Sustainable Use of GGBS and RHA as a Partial Replacement of Cement in the Stabilization of Indian Peat

Abstract

The cement stabilization of peat has been prevalent traditionally throughout the years across the world. However, the drawbacks associated with the manufacturing process of cement finally lead to a great climatic change and environmental threats. Therefore, considering this issue, the present study encourages the use of industrial waste, ground granulated blast furnace slag (GGBS) and agricultural waste, rice husk ash (RHA) as a partial replacement of cement in the stabilization of Indian peat. The collected peats varies with four diverse ranges of organic content (20–76%) comprising three different states in the northeastern province of India. The collected peats were stabilized using cement (5–30%) followed by the determination of optimum cement content based on strength and acidity criteria. The replacement of the cement with GGBS and RHA was done in three different percentages (i.e., 30%, 50%, and 70%) at their optimum cement content. The experimental investigations include compaction, unconfined compressive strength (UCS), pH, electric conductivity (EC), field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The influence of the various proportions of cement–GGBS and cement–RHA mixture, organic content and curing days were addressed precisely. The UCS results reveal that the replacement of cement with GGBS and RHA brings a relatively less strength development as compared to cement alone. However, this study suggests a maximum of 30% cement replacement from their optimum cement content for low organic peat ( 66%) is seen to be more. The pH and EC decreases after the replacement of cement which reduces the ion (Ca2+ and OH−) generation in pore fluid system. FESEM and XRD analyses confirm that the reaction products responsible for strength gain are the same as obtained in cement stabilization. Finally, the replacement of cement with GGBS gives relatively better performance than that of RHA. As GGBS and RHA are an environs threat, thus use of such waste materials can be a well sustainable solution for treating organic soil and peat.