Structure characteristics of organic bentonite and the effects on rheological and aging properties of asphalt

Abstract

In this paper, the organic bentonite (OBT) was obtained by reacted the bentonite (BT) with surfactant cetyltrimethyl ammonium bromide (CTAB). The microstructures of OBT and OBT modified asphalt were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TG). The CTAB successfully entered the OBT interlayer, and the OBT forms an exfoliated structure in modified asphalt. Effects of OBT on the high and low temperature properties of matrix asphalt were investigated. The dynamic shear rheometer (DSR) and bending beam rheometer (BBR) analysis indicates that the high and low temperature rheological properties of asphalt were improved attribute to the addition of OBT. The short-term aging, long-term aging, and ultraviolet (UV) aging resistance properties of asphalt were also evaluated. Compared with the matrix asphalt, the OBT modified asphalt exhibited smaller changes in rutting parameter and softening point after short-term aging, and lower creep stiffness and fatigue factor after long-term aging. In the meantime, the UV aging index of OBT modified asphalt was obviously lower than the matrix asphalt. The OBT modified asphalts display better performance both at high and low temperature and better aging resistance under the OBT mixing amount of 4% ~ 6%, especially for the high temperature performance.