Advice required on Ready Mix Concrete (RMC)

[kvanbu]

Hello all,

I need your advise on RMC. My contractor is advising me to go with RMC for footings & molding. It is a 30X40 site with G+3 floor construction. It is a full contract. As per agreement, the choice is mine and he also agree with my decision. He is fine to go with any brand of RMC or manual mix with M-Sand. I need to give the difference if i need river sand.I see a different view from each on this topic. I have few questions

1. Is it good to use RMC?
2. Is it better than manual mix?
3. Shall i go with ACC RMC or any other better brand if i opt to go with RMC?
4. Is there any specific recipe we have to select for good RMC mix?

Please share your inputs. Thanks in advance.

Thanks,
Anbu

[rajnikant]

Hi Mr.Anbu,

1.Going with RMC is always better than manual mix as the mixture is mixed well.
2.The minimum cement content should be "not less than 300 kgs/Cu.M" of concrete if the grade is M20.
3.Some RMC's add fly ash as one of the components which might result in surface cracks after concreting if curing is not started at the right time.If this cannot be allowed kindly avoid RMC's which add flyash.
4.Instead of Sand RMC's use crusher dust(Robo Sand,Manufactured sand),GGBS, etc.,this can be used for RMC works.

[kvanbu]

Thanks Rajinikanth for your valuable inputs. I have inquired it with ACC RMC. They use 50% cement and 50% GGBS for M25. They use 160KG cement per cubic meter and rest GGBS. They are using only m-sand. (I am going to use 100% m-sand for construction except plastering. Please advise me if any issue in using m-sand) I went with ACC M25 for footing. Do you see any issue with M25 with above combination?. I am planning to go with same for slabs. Do you have any better mix design proposal and curing advise for me? ACC takes custom mix design also. Is there any better RMC i can go?

Thanks,
Anbu