AbstractThis paper presents a detailed study focused on investigating the effects of fines content on the engineering properties of sand-fines mixtures. Specimens with a low-plastic fines content of 0, 15, 30 and 50% by weight were tested in static triaxial and consolidation tests to determine such parameters as compression index, internal friction angle and cohesion. The test procedures were performed on specimens of three cases: constant void ratio index, e = 0.582; same peak deviator stress of 290kPa; and constant relative density, Dr = 30%. The test results obtained for both the constant-void-ratio-index and constant-relative-density specimens showed that as fines content increased, the internal friction angle decreased, but cohesion increased. In testing of the same deviator stress specimens, both cohesion and internal friction angle were insignificantly altered with the increase in fines content. Furthermore, undrained behavior of sand-fines mixtures were recognized and discussed in three types of specimens.