Rheological Characteristics of Polyphosphoric Acid-Modified Asphalt Mastic

摘要

In this study, a dynamic shear rheometer (DSR) and bending beam rheometer (BBR) were employed to characterize the rheological properties of asphalt modified with polyphosphoric acid (PPA) and containing different mineral fillers, forming a material referred to as asphalt mastic. Pulverized limestone filler (PLF), portland cement (PC), and hydrated lime (HL) were selected as mineral fillers. Filler-to-binder (F/A) ratios of 0.6, 0.9, 1.2, and 1.5 were chosen, which are defined as the weight ratio of filler and asphalt binder. The effects of F/A ratio and filler type on the complex shear modulus, phase angle, rutting parameter, fatigue parameter, m-value, and creep stiffness of various PPA-modified asphalt mastics were studied. Regression functions were built to express the relations between rutting parameter, fatigue parameter, creep stiffness, and F/A. The results indicated that the F/A significantly affected the stiffness of the modified asphalt mastic regardless of testing temperature, but had little effect on m-value at low temperatures. The modified asphalt mastics with different fillers showed different stiffness values but almost the same phase angle at the identical testing temperature. (C) 2018 American Society of Civil Engineers.