Performance Assessment of Asphalt Mixtures Containing Dry-Processed Waste Cooking Oil Granulates

Abstract

Abstract The consumption of waste cooking oil (WCO) as a bitumen modifier offers a sustainable route for waste valorization, yet challenges persist concerning stability and mechanical performance at high content. This study explores the performance of asphalt mixtures containing modified waste cooking oil granulates (MWCOG), produced by dry-blending WCO with styrene-butadiene-styrene (SBS) at two ratios (45:55 and 50:50). Asphalt mixtures were prepared using MWCOG-modified bitumens at 5%, 10%, and 15% contents and assessed through Marshall stability, rutting resistance, resilient modulus, and Cantabro durability tests. The results confirmed that MWCOG addition significantly enhanced mixture performance, particularly at 10% dosage. Marshall stability increased from 13.75 kN (control) to 16.42 and 16.59 kN for 45∶55-10% and 50:50-10% mixes, respectively, indicating comparable stability performance for both blends, with the small difference falling within typical experimental variability. Cumulative rutting strain was reduced by up to 27% at 5% MWCOG, with permanent strain declines and creep modulus improvements of 35% over the control observed at 10%. Resilient modulus at 25°C increased by 16% and 12% for the 45∶55-5% and 50∶50-5% mixes, respectively. The cohesion and mass loss further confirmed the enhancement in the asphalt mixture by the Cantabro test. The results revealed a mass loss reduction of 61% and 52% for 45∶55-15% and 50∶50-10% mixes compared with the control. However, performance declined at 15% MWCOG due to excessive softening. The study confirms that MWCOG inclusion at 10% yields optimal stiffness, durability, and strength, supporting its practical perspective as a sustainable, high-performing asphalt mixture for pavement applications.