# Mechanical-Empirical Pavement Design Guide Applied to Portuguese Pavement Structures
## 3 Application of MEPDG to the Portuguese Pavement Structures
### Results  
The application of the MEPDG software produces a file with all the input data and results of the evolution of each pavement performance indicator along with the entire design life of 20 years. Table 4 presents the predicted values for each pavement performance indicator (i.e., longitudinal cracking, alligator cracking, AC rutting, total rutting, and IRI) corresponding to each combination of traffic class, pavement foundation class, and pavement structure. Figures 4-8 show the predicted values for each pavement performance indicator in each year of the design life. The pavement structures recommended by the Portuguese manual were defined using the Shell pavement design method considering an accumulated damage between 80% and 100%, with an additional verification performed with the University of Nottingham and Asphalt Institute pavement design methods. Therefore, using the MEPDG, it would be reasonable to expect values in the same range (i.e., between 80% and 100%) for at least one of the following pavement performance indicators: alligator cracking (bottom-up fatigue) or total rutting (permanent deformation). For the other pavement performance indicators, only small variations would be expected, because each pavement was designed for a specific combination of traffic and pavement foundation. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & **Traffic** & & & **Foundation** & **Pavement** \\ \hline
**Class** & **AADTT** & **Traffic Growth Rate** & **Truck Factor** & **Heavy Trucks (20 Years)** & **Class** & **E (MPa)** & **Class** \\ \hline \multirow{3}{*}{T\({}_{6}\)} & 150 & 3\% & 2 & \(1.47\times 10^{6}\) & F\({}_{2}\) & 60 & P\({}_{3}\) \\  & 150 & 3\% & 2 & \(1.47\times 10^{6}\) & F\({}_{3}\) & 100 & P\({}_{2}\) \\  & 150 & 3\% & 2 & \(1.47\times 10^{6}\) & F\({}_{4}\) & 150 & P\({}_{1}\) \\ \hline \multirow{3}{*}{T\({}_{5}\)} & 300 & 3\% & 3 & \(2.94\times 10^{6}\) & F\({}_{2}\) & 60 & P\({}_{7}\) \\  & 300 & 3\% & 3 & \(2.94\times 10^{6}\) & F\({}_{3}\) & 100 & P\({}_{4}\) \\  & 300 & 3\% & 3 & \(2.94\times 10^{6}\) & F\({}_{4}\) & 150 & P\({}_{3}\) \\ \hline \multirow{3}{*}{T\({}_{4}\)} & 500 & 4\% & 4 & \(5.44\times 10^{6}\) & F\({}_{2}\) & 60 & P\({}_{11}\) \\  & 500 & 4\% & 4 & \(5.44\times 10^{6}\) & F\({}_{3}\) & 100 & P\({}_{6}\) \\  & 500 & 4\% & 4 & \(5.44\times 10^{6}\) & F\({}_{4}\) & 150 & P\({}_{5}\) \\ \hline \multirow{3}{*}{T\({}_{3}\)} & 800 & 4\% & 4.5 & \(8.70\times 10^{6}\) & F\({}_{2}\) & 60 & P\({}_{13}\) \\  & 800 & 4\% & 4.5 & \(8.70\times 10^{6}\) & F\({}_{3}\) & 100 & P\({}_{9}\) \\  & 800 & 4\% & 4.5 & \(8.70\times 10^{6}\) & F\({}_{4}\) & 15  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{1}{c}{ \begin{tabular}{c} **Traffic** \\ **Class** \\ \end{tabular}  } & \begin{tabular}{c} **Foundation** \\ **Class** \\ \end{tabular}  & \begin{tabular}{c} **Pavement** \\ **Class** \\ \end{tabular}  & \begin{tabular}{c} **Longitudinal** \\ **Cracking (m/km)** \\ \end{tabular}  & \begin{tabular}{c} **Alligator** \\ **Cracking (\%)** \\ \end{tabular}  & \begin{tabular}{c} **AC** \\ **Rutting** \\ **(mm)** \\ \end{tabular}  & \ \begin{tabular}{c} **Total Rutting** \\ **(mm)** \\ \end{tabular}  & \begin{tabular}{c} **IRI** \\ **(mm/km)** \\ \end{tabular}  \\ \hline \multirow{3}{*}{T\({}_{6}\)} & F\({}_{2}\) & P\({}_{3}\) & 14.1 & 0.81 & 5.1 & 12.1 & 1578 \\  & F\({}_{3}\) & P\({}_{2}\) & 23.9 & 2.11 & 5.8 & 12.0 & 1  
Figure 5: Evolution of alligator cracking during the design life. Figure 6: Evolution of rutting in AC layers during the design life. Figure 8: Evolution of IRI during the design life. Figure 7: Evolution of total rutting during the design life. Analyzing Table 4 and Figure 4, one can see that there is a small variation in the longitudinal cracking (top-down fatigue) at the end of the design life of 20 years. More specifically, it ranged from 1.0 to 40.7 m/km, which corresponded to combinations P15T2F2 and P5T4F4, respectively. This variation occurred essentially by changing the foundation class within the same traffic class.