Take a look at this link.

Mix desgin is an important step in concreting. For this, first you should select the source of good concrete making materials. Once the sources are finalized (through testings), you can take samples and send the same to a reputed lab for mix design of M20 concrete. The mix-design is done as per IS 10262. Else, you can follow nominal mix proportions of 1:3:4.5 (cement:sand:aggregate) by vol. The quantity of water should be decided as per use but try to keep slump in the range of 50-60 for manual placing.

Make sure, the mix design is done with the same material that you intend to use actually at site. Also, after mix design report is sent by the lab, validate the same by doing trial at site and checking the concrete cubes for required strength.

what should be the least value of m20(lab report)

Dear Sir,

As per our Consultant Mix Ratio is 1: 1 1/2: 3, Cement Grade of 53, Cement is 410 Kgs, Sand is 765 Kg and Stone is 1485 kgs, and water is 30 Litres.

But i wanted to cross check, but i dont know how to calculate please help me to do the same.

With regards,

Babu.

Dear Babu,

It would be easier if you provide the mix-design report of your consultant. The mix-design report contains all the calculations and steps followed in arriving at this proportion. By going through that report you can understand the logic of this proportion. Primafacie, it seems your consultant is inclined to use more cement. Generally, we use M43 grade for M20 and that also in the range of 350~370 kg at the most. For such high grade and quantity of cemet you need to do proper curing to protect your concrete from cracking.

For cross checking, you can collect the samples of your materials and send them to reputed labs for doing mix-design.

Dear Sir,

Thanks for ur valuable suggestion regarding importance of curing, Regarding calculation, My consultant hadn't given us any calculation, they said us only the Mix proportion and Quantity.

With Regards,

Babu.

Hi Babu

1:2:4

Cement 300 kgs

Water Cement Ratio- .5 to .55( 150 to 170 Kgs)

Thanks

Based on my experience, I can suggest:

Cement- 380 kg

Water- 200 ltr

Sand- 650 kg

Aggregate- 1175 kg

Please make the trail mix and do the testing of cubes for strength. You can also try by changing the proportion to optimize the ratio.

Good luck!