Temperature adjustment of Surface Curvature Index from Traffic Speed Deflectometer measurements

ABSTRACT

Pavement structural condition evaluation plays an important role in assessing rehabilitation needs and making prudent investment decisions. Recently the use of Traffic Speed Deflectometer (TSD), is being considered for pavement structural evaluation especially for network level pavement management applications. Among various TSD data measurements and indices, Surface Curvature Index (SCI_TSD), is a widely-used index for assessing the structural condition of the AC layers. Since asphalt modulus is temperature sensitive, measured deflections and consequently the computed SCI_TSD are also affected by pavement temperature at the time of testing. For consistent pavement evaluation, SCI_TSD computed across sections and over time should be adjusted to a reference temperature. This study presents an applied method for adjusting SCI_TSD to a reference temperature. The method was based on a model developed from a dataset built from responses computed with dynamic-viscoelastic analyses under TSD moving load in a wide range of pavement properties. The method was field evaluated with TSD data from three locations within the US and one location each in Europe and Australia. The results showed that the proposed method can reasonably adjust SCI_TSD to a reference temperature which enables its application in pavement structural assessment and subsequent use in pavement management activities.

KEYWORDS:

• Surface Curvature Index
• temperature adjustment
• viscoelastic analyses
• Traffic Speed Deflectometer
• pavement management system

Acknowledgements

The authors would also like to thank Dr Adam Zofka of Road and Bridge Research Institute (IBDiM), Poland, and Mr Richard Wix of ARRB Group, Australia, for sharing TSD data collected in Europe and Australia, respectively.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was performed while the first author held National Research Council (NRC) Research Associateship award administrated by the National Academies of Sciences, Engineering, and Medicine fellowships office and their support is greatly acknowledged.