Rheological responses and microstructural evolution of asphalt ageing and chloride erosion based on black space diagram

Document Type

Article

Publication Date

10-17-2026

Abstract

To investigate the degradation and failure mechanisms of the rheological behavior of asphalt subjected to long-term aging in chloride environment, this study employed a dynamic shear rheometer to conduct wide-temperature-range and low-frequency dynamic frequency sweep tests on 90# matrix asphalt (A90) and SBS-modified asphalt (SBS) before and after thermal-oxidative aging. Based on rheological master curves and Black Space Diagram (BSD), the study systematically evaluated the control mechanisms of NaCl concentration and erosion cycles on the linear viscoelastic characteristics of asphalt, and thereby constructed a cross-scale micro-evolution mechanism model. The results indicate that the rheological response of both types of asphalt to chloride erosion exhibits significant concentration and time-dependent behavior. For A90, as the NaCl concentration increases, the material undergoes progressive dissolution and softening, manifested as a monotonically decreasing complex modulus and a smooth shift of the BSD trajectory to the lower right. Aging exhibits a time-domain hysteresis effect on its rheological degradation, it demonstrates sensitivity to low NaCl concentrations during short-term erosion, with a significant reduction in modulus only occurring after 15d of long-term erosion. SBS exhibits nonlinear time-domain behavior and concentration-dependent threshold transitions, in the early stages of erosion, the constraints of the multiphase network structure cause all concentration groups to exhibit rheological response hysteresis.With 15d long-term erosion, the 15% NaCl group underwent a sudden multiphase discontinuous transition, exhibiting a coexistence phenomenon of an increase in the phase angle in the low-frequency region and a reverse rise in modulus in the medium-high-frequency region. This phenomenon is primarily controlled by the delamination and debonding of water at multiphase interfaces, as well as the rigid interlocking effect caused by the in-situ precipitation of inorganic salt crystals within microporosity. This study achieved a closed-loop mutual validation of macroscopic rheological parameters and microscopic evolution characteristics, providing cross-scale theoretical support for the durability design of pavement materials in high-salt and high-humidity regions.

Publication Title

Construction and Building Materials

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