Mechanical Properties of Cementitious Materials at Microscale

477 Pages·2022·20.382 MB·English

by  Ya Wei, Siming Liang, Weikang Kong

Ya Wei
Siming Liang
Weikang Kong
Mechanical
Properties
of Cementitious
Materials
at Microscale
Mechanical Properties of Cementitious Materials
at Microscale
· ·
Ya Wei Siming Liang Weikang Kong
Mechanical Properties
of Cementitious Materials
at Microscale
Ya Wei Siming Liang
Department of Civil Engineering School of Civil Engineering
Tsinghua University Sun Yat-sen University
Beijing, China Guangzhou, China
Weikang Kong
Department of Civil Engineering
Tsinghua University
Beijing, China
ISBN 978-981-19-6882-2 ISBN 978-981-19-6883-9 (eBook)
https://doi.org/10.1007/978-981-19-6883-9
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature
Singapore Pte Ltd. 2023
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To Jiren, Jiyuan, Liangchun, Yulan, Dewei,
and Xiaohong.
Preface
The measurement of micro scale mechanical properties of cementitious materials
has gained interest in the last one to two decades. This book grows out of the ten
years of research work by the authors in this area, with the intention to (1) provide the
methods of preparing the samples for the micro scale mechanical testing, (2) address
the techniques for measuring and analyzing the elastic modulus, the stiffness, and
the fracture toughness of cementitious materials at micro scale by instrumented
indentation, (3) describe a method for measuring and interpreting creep behavior
of cementitious materials at micro scale, and (4) demonstrate the homogenization
method for obtaining the mechanical properties of cementitious materials across
scales.
This book is designed primarily for use at the undergraduate level, but it can also
serve as a guide for professionals working with cementitious materials and other
composite materials. The information in this book is illustrated by large amounts of
figures, tables, text, and the references, which is helpful to a wide readership in the
various fields of civil engineering and materials science. Although we have cited and
compiled a list of references that we believe are most relevant to the text, listing such
a limited number of references does not represent the breadth and depth of this field.
We sincerely apologize to those authors whose works were not cited.
Finally, we would like to express our gratitude to our students and colleagues at
Tsinghua University for their valuable input and collaboration. This book would not
have been completed without the supports from our families; this book is dedicated
to them.
Beijing, China Ya Wei
Beijing, China Weikang Kong
Guangzhou, China Siming Liang
vii
Contents
1 Introduction .................................................. 1
1.1 Background ............................................. 1
1.2 Objective of the Book ..................................... 2
1.3 Organization of the Book .................................. 3
References .................................................... 4
2 Samples Preparation .......................................... 5
2.1 Introduction ............................................. 5
2.2 Mixing, Casting, and Curing ............................... 6
2.2.1 Mixing .......................................... 6
2.2.2 Casting and Curing ............................... 8
2.3 Hydration Stoppage ...................................... 9
2.3.1 Direct Drying Method ............................. 10
2.3.2 Organic Solvent Exchange Method .................. 11
2.4 Epoxy Impregnation ...................................... 12
2.5 Grinding and Polishing .................................... 13
2.5.1 Grinding ........................................ 14
2.5.2 Polishing ........................................ 16
2.5.3 Images of Polished Sample ......................... 18
2.6 Surface Roughness Examination ............................ 19
2.7 Storage ................................................. 23
2.8 Influence of Epoxy Impregnation on Characterizing
Microstructure and Small-Scale Mechanical Properties
by Different Techniques ................................... 24
2.8.1 On Quality of Optical Microscopic Images ........... 25
2.8.2 On Quality of BSE Images ......................... 26
2.8.3 On Surface Elevation Quantified by SPM ............. 27
2.8.4 On Characterizing ITZ Between Aggregate
and the Paste Matrix (ITZ ) ................... 28
agg-paste
2.8.5 On Characterizing ITZ Between Residual C S
3
Clinker and Hydration Product ...................... 33
ix
x Contents
2.8.6 On the Small-Scale Mechanical Properties ........... 33
2.9 Summary ............................................... 36
References .................................................... 37
3 Experimental Techniques ...................................... 41
3.1 Introduction ............................................. 41
3.2 Instrumented Indentation Test .............................. 42
3.2.1 Development of Indentation Technique .............. 42
3.2.2 Geometry of Indenter Probes ....................... 42
3.2.3 Method of Indentation Test ......................... 43
3.2.4 Indentation Scale in Multiphase Materials ............ 45
3.2.5 Calculating Microscale Mechanical Properties ........ 47
3.2.6 Method of Grid Indentation Test .................... 53
3.2.7 Microindentation (MI) Test ......................... 54
3.3 Scanning Probe Microscopy (SPM) Technique ............... 56
3.3.1 Development of SPM Technique .................... 56
3.3.2 Test Method ..................................... 57
3.4 Continuous Stiffness Measurement Test ..................... 60
3.5 Nanoscratch Technique ................................... 63
3.5.1 Development of Nanoscratch Technique ............. 63
3.5.2 Testing Method ................................... 63
3.5.3 Parameter p(d)A(d) for Different Indenter ............ 65
3.5.4 Redefining Vertical Loading Rate ................... 69
3.5.5 Calibration of Scratching Probe ..................... 70
3.5.6 Start Point of Scratching ........................... 70
3.6 Scanning Electron Microscope (SEM) Test and Associated
Techniques .............................................. 71
3.6.1 Development of SEM Technique .................... 71
3.6.2 Principle of SEM ................................. 72
3.6.3 Principle of BSE .................................. 73
3.6.4 Principle of EDS ................................. 74
3.7 X-Ray Computed Tomography (CT) Technique ............... 75
3.7.1 Development of X-Ray CT ......................... 75
3.7.2 Principle of X-Ray CT ............................. 76
3.7.3 Commonly Used CT Scanners ...................... 76
3.8 Mercury Intrusion Porosimetry (MIP) Technique .............. 79
3.8.1 Development of MIP .............................. 79
3.8.2 Principle of MIP .................................. 80
3.8.3 Calculation Method ............................... 82
3.9 Summary ............................................... 83
References .................................................... 84
Contents xi
4 Phase Quantification by Different Techniques .................... 91
4.1 Introduction ............................................. 91
4.2 Phase Quantification by Backscattered Electron (BSE)
Mapping Technique ...................................... 92
4.2.1 Identifying Phase ................................. 92
4.2.2 Phase Segmentation from BSE Images ............... 94
4.2.3 Quantifying Degree of Hydration ................... 94
4.3 Phase Quantification by Energy Dispersive Spectrometer
(EDS) Technique ......................................... 96
4.3.1 Variation of Chemical Composition by EDS Line
Scanning Across the Featured Phases ................ 96
4.3.2 Chemical Composition of IP and OP in OPC
and Slag-Blended Systems ......................... 98
4.4 Phase Quantification by Nanoindentation Technique ........... 99
4.4.1 Categorization and Mechanical Property of Phase
by Discrete NI .................................... 99
4.4.2 Deconvolution of Grid Indentation Data .............. 101
4.4.3 Fraction of Single Phase with Different w/cm
Ratios and Slag Contents .......................... 101
4.4.4 Phase Distribution and Mechanical Properties
of CSH .......................................... 102
4.4.5 Nanoindentation (NI)-Based Degree of Hydration ..... 105
4.4.6 Comparison of Different Techniques in Estimation
of DOH ......................................... 105
4.5 Phase Quantification by Scanning Probe Microscopy
(SPM) Technique ........................................ 106
4.5.1 Methods of Data Extraction from Mapping ........... 107
4.5.2 Mapping Images Based on Different Measuring
Parameters ....................................... 109
4.5.3 Resolution of Modulus Mapping .................... 111
4.5.4 Quantifying Thickness of CSH Layer ................ 111
4.5.5 Quantifying Thickness of ITZ Between C S
3
and Matrix ...................................... 113
4.6 Phase Quantification by Nanoscratch Technique .............. 114
4.6.1 Scratching Results ................................ 115
4.6.2 Phase Identification ............................... 116
4.6.3 Probability Distribution of Fracture Toughness ........ 120
4.6.4 Fracture Toughness of Individual Phases ............. 122
4.6.5 Thickness of Clinker and Hydrates Assessed
from Fracture Toughness ........................... 124
4.6.6 Thickness of ITZ Assessed from Fracture
Toughness ....................................... 125
4.7 Phase Quantification by X-Ray Computed Tomography ........ 128
4.7.1 Reducing Background Noise of Original CT
Image by Image Filtering .......................... 128
xii Contents
4.7.2 Determining Gray Level Range of Phases
for Threshold Segmentation ........................ 130
4.7.3 Determining Phase Boundary Using Edge
Detection ........................................ 133
4.7.4 3D Reconstruction of Microstructure ................ 136
4.7.5 Calculation of Degree of Hydration Based on CT
Images .......................................... 138
4.8 Summary ............................................... 140
References .................................................... 141
5 Porosity Characterization and Permeability Prediction
of Cementitious Materials ...................................... 145
5.1 Introduction ............................................. 145
5.2 Pore Characteristics Quantified from Different Techniques ..... 146
5.2.1 Pore Characteristics from MIP Technique ............ 146
5.2.2 Pore Characteristics from BSE Technique ............ 151
5.2.3 Pore Characteristics from X-Ray CT Technique ....... 156
5.2.4 Comparison of Pore Size Distribution Quantified
by Different Techniques ........................... 158
5.3 Calculated Permeability Based on Katz-Thompson
Equation ................................................ 160
5.3.1 Katz-Thompson Equation Theory for Permeability .... 160
5.3.2 Assessment of Katz-Thompson Equation ............. 162
5.3.3 Determination of L and L ....................... 162
c max
5.3.4 Results of Permeability Prediction
from the Katz-Thompson Equation .................. 163
5.4 Calculated Permeability Based on GEM Method .............. 167
5.4.1 General Effective Media (GEM) Theory
for Permeability .................................. 167
5.4.2 Calculation for k and k ........................... 168
h l
5.4.3 Results of Permeability Prediction from the GEM
Method .......................................... 170
5.5 Computed Permeability Based on Navier–Stokes Method ...... 172
5.5.1 Navier–Stokes Theory for Permeability .............. 172
5.5.2 Six Conditions of Space Step Direction .............. 174
5.5.3 Process of Calculating Permeability Based
on Navier–Stokes Method .......................... 179
5.5.4 Brief Introduction of Stokes Permeability Solver ...... 179
5.5.5 Results of Permeability Prediction
from the Navier–Stokes Method .................... 180
5.6 Summary ............................................... 183
References .................................................... 184