## 6 Phase 5: Construction and Section In Situ Tests
### Trial Sections Survey
#### 6.2.2 Plate-Bearing Test  
The plate loading test is an in situ test used to measure the final bearing capacity of the subgrade built from the sections designed through its compressibility modulus.  
The plate bearing test was performed according to UNE 103808:2006, and it consists of measuring the settlement of a rigid circular plate resting on the ground, subjected to different loads in a staggered manner, called the load cycle. This circular-shaped plate has a surface area of 700 cm\({}^{2}\) (diameter 298.5 mm), and the measurements enable determining the compressibility modulus in the first load cycle (\(E_{v1}\)) and in the second load cycle (\(E_{v2}\)).  
The plate bearing test enables the calculation of the punctual behaviour of the section in the place where the load was applied, so its result was not as representative as those obtained in FDW; however, it enables verifying the behaviour of the subgrade and analysing its evolution over time.  
The results of the plate loading test are shown in Figures 15-17.  
As is shown in Figure 15, all the sections presented a medium quality, which verified the adequate structural behaviour in relation to the volume of the loads the sections will support during their useful life.  
An improvement in the quality of subgrades AS-2 and AS-3 was observed due to the addition of nanomaterials, similar to that observed in the FDW results.  
Analysing Figure 16, a drop in the equivalent modulus was observed in all three sections due to the rainy period; however, this drop was greater in sections AS-2 and AS-3 than AS-1.  
This sharp drop may be due to a lack of bearing capacity in some of the layers that make up the section because of the rain or perhaps a specific problem associated with the uncertainty of the plate loading test.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Trial Section**} & **Anual Average** & **Weighted Deflection** & \multirow{2}{*}{\(E_{\text{p}}\) **(MPa)**} \\  & **Deflection (0.01 mm)** & & \\ \hline AS-1 & 183 & 108 & 122 \\ AS-2 & 168 & 99 & 133 \\ AS-3 & 159 & 93 & 142 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Modulus of the compressibility mean in each section.  
Finally, Figure 17 shows the average annual behaviour of the sections. Despite the large drop observed in the rainy weather for sections AS-2 and AS-3, an adequate mechanical behaviour was observed, being practically identical to that obtained in the theoretical analysis using the multilayer elastic model, which confirms the validity of the multilayer elastic method used and the validity of the sections constructed.  
Comparing the results with those obtained by [PERSON] et al. [32], an increase in the modulus of the compressibility of the current hybrid sections was observed. This increase confirmed the adequate behaviour of the new solutions constructed with a reduction of the input materials.  
Additionally, the evolution of the \(E_{\mathrm{v2}}/E_{\mathrm{v1}}\) ratio was shown, limited by Spanish specifications to 2.2, a limitation that was met by all sections in both the dry and wet seasons.  
Figure 16: Plate bearing test results in the wet season.  
Figure 15: Plate bearing test results in the dry season.