Investigation of the properties of carbon black modified bitumen and hot mix asphalt mixtures

Abstract

The traffic volume, tyre pressure, and environmental conditions cause the depletion of road pavement performance levels. However, to enhance road quality, improving pavement performance is vital. Researchers have been studying ways to improve the performance of pavements by modifying the asphalt using various materials. With the emerging trend towards low carbon emission materials, waste-based materials are usually investigated on their ability to modify conventional construction materials. Pyrolysis Carbon Black (PCB) is a by-product of the waste tyre recycling process, which can potentially improve pavement performance. This study aims to investigate the properties of PCB modified bitumen and its performance impact factors. Further to evaluate the manufacturing process of PCB-modified asphalt concrete by comparing the effects of wet and dry mixing methods on pavement performance when PCB is incorporated with asphalt. Penetration, softening point and Dynamic Shear Rheometer (DSR) test was conducted to investigate the Rheological and Physical properties. Marshall Stability and flow tests are used to evaluate the volumetric properties. The bitumen properties provide the evidence of ability to improve the rutting resistance and high temperature performance of the asphalt by adding PCB. Further volumetric properties show that both methods have improved the asphalt properties where the flow has increased in wet and dry mixing mixtures, compared to the conventional mixture. Moreover, PCB modified road section was evaluated and calculated Pavement Condition Index (PCI). For better insight, another section from the same road prepared with conventional asphalt at the same period was evaluated. The calculated PCI values are 85% and 88% for conventional and PCB-modified pavements, respectively demonstrating the potential for long-term performance in PCB-modified pavements. PCB can be recommended as a promising modifier option to develop pavement performance while adhering to sustainability guidelines. Furthermore, additional investigations into low-temperature performance and wet mixing manufacturing process of PCB-modified asphalt are encouraged.