Table of Contents
Journal of Structures
Volume 2014, Article ID 859879, 7 pages
http://dx.doi.org/10.1155/2014/859879
Research Article

Characterization and Degradation of Masonry Mortar in Historic Brick Structures

Clemson University, 100 Clemson Research Boulevard, Anderson, SC 29625, USA

Received 7 January 2014; Revised 16 March 2014; Accepted 18 March 2014; Published 27 April 2014

Academic Editor: Elio Sacco

Copyright © 2014 Denis A. Brosnan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study characterized mortars from a masonry fortification in Charleston, South Carolina (USA), harbor where construction was during the period 1839–1860. This location for analysis was interesting because of the sea water impingement on the structure. The study was included as part of an overall structural assessment with restoration as an objective. The mortars were found to be cement, lime, and sand mixtures in proportions similar to ones expected from the historic literature, that is, one part binder to two parts of sand. The binder was found to be American natural cement, a substance analogous to the European Roman cement. The results suggest that the thermal history of the cement during manufacturing affected setting rate explaining why the cements were considered as variable during the mid-to-late 1800s. Fine pores were found in mortars exposed to sea water resulting from corrosion. Contemporary natural cement was shown to release calcium in aqueous solution. While this release of calcium is necessary for setting in natural and Portland cements, excessive calcium solution, as exacerbated by sea water contact and repointing with Portland cement mortars, was shown to result in brick scaling or decay through cryptoflorescence.