[Greenbuilding] on concrete

[Alan Abrams]

< The availability of portland cements will be affected for years to come by
energy and pollution requirements. In fact, the increased attention to
pollution abatement and energy conservation has already greatly influenced
the cement industry, especially in the production of low-alkali cements.
Using high-alkali raw materials in the manufacture of low-alkali cement
requires bypass systems to avoid concentrating alkali in the clinkers, which
consumes more energy (Energetics, Inc. 1988). It is estimated that 4% of
energy used by the cement industry could be saved by relaxing alkali
specifications. Limiting use of low-alkali cement to cases in which
alkali-reactive aggregates are used could lead to significant improvement in
energy efficiency (Energetics, Inc. 1988).>

maybe a materials expert among us could comment on this passage that I
stumbled over at a fed site:

http://www.fhwa.dot.gov/infrastructure/materialsgrp/cement.html

nonetheless, my intuition is-that the above discussion leads us to the
conclusion that when we must use concrete, we should consider the
reinforcement we use.  I would not be surprised to learn that corrosion of
rebar is the limiting element in the service life of a concrete assembly.
Assuming such, and given that durability is an important sustainable
attribute, it would follow that we consider corrosion resistant coatings on
our reinforcement.  Likewise, formulations of concrete that resist moisture
intrusion.

-AA