Optimum Water Content and Maximum Dry Unit Weight of Clayey Gravels at Different Compactive Efforts
Compaction is one of the efficient ways to improve the strength and stiffness properties of soils, such as elasticity modulus and shear modulus. Moreover, compaction decreases soil settlement, improves bearing capacity and the stability of sloped embankments. An optimum water content is required to provide the best path to enter energy into soil and compact it. A constant value of energy applied to a particular type of soil, at optimum water content, leads to a maximum dry unit weight. The aforementioned parameters (γdmax , wopt) are not unique for various types of soils and vary with the type of soils and the compaction energy. At the present study, an empirical method is presented to estimate the maximum dry unit weight, and the optimum water content of clayey gravel at different compaction energy levels. The study is performed at four different compaction energy levels. Based on the results, it is observed that γdmax and wopt hold a linear relationship with log E. The two quantities, i.e. γdmax and wopt are function of the fine grain (clay) content. Finally, the mathematical models are developed to determine γdmax , wopt of the studied soils regarding two variables, i.e. energy levels and the clay percentage and the spatial surface is presented. A comparison performed on the empirical and predicted values of γdmax and wopt shows high and acceptable accuracy of the equations. Since the clayey gravels(GC) are one of the very common used soils in construction projects, for instance, as priority in the crust or core of embankment dams, using the equations and the figures at the present study, a correct estimation can be made for γdmax and wopt of such soils.