Surface Retarder 3

[dik]

Has anyone used a surface retarder for finishing concrete. We have a project where the contractor is proposing to use one; I'm kind of reluctant to use one since the surface can be affected... anyone used one with/without success?

Dik

 

[jike]

I have used it for exposed aggregate to allow you to wash off the paste.

 

[msquared48]

It's called sugar...

Mike McCann
McCann Engineering

 

[dik]

Jike:
It's not for exposing the aggregate... just for allowing a greater time for finishing. It's my first encounter with this product.

Dik

 

[shin25]

If the contractor wants a longer set time for finishing, then he should add retarder in the mix. It does not sound right that top of the concrete where the finishing will be done will be still plastic, whereas the layer just below will be about to set. This probably will not give good finish from the durability stand point.

 

[jike]

Agreed, he should be using a retarder in the mix, not a spray on retarder on the surface. Make sure that it does not have any calcium chloride in it.

 

[dik]

Thanks, guys... just wanted to know if anyone had experience with this... I've not encountered it before and I didn't think it was a particularly good idea, but wanted to know if anyone had experience with this before I suggested it was a poor idea.

Thanks, Dik

 

[Zambo]

As a Contractor I have on a coule of occasions come across cases where the concreting gang have "lost control" of a large slab finishing operation. This is of course due to poor planning or insufficient workers. But this question makes me wonder whether, in an emergency, a surface retarder would give the team time to catch up.

 

[dik]

Thanks... I've located a product called "Confilm" by BASF that seems to accomplish the same... it's called an "Evaporation Reducer"... anyone have experience with this material?

Dik

 

[Zambo]

Jike,

I think msquared48 is correct in stating sugar is a retarder. Calcium chloride on the other hand is an accelerator and not applicable to this topic.

dik,

what is the manufacturer/name of the product?

 

[dik]

CONFILM by BASF... btw, sugar is a real retarder <G>... I think Jike's comment is that many retarders work adversely with calcium chloride... I specifically state that calcium chloride not be used for anything but temporary structures...

Dik

 

[jike]

Zambo: Yes, I agree that CC is an accelerator but you need to carefully read the ingredients in all admixtures to make sure there is nothing detrimental to the finished product. I include that statement in our specs for all admixtures as a precaution.

dik:

We have used Confilm for many years and it is an excellent aid in finishing but not a retarder. it will help in keeping the surface from drying out prematurely.

 

[samdamon]

dik- Look into a finishing aid called Eucobar. Have asked for its use twice in the last two years with no problems or issues arising. Mfgr calls it an "evaporative retardant", its purpose is to help reduce possibilities of shrinkage cracking due to evaporative loss of water from the top of flatwork in windy or sunny areas. Is this what your Contr is worried about?