Property optimisation of bitumen modified with graphene nanomaterials using Taguchi method

The effects of two nanomaterials – graphene oxide (GO) and reduced graphene oxide (RGO) – as bitumen modifiers were investigated. Using varying percentages of the nanomaterials, ageing, chemical and rheological properties of the modified bitumens were investigated. Fourier transform infrared spectroscopy of the nanomaterial-modified bitumens revealed shifts in characteristic peaks after and before ageing, indicating changes in oxidation and functional groups. The peak intensity variations of the GO-modified bitumen (GOMB) and RGO-modified bitumen (RGOMB) indicated distinct interactions with the bitumen matrix. The physical properties of the bitumen were enhanced by both GO and RGO. A dynamic shear rheometer was used to analyse the rheological parameters. The Taguchi technique using three effective factors (type of nanomaterial, percentage of nanomaterial and test temperature) was used analysis of the experimental design. Concentrations of 0.3% GO and 0.3% RGO were determined to be optimum. The Taguchi approach also revealed that GO was better than RGO. Multiple stress creep recovery tests showed significant improvements in rheological properties for both GOMB and RGOMB at nanomaterial concentrations of 0.3%. Under ageing conditions, the RGOMB outperformed the GOMB in terms of recovery percentage and non-recoverable creep compliance. GO and RGO were found to be innovative bitumen enhancers with the potential to improve ageing resilience, creep recovery and chemical composition of bitumen.