Linear viscoelastic behavior of asphalt mixes from dynamic frequency response functions

Abstract

Summary In the small strain domain, asphalt mixes (AM) have a linear viscoelastic (LVE) behavior that is strongly dependent on frequency and temperature. The maximum ratio of modulus values can be up to 1000, and traditional elastic analyses are not pertinent. The possibility to characterize AM from frequency response functions (FRFs) was studied. A new optimization process using the finite element method (FEM) has been developed to back‐calculate the LVE properties of AM from FRFs. The numerical optimization process was applied to a reference material with averaged LVE properties determined from tension‐compression tests performed on a wide variety of AM types. The LVE properties were modeled considering the 3‐Dim version of the model 2S2P1D (2 Springs, 2 Parabolic elements, and 1 Dashpot). Reference FRFs for the considered reference material were obtained from FEM simulations. Three different configurations that may be of interest for practical tests were studied at five different temperatures. The proposed numerical optimization method consists in performing separate optimizations at each temperature to obtain the LVE properties for the considered temperature. Then values obtained at each temperature are considered to optimize 2S2P1D and Williams Landel Ferry (WLF) Equation constants to simulate the global LVE behavior of the material. The accuracy of the process was assessed regarding both the calculated FRFs and the complex modulus evaluation. Results indicate that the proposed optimization process converges almost perfectly towards the reference FRFs. The simulated complex modulus values are also in very good agreement with the values of the reference material.

Determinação do módulo dinâmico de misturas asfálticas por meio de testes ultrassônicos

“…A plotagem da curva mestra é realizada com o auxílio dos fatores de translação conhecidos da mistura pelo ajuste de modelos reológicos anteriormente ajustados a resultados de ensaios clássicos (Di Benedetto, Sauzéat e Sohm, 2009;Mounier, Di Benedetto e Sauzéat, 2012;Larcher et al, 2015). Para uma caracterização mais ampla do espectro de frequências, são necessárias técnicas mais avançadas, que não serão abordadas aqui (Gudmarsson et al, 2015;Carret, Di Benedetto e Sauzeat, 2020).…”

Analysis of Highway Asphalt Modified with Recycled Rubber and Waste Plastics

“…11 that the penetration and softening points of WPE and WR composite modified asphalt are similar to the results of WR and LDPE composite modified asphalt mentioned above. The difference is that the dispersing effect of WPE in asphalt is not as good as LDPE, so the additional amount should not be too large [14]. This may be because the waste film used in the experiment contains other resins, resulting in poor masterbatch dispersion in the base asphalt.…”

Modeling the Dynamic Properties of the Polyurethane Mixture with Dense Gradation Using the 2S2P1D Model

“…The complex modulus is then back-calculated from the measured FRFs, employing the 2S2P1D model and Williams-Landel-Ferry (WLF) function. To simulate the overall LVE behavior of HMA, the procedure was conducted to optimize the parameters of the 2S2P1D model and WLF function [50]. Thermodynamic tests were performed on HMA specimens before and after rapid freeze-thaw cycles [51], and the influence of freeze-thaw cycles on the parameters of the 2S2P1D model was analyzed.…”