Experimental Study on the Influence of Date Palm Fibers Reinforced Bituminous Mixtures

Abstract

This study investigates the influence of date palm fibers (DPF) on the mechanical performance of bituminous mixtures using two experimental methodologies: the wet and dry processes. In the wet process, DPFs were pre-blended with bitumen at varying contents ranging from 1% to 5% by weight, prior to mixing with aggregates. The resulting mixtures were evaluated based on several key performance indicators, including Marshall stability, creep resistance, compactness, and water sensitivity. The inclusion of fibers generally enhanced mechanical properties, with optimal improvements observed at 2% to 4% fiber content. Notably, the mixture with 3% DPF content demonstrated a 35.7% increase in Marshall stability, while the lowest compactness reduction (−1.9%) occurred at 1% fiber addition. In the dry process, the effects of both fiber length (1 cm, 3 cm, and 5 cm) and fiber content (0.1% to 0.5%) were examined, focusing specifically on rutting and creep resistance. The results showed that 3 cm fibers significantly improved rutting resistance, whereas the 0.1% fiber content yielded the highest enhancement in creep resistance. However, no clear correlation was established between the two performance metrics, suggesting that the mechanical response is highly deformation-dependent. Overall, the addition of DPF contributed to improved durability, strength, and resistance to deformation in asphalt mixtures. The findings underscore the potential of date palm fibers as a sustainable, low-cost, and environmentally friendly additive in pavement engineering, particularly in regions where palm waste is readily available and underutilized.