Effectiveness of chitin on thermal susceptibility, rheological and ageing resistivity behaviour of sulphur modified bitumen binder

Abstract

The present investigation was carried out to understand the effectiveness of Chitin (Ch) on thermal susceptibility, rheological and ageing resistivity behaviour of Sulphur (S) modified bitumen binder (SMB). The modified bitumen binders were prepared in the laboratory using a VG-30 binder with 2% sulphur and different dosages of ‘Ch’. The dosages of Ch were varied as 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, and 3% by weight of VG-30. All combinations of ‘Ch’ modified SMB binders were subjected to three stages of ageing namely unaged, short-term ageing and long-term ageing as per test requirements. Rutting performance was evaluated using Superpave rutting factor (G*/sinδ) and MSCR parameters such as non- recoverable creep compliance (Jnr ), and percentage recovery (R). Fatigue damage behaviour was characterised using Superpave fatigue factor (G*sinδ) and linear amplitude sweep (LAS) tests. Ageing resistivity was calculated based on softening point, G*/sinδ, and Jnr values, and assessed in terms of the ratio of the respective parameter of aged sample upon unaged sample. The resulting trend indicates that the surface characteristics, elemental, and interaction potential of ‘Ch’ and ‘S’ may have a strong influence on the performance of the bitumen binder. Viscosity test results imply that addition of ‘Ch’ showed a lower degree of thermal susceptibility, which may require less compaction effort for applications of the bituminous mix in the field. G*/sinδ, Jnr , and R values signify a clear indication of an increase in rutting resistance ability with the incorporation of ‘Ch’ in SMB binder. It is observed that the inclusion of ‘Ch’ in SMB binder has the potential to enhance the fatigue life at intermediate temperature. Similarly, resulting ageing index values showed that SMB binder is less susceptible to ageing with addition of Ch. This study showed that the combination of SMB with Ch can be beneficial to enhance the rutting and fatigue resistance of bitumen binder with low thermal and ageing susceptibility behaviour.