From date palm waste to fracture-resistant mortars: natural fibres as an alternative to polypropylene

The use of plant-derived fibres in cement-based materials offers a sustainable alternative to synthetic reinforcement. This study investigates date palm fibres as reinforcement for cementitious mortars intended for non-structural applications, using polypropylene fibres as a reference. The experimental programme includes compressive, flexural and fracture toughness tests, focusing on the toughening mechanism of crack bridging. Untreated and treated date palm fibres are compared with polypropylene-reinforced mixtures, also considering less favourable geometrical conditions for the natural fibres. The results show that date palm fibres improve fracture resistance, post-cracking response and energy absorption, while providing flexural performance comparable to polypropylene fibres. Fibre treatment produced only limited additional benefits, supporting the use of untreated date palm fibres as a viable bio-based reinforcement.