Effect of zeolite properties on asphalt foaming

•Synthetic zeolites from fly ashes can be used in asphalt foaming technology.•The efficiency of asphalt foaming depends on the type of zeolite structure/property.•DTA/TG assesses amount and timing of water release from zeolite during foaming process. This study includes investigation of two zeolite additives to non-modified asphalt binder and associated foaming phenomena. Two zeolites differ in their crystalline structures, i.e. one was Na-P1 synthetic zeolite and second was clinoptilolite natural zeolite. Prior to asphalt foaming these materials were additionally soaked with water which resulted in total of four base materials for laboratory investigation. The amount of zeolite dosed to the asphalt binder was 5% with respect to asphalt mass. The foaming effect was examined in terms of dynamic viscosity and further analyzed as a function of physical and chemical properties of both zeolites. In conclusion it was noted that the foaming effect strongly depends on the amount of water in zeolite structure, mode of its release with time, type of exchangeable cations as well as silicone to aluminum ratio in zeolites and finally their texture properties.