Understanding the Aging Depth Gradient Distribution of High Viscosity Modified Asphalt under the Effect of Solar Radiation and Diffuse Oxygen

Abstract

The objective of this study was to investigate the aging depth gradient distribution of high viscosity modified asphalt (HVMA) under the effect of solar radiation and diffuse oxygen. The HVMA samples with different thicknesses were prepared to perform the weathering aging under different solar radiation intensities. Then, the Fourier transform infrared spectroscopy test, gel permeation chromatography test, and fluorescence microscopy test were used to study the chemical composition and micromorphology characteristic of HVMA at different aging depths. Afterward, the dynamic shear rheology test and multiple stress creep recovery test were applied to investigate the macroscopic rheological performance of HVMA. The test results showed that the effect of solar radiation aging diffused from the asphalt surface to the asphalt inside gradually. As the solar radiation intensity and aging time increased, the significant aging depth of HVMA increased continuously. At the surface, HVMA absorbed the solar light near the characteristic absorption band to activate the asphalt molecules and polymer molecules and had oxidation and depolymerization reactions with the full participation of diffuse oxygen. Simultaneously, HVMA also showed continuous microcracks at the surface due to the direct radiation of solar light. As the aging depth increased, the cracking phenomenon disappeared, and the asphalt oxidation rate and polymer degradation rate of HVMA decreased gradually. The increase of solar radiation intensity causes more severe aging at the surface and a faster downward propagation rate of aging effect, thus resulting in accelerated deterioration of the macroscopic rheological performance of HVMA.

Microevolution of Polymer–Bitumen Phase Interaction in High-Viscosity Modified Bitumen during the Aging of Reactive Oxygen Species

“…Second, the fluorescence intensity changes of BB and HVMB during ROS aging were quantitatively evaluated using 100× FL images. The polymer molecules in HVMB have strong fluorescence reactions under fluorescence excitation, 9 and the various components in bitumen have different responses to the fluorescence effect. 10 Consequently, the changes in bitumen components and the degradation of polymer during aging can be quantified according to the fluorescence intensity, as shown in Figure 4b.…”

“…The aging of the binder in PA pavement is mostly influenced by environmental factors . The main factors causing aging are temperature, solar radiation, rainfall, and reactive oxygen species. , Numerous research studies on the aging of binders have taken into account the effects of solar radiation, temperature, and humidity. Hu et al conducted the weathering aging test to investigate the effect of solar radiation on the performance of HVMB .…”

“…Hu et al conducted the weathering aging test to investigate the effect of solar radiation on the performance of HVMB. 9 Their results showed that solar radiation induces a large depth gradient in aging. The macroscopic rheological property of HVMB deteriorated more severely as the significant aging depth increased.…”

Down-Cycling Sustainability of Flexible Polyurethane Foam in Improving Asphalt Performance through a Proper Pyrolysis Approach

“…4 However, various asphalt pavement diseases, including rutting, cracking, and fatigue, were triggered by the incompatibility between the limited comprehensive performance of asphalt binder and the combined effects of traffic loads and ambient environment. 5,6 In most cases, waste polymers retain good physical and mechanical properties after prolonged use in their target application scenarios. 7−9 As a result, down-cycling is a sustainable concept that motivates the incorporation of highperformance waste polymer material into asphalt pavement engineering.…”

“…The concept of down-cycling various waste polymers into the asphalt binder has attracted significant interest and attention from both researchers and engineers. − Asphalt binder acts as a high-quality viscoelastic material and is becoming increasingly popular in pavement construction . However, various asphalt pavement diseases, including rutting, cracking, and fatigue, were triggered by the incompatibility between the limited comprehensive performance of asphalt binder and the combined effects of traffic loads and ambient environment. , In most cases, waste polymers retain good physical and mechanical properties after prolonged use in their target application scenarios. − As a result, down-cycling is a sustainable concept that motivates the incorporation of high-performance waste polymer material into asphalt pavement engineering.…”