## 1 Introduction  
Rapid development of warm mix asphalt (WMA) production technology occurred after 1996, when the European Union introduced legal obligations limiting the emission of fumes and aerosols created in the production and compacting of mixtures using hot asphalt. On the other hand, the first attempts at decreasing warm asphalt temperature include foaming bitumen with water, which was first done in 1956 in the USA by [PERSON] et al. [1]. Despite studies involving various WMA technologies that have been conducted for over 20 years, the popularity of these mixtures remains low in Europe. Only in France was a WMA production index of more than 10% obtained [2]. In many other countries, including Poland, WMA technologies are limited to laboratory tests and experimental sections [3, 4]. A considerably higher proportion of WMA technologies in mix asphalt production is seen in the United States. In 2014 WMA amounted to 32% of total mix asphalts [5].  
In view of the increasing awareness and legal regulations in terms of environment protection, one should expect development and spreading of this technology type in the following years, also in Europe.  
Mix asphalt production temperature could be decreased through:  
* Additives decreasing bitumen viscosity and improving its adhesion to the aggregate (e.g., waxes, chemical additives);* Foaming asphalt through the addition of water, which increases the bitumen volume by several times and decreases its viscosity over a short time period.  
The test results described in the literature show that the use of WMA allows a decrease in temperatures of 20 \({}^{\circ}\)C-40 \({}^{\circ}\)C [6; 7; 8; 9]. As a consequence, the energy consumption and the harmful compound emissions to the atmosphere can be reduced significantly. An additional benefit is that it is possible to transport the mix over longer distances and this, in turn, increases the area of operation for companies with stationary asphalt mixing plants. The level of necessary financial expense is important for road companies selecting a WMA technology with a potential for application. The amount of expenses incurred often exceeds the economic benefits obtained through the use of WMA technologies, especially in the beginning [10]. In order to decrease investment spending, contracting companies seek solutions which can be used at existing plants or with minor modifications.  
The type of asphalt mixing plants used is one of the reasons behind the increase in WMA use in the USA compared to European countries. In the United States, the counterflow drum mix is often used [11]; it is easier to foam asphalt with water at these factories. In Europe, the use of batch plants prevails. WMA production using additions in the form of synthetic waves or chemical additions is possible at these plants without major technological modifications [12; 13]. The so-called \"water-containing technologies\" are a combination of WMA technology based on water foaming and dosing as an addition. This group of technologies includes zeolites. The presence of water particles in their composition, known as \"zeolite water\", is a characteristic property of these minerals. On heating the mineral, this water is released from zeolite structure in a continuous manner, without changes in the volume of the crystal [14]. During the contact with hot asphalt, the water vapour being formed allows bitumen to foam.  
The aim of this study was to present the results of current research regarding asphalt foaming using WMA technology with zeolite addition. Significant aspects of the WMA development and production process were also included. A number of benefits resulting from the use of minerals of this group was shown, along with their effect on the properties of asphalts and mix asphalt. The need to perform further research on the technology of WMA with zeolites was demonstrated, and its direction was indicated.