TY - JOUR
T1 - Pore network structure linked by X-ray CT to particle characteristics and transport parameters
AU - Hamamoto, Shoichiro
AU - Moldrup, Per
AU - Kawamoto, Ken
AU - Sakaki, Toshihiro
AU - Nishimura, Taku
AU - Komatsu, Toshiko
PY - 2016
Y1 - 2016
N2 - Mass transport in soils occurs through pore networks that are highly affected by basic physical properties such as the degree of compaction, and particle size and shape. In this study, micro-focus X-ray computed tomography (CT) was used to obtain information on the pore network structure at different compaction levels for repacked columns of sands and glass beads representing different size fractions and particle shapes. Mass transport parameters, including gas diffusion coefficient (D p) and air permeability (k a) at variably saturated conditions, were measured on the same columns using standard methods, and literature data on saturated hydraulic conductivity (K sat) for the same materials were analyzed. A comparison of X-ray CT derived pore network structure and physical parameters showed that the round sands and glass beads exhibited larger pores, a higher pore coordination number, and a lower volumetric surface area than that of angular sands at the same particle size, resulting in higher K sat as well as higher D p and k a under relatively dry conditions. The X-ray CT derived the mean pore diameter (d), and the pore coordination number (C n) for each material correlated well with key gas transport properties such as percolation thresholds and pore network connectivity. A predictive D p model from wet to dry conditions based fully on X-ray CT derived parameters (d and C n) was developed and showed good agreement with measured D p for both round and angular sands.
AB - Mass transport in soils occurs through pore networks that are highly affected by basic physical properties such as the degree of compaction, and particle size and shape. In this study, micro-focus X-ray computed tomography (CT) was used to obtain information on the pore network structure at different compaction levels for repacked columns of sands and glass beads representing different size fractions and particle shapes. Mass transport parameters, including gas diffusion coefficient (D p) and air permeability (k a) at variably saturated conditions, were measured on the same columns using standard methods, and literature data on saturated hydraulic conductivity (K sat) for the same materials were analyzed. A comparison of X-ray CT derived pore network structure and physical parameters showed that the round sands and glass beads exhibited larger pores, a higher pore coordination number, and a lower volumetric surface area than that of angular sands at the same particle size, resulting in higher K sat as well as higher D p and k a under relatively dry conditions. The X-ray CT derived the mean pore diameter (d), and the pore coordination number (C n) for each material correlated well with key gas transport properties such as percolation thresholds and pore network connectivity. A predictive D p model from wet to dry conditions based fully on X-ray CT derived parameters (d and C n) was developed and showed good agreement with measured D p for both round and angular sands.
KW - Mass transport parameters
KW - Micro-focus X-ray CT
KW - Pore structure
KW - Mass transport parameters
KW - Micro-focus X-ray CT
KW - Pore structure
UR - http://www.scopus.com/inward/record.url?scp=84979747903&partnerID=8YFLogxK
U2 - 10.1016/j.sandf.2016.07.008
DO - 10.1016/j.sandf.2016.07.008
M3 - Journal article
AN - SCOPUS:84979747903
SN - 0038-0806
VL - 56
SP - 676
EP - 690
JO - Soils & Foundations
JF - Soils & Foundations
IS - 4
ER -