Study of Interfacial Interactions between Bitumen and Various Aggregates Used in Road Construction

Our objectives were first to develop new physico-chemical methods to characterise the aggregate, the bitumen, and the bitumen emulsion surfaces, then to compare the properties of the new sustainable emulsifiers with those currently used in the road industry, and finally to explain the role of the bitumen/aggregate interactions in the bitumen emulsion breakdown. It was possible by using a Drop Shape Analysis System to determine the surface tension of complex liquids such as bitumen, surfactant containing aqueous phase, and bitumen emulsions. The interfacial phenomena between a bitumen emulsion and an aggregate are driven by the polar and dispersion interactions. The polar interactions play a major role in the emulsion adhesion to the aggregate and also in the emulsion breakdown. (C) Koninklijke Brill NV, Leiden, 2012