Abstract: “Study of processes and mechanisms of realization of them in contact zone for construction composite materials is a very big problem. For fly ash (FA) based bitumen-mineral compositions studied in this paper adhesive strength between bitumen and FA particles is the base factor effected on properties of road-building material. Earlier was reported that low-calcium FA (type F) from Omsk power station (Russia) can adsorb much more content of bitumen vs. high-calcium one from Nazarovsk power station (Russia). It can be connected not only with structure as well as physical and mechanical characteristics of bitumen-mineral compositions but surface energy effect when bitumen and fly ash interaction. It is studied in this research. Adhesion between bitumen and FA particles was determined by adsorption/desorption effect of bitumen as well as energy between two contacted surfaces. It was found, that F-type FA has a quite high adsorption capacity. At the same time adsorption capacity for C-type FA”

Keywords: fly ash from power plants, wetting effect, surface energy, work of adhesion, adsorption/desorption effect of bitume