Investigation of Aging Resistance of Asphalts from Different Crude Oils Based on Molecular Structure and Rheological Properties

Abstract

This research aims to investigate the aging resistance of asphalts from different crude oils based on molecular structure and rheological properties. The average molecular structure of five types of asphalt from different crude oils were analyzed with the element analyzer, nuclear magnetic resonance, gel permeation chromatograph, and the improved Brown–Ladner method. The rheological properties of the asphalts were tested by the dynamic shear rheometer before and after laboratory aging. The antiaging properties of the asphalts were evaluated by the rheological aging index (RAI). The findings indicate that there were significant differences in the molecular structures among the five types of asphalt. The asphalt with the least hydrogen–carbon ratio (H/C), the largest aromatic carbon ratio (f_A), and the largest condensation index (CI) had the lowest rate of decline in rheological properties and therefore, the best antiaging performance. The H/C, f_A, and CI had good correlations with RAI, which indicated that it was feasible to use these molecular structure parameters to evaluate the differences in the aging resistance of various asphalts.