Abstract: Described is a method of preparing foams, wherein a suspension comprising an aqueous liquid, particles and at least one surfactant is provided, wherein the at least one surfactant at least partially hydrophobizes a surface of the particles, and wherein the suspension comprising the particles having the at least partially hydrophobized surface is foamed. The at least one surfactant is selected from surfactants having a backbone chain comprising at least nine carbon atoms, the at least one surfactant preferably being an amphiphilic molecule consisting of a tail coupled to a head group, wherein the tail comprises the backbone chain comprising at least nine carbon atoms.

Abstract: An additive for a bituminous binder respectively a bituminous composite material, able to reduce bituminous binder respectively bituminous composite material viscosity when an alternating magnetic field is applied, in particular for healing pavement cracks and in-depth micro-cracks in asphalt, wherein the additive comprises an amount of magnetic iron oxide particles should be improved, in order to reach bituminous composite material respectively a bituminous binder which can be melted in a faster and simplified way, in particular usable for crack healing of asphalt structures on site. This is reached by forming the additive comprising at least a part of magnetic iron oxide nanoparticles with average sizes between 1 nm and 300 nm coated with a fatty acid.