Effect of various activation methods on the reactivity of ground dune sand as partial cement replacement

Dune sand obtained in the vicinity of Riyadh, Saudi Arabia was investigated to be used as partial cement replacement materials. Physical and chemical properties of dune sand were evaluated. Dune sand is inert and chemically inactive under normal curing condition. In this study, three different methods including chemical, mechanical and thermal activation were employed to enhance the reactivity of dune sand. The final products obtained were further analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), differential thermal analysis (DTA) and the thermogravimetric analysis (TGA) to investigate the promoting mechanism of the compressive strength. Replacement of cement with 30% dune sand displayed the highest compressive strength and lowest free Ca(OH)2 content when it was subjected to the thermal activation under autoclave curing.