Detecting Gilgai Relief Beneath Sealed Flexible Pavements Using Road Profile and Road Roughness Measurements

摘要

Expansive soils are those that expand and contract significantly when subjected to changes in moisture. The presence of such soils can accelerate the deterioration rate of pavements due to increased cracking and roughness, especially when Gilgai relief is allowed to manifest beneath the pavement structure. Gilgai relief is a naturally occurring topographical feature that results in a unique undulating ground surface. These undulations develop from deep seated swelling pressures within the underlying expansive soil layers. At present, current road roughness indices cannot isolate the roughness caused by Gilgai relief and the detection of Gilgai in the field can be difficult. This paper presents a new series of templates that can identify pavement sections that contain high concentrations of waveband roughness specific to Gilgai characteristics. These templates are based on the standard international roughness index and a variety of new calculated profile indices that measure waveband roughness quantities. The main outcome of this paper is that the influence of Gilgai relief can now be detected and quantified mathematically through these templates, which were developed from over 600 km of road profile data from flexible rural highway pavements located in north-west Victoria (Australia).