Exploring the potential of recycled PAN-type fibers as reinforcement in cement-based composites

In this study, the potential utilization of PAN (Polyacrylonitrile) type fibers, typically discarded during the production of wigs, as a reinforcement material in cement-based composites is explored. Fibers measuring 80 microns in diameter and with lengths of 3, 6, and 12 mm are incorporated into the mortar at varying ratios of 0.5, 1, and 1.5% relative to the composite volume. The flexural tensile strength, compressive strength, and shrinkage behavior of the resulting PAN-type recycled fiber-reinforced mortars are examined. Comparative analysis is conducted with a control sample, which consists of a fiber-free specimen. Moreover, the impacts of fiber length and dosage on performance are scrutinized. The findings of the investigation reveal notable alterations in flexural strength and shrinkage due to the integration of recycled fibers in cementitious composites. Enhanced flexural tensile strength is observed with increasing fiber length in the fiber-reinforced composites. Optimal fiber content is determined to be 0.5% for all fiber lengths. Despite the control sample exhibiting a compressive strength of 53 MPa, the fiber-reinforced mortars demonstrate no adverse effects on compressive strength. Notably, fibers measuring 3 mm in length enhance the compressive strength of the composite to ∼67 MPa. Shrinkage test results indicate reduced dimensional changes in fiber-reinforced composites with higher fiber lengths and content. These outcomes align with weight loss measurements, suggesting that decreased water loss contributes to diminished shrinkage.