Holistic correlation of physical and mechanical properties of selected natural stones for assessing durability and weathering in the natural environment.
Beschreibung
vor 17 Jahren
The main purpose of this study is to understand influences of bulk
structure of materials on strength behavior as well as water
storage and transfer in order to assess durability and weathering.
Therefore, a selection of different methods are applied and
compared to optimize the understanding of material structure and
physico-mechanical behavior. Optical microscopy (Digital Image
Analysis) and scanning electron microscopy as well as water vapor
permeability, biaxial flexural strength and ultrasonic velocity are
measured on different natural materials: sandstones with clayey,
silicious or calcareous binder, oolithic and micritic magnesian
limestones and a thermally aged Proconnesian marble.
Microstructurales and macrostructurales properties of these
materials are studied before and after artificial weathering
(freeze-thaw cycles). First, and in order to validate the
efficiency of the digital image analysis to characterize porosity
and structure, traditional porosity measurements as water ad- and
absorption and mercury porosimetry are crosschecked with the result
obtained from digital image analysis. Limits of each methods are
also defined. Then, validations of non-destructive and
semi-destructive methods are also pursued to evaluate their
potential value to replace and complement standardized methods. By
analysis of linear correlations, some essential mechanisms should
be underlined, which may connect the macrostructure to the
microstructure of the material. A systematic method of analysis
should clearly appear and emphasize the role of the structure
(grain size, grain contact and pore shape) on physical and
mechanical behavior. The main parameters leading to weathering
should then be identified and models of correlations drawn.
Correlations between the various physico-mechanical properties
could ameliorate the possibilities to assess durability and
weathering in the natural environment.
structure of materials on strength behavior as well as water
storage and transfer in order to assess durability and weathering.
Therefore, a selection of different methods are applied and
compared to optimize the understanding of material structure and
physico-mechanical behavior. Optical microscopy (Digital Image
Analysis) and scanning electron microscopy as well as water vapor
permeability, biaxial flexural strength and ultrasonic velocity are
measured on different natural materials: sandstones with clayey,
silicious or calcareous binder, oolithic and micritic magnesian
limestones and a thermally aged Proconnesian marble.
Microstructurales and macrostructurales properties of these
materials are studied before and after artificial weathering
(freeze-thaw cycles). First, and in order to validate the
efficiency of the digital image analysis to characterize porosity
and structure, traditional porosity measurements as water ad- and
absorption and mercury porosimetry are crosschecked with the result
obtained from digital image analysis. Limits of each methods are
also defined. Then, validations of non-destructive and
semi-destructive methods are also pursued to evaluate their
potential value to replace and complement standardized methods. By
analysis of linear correlations, some essential mechanisms should
be underlined, which may connect the macrostructure to the
microstructure of the material. A systematic method of analysis
should clearly appear and emphasize the role of the structure
(grain size, grain contact and pore shape) on physical and
mechanical behavior. The main parameters leading to weathering
should then be identified and models of correlations drawn.
Correlations between the various physico-mechanical properties
could ameliorate the possibilities to assess durability and
weathering in the natural environment.
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vor 8 Jahren
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