## 3 Results
### On-Site Tests  
The on-site experimentation involved four test fields to be repaired, arranged in a 12-m diameter circle (Figure 11). The test fields were sized to avoid the disturbance effects due to the loads from the adjacent test fields. Their characteristics were:  
Figure 11: Diagrams of test fields (unit of measure: m). Figure 10: Marshall stability depending on time. * Test field 2: consisting of a D40-70 stone foundation and M1 wearing (rigid pavement);
* Test field 3: consisting of a D40-70 stone foundation up to 20 cm from the ground level, overlaid by a geotextile and a further layer of crushed stone with M4 used by percolation, (rigid pavement);
* Test field 4: consisting of an expanding resin injected into a stone foundation (40-70 mm) to increase its bearing characteristics and to create a support for concrete slabs. During the execution of the expanding resin injection into the layer of stone, there was a strong expansion of the mixture, even up to 20 cm (Figure 12). The on-site experimentation allowed the verification of the load bearing during time through Light Weight Deflectometer (LWD) and Heavy Weight Deflectometer (HWD) tests. LWD was used to evaluate the pavement Deformation Modulus M\({}_{\text{d}}\) under the resin-treated area [39]. HWD technology allowed to back calculate the elastic modules of the repair layers by mean the software Elmod(r) 6.1.75 (Dynatest: Seborg, Denmark) [40]. According to the measured site deflection data, the software gave back an approximated deflection basin with decay curves according to the material under study. Table 10 lists the results of LWD tests on three resin-treated points represented in Figure 13.  
Figure 12: Expansion of expanded resin. Figure 13: Resin-treated points of light weight deflectometer (LWD) tests. The results listed in Table 10 highlight high variable values of M\({}_{\rm d}\), as confirmed by the statistical results listed in Table 11. The set of values for conducting this analysis corresponds to the M\({}_{\rm d}\) values of the different tested points at different times. For every testing time, the mean, standard deviation, and coefficient of variation (CV, defined as the ratio of the standard deviation to the mean) were calculated. The high values of CV reveal that this technology is not reliable, as confirmed by the decreasing trend of M\({}_{\rm d}\) in Figure 14.  
The observed decreasing of M\({}_{\rm d}\) is caused by the viscous properties of the resin and its pronounced expansion which mobilizes the granular material. Indeed, this process alters the lithtic skeleton because the resin replaces the stones instead of occupying the gaps between them. The mechanical performances shown in Table 10 and Figure 14 prevent the use of the expanding resin as material useful for RRR. As done for LWD tests, the results of HWD tests and back calculation were performed for different times. During the analysis of the data some inconsistencies were found in the evaluation of the elastic \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Time (h)**} & \multicolumn{8}{c}{**M\({}_{\rm d}\) (MPa)**} \\ \cline{2-10}  & **0** & **3** & **6** & **24** & **48** & **72** & **168** & **672** \\ \hline Point 1 & 7.37 & 2.87 & 4.19 & 4.5 & 2.9 & 3.41 & 4.1 & 2.71 \\ Point 2 & 13.38 & 6.9 & 9.58 & 10.3 & 10.9 & 8.66 & 7.4 & 7.83 \\ Point 3 & 14.99 & 10.13 & 11.42 & 7.6 & 9.8 & 10.73 & 15.3 & 10.11 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Deformation modulus of the resin-treated area. Figure 14: Deformation moduli after the resin injection. moduli. For a more accurate evaluation of the moduli, filtering of data measured by the tenth geophone, which was always on the extreme edge of the test fields, was carried out (Figure 15). The filtering process gave more precise and realistic results in terms of elastic modulus E of the pavement layers. In the first measurements (3 h), only the contribution of five geophones was filtered, according to the Dynatest guidelines [41].