Preliminary results of the use of hydroxyapatite as a consolidant for carbonate stones

Enrico Sassoni, Sonia Naidu, George W. Scherer

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations

Abstract

The effectiveness of using hydroxyapatite (HAP) as a consolidant for carbonate stones was evaluated. HAP was chosen as a consolidating agent since it is notably less soluble than calcite and has a similar crystal structure and a close lattice match to it. Among possible methods for forming HAP, the reaction between the calcite of the stone and a solution of diammonium hydrogen phosphate (DAP) in mild conditions was chosen. Indiana Limestone samples, artificially damaged by heating to 300°C for 1 hour, were treated with a 1 molar DAP solution by partial immersion and capillary absorption for 48 hours or by brushing until apparent refusal and wrapping with a plastic film for 48 hours. After washing in deionized water for 3 days and drying under a fan at room temperature until constant weight, the improvements in dynamic elastic modulus and tensile strength were evaluated. The formation of calcium phosphate phases was observed by scanning electron microscopy (SEM) and the phase characterization performed by energy dispersive X-ray spectroscopy (EDS) and electron back-scattered diffraction (EBSD). The water absorption modification after the consolidating treatment was then assessed. Results show that treated samples experienced significant increases in dynamic elastic modulus and tensile strength, as a consequence of crack reduction and pore filling consequent to HAP deposition at grain boundaries. The sorptivity of the treated samples is reduced by 26-44% (based on treatment technique), so that water and water vapor exchanges with the environment are not blocked.

Original languageEnglish (US)
Title of host publicationMaterials Issues in Art and Archaeology IX
Pages189-195
Number of pages7
DOIs
StatePublished - Dec 29 2011
Event2010 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 29 2010Dec 3 2010

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1319
ISSN (Print)0272-9172

Other

Other2010 MRS Fall Meeting
CountryUnited States
CityBoston, MA
Period11/29/1012/3/10

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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