The accelerated deterioration of pavements subject to increased axle loading needs the development of interim road deterioration (RD) models so that the cost of accelerated deterioration can be estimated on a pavement life-cycle costing basis. These RD models were based on selected assemblies of road condition data in the rapid deterioration phase. The bulk of the condition data identified in the rapid deterioration phase was from selected data from the Department of Planning, Transport and Infrastructure, South Australia (DPTI SA) and past accelerated loading facility (ALF) experimental data in both the gradual and rapid deterioration phases. The work undertaken in 2013—14 produced the following outcomes for interim RD models in the rapid deterioration phase, based on use of the above data: • A cumulative rutting model, using independent variables for pavement age, Thornthwaite Moisture Index, initial pavement strength and cumulative cracking, which predicts the expected increase in the rate of cumulative rutting deterioration in the rapid deterioration phase. • A cumulative cracking model using independent variables for cracking age, Thornthwaite Moisture Index and initial pavement strength which predicts the expected increase in the rate of cumulative cracking deterioration in the rapid deterioration phase. • A cumulative roughness model using independent variables for cumulative rutting, cumulative cracking, Thornthwaite Moisture Index and pavement age. • An exploratory RD model, based solely on the ALF data, for the prediction of the loss of surface area in both the gradual and rapid deterioration phases. These interim RD models, although based on a relatively limited dataset, are expected to be a useful tool for the initial assessment and prediction of the road wear cost consequences of reduced maintenance on pavement conditions and increased axle mass loading. These RD models can also be used to limit the number of high productivity freight vehicles (HPFV) on roads identified as being at risk of serious failure. However, as the interim RD models are based on limited data they cannot be regarded as robust and adaptable to a range of road types and conditions beyond the data set (low volume sealed roads in a dry climate) they were derived from. The prediction of pavement distress in the rapid deterioration phase under increased axle loading is a challenging task due to the lack of reliable and extensive data available for model development. Further work in gaining performance data on selected poorly maintained pavements across Australia using the accelerated loading facility (ALF) or a similar testing facility is a means of being able to produce more robust and reliable RD models in the rapid deterioration phase. This ALF experimental work should be conducted in conjunction with the regular monitoring of selected un-maintained road segments on a range of sealed roads. (Author/publisher)
Samenvatting