**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

c) FINE AGGREGATE (Coarse sand)

i) Type Natural (Ghaggar)

Specific gravity = 2.6

Water absorption = 0.5

Free (surface) moisture = 1.4

**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 %

**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:-

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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.

### 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**.

How many bags will be required for cenment Mortar ratio 1:3 for M20 concrete.It is used for

Gunniting of pipes.Give me suggestion regarding this same.

I am a civil engineer and now working in a construction company in Gurgaon.pls send the various grades of concrete for construction,where they are

use in construction,their characteristics strenght and mix ratio.

Please send me the formula of Ratio finding?

Eg;How much cement to be used for M20 grade concrete?

Thanking you

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

thank you

Hi Im working in construction field.. please send me detailed of various concrete grades with

ratio & send latest technology details.

Thank you,

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

how is steel is calculated and can u please give me the labour constant of the steel

Sir,

I am a fresher civil Engineer, i have to do estimating and costing…Please send me details about concrete mix…

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

20. shambu herur said:

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……..

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.

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.

Sir,

I am an Civil Engineer, I want to know M-10 means 1:2:4 ratio ,how to find cement quantity can you tell me the procedure. Is it volumetric or weight ratio.

I am in construction field,pl.send me the value of max. and min.crushing strength of M15 M20 grade concrete in 7days,28days and 60days.

Sir.

I am final year civil engineering student. i m doing my project on fly ash concrete.

Sir plz send me information @ procedure , types, mix design of diffrent grade by changing

proportion of fly ash & related any information.

am a civil engineer… nom i am working in construction field.. please send me ratio tabulation of M15,M20

& M25 etc…. plus, i need the exact meaning of workability and some example of it…

thank you

Can you please confirm whether the compression strength for M 20 RCC slab results are as below 15.6 15.1 23.1 N/mm2,

The Propportion of Cement, Sand and Aggregate in concrete is 1:2:3

sir, i want to know about the latest admixtures

Sir,

I am a civil engineer.I am working in construction field..

I need mix design process for M20 & M30 using PPC.

Thank you

Sunil

Sir,

im am final yr undergraduate student. Now im conducting a research.could u please send me detailed of M30 concrete grade with

ratio & send latest technology details.

regard

nurrulafifza