## 4 Discussion of the Results
### Asphal Mixture Degradation  
According to test results presented in Table 3, eight major observations related to asphalt mixture degradation were listed. 1. Water and frost impact implication reduced the stiffness modulus of all mixes; the material was degraded. The degradation ratio value shown in Figure 9 is relatively high; the decrease in the value of the stiffness modulus was even about 15%. The same observations involved road salt impact, which negatively affected mixture stiffness; the degradation ratio was equal to about 12%. The degradation caused by water, frost, or road salt depends on the type of asphalt used. 2. According to Figure 9, the mixture based on highly modified asphalt D4 showed the lowest sensitivity to water and frost impact. Mix is one of the most resistant among all the respondents. Stiffness decreased by 7.2%. The C4 material with modified binder demonstrated comparable resistance, with a 9.7% decrease. In the case of common asphalts, the greater susceptibility of mixtures to degradation caused by water and frost is observed. The B4 mixture performs worse than C4 but better than A4. MMA  
Figure 9: Asphal mixtures degradation caused by environmental factors. (B4): stiffness decreased by 14.0%, and (A4): stiffness decreased by as much as 14.9%. The A4 mix was the worst. It was found that the mixture of A4 and B4 at lower binder levels might show insufficient resistance to the effects of water and frost in in-situ conditions. The probable consequence of warm mix A4 application is the premature exhaustion of the construction durability, which will result in numerous issues (e.g., cracks or chipping). 3. Comparing the B4-D4 mixtures considering hot technology (Figure 9), due to water and frost impacts, the ones with the matrix modification with the SBS polymer are unmatched. The material degradation ratio \(DI_{(S)}\) was approximately two times lower (for D4 with HIMA) compared to MMA based on common road asphalts (B4). The mixtures C4 and D4 were more resistant than B4. The use of SBS polymer to modify the asphalt matrix greatly increases the mixture's resistance to water and frost impact. 4. Comparing the mixtures made in the warm WMA (A4) and hot (B4) technologies (Figure 9), mixture B4 is less sensitive to water and frost impact than A4 by about 6.2%. Hot technology mixes could provide better resistance to water and frost impacts. 5. According to Figure 9, the mixture based on highly modified asphalt D4 marked the lowest sensitivity to road salt and was the most resistant. The stiffness modulus decreased only by 4.15%. The C4 mix based on a modified binder resulted in similar resistance--a decrease of 5.54%. In the case of common road asphalts, a greater decrease in the modulus value is observed. Mixture B4 was even better than C4; the degradation ratio was about 0.6% lower. It was caused by a lower amount of air-void content. Mix B4 is definitely better than A4. MMA (B4): stiffness decreased by 4.85%, and (A4): stiffness decreased by 11.99%. It has been found that mixes of A4 with lower levels of binder content might exhibit insufficient in-situ resistance to road salt impact. The probable consequence of warm mix A4 application is the premature exhaustion of the construction's durability, which will result in numerous issues, such as cracks or chipping. Occurrences will be more severe, especially when two factors (water and frost + road salt) interact. 6. Comparing the B4 and D4 mixtures inside the hot technology (Figure 9), due to the road salt impact, all the mixtures resulted in similar vulnerability; the degradation is about 5%. Still, the D4 mixture with highly modified asphalt is better than C4 and B4. 7. When comparing the mixtures made in the warm WMA (A4) and hot B4 technologies (Figure 9), the hot one is clearly more resistant to road salt, up to 147%. Hot technology mixes could provide better resistance to road salt impact.