The poor compatibility between crumb rubber (CR) and asphalt binder limits the performance of rubberized asphalt (RA). To address this, CR was pretreated using potassium permanganate (KMnO 4 ) and hydrogen peroxide (H 2 O 2 ) as solution-based oxidizing agents. This study investigated the effects of these pretreatments on rutting resistance. The chemical modifications of CR were characterized using Fourier-transform infrared spectroscopy (FTIR) and thin-layer chromatography with flame ionization detection (TLC-FID). The rheological and mechanical performances were assessed using a dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), and wheel-tracking (WT) tests. Statistical approaches, including principal component analysis (PCA), partial least squares regression (PLSR), response surface methodology (RSM), and Arrhenius-based kinetic modeling, were employed to elucidate chemical-mechanical relationships. The results showed that pretreatment significantly increased the intensities of carbonyl (C=O) and sulfoxide (S=O) groups in CR, leading to a higher asphaltene fraction and enhanced binder stiffness and hardness. Both KMnO 4 and H 2 O 2 pretreatments improved rutting resistance, with KMnO 4 demonstrating superior effectiveness. The aggregate type also played a critical role, with limestone mixtures exhibiting greater relative improvements (up to 46% with KMnO 4 and 23% with H 2 O 2 ) than basalt mixtures (41% and 34%, respectively). While pretreatment enhanced rutting parameters and asphalt–rubber interaction, it also increased recoverable creep compliance, indicating potential trade-offs with elasticity and fatigue performance. These findings highlight that chemical pretreatment of CR is an effective approach to improve rutting resistance but requires careful balance with long-term durability.
Badughaish et al. (Wed,) studied this question.