Famous men busts decorating a Parisian facade: Characterization and decay process of a cast artificial stone from the XIXth century

Title: Famous men busts decorating a Parisian facade: Characterization and decay process of a cast artificial stone from the XIXth century
Author(s): A. Bourgès, S. Cord, V. Vergès-Belmin
Paper category : conference
Book title: 2nd Conference on Historic Mortars - HMC 2010 and RILEM TC 203-RHM final workshop
Editor(s): J. Válek, C. Groot and J.J. Hughes
Print-ISBN: None
e-ISBN: 978-2-35158-112-4
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 65 - 72
Total Pages: 8
Nb references: 4
Language: English

Abstract: After cleaning, four 19th century cast busts of illustrious men decorating a Parisian façade revealed severe deterioration. A network of large cracks 0.5 cm wide gave the appearance of a broken up puzzle, although each individual piece maintained good general cohesion. In order to determine the cause of the intense decay and to propose an adequate conservation protocol, the composition of this artificial stone was thoroughly investigated. Sample analyses showed that the material was composed mainly of crushed and probably sieved limestone aggregate bonded with hydrocerussite and an amorphous silica gel containing a small amount of potassium. The binder surrounded and linked calcite aggregates together. Analytical results were consistent with artificial stone recipes from the 19th century. In this paper, we report the results of analyses performed on those strange objects. We also will discuss two hypotheses of composition based on potassium silicate and propose an explanation for the peculiar degradation patterns.

Online publication: 2010-10-25
Publication type : full_text
Public price (Euros): 0.00