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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.

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

1 2 3 17
Er.s.syed abdul kader,B.E says:

i am a civil engineer… nom i am working in construction field.. please send me ratio tabulation of m20& m25 etc….

thank you

Er Sanjay Kr Sahu says:

It may be good but what is location from where samples were taken? as CA/ FA qualities are different at different locations. I hope in next he will provide the location too, so that our fellow engrs, can use without any hassle.

Anil Nair says:

i am a civil engineer… nom i am working in construction field.. please send me ratio tabulation of m20& m25 etc….

thank you

vivek says:

i am into construction field,pls send me the values of compressive strength to be attained for M15,M20,M30 for 7days,14days,28 days

A.kumaraswamy says:

Sir,
I am a civil engineer,and searching for a job.I want mix ratios and design for M15,M20 etc….

obinna says:

am a civil engineer.pls send the various grades of concrete for construction,where they are
use in construction,their characteristics strenght and mix ratio.

obinna says:

am a student in civil engineering,pls,send factoers to be considered on economical reinforcement
concrete structures in both design and construction to me.thanks

Melaku says:

I am hydraulic engineer please send me ratio of cement gravel, sand and water for the weakest grade to the strongest grade of concrete in tabular form.
I thank you very much.

Saneesh says:

i am a civil engineer. Plese send the classification of Mixes and it casting ratios

naidu says:

i am acivil engineer,working in maytas infra as a Dy.manager. please send the desin mixes of M20 AND what are formats
maintained usevally.

Thanks & Regards,
Naidu.

Raj Dhanshetti says:

I am a civil Engineer.can u send me the mix design details for diff Grade
s of concrete and concern areas which we are using.

Regards,
Raj

rajendra says:

Sir,
how to decide grade of concrete from mix design. pls give me suggestion regarding the same, i am very confuse about that,II

arun.k says:

sir, how to design for high strength concrete please send me

vijay kumar gupta says:

i am a civil engineer… nom i am working in construction field.. please send me ratio tabulation of m20& m25 etc….

vijay kumar gupta says:

I want mix ratios and design for M15,M20 etc…

paul tensingh says:

hi Im working in interior field.. Now i am going back 2 civil side… could u please tell me the deffertiation of concretes… thank u!

Deeno says:

How strong is 20N/Sq mms?
For 3 storey building, would it suffice?

Prakash L M says:

Hi Im working in construction field.. please send me detailed of various concrete grades with
ratio & send latest technology details.

manoranjan dhal says:

Sir,
how to decide M 30 grade of concrete from mix design in ppc . pls give me suggestion regarding the same.

Regard

manoranjan dhal

shambu herur says:

Sir,
i am doing my m.tech.now m in final semester doin project
of carbon fibre reinforced concrete so send me the procedure and
were i get the corbon fibre……..

1 2 3 17

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