## 9 Conclusions  
This article provides a review of experimental results associated with the possibility of decreasing mix asphalt production temperature, using the addition of zeolite. Previous studies have focused on three structural types of zeolites: synthetic (Linde A (LTA)), Na-P1 (GIS), and natural (clinoptiolite \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Hazardous Compounds** & **Measured Amount** & **Reduction (\%)** & **Source** \\ \hline
**-** & **HMA** & **WMA** & **-** & **-** \\ \hline
**Aerosols** & 172.1 mg/m\({}^{3}\) & 7.3 mg/m\({}^{3}\) & 95 & [32] \\
**Total fume + aerosols** & 350.7 mg/m\({}^{3}\) & 90.4 mg/m\({}^{3}\) & 75 & [32] \\
**SO\({}_{\mathbf{2}}\)** & 0.109 kg/h & 0.018 kg/h & 83 & [63] \\
**NO\({}_{\mathbf{x}}\)** & 2.36 kg/h & 1.63 kg/h & 31 & [63] \\
**CO** & 28.62 kg/h & 10.89 kg/h & 62 & [63] \\
**VOC** & 3.54 kg/h & 1.32 kg/h & 63 & [63] \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Effect of decreasing production temperature of WMA with the addition of Linde A zeolite: on the reduction of hazardous compounds. (HEU)). The results of studies related to the process of foaming asphalts with zeolites modified through water soaking are also presented here. The compaction temperature and amount of dosed additive are significant factors when designing mix asphalt with zeolites. Both of these parameters should be determined based on compactibility in a gyratory compactor. Due to the iterative character of this process, development of a uniform research procedure is necessary. According to the latest studies it seems that an optimal amount of zeolite addition can be associated with material structure [16]. Previous studies did not clearly determine the effect of zeolite addition on asphalt viscosity. One should note that zeolite is not an asphalt modifier, it does not form a homogeneous liquid with the binder. Zeolite presence in bitumen, in the form of a non-dissolved solid body, affects the test result. At the same time, viscosity testing is necessary to determine possibility of affecting asphalt foaming through zeolite addition. Due to the character of zeolite water release character, it is necessary to develop an appropriate research procedure. The result of physical and chemical property tests in case of WMA with zeolites provide inconsistent results in terms of resistance to water and resistance to permanent deformation, as well as mix stiffness. These measurements surely depend, at least in part, on the type of materials being used (type of aggregate, asphalt, and zeolite), as well as the testing method and parameters. According to the authors of this review, a necessary decrease in the quality of WMA with zeolites may result in ineffective asphalt foaming, arising from too low an amount of released zeolite water. It becomes important to determine the impact of zeolite structure on asphalt foaming effect and conduct comprehensive studies using different zeolite structures. Zeolites, depending on the type of structure, present significantly different parameters, which determines the possibility of their industrial use. The amount and means of zeolite water binding are significant in asphalt foaming technology. In order to determine the amount of water released at the WMA technology temperature range, a test should be performed using the thermal analysis method. Reference literature analysis shows high zeolite application potential related to using them as an additive in WMA production. These results indicate the possibility of decreasing mix asphalt production temperature by approximately 30 \({}^{\circ}\)C. Despite many potential benefits, discrepancies between some results indicate a need to develop a standardized study methodology and to continue studies in this scope. This research was financed within the statutory funds Nos. S12/II/B/2016 and S-50/B/2016. [PERSON] analyzed the literature data about zeolite materials and benefits of WMA, and [PERSON] analyzed the literature data about WMA with zeolites.