DIY type forum members may find this interesting.  I stumbled on when doing some research before doing a bit of repairs on my own house.  ever wonder why some old structures in Europe, including Roman structures, seem to endure for forever, when modern construction crumbles away in a few short years.   the answer i think is in the lost art of lime construction, specifically hydraulic lime, both as mortar, and in cement (Roman construction).  it turns out that hydraulic lime, like aircraft aluminum, is "self healing".  that is, cracks reseal themselves...  and the material is very flexible.  lending itself to the construction of buildings that can last a very long time. 

thankfully, the art of hydraulic lime is being rediscovered...  anyway, here is a blog that goes into a bit of detail on haydraulic lime.  i hope that it continues to spread. modern construction is pretty awful and in need of going back to the basics:

"I am coming to the end of a long-term project involving the stone foundation that supports our early-1890’s home. Looking around the city where I live, many 19^th Century era stone foundations, and many brick homes and chimneys as well, are in dire need of repair, ours being no exception. Originally bound together with a mixture of locally-sourced fired-limestone, sand and water, the joints between the stones had been long neglected and/or the sorry recipient of a common “repair” method involving cement-based mortar lain over the original lime mortar mix. This post examines my ventures into the ancient world of lime mortar and the rekindling of a largely forgotten practice. "

the rest:

http://2cycle2gether.com/2010/09/reviving-lime-mortar/