Comparative assessment of the effect of micro- and nano- fillers on the microstructure and linear viscoelasticity of polyethylene-bitumen mastics

In order to minimize permanent deformation in bitumen mastics, the combined addition of traditional mineral filler and an organo-modified nano montmorillonite to different bitumen/polymer matrices was evaluated by dynamic shear/torsional tests and microscopy techniques. Individual addition of microfiller or nanoclay was also studied. The most remarkable result corresponded to a polymer modified mastic containing a mix of 40 wt% microfiller and 5 wt% nanoclay. As compared to a reference mastic with 45 wt% microfiller, the complex modulus at 65 °C increased more than two decades. The nanoclay has thereby shown high reinforcing potential if combined to standard mineral filler in bitumen mastics.