Performance Recovery of Aged Asphalt in RAP Mixtures Using Sugarcane Bagasse Bio-Rejuvenator: Moisture Susceptibility and Rutting Behaviour Analysis

Abstract

The incorporation of Reclaimed Asphalt Pavement (RAP) into hot mix asphalt offers substantial environmental and economic advantages; however, the presence of aged asphalt binder often leads to excessive stiffness, reduced durability, and limited workability, necessitating the use of rejuvenating agents to restore performance. This study investigates the potential of a sugarcane bagasse–based bio-rejuvenator to enhance the mechanical and durability characteristics of AC-WC mixtures containing varying RAP contents. Three mixtures were prepared at their respective optimum asphalt contents and evaluated through Marshall Stability, Marshall Immersion, and wheel tracking tests to assess structural integrity, moisture susceptibility, and resistance to permanent deformation. The incorporation of the bio-rejuvenator consistently improved the performance indicators across all RAP levels, demonstrating its capability to restore binder functionality, enhance mixture cohesion, and strengthen resistance against moisture-induced damage. Furthermore, the rejuvenated mixtures exhibited improved deformation resistance under repeated loading, indicating a more stable internal structure and better long-term rutting performance. These findings indicate that sugarcane bagasse bio-rejuvenator not only restores workability but also significantly enhances moisture resistance and rutting performance of RAP asphalt mixtures.