Development and characterisation of a novel thermosetting natural rubber-modified asphalt

In this study, a novel thermosetting natural rubber-modified asphalt (TNRA) was developed using natural rubber, with the aim to enhance the performance and sustainability of asphalt pavements. Firstly, key parameters such as the optimal natural rubber and vulcanising agent contents, curing temperature, and curing time were determined through a series of experiments. Subsequently, the mechanical and rheological properties of the TNRA were evaluated. Finally, the curing reaction and process of the TNRA were analysed. The results showed that the optimal curing temperature and curing time for the TNRA were 140 °C and 3 h, respectively, and the retention time of the TNRA was 30–35 min. The TNRA exhibited superior resistance to high-temperature deformation and improved flexibility at low temperatures with significantly reduced temperature sensitivity, among which the performance of the TNRA7-V15 was the best. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analyses revealed that the TNRA was formed by vulcanising the natural rubber within the asphalt matrix, creating a three-dimensional network structure that imparted thermosetting properties. In addition, the TNRA offers a lower material cost, positioning it as a potential substitute for other thermosetting binders, and making it widely applicable for asphalt pavements. This study provides a promising approach for developing sustainable high-performance thermosetting asphalt binders for pavement engineering.