Saturday, January 22, 2011

Sustainable Re-Construction in Small Closed Systems

Rubble in streets of Haiti (image from Gerald Herbert/Associated Press - source).

A year after Haiti's devastating earthquake, re-construction efforts there have come upon significant hurdles.  In the latest issue of the American Ceramic Society Bulletin is a great article detailing these hurdles [1] (info also over at ScienceDaily).  According to the article authors DesRoches et al:

"The unprecedented damage was caused by, to a large extent, the absence of seismic details, poor-quality materials (concrete and steel) and lack of quality control in construction."

And more, it is the debris itself which is limiting progress:

"...we believe that landfilling this volume of debris is impossible.  And, our calculations show typical disposal techniques are simply not practical.  The debris has created a huge logjam that is blocking re-construction.  Land can't be cleared, streets can't be opened and even foot traffic must be re-routed over long distances.  Nevertheless, the concrete and other debris largely remain where it was when the earthquake struck ... we estimate that debris removal could take 20 years or longer to accomplish at current removal rates."

Sustainability has different meanings in different areas of the world.  Improved materials, extended means for waste removal / treatment, and higher quality control are possible in more affluent, large, or capable areas.  Haiti, on the other hand, in the state as described by DesRoches et al, may be better thought of as a small closed system, e.g., such as Easter Island [2].  Sustainable re-construction in a small closed system means:
  • Given the inability to ship rubble elsewhere, new construction materials must incorporate a maximum amount of rubble; 
  • Given the need to re-use rubble in new construction, the construction materials must possess maximum recycle-ability; and
  • Incorporation or utility of complex / process-intensive / energy-intensive materials during re-construction can be minimal.
On its face, the latter point is particularly important for Haiti, given the difficulty of maintaining high levels of quality control.  However, the latter point also reflects the more subtle but important links between thermodynamics and sustainability in small closed systems.  More specifically, that the energy and entropy in a system must be closely in tune with the physical limitations of that system; and that is no more true than when evaluating or designing materials for small closed systems. 

[1] R.R. DesRoches, K.E. Kurtis, and J.J. Gresham.  Breaking the reconstruction logjam: Haiti urged to recycle concrete rubble.  Bulletin of the American Ceramic Society, Vol. 90 (2011), pp. 20-26.
[2] P. Nagarajan.  Collapse of Easter Island: Lessons for sustainability of small islands.  Journal of Developing Societies, Vol. 22 (2006), pp. 287-301.

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