Thermo-mechanical behaviour and structure of novel bitumen/nanoclay/MDI composites

Novel ternary bituminous composites have been prepared by mixing neat bitumen with an organically modified montmorillonite (Cloisite 20A®) and polymeric MDI (diphenylmethane diisocyanate). Rheological measurements (flow curves and temperature sweeps in oscillatory shear), X-Ray diffraction, Atomic Force Microscopy (AFM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to analyse the individual and joint effects of both modifiers. The results obtained show that the addition of 10 wt.% nanoclay provokes a very remarkable enhancement in the bitumen rheological response. The addition of 2 wt.% MDI and subsequent curing at 150 °C, resulting from the chemical interaction between the bitumen/clay composite and MDI, improves the composite properties at low-to-intermediate temperatures but deteriorates them when temperature is further increased.