Pullout testing of recycled construction and demolition waste aggregates in full-scale geogrid-reinforced embankments

The use of recycled aggregates (RAs) derived from construction and demolition waste (C&DW) in geogrid-reinforced embankments was investigated through a near-real-scale experimental approach, bridging the gap between laboratory research and field application in sustainable geotechnical engineering. Embankments were constructed using different fill types: RAs with particle size classes 15 ÷ 30 mm and 0 ÷ 80 mm, and a mixture of RAs with excavation soil. Material properties were characterised through laboratory testing, and full-scale pullout tests were carried out at low normal stress levels (10÷12 kPa), which are critical for shallow embankments, to evaluate RA-geogrid interaction. The results demonstrated pullout peak forces ranging from 20 to 30 kN/m for soil–RA mixtures to 40÷50 kN/m for coarse granular RA, exhibiting mechanical behaviour comparable to that of natural aggregates. The full-scale setting and the heterogeneity of the RA materials provide valuable insight into the field performance of recycled materials in reinforced embankment applications. The test campaign also provided procedural insights relevant for future field-scale testing and applications. These findings support design practices involving RAs and offer practical evidence to advance circular-economy principles in geotechnical infrastructure.