Abstract
The permeability of recycled materials such as recycled concrete aggregate (RCA) and rubber tire waste (RTW) significantly affects their suitability in geotechnical applications. RCA is typically more porous than natural aggregates, while RTW can either increase or decrease permeability depending on its content and form. This study investigates the hydraulic conductivity of fine RCA (fRCA), fRCA-RTW mixtures, and compressed shredded tire waste (RTWS) using variable-gradient tests under various consolidation pressures. Permeability is closely related to material quality, depending on intended use: low permeability suits barrier or fill layers, while high permeability benefits drainage applications. Both behaviors were achieved in this study-fRCA showed low permeability (10(-6) to 10(-7) m/s), while RTW addition significantly increased water flow, with filtration coefficients exceeding 1 × 10(-3) m/s. The permeability of fRCA-RTW mixtures increased with rubber content, though greater heterogeneity was observed. The results demonstrate that recycled materials can be tailored for specific hydraulic functions, supporting their use in sustainable construction.