Improvement and performance of pavement gravels used by Toowoomba Regional Council for unsealed roads

Abstract

[Abstract]: In recent years the traffic using the Australian Road Network has increased and this traffic is asking for the same performance from the road network, despite the increase in traffic volumes, wheel loads and percentage of heavy vehicles. The performance of both sealed and unsealed roads is being scrutinised by road users. Local Road Authorities are challenged with maintaining and upgrading the unsealed road network with varying qualities of natural gravels to provide economical and durable pavements. Toowoomba Regional Council (TRC) has an extensive road network of 9650 km of which 3330 km are sealed and 6320 km are unsealed. To improve the performance of the unsealed gravel roads an investigation was requested to determine the suitability and characteristics of the current gravels used. A literature review revealed that extensive research has been undertaken, in Australia and internationally, into the characteristics and performance of pavement gravels used on unsealed roads. The diminishing quality and quantity of suitable gravels has led Government Agencies to investigate how to achieve optimum performance from these materials. This project aimed to gather information on gravels used across TRC in respect to their physical characteristics, the construction processes used for them, and their field performance. This information was then used to identify areas where TRC could implement changes to improve l performance of their gravel pavements. The study found that changes in the gravel resheeting process currently used could lead to a better performing unsealed road network in the region.