A. Elena Charola

Salts in the Deterioration of Porous Materials: An Overview

Abstract The present overview on salt-induced deterioration of inorganic porous materials focuses on those topics considered the most relevant for understanding this phenomenon. These are movement of both water/moisture and salts within the pore system; influence of the presence of salts in moisture absorption; effect of the simultaneous presence of more than one salt; salt distribution in masonry; deterioration mechanisms; and weathering patterns. Of the latter, the most ubiquitous are powdering and scaling, and they have been found to occur on most stone types. However, the mechanism that induces the same outward appearance on different stones can vary significantly depending on the synergism that develops among porous material, salt, and moisture.

Building pathology : deterioration, diagnostics, and intervention

Preface. Introduction. Mechanisms and Diagnostics. Structural Systems. Vertical Closure Systems. Horizontal Closure Systems. The Active Systems. Epilogue. Glossary. Index.

The New York Public Library: Protective Treatment for Sugaring Marble

Abstract The marble of the New York Public Library was found to be in a fairly good state of conservation except for the more exposed elements, such as quoins and the many delicately carved elements that decorate the building. This paper focuses on the treatment developed for areas that showed significant sugaring. For this purpose, laboratory examinations and analyses were carried out and preliminary tests were made with silicate ester-based consolidants. These, however, did not perform well in test studies and therefore an approach using inorganic materials was developed. The treatment consisted of spray application of an ammonium oxalate solution that reduced the intensive sugaring of the marble. To further protect these eroded surfaces, a shelter coat based on Type S hydrated dolomitic lime was also applied. This method is fully compatible with the marble substrate and follows the overriding principle of minimum intervention, as stated by the Venice Charter.

ANALYSIS OF GYPSUM-CONTAINING LIME MORTARS: POSSIBLE ERRORS DUE TO THE USE OF DIFFERENT DRYING CONDITIONS

Abstract Analyses of mortars require that they be dried to eliminate sorbed moisture. There is no consensus regarding the temperature at which the samples need to be dried. If mortars contain gypsum, hydration water may also be lost depending upon the drying temperature. The results presented show that the dehydration behavior of gypsum is influenced by the presence of other materials. The errors introduced into the results of the analysis as a function of the drying temperature chosen are discussed.

COATINGS ON BRICK MASONRY: ARE THEY PROTECTIVE OR CAN THEY ENHANCE DETERIORATION?

Abstract The study examines the protection from deterioration by salt provided by four coatings applied to new, commonly used, high-quality brick. The coatings are Keim Granital, a silicate-based mineral paint; Benjamin Moore Acrylic Exterior Masonry Paint, an acrylic latex paint; PROSOCO Siloxane WB, a siloxane water repellent; and Atofina Kynar RC-10, 152 PWD PVDF, a fluoropolymer-based water repellent. Masonry samples were artificially weathered using sodium carbonate as the deteriorating salt. Results show that a brick surface will be protected by a coating by: 1) reducing water infiltration from driving rain, 2) reducing the depth of the damage zone by moving the crystallization front to the surface (when salts are present and water infiltrations occur), 3) extending the lifetime of the substrate, and 4) providing a more visible warning of moisture-related deterioration by the spalling of the coating. This protection is provided when the formulation of coating is matched to the nature, porosity, and water vapor permeability of the substrate. In addition, the adhesion of a coating to the substrate will determine whether the coating will exacerbate deterioration when it fails.

Does argon anoxia cause a color change in Prussian blue pigment

ABSTRACT The study focused on the effect of anoxic treatment on the discoloration of Prussian blue-dyed textiles and paper. Prussian blue pigment has been known to change color in the presence of light and heat in a vacuum for quite some time, but some claims were made that a low-oxygen environment alone contributed to its fading. The aim of this study was to determine whether argon anoxic treatment would induce the same changes when kept in the dark or in the light. The results clearly show that fading of Prussian blue in an argon anoxic condition occurs in the light but not in the dark.

Stone Conservation: An Overview of Current Research

This second edition reflects the explosion of new research, enlarging the discussion ofpreventive conservation and adding new sections on rock art and other ...