Mechanical and Physical Characterization of Traditionally Processed <i>Festuca dolichophylla</i> Fibers for Heritage Structural Use

This study characterizes Festuca dolichophylla fibers, a native species traditionally used to fabricate structural cables for the Q’eswachaka suspension bridge in Peru. The moisture content was determined by oven-drying, and the apparent density was assessed using volume by water immersion and flotation tube methods. Tensile tests were conducted on three distinct groups: Untreated (UN) fibers, Humidified and Pressed (HP) fibers soaked in water and compressed with a smooth stone, and Dry Impact (DI) fibers treated without prior humidification. The average moisture content was found to be 5.31 ± 0.73%, while the densities were recorded as 483.23 ± 31.56 kg/m3 (immersion) and 472.80 ± 19.20 kg/m3 (flotation). Untreated fibers demonstrated a tensile strength of 72.4 MPa, with a standard deviation of 20.7 MPa. The application of HP treatment resulted in an increase to 97.4 ± 34.4 MPa, presumably due to improved internal alignment and reduced stress concentrations. DI-treated fibers showed a decrease in strength (54.2 ± 11.7 MPa), indicating possible internal damage. All groups exhibited properties compatible with temporary structural applications. These results confirm the mechanical viability of Festuca dolichophylla fibers and support their use in heritage restoration and sustainable design.