Dynamic mechanical properties degradation model of cement- emulsified asphalt paste under calcium leaching

Quantitative prediction of dynamic mechanical degradation in cement-emulsified asphalt (CA) paste under calcium leaching is vital for the long-term safety of high-speed railway ballastless tracks. In this work, the degradation behavior of CA paste under calcium leaching was systematically investigated using dynamic mechanical thermal analysis (DMTA). The mathematical relationships between the volume fractions of constituent phases and the dynamic mechanical performance were established through combined theoretical modeling and experimental validation. The results indicate that the modified Nielsen model and Ramakrishnan model can accurately predict the storage modulus of CA paste with high and low asphalt–cement (A/C) ratio, respectively, with prediction accuracy exceeding 90 %. In addition, a modified K. Ziegel equation was proposed to estimate the loss factor by incorporating the coupled effects of temperature, porosity, and phase composition, with prediction accuracy about 92 %. The increase in porosity induced by calcium leaching was found to follow Fick’s first law, and the integration of this law into the proposed framework enables effective simulation of the evolution of dynamic mechanical performance under leaching conditions, with overall accuracy above 80 %. This work provides a quantitative framework for assessing the degradation of CA paste at the material scale, offering important insights for service life prediction of ballastless track structures.