Civil Engineering and Architecture 11(2): 560-568, 2023 http://www.hrpub.org DOI: 10.13189/cea.2023.110203 Portland Cement Treated Soil: Evaluation and Conflict Results Ibtehaj Taha Jawad 1,* , Mohd Raihan Taha 2 1 Department of Civil Engineering, College of Engineering, University of Babylon, Babylon, Iraq 2 Department of Civil and Structural Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia Received July 12, 2022; Revised November 20 2022; Accepted December 22, 2022 Cite This Paper in the Following Citation Styles (a): [1] Ibtehaj Taha Jawad, Mohd Raihan Taha , "Portland Cement Treated Soil: Evaluation and Conflict Results," Civil Engineering and Architecture, Vol. 11, No. 2, pp. 560 - 568, 2023. DOI: 10.13189/cea.2023.110203. (b): Ibtehaj Taha Jawad, Mohd Raihan Taha (2023). Portland Cement Treated Soil: Evaluation and Conflict Results. Civil Engineering and Architecture, 11(2), 560 - 568. DOI: 10.13189/cea.2023.110203. Copyright©2023 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Abstract In spite of soil treatment using Portland cement being well documented, it is hard to find all of the contents related to this topic in one document. This paper aims to provide information inventory about chemical and mechanical changes that take place in soil properties, and the alteration in engineering characteristics which occur in soil - cement mixtures. The mechanism of treatment over time is documented as well. Some conflicted results were detected in literature such as moisture – dry density relationship and dynamic properties of soil treated by cement. The suitability of cement as an additive for different soil types is discussed based on the results which were obtained by different authors. Based on the methodologies followed by laboratory and field studies, the mixture process involves deep and shallow mixing using cement as powder or slurry (grout). Finally, the paper discusses the sustainability of Portland cement as a manufacturing product. Generally, using cement as soil stabilizer induces a significant increase in soil strength, workability, and durability. Permeability and swelling potential are significantly decreased. In addition, a considerable improvement in soil compressibility is achieved for the soil – cement mixture. Negative environment impact is one of the major inherent disadvantages in cement production, where the cement production process is responsible for 5 – 8% of the total anthropogenic CO 2 emission. Furthermore, high energy consumption, depletion of resources and weakness against sulfate attack, carbonation and organic materials effects are significant inherent disadvantages in cement-treated soil. So, partial or full replacement of cement by more sustainable materials is recommended. Keywords Soil Stabilization, Treatment Mechanism, Portland Cement, Conflict Results, Negative Environmental Impact 1. Introduction In ancient civilizations, soil was used as construction material since it is a strong and durable material [1]. Moreover, it is cheap and available compared to other materials [2]. From a geotechnical engineering point of view, some soil properties could be inappropriate for some projects, such as soft low strength soil, high compressibility soil, high volume change soil, high gypsum content soil, peat and organic soil and more. Subsequently, stabilization or improvement was needed for such soils and to achieve that and techniques which involved using proper procedures to resolve the problem that the soil was experiencing were applied. The improvement of soil properties can be achieved mechanically without any additives. Compaction is one of the mechanical methods which comprise of increasing the soil density by using a suitable compacter to increase the packing of the particles and in turn improve soil strength. Moreover, preloading is a mechanism that can be used to decrease the compressibility of soft clay soil. On the other hand, the improvement of soil can be done by using additives; some of these additives make physical