Experimental Evaluation of the Mechanical Performance and Deformation Strength of Glass Fiber-Reinforced Asphalt Mixtures

In this work, the mechanical properties and deformation behavior of Hot Mix Asphalt (HMA) reinforced with Glass Fiber (GF) are analyzed. The focus was mainly on determining the effects of different GF content on the behavior/ stability/ stiffness/ permanent deformation of asphalt concrete in wearing courses. The experimental protocol was based on asphalt Al-Daurah cement (40/50 penetration grade) and crushed aggregates obtained from Kavin Company (Zakho, Duhok), with a nominal maximum aggregate size (NMAS) of 12.5 mm, as per ASTM D3515. The study was carried out in two stages. The Optimum Asphalt Content (O.A.C.) was determined to be 5.1% using Marshall mix techniques. In phase two, 5 mixtures were made together with the dry mixing method, adding (GF) at 0% (Control), 0.3%, 0.5%, 0.7%, and 0.9% by weight of the mix. Experimental results showed improved structural integrity of the asphalt when glass fibers were applied. The Marshall Stability was at its maximum at 0.5 % GF (12.5 kN), 25 % higher than the control mixture. Additionally, the Kim Test was used to probe the high-temperature effect, and the Deformation Strength (SD) level increased by ≈ 50% at the same dosage (2.706 MPa > 4.048 MPa). The maximum Marshall Stiffness was 3.8 kN/mm at 0.5% GF, indicating superior shear resistance. Yet, fiber levels above 0.5% lead to decreased performance due to fiber agglomeration and poor workability. The Optimum Glass Fiber Content (O.GF.C.) is 0.5% GF for improving both the durability and rutting resistance of flexible pavements in hot weather.