Parametric study of the compactness assessment of a new road containing recycled asphalt pavement through non-nuclear method

The aim of this work is to show the relevance use of the Step Frequency Radar (SFR) to assess the compactness of a Hot Mix Asphalt (HMA). Herein, compactness assessment of a new paved highway containing 38 % in weight of unknown recycled component is performed through SFR. Three different methods of analysis are developed to assess accurately the compactness of the investigated road. The first method does not require lab measurement or core drilling. The second method is based on laboratory measurements of aggregate permittivity. Finally, the third method leans on lab measurements and core drilling calibration. It turns out that the calibration through core drilling was not necessary for reaching the 1 % accuracy mandated for the compactness assessment. The effect of the roughness on the reflected signals is investigated and highlights that a correlation with the high HMA roughness and the scattering obtained with SFR can be performed. The influence of the properties in the electromagnetic models was investigated and shows that the knowledge of the main component permittivity of the HMA is primordial to assess accurately the compactness.