Field data to investigate the impact of initial air-voids on the performance of bituminous pavements – a case study

Abstract

The aim of this study was to examine the relationship between initial compaction and pavement performance of a road with low-volume traffic. Data was collected from Telangana State in India. Binder was extracted from the field core samples after measuring the volumetric properties. The binder rheology was then compared with laboratory-aged VG30 bitumen. Higher air-voids in the newly constructed bituminous surface have caused binder ageing and raveling. Flaky, water-absorptive trap-aggregate worsened the problem. The fine aggregate and bitumen were stuck to the rubber-coated steel wheel in the Hamburg wheel tracking study indicating raveling. Binder reduction due to raveling was shown by slicing 30 mm field cores into two sub-layers; the bitumen content was reduced in the top slice (5.3% to 4.3%) and not in the bottom. For roads with low-volume traffic, a target density of 94% G_mm is recommended instead of the usual 92% to minimize binder ageing and raveling.

KEYWORDS:

• Binder ageing
• Air-voids
• Trap-aggregate
• Raveling

Acknowledgement

The authors express their gratitude to the engineers for their help and cooperation during the field visits. The authors are thankful to the Central Analytical Laboratory team at BITS Pilani, Hyderabad Campus, for giving access to the dynamic shear rheometer.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was a two-year study supported by the Office of the Engineer-in-Chief, Roads & Buildings (R&B) Department, Telangana.