Transitions in rheological properties of modified bitumen containing chemical additives

Bitumen typically performs the function of a binder due to its adhesive properties and the ability to assume liquid form when heated and solid form when cooled. The softening of pavement bitumen during summer temperatures causes rutting on roads and its winter fragility leads to low-temperature cracking. In order to address these issues, a variety of additives have been proposed over the years as modifiers to improve the performance of bituminous concrete. In this direction, the aim of the present work was to establish the efficacy of the chemical additives, namely, titanium dioxide and carbon black in bitumen. To accomplish this objective, plain bitumen and modified bitumen samples with different percentages of titanium dioxide and carbon black were prepared and tested for various rheological properties. The study also examined the viscoelastic behaviour of the samples using dynamic shear rheometer. The findings of this study demonstrated that titanium dioxide and carbon black in bitumen are strong viscosity enhancers. Also, the modified bitumen specimen yielded in high phase angle indicating high viscous behavior and higher resistance to rutting and fatigue. The research findings also suggested that titanium dioxide and carbon black aid in the preparation of durable and sustainable mixtures for flexible pavements.