Evaluating the impervious performance of hydraulic asphalt concrete in embankment dams: A study of crack evolution at different temperatures

Abstract

Hydraulic asphalt concrete (HAC) is extensively utilized as impervious interior core walls or upstream facings in embankment dams. This study examines the evolution of crack growth in HAC and its impact on its impervious performance under varying external loadings and temperatures. By employing X-ray computed tomography (CT) scanning in-situ triaxial compressive tests, the behavior of HAC specimens at 5 °C and 20 °C was analyzed. Statistical methods enabled the categorization of cracks by their equivalent diameter, revealing their evolution from shrinkage and initiation to expansion, interconnection, and convergence with increasing deformation. The fractal dimensions of these cracks initially decreased gradually, then stabilized, before increasing sharply. Furthermore, a logarithmic relationship between the fractal dimensions of cracks and the crack ratio was established. At equivalent deformation levels, crack development was more pronounced at 5 °C than at 20 °C. Notably, the specimens did not exhibit complete external interconnection of cracks at either temperature near the peak stress, highlighting HAC's robust impervious qualities at the meso scale. Compared to clay and concrete, HAC demonstrated superior deformation resistance and impervious capabilities in the anti-seepage structure of embankment dams. This research provides valuable insights for the application of HAC as a water barrier in complex geological settings.