Influence of crushed granulated blast furnace slag and calcined eggshell waste on mechanical properties of a compacted marl

Marls are considered difficult soils in the construction of road infrastructure. They are generally associated with high compressibility, high plasticity, and evolutionary behavior, resulting in many structural failures in the road embankment. The objective of this research is to study the mechanical behavior of a compacted marl treated with a new hydraulic binder composed of Crushed Granulated Blast Furnace Slag (CGBS) active by Calcined Eggshell Waste (CES). To conduct this research, unconfined compressive strength tests (UCS), soaked California Bearing Ratio (CBR) tests, and triaxial shear tests are performed for different cure periods. The specimens were prepared with a binder content, which varies between 0 and 15% by dry weight. The results indicate that the mechanical properties of the treated marl improved significantly. The addition of 15% of this new binder is capable of increasing the CBR index 22 times its initial value. Furthermore, an appreciable improvement in cohesion and internal friction angle is observed due to treatment, especially at later ages. The new hydrates produced by the pozzolanic reaction (C-S-H) were identified after treatment by Scanning Electron Microscopy (SEM). Overall, it appears that calcined eggshell activated blast furnace slag can be used as an effective binder for the stabilization of clay soils.