Effects of 3D Printing on Clay Permeability and Strength

Advances in additive manufacturing create unique opportunities for the investigation of permeability of fine-grained soils. The permeability of fine-grained soils, such as clays, plays an important role in various design considerations in the geotechnical, environmental, and stormwater management systems. This research investigates the application of 3D printed specimens in studying the hydraulic and mechanical properties of clayey soils. The effects of 3D printing, specifically direct binder jet printing, on the permeability, and other physical properties of clay were investigated. Cylindrical clay specimens were prepared using an advanced direct binder jet printing and tested in a flexible wall permeameter and triaxial compression setup under effective confining stresses representing clay at very shallow depths. The results of this study show that the 3D printing process affects the permeability of clay through changes in physical properties such as the specific surface area. However, the printing provides consistent and repeatable specimens with very low disturbance and efficient controlled geometry. Also, due to stiffer 3D printed specimen, less confinement impact was observed in 3D printed specimens. Also, 3D printed specimens showed significantly higher shear strength and friction angle. The outcome of this research could pave the path for future studies dealing with flow through fractured clays. Article Highlights 3D printing and sintering change the physical properties of clay powder leading to higher permeability. The impact of confining pressure on 3D printed specimens is considerably low. 3D printing increases the shear strength of soil specimens.