Effect of recycled vegetable oil on the performance of nanomarl-modified asphalt mixtures
Authors: Usanga Idorenyin Ndarake , Okafor Fidelis Onyebuchi , Ikeagwuani Chijioke Christopher 
Published: October 2023

In response to the demand for a greener approach to pavement infrastructure and the economic benefits associated with alternative materials, the modification of neat binders has been a consistent focus. This research aimed to enhance the characteristics of asphalt binders and mixtures by incorporating recycled vegetable oil (RVO) and nanomarl. RVO was added to 60/70 penetration bitumen at concentrations of 1%, 3%, and 5% by weight, while nanomarl was kept constant at 5% by weight of the bitumen. Various physical, rheological, and microstructural properties of the modified binders were evaluated, including penetration, softening point, viscosity, rutting resistance, fatigue resistance, creep, stiffness, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Furthermore, the moisture susceptibility and rutting resistance performance of asphalt mixtures incorporating these modified binders were investigated through analyses of tensile strength ratio and Hamburg wheel tracking. The test results revealed that the incorporation of RVO in bitumen led to a gradual increase in the penetration value of the modified bitumen. Simultaneously, the softening point and viscosity of the modified bitumen decreased, indicating that the addition of oil rendered the modified bitumen softer. However, the inclusion of nanomarl in RVO-modified bitumen improved its viscoelastic behavior and positively influenced its rheological properties under both unaged and aged conditions. Specifically, the addition of 5% nanomarl resulted in reduced penetration value, increased softening point, viscosity, rutting resistance, fatigue resistance, creep stiffness, and improved relaxation behavior at low temperatures. The most favorable outcomes were observed when incorporating 1% RVO with 5% nanomarl. Moreover, SEM and FTIR analysis demonstrated successful blending of the additives into the bitumen, without any evidence of phase separation. This indicates a homogeneous distribution of the additives within the bitumen matrix.

Practical application: The modification of bitumen with waste or recycled oils for the production of asphalt mixture has been successfully studied in numerous researches. However, this study introduces a novel approach by synergistically combining recycled vegetable oil (RVO) modification with the incorporation of nanomarl particles into asphalt mixture. The innovation aspect lies in the integration of two sustainable and environmentally friendly components, RVO and nanomral, to enhance asphalt performance. The findings offer a blueprint for incorporating sustainable materials and approaches in road construction projects. Pavement engineers can adopt the use of RVO modification and nanomarl particles to create longer-lasting and environmentally friendly asphalt pavements. In regions with challenging climatic conditions, the use of this modified asphalt can lead to improved infrastructure resilience. Roads built with these materials can better withstand temperature fluctuations. The integration of RVO and nanomarl particles offers improved performance, cost-effectiveness, reduced environmental impact, and also opens avenue for further exploration and optimization of asphalt mixtures incorporating innovative additives.