Presentation Date: Feb 14, 2026
AGSA Abstract
Nowadays, SBS (styrene-butadiene-styrene block copolymer) modified bitumen is among the most commonly used polymer-modified bitumens. Yet, its performance remains limited by persistent issues, including rutting, cracking, and fatigue failure, under extreme temperature conditions. However, research indicates that polymeric modification alone cannot meet the requirement of heavy traffic utilization of asphaltic pavements, and in view of this, the enhancement of the physical and rheological properties of Polystyrene Co-Butadiene (PSCB)-modified bitumen by incorporating Multi-Walled Carbon Nanotubes (MWCNTs) was investigated in this paper. The natural bitumen sourced from LODA was purified and modified through a dry mixing process, with MWCNTs incorporated at concentrations of (0.1- 0.3wt%), mixing time (20-40 mins), and speed (1000-1500rpm) were considered for ternary modification at 140 ºC. The modified bitumen was characterized using various techniques, including EDX, SEM, and TGA analysis. The modified bitumen was optimized, and the effects of MWCNTs on its physical and rheological properties were evaluated. The penetration point, softening point, flash point, and viscosity of the modified bitumen were evaluated using the ASTM standard method. According to the results, MWCNTs enhanced the performance of PSCB in improving the rheological and physical performance of the Loda natural bitumen. The properties of bitumen, such as penetration and softening points, improved with the addition of MWCNT. In addition, Scanning Electron microscopy (SEM) tests showed that MWCNTs improved the dispersion of PSCB and stability of the binder. Thermogravimetric analysis curves showed that the decomposition and volatilization rates of saturates and aromatics decreased, resulting in improved thermal stability of the bitumen. Statistical optimization using Response Surface Methodology (RSM) identified the optimal mixing conditions as 0.3 wt% MWCNTs, a mixing speed of 1353.33 rpm, and 39.14 minutes for the ternary mixture, achieving a desirability value of 0.88. The observed improvements exceed those of standard polymer-bitumen blends while satisfying ASTM performance criteria.
