Admixture in Concrete 5

[gosai]

At one of our project contractor wants to use 2% Krystol Internal Membrane (KIM)as an admixture for water proofing purposes. The information for product is uploaded. I never came across using this type of product. Is there someone who knows anything about such products and its suitability to use along with other admixtures like Eucon WR, Eucon 37.

Thanks to all

 

[Ron]

In general, waterproofing admixtures do not work very well. What is your project and what type of waterproofing do you actually need?

 

[Zambo]

I couldn't open the file and haven't time just now to search on the internet for the data sheet.

There are various ways to waterproof concrete by densifying (such as the use of silica fume)or using a hydrophobic admixture. If you choose a product testing can be carried out and warranties can be provided (but of course the warranty doesn't cover workmanship issues).

http://www.xypex.com/specs/csi_a.php?t=general&pageID=54

Whether to try to waterproof the concrete or deciding to use a membrane can often come down to cost and the section size. For example a thin wall could be suitable for using a waterproofing admixture, but a thick slab due to the large volume of concrete to be treated may be more suited to a membrane.

 

[hokie66]

Advertising Krystol or Xypex as an "internal membrane" is deceptive. They work to seal porosity and cracks in much the same way as normal concrete pipes sometimes stop leaking over a period of time by autogeneous healing. There has to be moisture present, and thus leakage, for the products to even start to work. I have several times been asked to investigate why slabs over basement carparks, cast with Xypex admixture, are leaking. The slabs leak because they have restraint shrinkage cracks, have not been built as water retaining structures, and do not have a membrane. Not a good thing to have alkaline leakage onto a lot of BMW and Mercedes automobiles in a residential highrise carpark.

When these products originally came on the market, the companies insisted on strict adherence to minimum reinforcement, minimum cement content and maximum w/c ratio, and wet curing...all to be supervised by their own personnel. In other words, they required quality in construction which would largely make their admixture redundant. These specifications appear to have disappeared from the current manufacturers' literature.

 

[Ron]

Bingo, hokie66.

 

[JedClampett]

One other aspect of these "magic beans" is that they work by using free calcium from the cement reaction. However, so does Fly Ash. So if you have a fly ash mix (very common in these parts), the admixture has nothing to react with and is basically worthless. Very few of these manufacturers fess up to that.
I'm not a believer. Good construction technique and jointing is the way to make concrete waterproof.

 

[BigH]

JedClampett - your last sentence is the clincher . . . but woe is us who don't have this expectation.