EFFECT OF MODIFIED AND UNMODIFIED BITUMEN ON A SURFACE LAYER- A CASE STUDY

摘要

While the road agencies spend a significant amount of money on pavement construction and maintenance, it is critical to use more durable materials for sustainable pavements. The material selection is one of the critical parameters in the construction of sustainable pavements. The aim of this study was to demonstrate that a Polymer Modified Bitumen (PMB) is a sustainable pavement material, considering a case study from Telangana State. For this study, two road sections were considered, one was a resurfaced BC layer with a PMB, while in the other was a new BC layer constructed using a Viscosity Grade Bitumen (VG30). The visual condition survey of both the pavement sections showed that VG30 pavement section had raveled within one year of construction, whereas the PMB pavement, section remained in a good condition after one year. Further, to carry out the laboratory studies, fourteen field core samples were taken from each of the pavement sections. The bulk specific gravity of the field core samples was measured using a Bouncy balance and the other volumetric properties were calculated. Using a Soxhlet apparatus, bitumen was extracted from BC field core samples. Further, the rheology tests were carried out on the extracted binder using a Dynamic Shear Rheometer (DSR), and the oxidative ageing was assessed from the Fourier transform infrared spectroscopy (FTIR) studies. The DSR investigation showed that the PMB binder exhibited 34% higher resistance against rutting and 50% higher resistance against cracking when compared to VG30 binder. From the FTIR studies it was observed that there was 50% lesser ageing in PMB binder.