RCC slab and Beam - Concrete mixture gone wrong (Used 2:5:7)

Question

Site dimension is 30ft*40ft and we have total 14 columns in the plan.. We have lift planned in the plan too. Also our final roof height for each floor is 11" as per the plan. We are planning to construct Ground + 2floors of 1000sqft each on first and second floor. Ground floor we will have 1 BHK of approx 550 sqft and 2 car parking.
Construction was going fine but for our ground floor roof slab (or first floor bottom slab), contractor used wrong concrete mixture of 2:5:7(Cememnt: Sand: agregates) instead of M20 (1:1.5:3 ratio). Now we are not sure whether our RCC slab and beam safe for constructing first and second floors.

How to check whether the RCC slab and beam is safe and can we construct first and second floor?

Who will do the core cutting testing in bangalore and what is the contact details?

What additional measures to be taken to correct the wrong concrete misture ration. Can we plan steel bars as beams and/or additional columns to ensure that the structure supports the required load?

RCC slab was only put yesterday (27-Sep-2015) and we are very worried about this. Do we nede to break the RCC slab and do again?

Please advise and my contact number is 96111 00513 and please request you to provide the required advise to correct the mistake made by the contractor.

Thanks and Regards
Darshan

Answer 1

You have put very less grade concrete compared to the design mix. I think, it is not vise to brake the structure. Let it to gain the strength. If you can modify the structure, you can solve the problem.

You may  construct load bearing walls to transfer the beam loads to foundations and through the columns. Even for slabs you may do the same. Where ever you can not construct or support larger spans, It is better to have additional columns for supporting the structure.

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