Sassoni, Enrico ;
Graziani, Gabriela ;
Scherer, George W. ;
Franzoni, Elisa
(2016)
Preliminary study on the use of ammonium phosphate for the conservation of marble-imitating gypsum-stuccoes.
DOI
10.6092/unibo/amsacta/5705.
In: Proceedings of the 4th Historic Mortars Conference HMC2016 10th-12th October 2016, Santorini, Greece.
A cura di:
Papayianni, Ioanna ;
Stefanidou, Maria ;
Pachta, Vasiliki.
pp. 391-398.
ISBN 978-960-99922-3-7.
Full text available as:
Abstract
In this study, a novel method for consolidation and improvement of resistance to water of gypsum-stuccoes was preliminarily investigated. The idea is treating gypsum with an aqueous solution of diammonium hydrogen phosphate (DAP, (NH4)2HPO4) to form hydroxyapatite (HAP, Ca10(PO4)6(OH)2), which has much lower solubility than gypsum. Tests carried out on gypsum paste samples, manufactured to resemble historic stuccoes, showed that, after treatment with the DAP solution, a significant improvement in mechanical properties was achieved and brushite (CaHPO4∙2H2O) was formed (alongside some other by-products, that can be removed by an additional poultice treatment). Even if brushite is more soluble than HAP, still its formation is expected to be beneficial for stuccoes conservation, as brushite is significantly less soluble than gypsum.
Abstract
In this study, a novel method for consolidation and improvement of resistance to water of gypsum-stuccoes was preliminarily investigated. The idea is treating gypsum with an aqueous solution of diammonium hydrogen phosphate (DAP, (NH4)2HPO4) to form hydroxyapatite (HAP, Ca10(PO4)6(OH)2), which has much lower solubility than gypsum. Tests carried out on gypsum paste samples, manufactured to resemble historic stuccoes, showed that, after treatment with the DAP solution, a significant improvement in mechanical properties was achieved and brushite (CaHPO4∙2H2O) was formed (alongside some other by-products, that can be removed by an additional poultice treatment). Even if brushite is more soluble than HAP, still its formation is expected to be beneficial for stuccoes conservation, as brushite is significantly less soluble than gypsum.
Document type
Book Section
Creators
Keywords
Gypsum; Hydroxyapatite; Marble; Protection; Consolidation; Cultural Heritage
Subjects
ISBN
978-960-99922-3-7
DOI
Deposit date
18 Oct 2017 07:53
Last modified
18 Oct 2017 07:53
Project name
Funding program
EC - H2020
URI
Other metadata
Document type
Book Section
Creators
Keywords
Gypsum; Hydroxyapatite; Marble; Protection; Consolidation; Cultural Heritage
Subjects
ISBN
978-960-99922-3-7
DOI
Deposit date
18 Oct 2017 07:53
Last modified
18 Oct 2017 07:53
Project name
Funding program
EC - H2020
URI
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