Holistic correlation of physical and mechanical properties of selected natural stones for assessing durability and weathering in the natural environment [Elektronische Ressource] / von Ann Bourgès

Bourgès_Ann

Informations

• Publié par: ludwig-maximilians-universitat_munchen
• Publié le: 01 janvier 2006
• Nombre de lectures: 8
• Langue: English
• Poids de l'ouvrage: 2 Mo

Extrait

Dissertation der Fakultät für Geowissenschaften
der Ludwigs-Maximilians-Universität München






HOLISTIC CORRELATION OF PHYSICAL AND MECHANICAL
PROPERTIES OF SELECTED NATURAL STONES FOR ASSESSING
DURABILITY AND WEATHERING IN THE NATURAL
ENVIRONMENT



100 µm


Von
Ann Bourgès




Dissertation eingereicht am 17.03.2006

1. Berichterstatter: Pr. Dr. Rolf Snethlage
2. Berichterstatter: Pr. Dr. Karl Thomas Fehr

Müdlichen Prüfung am 21.06.2006

Introduction

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.







3

TABLE OF CONTENT


LIST OF FIGURES .....................................................................................................................................8
LIST OF TABLES.......12
LIST OF ABBREVIATIONS: ......................................................................................................................13
A. PRESENTATION OF THE STUDY..........................................................................................15
I. STATE OF THE ART.........................................................................................................................17
I.1. HOW TO ASSESS WEATHERING....................................................................................................17
I.2. THE USE OF NON-DESTRUCTIVE METHODS.................................................................................17
I.2.1. Ultrasonic velocity ....................................................................................................................18
I.2.2. The drilling resistance (DRMS) ................................................................................................19
I.3. METHODS TO EVALUATE POROSITY: QUANTIFICATION BY DIGITAL IMAGE ANALYSIS (DIA)
AND RELATIONSHIP WITH PHYSICAL-MECHANICAL PROPERTIES -......................................................20
I.4. PHYSICAL PROPERTIES................................................................................................................22
I.5. MECHANICAL PROPERTIES .........................................................................................................24
I.5.1. Strength and porosity.................................................................................................................24
I.5.2. Compressive strength – static and dynamic modulus of elasticity ............................................25
I.6. FROST DAMAGE ON POROUS MATERIAL .....................................................................................27

II. MATERIALS AND METHODS32
II.1. MATERIALS OF THE STUDY........................................................................................................32
II.1.1. The sandstones, three different binders....................................................................................32
II.1.2. Classification of sandstones .....................................................................................................34
II.1.3. The magnesian limestones, three different quarries.................................................................36
II.1.4. Carbonate classification ...........................................................................................................39
II.1.5. Proconnesian marble ................................................................................................................41
II.2. POROSITY MORPHOLOGY OF POROUS MEDIA ...........................................................................42
II.2.1. Intergranular porosity (primary)...............................................................................................42
II.2.2. Intraganular porosity (mostly secondary).................................................................................43
II.2.3. Porosity of cracks (secondary) .................................................................................................43
II.3. INVESTIGATION METHODS........................................................................................................44
II.3.1. Determination of the porosity ..................................................................................................44
II.3.2. Non-Destructive methods.50
II.3.3. Pore shape determination - methods ........................................................................................51
II.3.4. Physical properties.......53
II.3.5. Mechanical properties ..............................................................................................................57
II.3.6. Artificial weathering......58
II.3.7. Sample size ..............................................................................................................................59
II.3.8. Statistic analysis.......................................................................................................................59
II.3.9. Determination of variables.......................................................................................................61
B. RESULTS AND DISCUSSION – PART I: PROPERTIES OF FRESH STONES ................63
III. DETERMINATION OF THE STRUCTURE........................................................................................65
III.1. MEAN AND MAXIMAL GRAIN SIZE, GRAIN CONTACT...............................................................65
III.2. GRAIN SIZE DISTRIBUTION OF THE SANDSTONES ....................................................................67
III.3. PORE SHAPE DETERMINATION .................................................................................................68
III.3.1. The Quality Index, QI%..........................................................................................................68
III.3.2. Ultrasonic velocity of water saturated samples.......................................................................70
III.3.3. In summary .............................................................................................................................72
III.4. ULTRASONIC VELOCITY AND DYNAMIC MODULUS OF ELASTICITY ........................................72
5 IV. POROSITY – COMPARISON OF DIFFERENT METHODS..................................................................74
IV.1. ACCURACY OF DIA MEASUREMENTS.......................................................................................74
IV.1.1. Surface area needed for DIA...................................................................................................74
IV.1.2. Overlapping of two magnifications x 40 and x 100 – comparison of the range of pores 5-40
microns 74
IV.2. TOTAL POROSITY THROUGH WATER SATURATION (N ), MERCURY INTRUSION (MIP) AND T
DIA 75
IV.3. PORE SIZE DISTRIBUTION – COMPARISON OF PORE SIZE ENTRY BY MERCURY INTRUSION,
PORE SIZE DISTRIBUTION BY NITROGEN ADSORPTION AND AREA OF PORES BY DIA ..........................79
IV.4. CORRELATION POROSITY PROPERTIES VS. STRUCTURE CHARACTERISTICS AND ULTRASONIC
VELOCITY...............................................................................................................................................85
IV.4.1. In summary .............................................................................................................................89

V. PHYSICAL PROPERTIES........