- An empirical relationship between compression tests and impact tests was established for three kinds of particles: NaCl, GNP (fertilizer granule based on phosphate) and potash (fertilizer granule). As a result, the theoretical fatigue model that was previously developed for single particle strength (crushing strength) for repeated compression loads (fatigue) could be used to describe the decrease in particle strength due to repeated impact loads. The predictions of the theoretical model were validated by impact experiments for the three tested materials. In order to compare the theoretical and experimental findings, the experimental results were analyzed by tracking a defined population of particles after each impact test. The comparison showed good agreement (deviation of up to 25% for an impact number of 10). The results show that as the number of impacts and the impact velocity increase, the crushing strength decreases.