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Concrete Mix Design – M 20 Grade Of Concrete

1. REQUIREMENTS
a) Specified minimum strength = 20 N/Sq mm

b) Durability requirements
i) Exposure Moderate
ii) Minimum Cement Content = 300 Kgs/cum

c) Cement
(Refer Table No. 5 of IS:456-2000)
i) Make Chetak (Birla)
ii) Type OPC
iii) Grade 43

d) Workability
i) compacting factor = 0.7

e) Degree of quality control Good

2. TEST DATA FOR MATERIALS SUPPLIED
a) CEMENT
i) Specific gravity = 3.05
ii) Avg. comp. strength 7 days = 46.5 more than 33.0 OK
28 days = 55.0 more than 43.0 OK

b) COARSE AGGREGATE
i) 20mm Graded
Type Crushed stone aggregate
Specific gravity = 2.68
Water absorption = 1.46
Free (surface) moisture = 0

sieve_analysis_m20_grade_of_concrete

c) FINE AGGREGATE (Coarse sand)
i) Type Natural (Ghaggar)
Specific gravity = 2.6
Water absorption = 0.5
Free (surface) moisture = 1.4

sieve_analysis_fine_m20_grade_of_concrete

3. TARGET MEAN STRENGTH (TMS)
a) Statistical constant K = 1.65
b) Standard deviation S = 4.6
Thus, TMS = 27.59 N/Sqmm

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4. SELECTION OF W/C RATIO
a) As required for TMS = 0.5
b) As required for ‘Moderate’ Exposure = 0.55
Assume W/c ratio of 0.5

5. DETERMINATION OF WATER & SAND CONTENT
For W/C = 0.6
C.F. = 0.8
Max. Agg. Size of 20 mm
a) Water content = 186 Kg/cum
b) Sand as percentage of total aggregate by absolute volume = 35 %

Thus,
Net water content = 180.42 Kg/cum
Net sand percentage = 33 %

adjustments-m20-grade-concrete

6. DETERMINATION OF CEMENT CONTENT
W/c ratio = 0.5
Water content = 180.42 Kg/cum
Thus, Cement content = 360.84 Kg/cum Adequate for moderate exposure Say 360 Kg/cum

7. DETERMINATION OF COARSE AND FINE AGGREGATE CONTENT
Assume entrapped air as 2 %
Thus,
0.98 cum = [180.42+360/3.05 + {1/0.33}*{fa/2.6}]/1000
& 0.98 cum = [180.42+360/3.05 + {1/0.67}*{Ca/2.68}]/1000
Hence,
fa = 584 Kg/cum
Ca = 1223.8 Kg/cum

The final mix proportions of M-20 grade of concrete become:-

mix-design-concrete-m20

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Note: 1 The above recommended mix design must be verified, by actual cube tests.
2 The mix design is based on the quality and grading of the materials actually supplied, by the client.
Any variation in quality and gradation will result in changes in the mix design.

This mix design was submitted by a regular contributor to this site. We are thankful to him for his excellent service.

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Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

If you have a query, you can ask a question here.

384 comments on "Concrete Mix Design – M 20 Grade Of Concrete"

1 4 5 6 7 8 17
Bishnu says:

me student of civil engineering, thank u very much for your study supporting materials.

prajeesh m says:

i think u can do it much better….for eg: w/c ratio graph could b shown

Thanmanaselvi says:

The Study Material is really very good and useful. Thank You…

Shivling Gundad says:

What is the theorotical Mix Design Proportion for M 25 Grade Of Concrete and Details ???

Sushil Khurana says:

we have required for What is the theoretical Mix Design Proportion for M 25 Grade Of Concrete and Details with ratio n analysis ???

Vivek Kumar Pathak says:

Sir,this web site is not only usefull for students but alsofor proffessionals.
Sir pl provide design mix for rigid pavements and necessary information regarding PQC and letest repair techenology for repair of flaxible pavements.

S. K. Parida says:

Sir,
We have required for What is the theoretical Mix Design Proportion for M 25 Grade Of Concrete and details with ratio n analysis (Using 33 grade OPC, ‘moderate’ exposure, slump=180-190 mm & required water reducing admixture), as per IS standard.
Thanking U.

S. K. Parida.

Er.Bhavin shah says:

sir, this is such a very useful website. its very helpful to every person who is connected with construction and also to students.
sir pl.provide mix design of F.R.C. and G.F.R.C to me.

v.samba sivudu says:

please tell me how to calulate the cement quantity for m10,m15,m20,m25,m30,m35 & how to calculate aasfgvsdgfdthe curve calculation for canal lining for 2:1 slope(concrete)

v.samba sivudu says:

what is the volume of cement bag

umesh shirwadkar says:

i have details of M25 concrete slump test.

len archie says:

the figures given for the mix design above is for 1 cu m of concrete??

mohd. zuber says:

i want to know about the cement consumption in 1 cubic meter RCC (1:1.5:3) and PCC (1:2:4).

sreepriya says:

Sir
i need mix design calculation for M25 grade concrete

manish saini says:

its good to learn about more in mix design m20.

Utpal Bora says:

Nice to learn more about mix design of different grade of concrete

Sharan gokale says:

Its a very informative but i wanna know the minimum cement requirement for M25 grade concrete with OPC43

kumar says:

i want to know about the cement consumption in 1 cubic meter RCC (1:1.5:3) and PCC (1:2:4).

Siddharth Tandon says:

Generally we consider the ratio of m20 grade as (1:1.5:3)as cement , fine aggregates , and coarse aggregates
so is it also right (1:1.5:3) if we manually prepare concrete at site.
i will be grateful if you can reply on this

Mulji Gohel says:

I am a commerce graguateand having 7 years laboratory technician experiance.pls give me fully theortical details about concrete mix design

1 4 5 6 7 8 17

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