Water Distribution Variation in Partially Saturated Granular Materials Using Neutron Imaging

Area of Science:

• Geophysics
• Materials Science
• Hydrology

Background:

• Understanding water distribution in porous media is crucial for various scientific fields.
• Traditional methods may lack the resolution or non-invasive capabilities for detailed analysis.
• Neutron imaging offers a unique approach due to differential neutron interactions with different materials.

Purpose of the Study:

• To demonstrate neutron imaging for visualizing and quantifying water distribution in partially saturated granular porous media.
• To investigate the effect of particle morphology on water distribution.
• To analyze water phase distribution in compacted sand specimens.

Main Methods:

• Utilized neutron imaging at the Neutron Imaging Facility (NIF) at the National Institute of Standard and Technology (NIST).
• Employed an amorphous silicon flat panel detector with a spatial resolution of approximately 250 micrometers.
• Examined compacted granular columns of round and angular silica sand with varying water contents (0-12%).

Main Results:

• Achieved significant contrast between water, sand, and air in neutron transmission images.
• Quantitative analysis provided detailed information on particle, void, and water distribution.
• Observed spatial water phase-distribution influenced by particle morphology and water content.

Conclusions:

• Neutron imaging is an effective tool for visualizing and quantifying water in granular porous media.
• Particle morphology significantly impacts water distribution patterns.
• The study provides valuable data for understanding hydrological processes in granular materials.