Mechanical Properties of Cement-Solidified Oily Sludge

Abstract

In this study, the physical strength and mechanical properties of oily sludge treated through stabilization/solidification (S/S) with Portland cement were investigated. S/S treatment effectively immobilized heavy metals and had a relatively small effect on hydrocarbons; 1:4 was an appropriate oily sludge to cement ratio in terms of physical strength, hydrocarbon leaching, and heavy metal immobilization. Porosity of the S/S samples exhibited a negative correlation with physical strength. With 20–21% considered the optimal range, the pore size distribution had a single peak and the pore diameter was less than 50 μm. X-ray diffractometry and scanning electron microscopy analyses showed that hydration of Portland cement was a sequential process: C3S was fast, while C2S hydrated more slowly and had a substantial influence on the final strength of the sample. Formation of C–S–H and AFt may be closely related to heavy metal immobilization.