Evaluation of weathering aging on resistance of high viscosity modified asphalt to permanent deformation and fatigue damage

Abstract

Currently, high viscosity modified asphalt (HVMA) has broad application prospects in permeable asphalt pavement. However, the large-void structure of permeable asphalt pavement makes HVMA excessively exposed to extremely adverse coupling aging of solar radiation, heat, and moisture, which accelerates the performance deterioration of HVMA. In order to investigate the effect of weathering aging on the permanent deformation and fatigue resistance of HVMA during the long-term service period, an accelerated weathering aging tester considering solar radiation, heat, and moisture was used in this study to simulate different weathering aging environment. Dynamic shear rheometer and multiple stress creep recovery test were conducted to investigate the high-temperature rheology property of HVMA at different weathering aging stages. Linear amplitude sweep test was applied to evaluate the effect of weathering aging on the fatigue resistance of HVMA. Besides, gel permeation chromatography test and fluorescence microscopic observation were used to study the molecular weight distribution and surface micromorphology of HVMA during weathering aging, respectively. The results showed that the effect of weathering aging led to an increasing rutting factor and a decreasing non-recoverable creep compliance of HVMA. The strain recovery of HVMA decreased initially and then increased with the process of weathering aging. At 50 °C weathering aging condition, the decrease in the fatigue resistance of HVMA was not significant. However, the fatigue resistance of HVMA showed a significantly decreasing trend with the process of 70 °C weathering aging. After 12d of 70 °C weathering aging, the Nf2.5% (fatigue life at 2.5% strain) of HVMA decreased from 455,035 cycle numbers to 1908 cycle numbers sharply. The degradation of polymers, the increase of asphaltene content, and the extension of surface microcracks were the main reasons for the deteriorated fatigue resistance of HVMA after long-term weathering aging.