Lectures on Materials Science for Architectural Conservation Lectures on Materials Science for Architectural Conservation Giorgio Torraca The Getty Conservation Institute Los Angeles ©2009 J. Paul Getty Trust The Getty Conservation Institute 1200 Getty Center Drive, Suite 700 Los Angeles, CA 90049-1684 United States Telephone 310 440-7325 Fax 310 440-7702 E-mail
[email protected] www.getty.edu/conservation Production editor: Angela Escobar Copy editor: Dianne Woo Designer: Hespenheide Design ISBN: 978-0-9827668-3-5 (print on demand) The Getty Conservation Institute works internationally to advance conservation practice in the visual arts—broadly interpreted to include objects, collections, architecture, and sites. The GCI serves the conservation community through scientific research, education and training, model field projects, and the dissemination of the results of both its own work and the work of others in the field. In all its endeavors, the GCI focuses on the creation and delivery of knowledge that will benefit the professionals and organizations responsible for the conservation of the world’s cultural heritage. Contents vii Foreword Giacomo Chiari ix Preface Part 1 1 Electronegativity, Chemical Bonds, Crystals, Molecules, and Chemical Reactions 1 1.1 Electronegativity 2 1.2 Chemical Bonds 8 1.3 Properties of Materials as a Function of the Bond Type 14 1.4 Molecules 21 1.5 Chemical Reactions 30 1.6 Physical Transformations—Solutions and Emulsions 36 1.7 Hydrophilic and Hydrophobic Materials Part 2 38 Mortars, Bricks, and Concretes: