Walsh,J.A.(2008): Modelling the physical and chemical changes in roofing slate caused by weathering processes. Environ.Geol., 56, 561-569.

『風化過程により引き起こされた屋根材スレートの物理的および化学的変化のモデル化』


Abstract
 This research identifies the changes which takes place in roofing slate due to natural exposure and tries to replicate these changes experimentally. Traditional methods of testing, used by the British and other national standards, concentrate on the properties of unweathered samples and give no information on the relative durability of the different slates. Instead of concentrating on the initial properties, this research focuses on changes in the properties in order to assess durability. The effects of natural weathering were assessed by comparing old, used slates with new slates from the same or a similar source. The new slates were then weathered experimentally by repeated cycles of wetting and drying, and the increase in water absorbency compared with that observed in naturally weathering. Mineralogical differences due to both natural and experimental weathering were also measured using X-ray diffraction analysis. It was found that the effects of experimental weathering, using repeated cycles of wetting and drying, are similar to those observed in natural weathering. These include increased water absorbency and loss of crystallinity of the principal minerals. The greatest changes are found in those slates which are the most vulnerable to weathering, making it possible to identify poor quality slates.

Keywords: Roofing slate; Durability; Provenance』

Introduction
Context
Experimental weathering procedures
 The wetting and drying test
Methodology of the current study
 Test pieces
Experimental observations
 Changes in water absorbency due to natural weathering
  Identification of slates
  The age of the slate
  Welsh grey slate
  Welsh purple slate
  Cumbrian green slate
 Ballachulish slate
  Easdale slate (Toberonochy)
  Spanish slate
 Mineralogical changes in naturally weathered slates
  Quartz
  White mica
  Chlorite
 Changes due to experimental weathering of slates
  Water absorbency
 Mineralogical changes
Comparing the effects of natural and experimental weathering
Conclusions
Acknowledgments
References


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