Viscoelastic characteristics of blown bitumen at low temperatures

The deterioration of flexible pavements due to low-temperature cracking is a widespread and costly problem in cold regions. This paper investigates viscoelastic properties of blown bitumen at low temperatures from -21 degrees C down to -36 degrees C: stiffness, relaxation modulus, and relaxation-time spectrum. The results of creep testing of bitumen at low temperatures are presented. The results were analyzed using the equations developed for relaxation modulus and relaxation-time spectrum. Viscosities of tested bitumen at low temperatures were estimated. Examples of the calculated spectra are provided, along with discussion of the effect of viscosity and temperature susceptibility of binder on the modal relaxation time and shape of spectrum. (C) 2018 Elsevier Ltd. All rights reserved.