Evaluation of Rutting and Fatigue Behaviors of Asphalt Binders Modified with Calcium Lignosulfonate

Abstract

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.