Crushed angular aggregate
  11. k) Maximum cement (OPC) content: 450 kg/m3
  12. l) Chemical admixture: Superplasticizer

TEST DATA FOR MATERIALS

  1. a) Cement used: OPC 43 grade conforming to IS 8112
  2. b) Specific gravity of cement: 3.15
  3. c) Chemical admixture: Superplasticizer conforming to IS 9103
  4. d) Specific gravity of:
  5. Coarse aggregate: 2.74
  6. Fine aggregate :2.74
  7. e) Water absorption:
  8. Coarse aggregate: 0.5 percent
  9. Fine aggregate: 1.0 percent
  10. f) Free (surface) moisture:
  11. Coarse aggregate: Nil (absorbed moisture also nil)
  12. Fine aggregate : Nil

Step 1: TARGET STRENGTH FOR MIX PROPORTIONING

As per IS 10262: 2009,

f'ck =fck + 1.65 s

where,

f'ck = target average compressive strength at 28 days,

fck = characteristic compressive strength at 28 days, and

s = standard deviation.

From Table 1 IS 10262:2009, standard deviation, s =5 N/mm2

Therefore, target strength =50 + 1.65 x 5 = 58.25 N/mm2

Step 2: SELECTION OF WATER-CEMENT RATIO

From Table 5 of IS 456, maximum water-cement ratio = 0.45 (severe).

As per Graph of generalized relation between free water cement ratio and compressive strength of concrete of Page 7, IS 10262 : 2009 , the w/c ratio is 0.3

Whereas, as per graph of relation between free water cement ratio and concrete strength for different cement strengths, the water cement ratio is 0.34

Therefore, 0.3 (lowest) is adopted.

Step 3: SELECTION OF WATER CONTENT

From Table 2, maximum water content =186 litre (for 25 to 50 mm slump range)

for 20 mm aggregate

Estimated water content for 100 mm slump =186+ (6/100) x186=197 litre

As superplasticizer is used, the water content can be reduced up 30 percent.

Based on trials with superplasticizer water content reduction of 29 percent has been achieved. Hence, the arrived water content =197 x 0.71 =140 litre

Step 4: CALCULATION OF CEMENT CONTENT

Water-cement ratio =0.3

Cement content= 140/0.3 =466.67 kg/m^3

From Table 5 of IS 456, minimum cementitious content for 'severe' exposure condition = 320 kg/m3

466.66 kg/m3 > 320 kg/m3, hence, O.K.

Step 5 : PROPORTION OF VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE CONTENT

From Table 3. volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone I) the water-cement ratio 0.5 =0.60.

In the present case water-cement ratio is 0.3. Therefore. volume of coarse aggregate is required to be increased to decrease the fine aggregate content. As the water-cement ratio is lower by 0.10. the proportion of volume of coarse aggregate is increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in water-cement ratio).

Therefore. corrected proportion of volume of coarse aggregate for the water-cement ratio of 0.3 = 0.64.

NOTE - In case the coarse aggregate is non angular one. then also volume of coarse aggregate may be required 10 be increased suitably , based on experience.

For pumpable concrete these values should be reduced by 10 percent.

Therefore, volume of coarse aggregate = 0.64 x 0.9 = 0.576.

Volume of fine aggregate content = 1- 0.576 =0.424

  1. Volume of concrete = 1m3
  2. Volume of cement = Mass of cement x 1

Specific gravity of cement 1000

=(466.66 /3.15)x(1/1000)= 0.148 m^3

  1. Volume of water = Mass of water x 1

Specific gravity of water 1000

=(140/1) x(1/1000) = 0.140 m^3

  1. Volume of admixture = Mass of admixture x 1

Specific gravity of admixture 1000

=(7/1.145)x(1/1000) = 0.006m^3

  1. Volume of all in aggregate = (a-(b+c+d)) = 0.706 m^3
  2. Mass of coarse aggregate = e x volume of coarse aggregate x sp. gr. of CA x 1000

=0.706 x 0.576 x 2.7 x 1000 = 1097.97 kg

  1. Mass of fine aggregate = e x volume of fine aggregate x sp. gr. of FA x 1000

= 0.706 x 0.424 x 2.7 x 1000 = 808.23 kg

MIX PROPORTION FOR TRIAL NUMBER 1

Cement= 466.66 kg/m^3

Fine aggregate=808.23 kg/m^3

Coarse aggregate = 1097.97 kg/m^3

Chemical admixture = 7kg/m^3

Water=140 kg/m^3

Water cement ratio = 0.3

Your portfolio, next

Ship work like this
in your own course.

Talk to a career counsellor

Free 20-minute call. We'll map the right course to where you want to work.

By submitting you agree to our Terms and Privacy Policy.