title: A spectroscopic investigation of the weathering of a heritage Sydney sandstone.
abstract: Infrared spectroscopy has been employed in a study of the degradation of heritage Sydney sandstone used in St. Mary's Cathedral in Sydney, Australia. Spectra were used to characterise the clay components taken from weathered and unweathered sandstone blocks removed from the Cathedral as part of a restoration programme. Two types of kaolin clays - kaolinite and its polymorph, dickite - have been identified. A higher amount of dickite present in the clay of weathered sandstone indicated that a kaolinite-to-dickite transformation occurs upon weathering. X-ray photoelectron spectroscopy was also used to confirm the presence of a more thermally stable polymorph of the kaolinite in the sandstone.
authors.affiliation: Department of Chemistry, Materials and Forensic Sciences, University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia.
authors.forename: K H
authors.initials: KH
authors.lastname: Ip
authors.forename: B H
authors.initials: BH
authors.lastname: Stuart
authors.forename: A S
authors.initials: AS
authors.lastname: Ray
authors.forename: P S
authors.initials: PS
authors.lastname: Thomas
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D000077215:Clay; D003116:Color; D003252:Construction Materials / Q000032:analysis*; D007616:Kaolin / Q000737:chemistry; D008903:Minerals / Q000737:chemistry; D009517:New South Wales; D010084:Oxidation-Reduction; D017680:Potassium Compounds / Q000737:chemistry; D011791:Quartz / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013057:Spectrum Analysis; D014887:Weather; D014965:X-Rays
chemical_list: D000538:Aluminum Silicates; D008903:Minerals; D017680:Potassium Compounds; C016447:feldspar; D011791:Quartz; D007616:Kaolin; D012822:Silicon Dioxide; D000077215:Clay