Experimental study of performance enhancement in SBS modified asphalt binders and mixtures

Abstract Due to heavy loading and severe temperatures in Pakistan, bituminous pavements deteriorate early in their service life. This study aims to modify the conventional bitumen with polymers to improve its resistance to heavy loading and extreme temperatures. Styrene-butadiene-styrene (SBS) polymer, at a dosage ranging from 3 to 9% by weight of bitumen, was added to the conventional bitumen. The SBS-modified bitumen was evaluated through series of physical test, including bending beam rheometer (BBR) test, resilient modulus testing, wheel tracking test, and moisture susceptibility assessment. The results showed that SBS enhances performance significantly, improving tensile strength ratio and resilient modulus increased by 30–35% with the inclusion of SBS. Additionally, rut depth decreased by 42% indicating improved rutting resistance. SBS modification reduced 40% stiffness at extremely low temperature of -22 ◦ C, helping prevent thermal cracking. Overall, the optimal SBS dosage for asphalt performance in Pakistan’s environmental condition is 5%. Statistical analysis, including ANOVA and Tukey’s test confirmed significant relationship between SBS contents and improvements in asphalt performance. Overall, this study highlights the effectiveness of SBS-modified asphalt in addressing key pavement issues such as rutting and cracking, particularly under challenging climatic conditions.