Studying the strain field distribution of asphalt mixture with the digital speckle correlation method

Abstract

The mechanical behaviour is essential to asphalt mixture design but are difficult to obtain especially using traditional testing methods due to anisotropic and viscoelastic properties. To get the strain distribution characters of asphalt mixture, digital speckle correlation (DSC) method, elastic solution method and linear variable differential transformer (LVDT) method have been adopted to obtain the strain under indirect tension test in this study. It is found that the contour line of maximum strains correlates very well with the fracture path and strains at failure moment obtained by DSC method and these results are different from those calculated by elastic solution or LVDT method. The calculation (gauge) length is one of factors leading to the difference in strain result obtained by the three methods. The strain distribution is affected by the coarse aggregate so the calculation (gauge) length should consider the size of the aggregate to make the results reliable.