Study on properties and improving mechanism of OGFC-13 asphalt mixtures modified by novel rubber pellets

•The novel rubber-modified pellets (RMP)are investigated in OGFC-13.•RMP replace the traditional composite modification method.•The road performance of asphalt mixtures with RMP is improved comprehensively.•The asphalt mixtures with RMP still retains excellent drainage performance.•The reaction between RMP and the modifier in asphalt is a physical cross-linking. Wetting modification of asphalt with single crumb rubber modifier (CRM) can no longer meet the performance requirements of porous asphalt mixtures. The purpose of this research is to investigate the influence of novel rubber-modified pellets (RMP) on the performance of open-grade friction courses (OGFC) asphalt mixtures and its improving mechanism. The RMP were employed with and without high viscosity asphalt (HVA) and SBS as references. Firstly, OGFC-13 asphalt mixtures with the optimum content of RMP were prepared. Then its road performance was evaluated using UTM-25, Hamburg wheel tracker and Marshall tester. Meanwhile, the maximum drainage volume was determined by a self-made device. Additionally, Fourier-Transform Infrared Spectroscopy, Fluorescence Microscopy and Dynamic Shear Rheometer were used to investigate the improving mechanism. The results show that the OGFC-13 with 2% RMP possess fracture energy with the maximum increment of 23.1%, creep slope and spalling slope with the maximum decrease of 49.1% and 32.3%, respectively. Meanwhile, they still possess excellent drainage capacity with a 160 mL/min rainfall intensity emission. The improved performance is caused by a denser network structure detected in the asphalt, which is related to a physical cross-linking reaction between modifiers and RMP. In conclusion, the traditional composite modified asphalt was substituted with RMP and the application of RMP is potential to extend longer service life of OGFC-13 asphalt pavement.