Fort Jefferson

FIG. 1—Fort Jefferson, Dry Toitugas, Florida, offered 19th century engineers no fresh water for mixing of mortar and concrete. Seawater was used to no apparent detrimental effect. (Photograph courtesy of Michael Edison, 2(XH.)... 

FIG. 2—Fort Jefferson s remote location left 19th century engineers little choice but to make use of the excessively coarse calcareous beach sand that was at hand. (Photograph courtesy of Kenneth Uracius, 2004.)... 

This information was instmmental in corroborating the identity of original natural cement materials at Fort Jefferson, off the Coast of Florida. The site became one of the first major restoration projects to utilize natural cement in this century. The initial identification of the moitar used in this structure incorrectly concluded that it was some form of Hme. That conclusion was challenged based on historic documentation citing natural cement as the material used in Fort Jefferson. The final verification came in the form of a petrographic analysis by John Walsh. 

The masonry at Fort Jefferson was found to be in remarkable condition, despite lack of maintenance since the beginning of its construction in 1840. It has endured extreme weather and marine exposures without significant masonry deterioration. The need for restoration was a result of the corrosion of cast iron shutters used to protect artillery crews from incoming fire. The evaluation process included a mock-up phase which comprised one of the first modem day uses of natural cement on a significant scale. 

KEYWORDS naturai cement, iime, hydraulic lime, mortar, historic restoration. Fort Adams, Fort Jefferson... 

While looking for books on natural cement on the Internet, 1 met architect Mary Catherine Martin who was also interested in natural cement. After exchange of a few choice e-mails it was decided to share information. Martin was working on a restoration project at Eort Jefferson in Florida and was scheduled to speak about the mortar she had found there at the 2003 APT International Conference in Portland, ME [7]. She was provided with samples of the prototype natural cement material from Rosendale, NY, and used them in her presentation. It became evident through laboratory analysis [8] that Fort Jefferson, like Fort Adams, was built with Rosendale cement. Mock-ups at Fort Jefferson were completed using Rosendale cement in January, 2005. 

Commercial production of Rosendale natural cement was begun in November, 2004 by Edison Coatings, Inc., in Plainville, CT, and the first phase of major restoration began at Fort Jefferson several months later. This was the first commercial production and use of Rosendale cement in 35 years. 

Bucci, T.J., and R.M. Parker. 1992. Toxicity Studies on Agents GB and GD (Phase II) 90 Day Subchronic Study of GB (Sarin, Type II) in CD Rats. Final Report. FDA 224-85-0007. DTIC AD-A248618. Prepared by the National Center for Toxicological Research, Jefferson, Ark., for the U.S. Army Biomedical Research and Development Laboratory, Fort Detrick, Frederick, Md. 

Final Report. Prepared by the National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Ark., for the U.S. Army Medical Research and Development Command, Fort Detrick, Md. 

Bucci TJ, Parker RM, Gosnell PA (1992b) Delayed neuropathy study of sarin, type II, in SPF white leghorn chickens. NTCR Rep 478 and 479. National Center for Toxicological Research, Jefferson, AK. Prepared for U.S. Department of the Army, Biomedical Research and Development Laboratory, Fort Detrick, MD. 

Lutheran Medical Group 7916, W. Jefferson Blvd, Fort Wayne, IN 46804, USA... 

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