Preparation and properties of montmorillonite modified asphalts

Modified asphalts were prepared by melt blending with different contents of montmorillonite (MMT) and organomodified montmorillonite (OMMT). The X-ray diffraction (XRD) results show that the MMT modified asphalt may form an intercalated structure, whereas the OMMT modified asphalt may form an exfoliated structure. The addition of MMT and OMMT to asphalt increases both the softening point and viscosity of the modified asphalts at high temperatures. Furthermore, the modified asphalts exhibited higher complex modulus, lower phase angle. As a consequence, the MMT and OMMT modified asphalts displays enhanced viscoelastic properties, which improve its resistance to rutting at high temperatures. Compared with MMT, OMMT showed better effect in improving softening point and rutting resistance of asphalt, which contributes to the formation of exfoliated structure in OMMT modified asphalt. Storage stability tests disclose that the asphalts modified with MMT or OMMT are very stable when montmorillonite content is less than 3 wt%.