Investigating the permanent deformation of hot mix asphalt containing Styrene-butadiene-styrene (SBS) and analysis in KENPAVE software

• Published in: AIP conference proceedings 2024-10, Vol.3249 (1)
• Main Authors: Nadhim, Fatima, Al-Hdabi, Abbas
• Format: Article
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0236478

Road traffic in Iraq has increased significantly over the past 20 years, for both passengers and freight. As larger, more powerful vehicles with wider, heavier bodies arrive, loading conditions are worsening. Consequently, persistent deformation of flexible pavements has been observed with high ambient temperatures. Rutting, a common type of distress on flexible pavements, can impair the quality of vehicles. Despite constituting a small portion of the asphalt mixture, the properties of the asphalt binder are crucial for the pavement’s performance and its ability to resist rutting. Adding additives, such as polymers, is one method to enhance binder characteristics and improve resistance to rutting. The purpose of this study is to examine the resistance to rutting of the asphalt mixture and binder by simultaneously modifying the 40–50 penetration binder using Styrene-butadiene-styrene (SBS) polymer. Significant research has been conducted on polymer-modified asphalt (PMA) mixtures over the past 20 years. Polymers can effectively enhance the resistance of mixtures to fatigue cracking, thermal cracking, and permanent deformation, thereby improving the performance of asphalt pavements across a range of temperatures, including low, moderate, and high. In the study, these modified asphalt mixtures were created by incorporating two different proportions (3% and 5%) of polymer by weight of asphalt. To assess the performance of the mixture, the impact of polymer modification was examined through tests such as Marshall Stability, Indirect Tensile Strength, Resilient Modulus, and Wheel Track. Additionally, tests on penetration, softening point, ductility, and kinematic viscosity were conducted to evaluate the physical properties of the asphalt binder. When using Styrene-butadiene styrene (SBS) polymer as a modifier for asphalt cement materials, the parameters of the Marshall test, such as stability, Marshall flow, bulk specific gravity (bulk density), voids in total mix (VTM), voids in mineral aggregates (VMA), and voids filled with asphalt (VFA), were significantly enhanced. The results of the test for indirect tensile strength demonstrated that adding this type of polymer could enhance the indirect tensile strength of asphalt mixtures. Finally, use the KENPAVE program to determine the design life based on the damage ratio, the addition of polymer was found to increase the design life of the pavement.