Utilization of desert sand and PET FRP to develop eco-friendly composite structures: Validation from laboratory tests

• Self-compacting high-strength desert sand concrete (DSC) is developed. • The DSC has a good rheology and mechanical properties. • PET FRP jacket can mitigate the brittleness of DSC, thus enhance the strength and ductility of DSC substantially. • The stress-strain curves of PET FRP-confined DSC concrete exhibit a three-portion behavior, which can be predicted by an existing model. Desert sand concrete (DSC) is emerging as a promising alternative to natural aggregate concrete (NAC) for infrastructure development in desert regions. However, its inherent low strength and brittleness must be addressed to enable practical applications. This study introduces an innovative approach by employing fibre-reinforced polymer (FRP) composites incorporating recycled polyethylene terephthalate (PET) fibers—referred to as PET-FRP—as confining jackets for high-strength DSC (HSDSC). A total of 12 PET-FRP confined DSC columns and 4 plain DSC columns were fabricated and tested, with variables including the compressive strength of DSC and the thickness of the external FRP tube. The slump flow of the mix (760 mm) meets the requirements for self-compacting concrete. Experimental results confirm that HSDSC with a compressive strength of 94 MPa and excellent workability can be achieved through standard mixture proportioning. Scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) analyses further reveal improved hydration behavior and a denser microstructure. Notably, both the compressive strength and ductility of DSC were significantly enhanced through PET FRP confinement, with the confinement thickness playing a key role in strength improvement. The stress–strain behavior of PET FRP confined DSC columns, which exhibited dual peak responses, was predicted using an existing theoretical model developed by the authors. The model effectively estimated the first peak and peak ravine stresses but slightly overpredicted the ultimate strength. This research offers a novel and sustainable solution for improving the structural performance of DSC, advancing its viability for real-world applications in arid environments.