## 2 Materials and Methods  
Four road mixes, AC 22 asphalt concrete, intended for the binding and base course layers of flexible construction, were designed. The only difference between the mixtures was the type of asphalt applied. The mineral mix curve was identical. The stone material came from the same source. The asphalt binder was selected based on a similar penetration index and usage frequency in road construction. Assumptions applied allowed to analyze, compare, and take into account both variables: the type of binder and the technology of production (hot HMA and warm WMA among mixes). Table 1 shows the material composition for experimental tests involving water, frost, and road salt impacts. The designed mix recipes' usefulness was checked in accordance with the requirements included in the regulation on Polish roads, taking into account the EN standards [28; 29; 46; 47; 48]. All mixtures met the basic requirements. Prepared recipes and materials were named according to the following convention, referring to mixture and recipe:  
* A4-mix containing 35/50 WMA binder (warm technology),
* B4-mix containing 35/50 binder (hot technology),
* C4-mix containing 25/55-60 binder (hot technology),
* D4-mix containing 25/55-80 HIMA binder (hot technology). Prismatic beams with dimensions of 65 \(\times\) 65 \(\times\) 390 mm were prepared for the tests. Each side of the samples was polished. The prepared mixtures were appropriately selected to create 3 sets of samples per mixture and asphalt level: reference (ref), subjected to the effects of water and frost (f-t), and road salt (rs). Each set was made up of six beams with similar stiffness modulus. The tests were carried out using the 4-PB-PR stiffness modulus test [49]. The general stiffness modulus test parameters were emphasized in Table 2. \begin{table}
\begin{tabular}{c c c c} \hline
**Mix Type** & **Mix Destination** & **Mineral Mix Composition** & **Binder Type** & **Binder Content** \\ \hline \multirow{8}{*}{AC 22} & & & 35/50 WMA & \\  & & 16/22 gabbro grit-31.0\% & (common road asphalt) & \\  & & 11/16 gabbro grit–7.0\% & 35/50 & \\  & & 8/11 gabbro grit–10.0\% & (common road asphalt) & 1 identical level was \\  & binder course & 4/8 gabbro grit–10.0\% & 25/55–60 & analyzed for each \\  & base course & 2/5 gabbro grit–16.0\% & (modified asphalt, & binder type: \\  & & 0/2 gabbro crushed sand–18.0\% & polymer SBS) & 3.82\% \\  & & 0/1 milled stone extender–8.0\% & 25/55–80 HIMA & \\  & & & (highly modified \\  & & asphalt, polymer SBS) & \\ \hline \end{tabular}
\end{table} 
Table 1: Mineral asphalt mix composition. The tests were performed in a modern, specialized hydraulic strength press dedicated to asphalt mixtures, the _\"Dynamic Testing System 130 kN (DTS 130 kN)\"_, made by Pavetest industry. The device is equipped with a climatic chamber, a mounting frame (4-PB), a digital controller (maintaining the set test parameters in real-time), and appropriate sensors, e.g., displacement, temperature, and force. The machine and a sample on the test stand are presented in Figure 1.  
To investigate the degradation of mixtures caused by the influence of water, frost, and road salt, environmental variables simulating in-situ conditions were used in the study. The research was carried out using two proprietary experimental research methods. \begin{table}
\begin{tabular}{c c c} \hline
**Test Condition** & **Property** & **References** \\ \hline static diagram & 4-PB-PR & \\ \hline load diagram & cyclically determined & PN-EN 13108-1:2016-07 [47] \\ \hline load cycle type & oscillatory cycle & WT-2 [29] \\ \hline impulsive load shape & sinusoidal & [PERSON] [50] \\ \hline load condition & controlled displacement & \\ \hline frequency & constant, 10.0 Hz & \\ \hline  & & PN-EN 13108-1:2016-07 [47] \\  & & PN-EN 13108-20:2016-07 [48] \\  & & WT-2 [29] \\  & & [PERSON] [51] \\ temperature & constant, 10.0 \({}^{\circ}\)C & [PERSON] [52] \\  & & [PERSON] [53] \\  & & [PERSON] [54] \\  & & [PERSON] [55] \\  & & [PERSON] [56] \\ \hline \end{tabular}
\end{table}