Abstract
The rapid soils analysis kit uses a coffee grinder to break apart aggregated soil particles in fine-grained soils. This leads to the question of potential particle cutting or breaking due to the grinder. Hence, we performed a laboratory investigation to determine if the use of a coffee grinder to break apart aggregated soil particles produces fines from cutting or breaking sand-size and smaller particles and whether the production of more fines sometimes changes the USCS classification by some combination of adding soil fines and altering the Atterberg limits. Processing Ottawa Sand for 90 s in a coffee grinder established that the coffee grinder breaks down sand particles into fines. A silty sand (SM) sand was tested in the same way and the fines content increased significantly. Several tests were performed on fine-grained soils, and no significant increase in fines due to processing in the coffee grinder was noted. The Atterberg limits of all soils tested changed little due to processing with the grinder. In particular, the plastic limit was not changed by more than 2 (% water content). Several recommendations were made for potential future investigations.
