Effect of different montmorillonites on rheological properties of bitumen/clay nanocomposites

Abstract

Different composites of organomodified montmorillonite (OMMT)/bitumen were prepared by melt blending with hexadecyl dimethyl benzyl ammonium modified montmorillonite (HBM) and double octadecyl dimethyl ammonium modified montmorillonite (DOM). The structures of two kinds of montmorillonite modified bitumen were characterized by X-ray diffraction (XRD). The effects of different montmorillonites on the dynamic rheological properties of the modified bitumens were investigated by dynamic shear rheometer (DSR). The XRD results show that DOM modified bitumen forms an intercalated structure, whereas the HBM modified bitumen forms an exfoliated structure. DSR results indicate that OMMT modified bitumens exhibit higher complex modulus, lower phase angle than pristine bitumen, which means that the resistance to rutting at high temperatures of pristine bitumen is improved due to the introduction of OMMT. Compared with DOM modified bitumen, HBM modified bitumen shows better rutting resistance, which is contributed to the formation of exfoliated structure in HBM modified bitumen.