well this is sort of on topic since
we use a fair amount of cement making
decorations, edges, stepping stones,
it is good to hear that they are
working on finding out how to make
cements that do not add CO2 to the
atmosphere as much as the current
technology for making Portland
in the current issue of the Smithsonian
(Dec, 2011) has an article about someone
making cement from magnesium silicate (and
other things). the most notable features,
it absorbs CO2 and is whiter.
good thing to see, i hope it pans out.