Open Access ISSN: 2165-784X Journal of Civil & Environmental Engineering Review Article Volume 10:3, 2020 DOI: 10.37421/jcce.2020.10.344 Abstract This research paper summarizes published research works on the suitability of cement as an effective chemical stabilizer to improve the strength and durability requirements of sand to be used as subgrade and base courses for rail track and road construction respectively. Advantages and problems associated with soil stabilization using chemicals have also been briefly discussed in this report. It has been confirmed that ordinary Portland cement is an effective chemical stabilizer to improve both the index and strength properties of soils, however, the optima percentage of cement contents are varied from a soil type to another. In addition, further research has to be carried out as the percentage of cement content varies from region to region and from soil characteristics to another. This is necessary so as to determine the optimum percentage of cement content that would yield the desired subgrade CBR values with some other index properties to meet the specified requirements in any selected design manual. Keywords: Maximum dry density • Stabilization • Subgrade • Unconfined compressive strength • Cement • Optimum moisture content • Soil • Track subgrade • Stabilizer Cement Soil Stabilization as an Improvement Technique for Rail Track Subgrade, and Highway Subbase and Base Courses: A Review Habeeb Solihu* Department of Railway Engineering and Civil Infrastructure, Addis Ababa Institute of Technology, Addis Ababa University, Addis Ababa, Ethiopia *Address for Correspondence: Habeeb Solihu, Department of Railway Engineering and Civil Infrastructure, Addis Ababa Institute of Technology, Addis Ababa University, Addis Ababa, Ethiopia, Tel: +2347038949144; E-mail: solihuhabeebabolakale@gmail.com Copyright: © 2020 Solihu H. This is an open-access article distributed under the terms of the creative commons attribution license which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited. Received 11 May, 2019; Accepted 04 June, 2020; Published 11 June, 2020 Introduction Soil is one of the most important and primary media for any construction work. The strength and durability of any structure depends on the strength properties of soil. It has been found from several studies that, due to the detrimental characteristics of organic soil, the shear strength and bearing capacity of this soil are very low, while the compressibility is very high [1]. Soil is a mixture of minerals, organic matter, gases, liquids, and countless organisms that together support life on Earth. Deficient soils are regarded as soils which do not meet some or all the criteria required for their satisfactory performance as geotechnical structures. These could either be for base courses for road, embankment for dam or road, subsoil base for foundation, clay liners for containment of leachates and backfill for retaining walls [2]. In the tropical region, these soils could be lateritic soils, black cotton soils, collapsible soils or any other tropical soils [3]. Soil stabilization refers to the procedure in which a special soil, a cementing material, or other chemical or non-chemical materials are added to a natural soil or a technique use on a natural soil to improve one or more of its properties. One may achieve stabilization by physically mixing the natural soil and stabilizing materials together so as to achieve a homogeneous mixture or by adding stabilizing material to an undisturbed soil deposits and obtaining interaction by letting it permeate through soil voids [4]. Cement is one of the most common additives used as a stabilizing agent for expansive soils. Extensive evaluations have been carried out on the cement stabilization of expansive soils. However, cement stabilization usually results in high stiffness, and makes the soil brittle, which is undesirable in dynamic loading conditions such as pavement systems [5]. Advantages of soil stabilization • Technical advantage • Economic advantage • Savings by Design • Saves Time • Winter Working • Saves Environmental Impact • Saves Waste • Saves Landfill Taxes [5]. Possible problems due to soil stabilization The stabilization of soil also causes the following problems (IRC:SP:89-2010) • Due to thermal and shrinkage cracks stabilized layer may be crack. • Crack can reflect through the surfacing and allow water to enter the pavement. • If CO 2 has access to the material, the stabilization reaction is reversible and the strength of layer can decrease. • The construction operation requires more skill than unsterilized materials [6]. Cement soil stabilization Soil cement stabilization is soil particles bonding caused by hydration of the cement particles which grow into crystals that can interlock with one another giving a high compressive strength. In order to achieve a successful bond the cement particles need to coat most of the material particles. To provide good contact between soil particles and cement, and thus efficient soil cement stabilization, mixing the cement and soil with certain particle size distribution is necessary [7].