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[Q] Moisture through capillarity - prevention/cure products?!?

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I did some research for a nuclear waste repository.  The goal was to
have low permeability concrete.  We used silica fume, and silica sand
for our mix, with superplasticizer.  We tried several mixes, however,
we did not do enough extensive investigation to be able to give proper
guidelines for use.  The mixes were fairly non-permeable, and the
concrete reached up to 14 ksi compressive strengths.

This is probably not related to what you want, but it may give you a
direction.  If you seek Admixtures related to permeability, perhaps
you will find more information.  There are many admixture forms.
Rheobuild is one company I can recall.  I think they mainly produce
High Range Water Reducers, which will greatly reduce the required
amount of water.  With the silica fume and silica sand combined, you
have microscopic pores remaining (not sure about the micro or milli or
nano for these pore sizes).

The High Range Water Reducers are interesting.  They somehow coagulate
the sand and silica fume particles in good order, pushing the water
particles to the gain the best surface area or material particle to
water particle ratios, so you don't create large voids in the concrete
due to large accummulations of water and particles in separate

Although, since I used this product (Rheobuild HWR 1000) they have
probably increased the quantity and quality of products in market.
Perhaps there are better coagulators in the market now.

Another thing to keep in mind, is the quality of the aggregates.  If
you stay closer to certain aggregates, more pure forms of rock rather
than a conglomerate rock ( I don't remember the best qualities, I
think I recall limestone generally has some of the best qualities)
there will be greater adhesions, and less exterior environmental
impacts on finished products.

Silica Fume is interesting, however it consumes alot of water because
it is tiny, and has alot of surface area.  Need to where special
respiratory equipment when handling so not to breath, and get possible
silicosis.  Silica sand is generally very pure.

Refugio Rochin

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