column concrete cover fill in

[ticas]

How do you usually handle this issue where after the formworks for the column is removed, there is a shallow portion not concreted so instead of 40mm concrete cover, there is only 30mm. Do you put cement grout or epoxy to maximize the strength of that portion?

 

[hokie66]

Sounds like honeycombing, due to inadequate consolidation by vibrating, or leaky forms which allow the slurry to escape, leaving behind the aggregate. These areas should be chipped back to sound concrete and patched using concrete repair mortar, mixed and applied in accordance with the manufacturer's instructions.

 

[ticas]

How can you tell if there is honeycomb inside at the center of the column where it can't be seen outside?

 

[humanengr]

Search for GPR Concrete inspection. Firms that provide this service should be able to provide more information
regarding detecting voids inside the concrete using Radar Scanning.

 

[ticas]

The column corner has honeycomb, I'll have it chipped until it reaches sound concrete. But what if the honeycomb reaches 25% of the column section. How do you know when the entire column must be replaced or repoured with new concrete?

 

[msquared48]

When it fails?

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[ticas]

It is construction in progress. Will the column be as strong when you have to chip off 25% of the area and put new concrete or would you need to chip off (or demolish) the entire column and pour fresh concrete?

 

[hokie66]

Acceptance or otherwise requires engineering judgment. It depends on a lot of things. For example, the magnitude of load on the column would influence my decision if I were responsible. Also, proficiency of the party responsible for concrete repair would be a consideration. Advice on the internet is only good to an extent, and the engineer responsible still has to make the decision.

 

[ticas]

Concrete repair would be just to put in new glout and fine aggregrate just to fill in the gap brought by the honeycomb. Why, is this not sufficient?

 

[msquared48]

It isn't that the fix is not sufficient. The concern was at what point does it become insufficient enough to require a tearout.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com