Effect of magnesium chloride solution on the physico-chemical characteristics of tropical peat

Abstract

The stabilization of soils with additives is a chemical method that can be used to improve soils with weak engineering properties. Although the effects of non-traditional additives on the geotechnical properties of tropical soils have been subject of investigation in recent years, the effects of magnesium chloride (MgCl2) on the macro- and micro-structural characteristics of peat soil have not been fully studied. This study investigates the effect of MgCl2 on the physico-chemical characteristics of tropical peat. Unconfined compression strength tests were performed as an index of soil improvement in treated samples. In addition, the micro-structural characteristics of untreated and treated peat were investigated using various spectroscopic and microscopic techniques such as X-ray diffractometry, energy-dispersive X-ray spectrometry, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and Brunauer, Emmett, and Teller surface area analysis. From an engineering point of view, the results indicated that the strength of MgCl2-stabilized peat improved significantly. The degree of improvement was approximately six times stronger than untreated peat, after a 7-day curing period. Additionally, the micro-structural study revealed that the stabilization process led to a few changes in the mineralogical, morphological, and molecular characteristics of the selected peat. The pores of the peat were filled by newly formed crystalline compounds known as magnesium aluminate hydrate (M–A–H).