A constitutive model based on parallel rheological framework for large deformation and rate dependent behavior for SBS modified asphalt mortar

Accurate and reliable material parameters are the key of asphalt structure modeling and performance prediction. According to the working conditions of asphalt pavement with wide temperature domain and light-heavy variable load, the material performance parameters also produce significant differences. This paper aims to develop a constitutive model which addresses the large strain behavior and rate-dependent nonlinearity of SBS modified asphalt mortars at various temperature points from medium low temperature to high temperature, based on a parallel rheological framework (PRF) for integrating hyperelastic, viscoelastic, and elastoplastic behaviors through experiment, theory, model parameter fitting and Finite Element Method (FEM) verification. Uniaxial tensile tests on SBS-modified asphalt mortar dog bone specimens were conducted at five temperature points ranging from mid low to high temperatures, and at five stretching rates, and obtaining This force-displacement and nominal stress-strain curves at different temperatures. A parallel rheological framework (PRF)-based model was used to characterize the asphalt mortar's mechanical properties under large deformations (maximum nominal strain>0.7) and rate dependency at different temperatures. Genetic simulated annealing algorithm were employed to fit the experimental data to the parameters of the parallel rheological framework (PRF) constitutive model which were then validated using FEM. The research in this paper show the good consistency between the obtained theorical constitutive model and the experimental data by comparing the force-displacement and stress-strain uniaxial tensile curves, the constitutive model and FEM simulation results show very high consistency, thereby verifying the rationality and accuracy of the constitutive model parameters and FEM simulation. Fully demonstrated the excellent adaptability of the constitutive model to SBS modified asphalt mortar, and the FEM can replace physical experiments in studying the mechanical behavior of asphalt materials, reducing the time and cost associated with experimentation.