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Asphalt mixes encounter different distress during the life cycle of asphalt pavements, among which rutting and fatigue failure are prominent. Moreover, the addition of environmentally friendly modifiers into the asphalt binder to increase the performance of asphalt mixes has been a challenging phenomenon for researchers. Calcium lignosulfonate (CL) is a waste material that is a by-product of the wood industry. In this paper, the impact of the calcium lignosulfonate on the rutting and fatigue performance of the asphalt binder was investigated. For this purpose, the Dynamic Shear Rheometer (DSR) was utilized to run the Multiple Stress Creep Recovery (MSCR) test and evaluate G ∗ /sinδ and G ∗ ·sinδ indices for the asphalt binder containing different percentages of CL. The elastic recovery test was also conducted on the asphalt binder. In order to analyze the thermal storage stability of CL-modified asphalt binders, the storage stability test was considered. The Field Emission Scanning Electron Microscope test showed that using CL as a binder modifier makes the texture of the asphalt binder spongy and porous. The conventional test results indicated that increasing the CL amount in the asphalt binder led to an increase in the stiffness of the asphalt binder. The rheological test results showed that the rutting resistance of the asphalt binder improved by adding up to 15% of the CL powder; however, the fatigue performance and the elasticity of the asphalt binder declined by increasing the CL content in the asphalt binder. The storage stability test revealed that the dispersion of CL in the asphalt binder was uniform; moreover, the presence of CL in the asphalt binder could not adversely affect the thermal storage stability of the modified asphalt binder.

Using bitumen modifiers to prolong the asphalt mixture’s life has been considered a practical approach in constructing asphalt mixtures. Among various bitumen modifiers, biomass ones have been more noteworthy because of their abundance, cost-effectiveness, renewability, and sustainability. Calcium lignosulfonate (CLS), as a plant-based bitumen modifier, has been studied to enhance the rheological properties of bitumen. However, the feasibility of using CLS as a rutting retarder of asphalt mixtures is still unclear. This study focused on the durability of asphalt mixtures containing CLS powder as a bitumen modifier. Specifically, extensive laboratory tests were conducted to determine the performance of asphalt mixtures against traffic loadings. In this study, to begin, CLS-modified bitumen was manufactured using a high-shear mixer at various CLS dosages (5, 10, 15, and 20 wt.%). Afterward, the optimum bitumen content of asphalt mixtures was found using the Marshall mix design technique. Finally, a series of dynamic tests, including resilient modulus, dynamic creep, and wheel-tracking tests, were combined with Zhou’s three-stage model and Tukey method to determine the influence of CLS on asphalt mixture’s rutting potential. The Tukey method found that asphalt mixtures containing 15% CLS had the highest rutting performance among the samples tested under repetitive loadings. Meanwhile, the surface morphology and elemental analysis of CLS powder were investigated using a field emission scanning electron microscope (FESEM) and by energy-dispersive X-ray spectroscopy (EDX), respectively. The FESEM and EDX results showed that the CLS powder had a bumpy structure and its chemical structure contained metal oxide, carbon, magnesium, calcium, and silicon. The results indicated that the asphalt mixtures became stiff owing to the combination of CLS and bitumen, which significantly affected the rutting improvement of asphalt mixtures. Moreover, Zhou’s three-stage model revealed that the incorporation of CLS into bitumen enhanced the rutting resistance capacity of asphalt mixtures against traffic loadings.