Comprehensive review on virgin and reclaimed PET fiber concrete integrating surface treatment

Studies have explored the engineering properties of Polyethylene Terephthalate (PET) fiber-reinforced concrete, including mechanical strength, crack control, and durability. However, a comprehensive analysis incorporating surface treatment is lacking. This paper provides an extensive analytical database, including previous literature on the mechanical and durability properties of PET fiber-reinforced concrete and the effects of fiber surface treatment on concrete performance. Furthermore, the microstructural and pore-structural properties of PET fiber-reinforced concrete are discussed, detailing the mechanisms behind these properties. This examines the effect of incorporating virgin and recycled PET fibers at mass percentages (wt%) of 0–2 and volume percentage (v%) of 0–12 of total mass/volume. Key findings include that the optimum PET fiber content for tensile and flexural strength is 0.5 v%, while higher contents cause fiber balling, reducing concrete’s performance. Notably, PET fiber-reinforced concrete shows a maximum compressive strength loss of 24% in 3% H₂SO₄ and 10% loss in pH 12.6 alkaline medium after 120 days. Surface treatment with 20 wt% NaOH and Silane improves compressive strength from 54 to 60 MPa. PET fiber coating with Graphene-oxide and Polydopamine increases frictional and chemical bonding in concrete by 85 and 70%, respectively. The study concludes that surface treatments enhance concrete properties by improving bonding and minimizing fiber degradation.