Stabilization of Crude Oil Contaminated Soils with Alkali-Activated Slag

Abstract

The high exposure of areas in the vicinity of oil plants and refineries to crude oil and oil product contaminations and the problems they cause for the physical expansion of these facilities underscore the importance of stabilization of oil-contaminated soils. Soil stabilization with cost-effective stabilizing agents is widely regarded as a simple and fast way of limiting the impacts of such contaminations. For decades, cement and lime have been the standard binders for soil remediation and stabilization applications, but with the increasing awareness about their environmental impact and the notion of sustainable development in general, there is now a growing interest in the use of cleaner alternatives based on new technologies for this purpose. In recent years, alkali-activated binders have been the subject of much interest because of their high strength and durability and limited environmental impacts. The soil treatment solution investigated in this study is the use of slag, which is a steel production byproduct mostly consisting of calcium and magnesium alumina silicates, in combination with two activators, namely sodium hydroxide and sodium silicate. Direct shear tests were performed on the crude oil contaminated soil specimens in order to determine the best alkali-activated designs and the effect of exposure time, slag content, and treatment time on the outcomes. The test results showed that adding 10% slag, 1.15% sodium silicate, and 1.61% sodium hydroxide (all by dry weight of soil) to the crude oil contaminated soil improved its cohesion and friction angle by 70% and 50% respectively.