Dynamic inter-particle friction of crushed limestone surfaces

The frictional characteristics of granular materials are of major interest in research and practice in geotechnical and petroleum engineering. In this study, micromechanical sliding experiments were conducted at the contacts of crushed limestone grains in a range of vertical forces from 0.5 to 5.0 N capturing the frictional response during a steady state sliding. This was obtained after the completion of small shearing paths of about 100–300 µm. The results indicated that the dynamic coefficient of friction was slightly lower than that of reported values in the literature on quartz grain contacts. These differences might be, partly, due to the relatively smooth surfaces of the grains of the study. However there were not observed notable differences on the frictional response between surfaces tested in a fairly dry state and surfaces immersed in oil.