Modeling and experimental measurements of strain distribution in asphalt mixes

The objective of this study is to experimentally and theoretically estimate the strain distribution in an asphalt binder as it exists in hot mix asphalt (HMA). This is important to evaluate whether the strain magnitudes can cause nonlinear behavior for the binder and HMA. The experimental procedure relies on capturing images of the surface of an HMA specimen during deformation. A computer algorithm is then used to calculate the strain values within an image. Finite-element analysis of the internal structure of HMA is also used to estimate the strain distribution. The results are shown to have good correlation with the experimental measurements. However due to limitations imposed by the image resolution the strain distribution is computed within areas that include a combination of binder and fine particles (mastic) rather than the binder phase. Consequently micromechanics analysis of the mastic is used to calculate the binder strain. The results demonstrate that the binder strain magnitudes could reach high values well into the range of nonlinear behavior of the binder.