An overview of stabilisation methods and performance of local government roads in Australia

Australia has one of the largest road networks in the world. Three levels of government, Federal, State and Local are responsible for managing the 810,000 km long road network at present. But the combination of larger vehicle loads, increased traffic flows, ageing infrastructure and environment has led to degradation of many Australian roads. Local government roads comprise more than 80 percent of the total road networks in Australia. Local councils are responsible for local roads and some arterials, particularly in the larger urban areas. Australia is recognised as a world leader in theory and application of stabilisation of degraded roads with continuous innovation in equipment and stabiliser type. Although a large number of publications exist regarding use and performance of chemical stabilisation carried out on state highways, limited published information regarding chemical stabilisation of Australian local government roads is available. In view of the above, a survey was devised to determine current state of the practice in chemical stabilisation of road pavements in various councils in Victoria, New South Wales, Queensland and South Australia. The survey covered use of material and thickness in pavements; mode of rehabilitation of degraded pavements; type and quantity of chemical additives used; modes and basic reasons of pavement failure and constraints for wide use of chemical stabilisation in Australian local government roads. Clayey gravel/gravel and igneous crushed rocks are commonly used as pavement materials. Cementitious binders are used as main stabilising agents. Statewise variations in use of pavement materials, mode of failure of pavements and their rehabilitation and uses of chemical stabilisers have been observed. Cracking has appeared to be the foremost mode of failure or contributor to failure of chemically stabilised pavements. Shrinkage is considered to be most important cause of cracking in pavements. Current paper presents results of this survey.