Sustainable Road Construction: Clayey Soil Stabilization with Cement and Volcanic Ash.
Abstract:
A residual clay soil was collected from Bako village along Gwagwalada-Garki road in the Federal Capital Territory of Nigeria using disturbed sampling. The clay soil was subjected to comprehensive characterization, including X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Electron Dispersive Spectroscopy (EDS) tests. Additionally, the clay was compacted at the Standard Proctor energy level to determine its Maximum Dry Density (MDD) and Optimum Moisture Content (OMC).
Subsequently, Unconfined Compressive Strength (UCS) tests were conducted on both the natural clay and clay mixed with varying percentages (0%, 2%, 4%, and 6%) of cement. Each cement mixture was further admixed with different proportions (0%, 3%, 6%, 9%, 12%, and 15%) of Volcanic Ash (VA). The clay soil was found to contain significant amounts of montmorillonite, ankerite, calcium silicide, anorthite, anothoclase, and orthoclase minerals, as determined by XRD analysis.
SEM testing revealed a flaky nature of the clay, with observable pore spaces. Upon adding different proportions of VA to the natural clay compacted at the standard Proctor energy level, the Unconfined Compressive Strength (UCS) increased by a factor of 2.5 when compared to the value of the natural clay. Moreover, for clay mixed with 6% cement and varying VA contents, the UCS increased by 80% compared to specimens containing 6% cement without VA.
The optimal range of VA content for achieving maximum UCS values was found to lie between 6% and 9%. These findings suggest that the incorporation of VA can significantly enhance the strength properties of clay, making it a potentially viable additive for geotechnical applications.
Sustainable Road Construction: Clayey Soil Stabilization with Cement and Volcanic Ash.