Recycled construction and demolition aggregates as alternative fill materials for geosynthetic-reinforced systems

The reuse and recycling of construction and demolition (C&D) waste materials have become essential as the construction sector strives to reduce its carbon footprint and contribute towards environmental preservation. In addition, the benefits of incorporating geosynthetics in geo-infrastructure design have driven significant research efforts to evaluate their behaviour when combined with unconventional fill materials. In this context, a comprehensive research study has been conducted at the University of Porto to explore the potential use of recycled C&D aggregates as alternative fill materials in the construction of geosynthetic-reinforced transport infrastructure systems. Extensive laboratory tests were initially performed to evaluate the geotechnical and geoenvironmental properties of various recycled C&D materials and to assess the feasibility of their use in transport infrastructure applications, such as embankments and capping layers. Large-scale direct shear tests were then conducted to analyse the interface shear response between recycled C&D aggregates and geosynthetics under both static and cyclic normal loading. The geosynthetic mechanical damage induced by a standard aggregate and recycled C&D materials under repeated loading was also investigated. This paper outlines the aforementioned research and some relevant outcomes, with the overall aim of promoting the adoption of ecological practices in infrastructure design and construction, in line with the 2030 Agenda for Sustainable Development.