Answered How to Prevent Rusting Of Reinforcement to continue next pour ?

ARN

Newbie
This is really appreciated you to raised the concern and thoughts come in mind to stop the rusting within the span of two subsequent pour.

Let me first clear is that the the period between the first pour to second pour is too short and in worst condition it may be prolonged to 20 days up to curtail length of column from slab to slab.

The rusting occurs in this short period is very minor rusting and does not affect strength, stability and durability of structure. but in nearby coastal area, yes; it does affect ! (It is separate subject for discussion, how to control rust and precautions to be taken care in marine and near by coastal area).

This minor rusting is likely to start occurring within 2 hours as soon as contact to atmosphere and exposed to environment. Such rusting is impossible to stop or prevent specially in case of erected steel reinforcement of members like columns, etc.

As per IS 2502, certain amount of hard rust on reinforcement is acceptable in reinforced concrete works. But extreme rusting i,e loose scaling is not desirable. To avoid the same; the stack of reinforcement shall be suitably sheltered.

Thanks
ARN
 

Narendra

Staff member
This is really appreciated you to raised the concern and thoughts come in mind to stop the rusting within the span of two subsequent pour.

Let me first clear is that the the period between the first pour to second pour is too short and in worst condition it may be prolonged to 20 days up to curtail length of column from slab to slab.

The rusting occurs in this short period is very minor rusting and does not affect strength, stability and durability of structure. but in nearby coastal area, yes; it does affect ! (It is separate subject for discussion, how to control rust and precautions to be taken care in marine and near by coastal area).

This minor rusting is likely to start occurring within 2 hours as soon as contact to atmosphere and exposed to environment. Such rusting is impossible to stop or prevent specially in case of erected steel reinforcement of members like columns, etc.

As per IS 2502, certain amount of hard rust on reinforcement is acceptable in reinforced concrete works. But extreme rusting i,e loose scaling is not desirable. To avoid the same; the stack of reinforcement shall be suitably sheltered.

Thanks
ARN
Thank you Sir
 

Dnyan Deshmukh

Staff member
Rusting is good for concrete, it enhance the bond between reinforcement and concrete.

How to know is it good or bad.

Normal rebar do get rusted over period of time when it is expose to atmosphere (Pure steel or primary steel get rusted faster compare to re-rolled steel or secondary steel)

When we see a normal rusting which is redish color it is good.

When scaling on bar due to excessive rusting seen - it is bad for concrete (scaling happens due to contact of water or extreme weather conditions)
 
This is really appreciated you to raised the concern and thoughts come in mind to stop the rusting within the span of two subsequent pour.

Let me first clear is that the the period between the first pour to second pour is too short and in worst condition it may be prolonged to 20 days up to curtail length of column from slab to slab.

The rusting occurs in this short period is very minor rusting and does not affect strength, stability and durability of structure. but in nearby coastal area, yes; it does affect ! (It is separate subject for discussion, how to control rust and precautions to be taken care in marine and near by coastal area).

This minor rusting is likely to start occurring within 2 hours as soon as contact to atmosphere and exposed to environment. Such rusting is impossible to stop or prevent specially in case of erected steel reinforcement of members like columns, etc.

As per IS 2502, certain amount of hard rust on reinforcement is acceptable in reinforced concrete works. But extreme rusting i,e loose scaling is not desirable. To avoid the same; the stack of reinforcement shall be suitably sheltered.

Thanks
ARN