ORIGINAL PAPER Peaty Soil Improvement by Using Cationic Reagent Grout and Electrokintic Method Hossein Moayedi • Mansour Mosallanezhad • Ramli Nazir • Sina Kazemian • Bujang Kim Huat Received: 28 April 2012 / Accepted: 5 May 2014 Ó Springer International Publishing Switzerland 2014 Abstract Peat is known as soft soil with low shear strength and high compressibility. Electrokinetic injection technique is being used by applying a direct electrical potential across the soil specimens to improve physicochemical characteristics of the peat. Such applications cause electrochemical effects on the soil, leading to changes in the soil’s chemical, physical, and mechanical properties. This paper presents the results of the undrained shear strength, pH, water content across the electrokinetic box after injecting the cationic grouts. Four cationic grouts namely; calcium chloride, calcium oxide, Aluminum hydroxide, and sodium silicates were selected as grout. The microstructures of the stabilized peats were investigated by scanning electron microscopy and energy dispersive X-ray spectrometer analysis. The result showed that the cationic stabilizer injected by the electrokinetic technique could significantly increase the peat soil’s shear strength. Furthermore, the result showed that the effect of calcium oxide was the highest on the shear strength of peat due to its physico-chemical properties. The shear strength, pH and moisture content of peats across the electrokinetic box also altered depending on the used electrolytes and time. Keywords Peat  Geotechnical engineering  Soil improvement  Electrokinetic  Chemical grouting  Shear strength 1 Introduction Peats are found at many places around the world. It is a mixture of finely divided particles with organic matter, in some instances visible fragments of partly decayed vegetable matter, and shells are also present in the organic matter (Arman 1969; Edil 2001). In Malaysia, peat has been identified as one of the major soil group. Peat covers approximately 8 % of the land or 3 million hectares. The highly organic soils such as peat are categorized as electro-negative soils where the net electrical charge is negative (Kazemian et al. 2012; Moayedi et al. 2012). The electrical charges are carried by the surface of soil colloids, and these H. Moayedi (&)  R. Nazir Department of Geotechnics and Transportation, Faculty of Civil Engineering, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia e-mail: hossein.moayedi@gmail.com M. Mosallanezhad Department of Civil Engineering, Shiraz University, Shiraz, Iran S. Kazemian Department of Civil Engineering, Payame Noor University, Tehran, Iran B. K. Huat Department of Civil Engineering, Universiti Putra Malaysia, Serdang, Selangor, Malaysia 123 Geotech Geol Eng DOI 10.1007/s10706-014-9770-7 Author's personal copy