Uniaxial compression tests of different types of encased recycled concrete aggregate columns

Encased recycled concrete aggregate (RCA) columns can be employed in soft soil foundations for enhancing bearing capacity, minimizing settlement, and expediting consolidation. This study examines the impact of various encased materials (iron mesh, aluminum mesh, rhombus and ellipse polyethylene mesh), gravel particle sizes (2-6 mm and 6-10 mm), and pile length–to–diameter ratios (5.71, 3.19, and 1.96) on the mechanical and deformation characteristics of encased RCA columns, using uniaxial compression tests. The findings reveal that iron mesh encased RCA columns exhibit higher pile top stress, whereas polyethylene mesh encased columns demonstrate greater radial deformation. When the quantity of gravel is consistent, larger gravel particle sizes tend to elevate the pile top stress of the encased RCA columns, while smaller gravel particle sizes tend to increase the bulging deformation. Throughout the compression process, encased RCA columns with larger length–to–diameter ratios undergo a bending phenomenon, whereas columns with smaller length–to–diameter ratios manifest an increase in the bulging strain rate. The study examines the stress–strain response and particle breakage of various encased RCA columns under uniaxial compression. The results inform the selection of encasement materials, RCA particle size, and pile diameter ratio, providing a scientific basis for using RCA in granular columns foundations for soft soil improvement and promoting sustainable reuse of construction waste.