Enhancing the Mechanical Properties of EPS Mortar Using Waste Plastic Fibers

The aim of this research is to experimentally evaluate the mechanical characteristics of mortar mixtures containing expanded polystyrene (EPS) beads and reinforced with polyethylene terephthalate (PET) fibers. Fine aggregates were partially replaced with 10% and 20% replacement ratios of expanded polystyrene beads, as well as four PET fiber volume fractions set at 0%, 0.5%, 0.75%, and 1%. Standard specimens for compressive strength, density, split strength, and flexural strength were used to assess the mechanical properties of hardened samples, while the slump test was used to gauge the fresh-state workability. The findings showed that the weight of the mortar reduced when EPS beads were used in place of fine aggregates. However, incorporating EPS beads into the mortar led to notable decrease in its mechanical properties. The workability was negatively impacted by the addition of PET fibers. However, when 0.75% PET fibers were added, PET reinforcement significantly increased compressive strength by 32% and 27% in mixes with 10% and 20% EPS, respectively. Splitting tensile and flexural strength exhibited minor fluctuations, with overall improvements remaining within approximately ±10%. The density and ultrasonic pulse velocity reduce when adding PET fibers. At 20% EPS and 1% PET, the concrete's density dropped to approximately 2030 kg/m³.