Aramid Fiber Reinforcement in Asphalt Mixtures: A Holistic Study on Mechanical Enhancement, Life-Cycle Economics, and Sustainable Pavement Solutions

The escalating degradation of asphalt pavements demands advanced, durable materials. This study's primary scientific novelty is the development and validation of a multi-criteria framework that integrates standardized mechanical testing, a detailed life-cycle cost analysis (LCCA), and a sustainability assessment to holistically evaluate aramid fiber-reinforced asphalt, bridging the gap between laboratory data and infrastructure decision-making. This holistic investigation evaluates the efficacy of aramid-polyolefin fibers (Forta-Fi®) incorporated at 0.05% by weight into three standard mixtures: Asphalt Concrete (AC) 0/11 mm, AC 0/16 mm, and Binder Course (BC) 0/22 mm. A controlled comparative analysis was conducted following European standards, utilizing Marshall stability and flow tests (EN 12697-34) and Indirect Tensile Strength (ITS) tests (EN 12697-23). The core methodological innovation lies in integrating mechanical testing with a comprehensive LCCA and sustainability assessment. The results demonstrate that fiber reinforcement primarily enhances resistance to permanent deformation and cracking. While Marshall stability increased modestly (0.57--1.55%), a more critical finding is the substantial reduction in average flow values, from 3.03 mm to 2.39 mm for AC 0/16, 2.63 mm to 2.32 mm for BC 0/22, and 3.22 mm to 2.37 mm for AC 0/11, enhancing rutting resistance. Consequently, the stability-to-flow ratio improved significantly (14.81-36.65%). The average Indirect Tensile Strength (ITS) also increased markedly: from 1.03 MPa to 1.15 MPa for AC 0/16, 0.98 MPa to 1.07 MPa for BC 0/22, and 1.08 MPa to 1.23 MPa for AC 0/11. Economically, despite an 18--22% initial cost increase, a scenario-based LCCA demonstrates that extended service life and reduced maintenance can yield a positive long-term value proposition. However, this is highly sensitive to the actual service life achieved. From a sustainability perspective, enhanced durability promotes resource efficiency. This study establishes a novel, replicable frame-work that quantitatively links mechanical enhancement to economic and sustainability outcomes, supporting the adoption of aramid fiber reinforcement for resilient and sustainable pavements.