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.

Enrico Sassoni, Gabriela Graziani, George W. Scherer, Elisa Franzoni (2016). Preliminary study on the use of ammonium phosphate for the conservation of marble-imitating gypsum-stuccoes. Thessaloniki : Laboratory of Buildings Materials, Dept. of Civil Engineering, Artistotle University of Thessaloniki [10.6092/unibo/amsacta/5705].

Preliminary study on the use of ammonium phosphate for the conservation of marble-imitating gypsum-stuccoes

SASSONI, ENRICO;GRAZIANI, GABRIELA;SCHERER, GEORGE WALTER;FRANZONI, ELISA
2016

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.
2016
Proceedings of the 4th Historic Mortars Conference (HMC2016)
391
398
Enrico Sassoni, Gabriela Graziani, George W. Scherer, Elisa Franzoni (2016). Preliminary study on the use of ammonium phosphate for the conservation of marble-imitating gypsum-stuccoes. Thessaloniki : Laboratory of Buildings Materials, Dept. of Civil Engineering, Artistotle University of Thessaloniki [10.6092/unibo/amsacta/5705].
Enrico Sassoni; Gabriela Graziani; George W. Scherer; Elisa Franzoni
File in questo prodotto:
File Dimensione Formato  
Sassoni et al (2016) Ammonium Phosphate on Gypsum.pdf

accesso aperto

Tipo: Versione (PDF) editoriale
Licenza: Licenza per Accesso Aperto. Creative Commons Attribuzione - Non commerciale - Non opere derivate (CCBYNCND)
Dimensione 1.05 MB
Formato Adobe PDF
1.05 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/598206
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact