Cob cob / ceramics -->Have you heard of geopolymers?

[Ken Potter]

Hi everyone,

This is somewhat off topic but related.  I am also interested in ways to
build water containment structures from natural materials.  I came across a
material called geopolymer.  The only web reference on this topic is:

http://www.insset.u-picardie.fr/geopolymer/index.shtml

This material is a low temperature ceramic that is being used for:

-fire resistant matrix materials for use in aircraft composites
-external repair and structural retrofit for aging infrastructure and
     aging buildings
-stabilization of toxic materials

This material produces approximately 90% less CO2 than Portland cement.
Geopolymers are stable to extremely high temperatures (they have been used
for handling molten metal) and have a permeability less than that of
ordinary Portland cement.  This is clearly a material that could make your
house (or pond) waterproof as well as fire proof.  The real challenge is in
bringing it to the do-it-yourselfer.  I have experimented with the material
and had less than satisfactory results.

This material is an evolution of ancient Roman cements.  Clearly there must
be a low tech method for producing this type of material.  Note that the
Roman cement has held up for over 2000 years where Portland cement is doing
well to make it to 50 years.

If anyone on the list has knowledge of geopolymers, mineral chemistry, or
ancient Roman cement, perhaps they can shed some light on this topic.  My
training is in mechanical engineering.  I have a understanding of basic
chemistry, but I am clearly missing something here.  The above web site
includes several PDF files that you can download.  Most of the information
on this topic is in the patent literature which is referenced in the
downloadable papers.

Hope this spikes some interest out there!!

kpotter at flash.net