Alternative methods for assessing particle breakage in weathered soil

Particle size distribution (PSD), fractal dimension (FD), electrical resistivity, and penetration using the fall cone test were evaluated as alternative measures for assessing particle breakage in weathered soil. The percentage of particles passing through a 0.075 mm sieve (% fines) was used as the standard value to represent the estimated particle breakage, and then, the FD was estimated using a particle size analysis. The % fines and the FD of compacted specimens with the optimum moisture content (OMC) were found to increase for the original specimens, but the electrical resistivity was found to decrease. In particular, electrical resistivity, measured at 5, 10, and 20 MHz, was applied to minimize the error at each measurement frequency. At higher volumetric water contents (above 0.35), the values of electrical resistivity become similar and are difficult to differentiate. Therefore, to estimate the particle breakage at high water contents, an alternative method to the fall cone test was used. The fall cone penetrations were measured in the water content range of 35–55%. The water contents of the compacted specimens were lower than the values of the original specimens at the same penetration. This result signifies that the penetration increased at the same water content. Furthermore, the variation in % fines could be evaluated by measuring the variation in water contents at the same penetration.