irst many thanks to Lisa ,Tybil, and Rudy and all others for their great
imput on Rosendale.
The Coastal forts of the South east United states (1816-1860) known to the
Army Corps of engineers as The third System was a little like our missile
defense system.
Hugely expensive with constant up grades i;e These were massive masonry forts
built in strategic locations designed to protect the young republic from
invasion ...the idea of the third system was simple ....design build a man a
fort callable to hold off an invading force for 14 days until a militia could
arrive; thus slowing down the invasion  This looked good on paper  but to
construct forts in the hostile environments of the sand spits of the Gulf of
Mexico was a daunting task for the engineers.
They knew salt in any form was no good for fabrication of materials; but they
knew the very air was laden with it. To give the engineers credit their is
documentation that wells were dug to fabricate the cements and the mortar
required for the 30 million brick these monster forts required; this is also
true for the turn of century up grades that used the Rosendale cement because
as technology of weaponry advanced so must the structure of the fort.( big
guns make big changes). It is my guess that the sand was most likely washed
with the well water ... but the local fabrication of brick and clay must
surely contained good quantities of it ... they also used oytershell which
when burned makes a non hydraulic lime (I believe) but is the salt burned off
????
Lastly I understand that around the turn of the century salt added to cement
was considered a fire retardant  in and around I beams in new building
....Now according to British heritage as long as salt and lime leeching stay
Wet ; the breakdown of masonry is very slow indeed.Best Michael