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Concrete Mix Design – M 20 Grade Of Concrete

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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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Comments
  • abdulla hegazy December 30, 2008 at 8:27 pm

    can you inform me about pqc concrete mix which is used for airport runway

    thank you

  • Balaji m December 31, 2008 at 11:08 am

    Hi…I am a Civil Engineer… I need Rate analysis details for Concrete and Masonry Work please Send..”

  • khaleeq ahmed khan January 6, 2009 at 7:37 am

    sir I am civil engr pls give me details in asphalt test soil m35grade m20 grade also thanks

  • shiva January 6, 2009 at 8:29 am

    I am Working in Cons. Field 1m3 Of Concrete. (Requirement of sand,metal, Formula?)

  • NguyenTanHoai January 7, 2009 at 8:39 am

    I’m a material engineer,please send to me coast aggregate and Fine aggregate combine built chart. I have both grading but I don’t have up limit and low limit to combine.

  • R Chandra January 8, 2009 at 2:08 pm

    Sir,you did not talk about sump.Also fly ash cement(PPC)makes difference in design.Also give information regarding the chemical admixtures used in concrete & their effect on design mix.

  • ms.rajkumar January 9, 2009 at 11:30 am

    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,
    Rajkumar

  • sudhir January 10, 2009 at 3:10 pm

    What is the strength of 1:6:12 Cement/Sand/Brick Ballast. Is it better to GSB grade III 70 % agrregate + 30 % Stone Dust compacted with Roller after watering.Pl also let me know if polythene 50 micron thickness is used instead of 125 micrion over subase before laying 10 cm thick cc road.

  • thanukumari January 19, 2009 at 4:59 am

    I am a Civil Engineer doing my PhD IN FIBRE REINFORCED CONDRTE.I WANT TO design M60 fibre reinforced concrete. Please give
    an idea for the mix design of above concrete.

  • vikas jayaprakash January 22, 2009 at 4:33 am

    sir, please send me the copy of IS-456 to refer the formwork for precast wall panel as per IS-Standards

  • Syed saif ul haq January 25, 2009 at 8:46 am

    Hello sir i am a civil engineer plz send me a mix design of m20,25,35,40,45

  • Ajay sangave January 28, 2009 at 10:57 am

    hi, Iam field engg.i want some information from you . If in concrete mix design, natural is 4th zone that time how much %os sand will take.

  • Bharat Malani February 2, 2009 at 4:31 am

    Hello sir i am a civil engineer plz send me a mix design of m20,25,35,40,45

  • Asis panda February 4, 2009 at 5:40 am

    Dear sir
    PLZ send the ratio of M15,M20,M25,M30 grade of concrete

  • Aemal February 7, 2009 at 8:56 am

    Dear sir , i’m Civil Engineer , i need M15, M20, M25, M30 grade concrete mix design , please send me if there is no problem , thanks for hellping aemal

  • Moh.Yaqob February 7, 2009 at 9:03 am

    Dear sir , i’m Civil Engineer , i need any concrete mix design for M20, M25, M30 , and i also need the slump test range for conrete M20 M25 M30 , please do send me i need it and any information about concrete you people have do send me please
    i’m waiting for your response i’m from KABUL , AFGHANISTAN
    thanks , bye

  • abbas February 7, 2009 at 10:47 am

    can you send me a mix design of m20,25,35,40,45 please.
    thank a lot.

  • srinivas February 8, 2009 at 1:21 pm

    Dear sir , iā€™m Civil Engineer , i need M15, M20, M25, M30, M35, M40, M45, M60 grade concrete mix design , please send me if there is no problem , thanks

  • Jignesh Vyas February 8, 2009 at 9:46 pm

    Dear sir ,
    I am Civil Engineer , i need M20 grade concrete mix design with detailed calculation.
    material used Cement 53 grade, max. size of aggregate 20mm and mix sand confirming zone II and III. , please send me, it will help me if there is no problem.

    Thanking you,
    Jignesh Vyas

  • Eknath Sutar February 9, 2009 at 7:50 am

    Dear Sir,

    We are manufacturing carved RCC frames. These frames looks like carved in wooden. Please inform me which concrete grade I should use as per IS & what is the mix design for the same.

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