Papers »

Microstructure and nonlinear viscoelastic-viscoplastic characterization of binders used in warm mix asphalt

Warm-Mix Asphalt (WMA) is widely used in construction of pavements primarily because of its environmentally friendly characteristics in terms of reduction of fuel consumption and smoke emission in asphalt plants. This study focuses on microstructure characterization of WMA binders using Atomic Force Microscopy (AFM) and mechanical characterization of their response. The AFM results have highlighted the influence of adding WMA additives and aging of the binder on its microstructure morphology.
Most of the characterisation of binders used in WMA has focused in the past on measuring linear viscoelastic properties. However, localized strains in the binder phase could reach values high enough to induce nonlinear viscoelastic and viscoplastic deformations. Therefore, this study focuses on experimental and analytical evaluations of nonlinear viscoelastic and viscoplastic responses of selected binders modified using WMA technologies. The analytical nonlinear viscoelastic-viscoplastic approach is capable of separating the recoverable and non-recoverable strain components. Consequently, this approach is used to identify the nonlinear viscoelastic parameters and the permanent strain of the binder. The results have shown that there was a higher percentage of recovery for all WMA additives in comparison with the original binders (i.e. without WMA additives).

Author(s):

Eyad Masad    
Texas A&M University at Qatar
Qatar

Ilaria Menapace    
Texas A&M University at Qatar
Qatar

Mohammed Sadeq    
Texas A&M University at Qatar
Qatar