Effect of Short-Term Aging on Creep and Recovery Response of Asphalt Binders

Abstract

This study evaluates the creep and recovery response of different asphalt binders in unaged and short-term aged conditions. The multiple stress creep and recovery (MSCR) test has been carried out from 40 to 70°C at five different stress levels. Two conventional, two polymer-modified, and two warm mix asphalt binders were used. Polymer modification led to improvement in permanent deformation characteristics of the asphalt binders. The use of zycotherm as a warm mix additive did not have any positive effect on the creep and recovery response. The temperature susceptibility of the asphalt binders increased with ageing and stress levels. The variation of Jnr with temperature and stress levels was quantified using a simple equation, whose parameters have been discussed in this paper. A simple correlation between aged and unaged values of Jnr and Er is also established. Results from Fourier transform infrared spectroscopy (FTIR) and analysis of MSCR data indicated polymer degradation at higher temperatures because of short-term ageing, which affected the rutting characteristics of the polymer-modified binders.