# Assessing the Compaction Quality of Dolomitic Asphalt Pavements Using Ground Penetrating Radar
## 8 Conclusions  
In the comparative analysis of dielectric values derived from the PaveScan and horn antenna measurements, the dielectric values measured by the horn antenna were more closely aligned with the core data. This suggests that the horn antenna measurements are highly effective in estimating \(\epsilon\), demonstrating superior accuracy compared to the PaveScan measurements. Based on the laboratory findings, we concluded that the SR derived from the horn antenna method can be effectively utilized for reliable pavement investigations. Asphalt density assessments can be spatially extended by calibrating the GPR dielectric data using nuclear gauge measurements, and atomic measurements can be substituted. This is especially true regarding larger projects, in which the same, or a similar, AC mix is used on longer road sections. We concluded that the \(\epsilon\) depended on the density of the asphalt mixture--a higher density reduced air voids, leading to an increased dielectric constant. Additionally, we proposed a generalized function to describe the relationship between the \(\epsilon\) and bulk G\({}_{\text{mb}}\) under specified conditions, such as asphalt pavements with aggregate sizes ranging from 11 mm to 25 mm and composed of dolomite or limestone. Therefore, we concluded that the asphalt content influenced the dielectric constant, as the density of the Hot Mix Asphalt (HMA) was influenced by the components of air, mineral filler, aggregate, and asphalt binder. The compaction curve helps determine the required number of compaction passes to achieve the maximum asphalt mixture density, and the GPR measurement corresponding to the maximum density can be used as a reference to examine the density levels at other locations. The presented RD maps demonstrated that the relative compactness of in situ asphalt materials is not uniform. Variations in density within the same layer suggest variations in the compaction efficiency during construction. Specifically, Section II. 's left lane exhibited a lower compaction quality, indicating that additional roller passes should have been made during the construction of the wearing course. Although the general condition of the investigated section is good, the identified spatial differences in compaction quality, particularly in Section II., justify continuous monitoring of the road structure. This need for monitoring is further supported by the observed density variations beyond an acceptable threshold, which could impact the long-term performance. Incorporating literature on pavement-monitoring decision making could further strengthen this justification. We concluded that a method for density assessment was developed using GPR by surveying asphalt at different degrees of compaction. This way, more accurate RD maps were generated to visualize the spatial homogeneity of the density. The survey findings highlight that it is possible to indirectly determine the G\({}_{\text{mb}}\) of asphalts composed of dolomite and limestone aggregates using horn antenna GPR measurements calibrated with nuclear gauge data, as these methods demonstrated superior accuracy and reliability in estimating the \(\varepsilon\) and assessing the asphalt density. In addition, the RD maps generated in this study are important in predicting the long-term performance of the pavement, supporting maintenance strategies, and facilitating the detection of different defects. Conceptualization, E.A. and D.S. ; Methodology, E.A. and Z.T. ; Data Processing, E.A. and D.S. ; Physical Properties Analysis, E.A. and D.S. ; Validation, E.A. and Z.T. ; Formal Analysis, E.A. and D.S. ; Investigation, E.A., A.M.A., K.B., A.F., G.M. and V.B.-V.; Resources, E.A. ; Writing, original draft, E.A. ; writing, reviewing, and editing, all authors; visualization, E.A., D.S. and G.S. ; supervision, G.S. ; project administration, G.S. All authors have read and agreed to the published version of the manuscript.