Concrete
The Romans used concrete from the
earliest days of the republic. In Latin it is opus caementicium, from which we derive our modern word for cement,
an ingredient in concrete. Cement is a paste consisting of water hydraulic
ingredients, that is, a mix of minerals such as lime-ash with water and other
dry ingredients which when it sets become very hard. Once mixed it can be
poured under water and it still hardens. Concrete is the mixing of gravel or
crushed stone, to the cement. The Romans invented hydraulic cement-based
concrete, concretus, which is similar
to modern day Portland cement. After mixing the ingredients with water, the
laborers poured the mixture into wooden forms and allowed time for hardening or
setting. The time varies based on the accuracy of the mixture, and the type of
lime used. But once set they remove the forms from a now stone-hard object that
can last for ages.
The way of making this material was
lost during the middle-ages, and remained so up until the late 1700s when James
Parker of England developed what he called Roman Cement. Following that a
British brick layer, Joseph Aspdin applied for and received a patent for a
product he named Portland cement. His was similar to Parker’s but, his
contained artificial hydraulic lime. The Ancient Romans made cement from quick
lime, pozzolanic ash (which has hydraulic properties), and an aggregate of
pumice. Its consistency was very similar to Portland cement of today. Both of
these cements set under water too. This was a boon to the Romans; it allowed
them to build many seaports serving provincial coastal towns around the
Mediterranean seas.
Aspdin named the cement Portland
because, after curing and hardening, it is very similar in appearance to the
quarried limestone on the Isle of Portland, in Dorset County, England―thus, the
name―Portland Stone. Some buildings using this stone are: St. Paul’s Cathedral
and Buckingham Palace in London, England and the United Nations Building in New
York City.
The ancient Romans built many
buildings with poured concrete, the Pantheon, a fully intact temple, is one
example. Others are the Baths of Caracalla, and the aqueducts. The ancient
buildings constructed by layering of stones, as in the Coliseum, the people
were able to dismantle them and reuse them to build other structures. Those
made of cement they could not disassemble. Thus, because of the lasting nature
of the cement, many stand fully intact today. An interesting point to reveal is
that after the fall of Rome in the West, the people also lost the know-how to
mine lead. The buildings the Romans made from stones contain lead between the
blocks as a binder. The holes one sees in the walls of some of the existing
ruins are from people chopping into the seams of the stones to procure the lead
within. They used the lead to make bullets.
The major introduction of poured
concrete with Portland cement in the U.S. was two-fold. It was
introduced to America at the Centennial Exhibition in Philadelphia in 1876. However, during the building of the Erie
Canal, engineer Canvass White, who worked on the canal, went to England to
observe how they built them. He saw them using cement and that it was hardening
underwater. Nevertheless, it was very
expensive to ship home, so he instead, on his return in home 1818, created
cement from local resources. Since it
hardened under water, people did not think of using it other than for building
canals and underwater projects.
Franklin Smith, a philanthropist, a
founder of the Y.M.C.A, and an amateur architect, traveled to Spain and visited
the Alhambra, a famous Moorish castle. He became enamored with the art of the
structure. Subsequently, he went to Switzerland and there he saw laborers
pouring concrete made with Portland cement. He brought these two observances
home and built himself a house, based on the architecture of the Alhambra. It
is located on King Street in downtown St. Augustine, Florida. Today the
building is a museum, The Zorayda Castle. It is open to the public. Nearby,
there are three buildings made of poured concrete, two built in Spanish
architecture by Henry Flagler and the third in Moorish Style by Franklin Smith.
The construction of these building was between 1885 and 1888. They are: the
Flagler College, formerly the Ponce de Leon Hotel, The Lightener Museum and
City Hall, formerly the Alcazar Hotel, and the Hotel Casa Monica, designed by
Franklin Smith. He named the hotel after the mother of St. Augustine. The photographs as the appear are: La Casa Monica, La Villa Zorayda, 1836 painting of the Pantheon, The Alacazar containing the Leightner Museum, and Flagler College.
