Course Project for MSE 6120

1. +
Reconstruction and Characterization of 3-D Biaxial
Specimen Microstructure
Jie (Jessie) Cao
Advisor: Prof. J. David Frost
School of Civil and Environmental Engineering
MSE6120

2. +
Content
 Background
 3-D Microstructure Reconstruction
 Characterization of Microstructure
 Implications

3. +
Background
 Investigate the mechanism of strain localization; link the
microstructural properties with the engineering behavior of
Ottawa sands under biaxial shearing condition
Biaxial Shearing
Testing
UN
Microstructure
Characterization
Microscopy
Based Serial
Sectioning

4. +
Biaxial Shearing Testing
 Material
Ottawa 20-30 sands
 Specimen
Height: 140 mm
Length: 80 mm
Width: 40 mm

5. +
3-D Microstructure Reconstruction
 Cutting and mounting
 Grinding and polishing
 Image capturing and processing
montage technique
binarization

6. +
3-D Microstructure Reconstruction
 Render Processed images into 3D structures
(software VoxBlast from VayTek, Inc)
 Unsheared Microstructure
 Size: 1300×800×430
voxels=0.45 billion voxels with
side 14μm
 Number of slices: 430
 Resolution: 13.96 μm/pixel
 Number of particles: ≈3800
Sand Particles
Pore space

7. +
Characterization of Microstructure
 Dissection of Reconstructed Volume
 B
 slices: 300 x
430 pixels
 ~169 particles
 A
 slices: 1300 x
800 pixels
 ~312 particles
 C
 slices: 800 x
430 pixels
 ~104 particles

8. +
Characterization of Microstructure
 Void Ratio Per Slice
Void Ratio=total number of void pixels/ total number of solid pixels
= 1/(Vv)solid -1
1. Hands-on Measurement
2-D Analysis
2. Digital Image Analysis
3-D Analysis

9. +
Characterization of Microstructure
 Course Contents ( Hands-on Measurement )
Numerical
Extents
Vv; Sv; Lv
Number
Density
NA; Nv
Derived
Microstructural
Properties
Size, Shape,
and Orientation
Distribution
Spatial
Clustering and
Correlations

10. +
Characterization of Microstructure
 Void Ratio Per Slice
1. Hands-on Measurement
Point Counting for Vv  e
Slice Number#:
01 43 86 129 172 215
258 301 344 387 430
Cumulative Thickness(mm):
0 0.6 1.2 1.8 2.4
3.0 3.6 4.0 4.8 5.4 6.0
Void Ratio= 1/(Vv)solid -1
A

11. +
Characterization of Microstructure
Void Ratio Per Slice
Void Ratio= 1/(Vv)solid -1
1. Hands-on Measurement (systematic point counting)
 N=5
 PT=20
 Pi
 Pave=Pi/N
 Vv=PP=Pave/PT

12. +
Characterization of Microstructure
Void Ratio Per Slice
1. Hands-on Measurement
Void Ratio= 1/(Vv)solid -1
0.80
0.75
0.70
0.65
0.60
0.65
0.60
0.55
0.50
0.45
0.40
0 1 2 3 4 5 6 7 8
Void Ratio
Cumulative Removed Thickness (mm)
0.55
VV
eavg=0.506

13. +
Characterization of Microstructure
Void Ratio=total number of void pixels/ total number of solid pixels
Void Ratio Per Slice
2. Digital Image Analysis
Point Counting result
eavg=0.510
Slices A
Slices B
Slices C

14. +
Implications
 Application of Microscopy Based Serial Sectioning to
reconstruct the digital microstructures is feasible in soil
testing, and is widely accessible to researchers in
geotechnical engineering.
 Microstructure of soil materials can be characterized
quantitatively to obtain several geometric attributes
through simple unbiased counting measurements. Some
geometric attributes are closely related to material
properties and performance.

15. +
Thanks for Attention
Jie (Jessie) Cao
Advisor: Prof. J. David Frost
School of Civil and Environmental Engineering
MSE6120