Geochemistry characterisation of marine clay

Abstract

In evaluating a suitable type of stabiliser, investigating geochemical characteristics is important for improving the properties of soil. This paper assessed the geochemistry of marine clay samples collected from Batu Pahat, Johor, Malaysia. The parameters investigated were pH, loss on ignition (LOI) and the quantities of sulphate, chloride, nitrate and carbonate ions. The results revealed that the clay was an acidic soil with pH of 3.25 and containing 8% of organic matter. The clay also contained 6,071 mg/l, 281 mg/l and 22 mg/l of sulphate, chloride and nitrate ions, respectively. Sulphate and chloride ions from acid rain and decomposed organic matters are the leading causes of acidity found in clay. Further investigation of the physical properties of the soil further indicated that it belonged to a group of clay having high plasticity (CH) and is unsuitable for construction purposes in its natural condition. The concentration of sulphate ions in the clay sample also advocated that the soil is not suitable to be stabilised using cement or lime due to the risk of the formation of a complex compound of calcium sulphoaluminate hydrate (ettringite). Additionally, the sulphate in the marine clay is likely to attack the concrete of the foundation of future infrastructures that may be built in the study area.