Which evidence attests for soil aggregate rupture? A new criterion to determine aggregate tensile strength
Determining the aggregate compressive rupture force is useful to calculate aggregate tensile strength and to assess soil physical properties, such as soil friability. Here, we investigated two criteria to determine such a force, a commonly used criterion that considers it as the first force drop higher than 40 % (FD40) and a proposed one considering that the aggregate rupture force occurs simultaneously with aggregate equatorial cracks (EC). These criteria were compared based on results of aggregate compression tests, crack propagation monitoring, sound wave measurements, X-ray micro-computed tomography characterisation and analysis of numerical model based on Discrete Element Method (DEM). We demonstrated that EC is a more reliable empirical procedure to determine aggregate tensile strength than FD40, since there is a correspondence between the rupture force value and the formation of cracks in the equatorial region. Further, when using EC, the DEM model was more accurate in reproducing the empirical values of aggregate tensile strength.
Keywords: Aggregate rupture, Pore structure, Weibull modulus