Investigation of the Strength of Carbon-sand Mixture

The greatest stress that a composite soil can sustain is a critical value when dealing with slope stability, bearing capacity and lateral earth pressure. Cohesion and internal friction of soil composite particles will create tension and retain any stresses which are applied to the composite material. The soil composite will remain secure unless the applied external stress reaches its shear capacity. This research examined composite materials consisting of sand and various percentages of carbon. The sand used in this experiment was yellow sand which is available in Western Australia. For the purpose of testing strength, three different percentages of carbon (5, 10 and 15) were added and mixed homogenously with the sand. The strength of the composite material was tested using a small direct shear machine, in order to determine the effect of the presence of carbon on the soil strength. The experiment results provided evidences that the presence of carbon influenced the shear performance of the sand, with the shear strength of the sand-carbon composite being significantly lower than that of pure sand. The more carbon that was added to the mixture, the lower the shear strength. Carbon also takes up initial moisture content in the sand during the mixing process. The results of this research are potentially very useful in the geotechnical field, particularly with regard to construction sites containing carbon.