Waste By-product in Asphalt Concrete Pavement Construction: A Review

The sustainable modification of bitumen is essential for enhancing asphalt pavement performance, longevity, and environmental sustainability. This study investigates a wide range of modifiers, including sulphur, geopolymers, and mining wastes such as steel slag, red mud, fly ash, slag, and silica fume, to improve chemical, mechanical, and rheological properties of asphalt binders and mixtures. Mining by-products such as steel slag, red mud, and slag demonstrates a good result as an alternative filler, also by reducing the environmental waste while increasing durability. Steel slag, improves adhesion, resistance against stripping, and mechanical performance in both hot and cold mix asphalt. The effectiveness of these modifiers is assessed through rheological testing, penetration, softening point, viscosity, and aging tests. The findings indicate that combining mining waste by-products increases stiffness, rutting and moisture resistance, aging properties of mixtures, making them stronger for stresses. This review contributes to the development of cost-effective, eco-friendly, and high-performance road construction materials, helping the transition to sustainable infrastructure.