INFLUENCE OF PAVEMENT REHABILITATION ON ROUGHNESS

This paper examines the effect that various pavement rehabilitation techniques have on restoring the quality of the pavement surface and compares these techniques with other conventional methods used for the same purpose. Life cycle costing is also performed on all methods and a decision balanced by roughness and cost is made as to the most appropriate method. The rehabilitation techniques of in-situ stabilisation, asphalt mill and replacement, asphalt overlay and gravel overlay bitumen seal are examined. Pavement roughness data in the form of NAASRA roughness counts were collected over a period of up to eight years for a range of pavement surfaces throughout the state of New South Wales. These roughness counts were then converted to the international roughness index (IRI). The initial improvement in IRI for each method and the change in IRI values with time are examined. From the change in IRI, it is possible to determine a pavement's life based on the roughness characteristics of a pavement surface becoming unacceptable. From the analysis conducted in this research, it is evident that there is little difference in the change of pavement roughness in the early stage after rehabilitation for the techniques examined. Of the four techniques examined, asphalt mill and replacement exhibited the best initial improvement in pavement roughness. Performing net present worth of cost comparisons, the cheapest rehabilitation option proved to be in-situ stabilisation. Because its performance in improving roughness was comparable to that of asphalt mill and replacement, this technique was chosen. Comparing in-situ stabilisation with reconstruction and resealing, the cheapest technique in maintaining a road is resealing, however it is not as effective at reducing roughness as rehabilitation by in-situ stabilisation. (a) For the covering entry of this conference, please see ITRD E204151.