## 2 Materials and Methods
### Characteristics of the Analysis Section  
As the length of the built HMA surface is a high specification road of the Network of Toll Roads, which has 2 bodies, each body with 2 traffic lanes of 3.50 m each, and 1.80 m, the section under analysis has a length of approximately 71.2 km, with traffic conditions as shown in Table 3.  
Where the classification indicates Annual Daily Average Traffic (ADAT) of 4506 and 4618 mixed vehicles, of which there are motorcycles (M), light vehicles (A), and heavy vehicles (B, C2, C3, T3S2, T3S3, and T3S2R4), where there are buses (B), freight trucks (C), and tractor units (T) with semi-trailers (S) or complete trailers (R), and the number  
Figure 5: Example of density measurements of asphalt mixture using the EM density gauge. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Side** \\ **(Body)** \\ \end{tabular} } & \multirow{2}{*}{**ADAT**} & \multicolumn{8}{c}{**Vehicular Composition (\%)**} \\ \cline{3-10}  & & **M** & **A** & **B** & **C2** & **C3** & **T3S2** & **T3S3** & **T3S2R4** & **Others** \\ \hline A & 4506 & 1.0 & 59.4 & 7.8 & 9.8 & 2.4 & 13.5 & 1.7 & 3.9 & 0.5 \\ B & 4618 & 0.9 & 59.2 & 7.6 & 9.6 & 2.7 & 13.7 & 1.5 & 4.3 & 0.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Traffic conditions of the road section under analysis [37]. accompanying them is the number of axles composing them. According to the vehicle composition of the section (Table 3), it is estimated that there is a 39.6% and 39.9% traffic of heavy vehicles in A and B, respectively. The stretch is located in the state of Michoacan, where the prevailing climatic conditions (Table 4) consider it an area of \"temperate climate\". In addition, because the study was carried out in segments of construction work by segments, it was decided to carry out the analysis of the data on the densities of the asphalt mixture by segments, due to the discontinuity of the sections covered, all the works in Body A of the road. It should be mentioned that quality control analyses of the design of the asphalt mixture were carried out every day of production of the plant; in this way, we have 50 job mix formulae (JMFs), i.e., 50 asphalt mix designs, and each one has raw density data of the mixture (Gmb) and maximum theoretical density of the asphalt mixture (Gmm, total mass of the mixture excluding the volume of water-permeable pores). It should be mentioned that more than 50 JMFs were obtained for the preparation of asphalt mixtures, because the conditions of the stone aggregates (granulometry, mainly) and the asphalt to be used changed; although the material bank or asphalt supplier was not changed, production conditions in the plant can change from one day to another, so these characteristics were obtained within the internal quality control process. It is very important to mention that core extractions were carried out (at least 3 extractions per day for statistical averages) for each day of construction work. The extracted cores were taken to the laboratory to obtain the density parameters of the HMA in order to calibrate and more adequately correlate the results of the EM density gauge. Once obtained the density readings of the asphalt mixture in field to perform the compaction calculation of it, which is indirectly associated with the maximum theoretical gravity of the mixture (Gmm), because this parameter is taken as design data in the laboratory of the mixture, and, by making a direct relationship of the field specific gravity divided with Gmm, it is possible to find the percentage of compaction, and the difference from 100% is the air void content is shown in Equations (3) and (4):  
\[\%\text{C}=(\text{Gmb}_{\text{in situ}}/\text{Gmm}_{\text{design}})\times 100 \tag{3}\]  
\[\%\text{AV}=((\text{Gmm}-\text{Gmb})/\text{Gmm})\times 100 \tag{4}\]  
As shown in Equations (3) and (4), the calculation of the percentage of compaction of the asphalt mixture is relevant, since this data allows us to know the content of air voids within the asphalt mixture.