Structural Investigation of modified bitumens by physical chemistry techniques

Bituminous binders are organic materials whose binding and hardening properties are caused by the temperature-related change of adhesion and cohesion of their molecules. Bitumen is often characterized by its chromatographic fractions, the maltenes (saturates, aromatics and resins) and the asphaltenes, soluble and insoluble in n-heptane respectively. The structure of bitumen is commonly modeled as a colloid, with maltenes as the continuous phase and micelles of asphaltenes stabilized by associated resins as the dispersed phase [1]. Here the composition and the colloidal structure is described by its physical and rheological properties. In this work, we want to explore, by different physical chemistry techniques as AFM, Time-Domain Nuclear Magnetic Resonance (TD-NMR), Rheology and Wide Angle X ray Scattering (WAXS), the influence of some opportunely chosen surfactants on the bitumen structure with the aim to ultimately correlate the structural findings with the bitumen performances.