Short-Term Drainage Performance of Geotextile-Recycled Asphalt Pavement Filter Systems

In recent years, rapid technological advancements and population growth have led to a surge in global natural resource consumption. Recycling is crucial for environmental protection and sustainable resource utilization, notably through reusing construction and demolition waste materials and industrial by-products in civil engineering. Such initiatives promote sustainable resource utilization and contribute to the development of an eco-friendly environment and sustainable construction practices. The hydraulic properties of waste materials and by-products are among their characteristic features. This study explores the drainage behavior of a soil-geotextile system, employing recycled asphalt pavement (RAP) as an alternative to natural aggregates, and utilizes five different geotextiles with varying apparent opening sizes (AOS). To assess the hydraulic conductivity characteristics, a series of bubble tube permeameter tests were conducted. The samples were prepared to represent the worst-case filtration scenario, based on the filtration material requirements outlined in the Technical Specifications published by the General Directorate of Highways in Turkey. The samples were compacted at both standard proctor and modified proctor energy levels. Additionally, index property tests and California bearing ratio (CBR) tests were performed on the RAP material under both unsoaked and soaked conditions. The study evaluates the applicability of these systems in different fields, with a focus on their drainage and filtration capabilities, particularly in pavement drainage systems.