IJE TRANSACTIONS B: Applications Vol. 35, No. 05, (May 2022) 908-916 Please cite this article as: S. D. Turkane, S. K. Chouksey, Partial Replacement of Conventional Material with Stabilized Soil in Flexible Pavement Design, International Journal of Engineering, Transactions B: Applications, Vol. 35, No. 05, (2022) 908-916 International Journal of Engineering Journal Homepage: www.ije.ir Partial Replacement of Conventional Material with Stabilized Soil in Flexible Pavement Design S. D. Turkane*, S. K. Chouksey Department of Civil Engineering, National Institute of Technology, Raipur, India PAPER INFO Paper history: Received 21 October 2021 Received in revised form 28 January 2022 Accepted 03 February 2022 Keywords: Low Plastic Soil Fly Ash Geopolymer Flexible Pavement IIT PAVE ABSTRACT Due to rapid urbanization and industrialization, the construction of roads increases rapidly for easy and fast transportation. Adequate land is not available everywhere to construct good roads; hence, roads are forcefully built on locally available soil such as loose soil or expansive soil. In this paper, an experimental investigation was carried out on low plastic soil (LPS) to enhance engineering properties by using chemical soil stabilization (fly ash-based geopolymer). The design of flexible pavement thickness was carried out for conventional and stabilized soil material using IITPAVE software as per IRC 37 guidelines. The results show the feasibility of fly ash-based geopolymer significant enhancement of strength were observed in terms of unconfined compressive strength (UCS) for various curing days (0 to 128 days), California bearing ratio (CBR), and Resilient modulus (MR). The microstructural analysis via Scanning Electronic Microscope (SEM) and X-Ray Diffraction Analysis (XRD) was also reveling the formation of geopolymeric gel which leads to the dense matrix to soil mass. The flexible pavement thickness significantly reduces with the application of stabilized low plastic soil. doi: 10.5829/ije.2022.35.05b.07 1. INTRODUCTION 1 The road is the lifeline of any developing country; the economic growth is majorly dependent on the development of the road network. India has the second- largest road network in the world, spanning a total of 5.89 million kilometers. This road network transports 64.5% of all goods in the country and 90% of India’s total passenger traffic uses the road network to commute as per Indian Road Industry Report [1]. Road transportation has gradually increased over the years with an improvement in connectivity between cities, towns, and villages in the country. With this increasing road transport, a huge amount of natural resources get consumed which is not healthy from an environmental perspective. Also, the stability of the road is a major issue caused due to the underlying subgrade or sub-base layer material. Therefore, to reduce the use of natural resources and construct sustainable roads by means of maximizing the use of locally available material or industrial *Corresponding Author Email: sagarturkane24@gmail.com (S. D. Turkane) byproducts. Generally, the majority of roads are constructed on locally available soil which may not have adequate properties to bear the upcoming loads. The local soil has low shearing strength, high swelling-shrinkage behaviour, large deformation [2]. Therefore, it is necessary to treat the existing land through ground improvement techniques to fulfill the increasingly demanding situations. Many techniques are widely in practice to treat the existing soil as subgrade and sub-base material, out of that chemical treatment is most common, cost-effective, and widely used. Traditionally, cement and/or lime are the most common stabilizers (binders), which form the cementitious material and hold the soil particles closely by internal chemical reactions in the presence of water. However, the production of this stabilizer causes more emissions of a greenhouse gas like carbon dioxide (CO2) which is hazardous to the environment. Therefore, researchers or engineers always search for new, sustainable, cost- effective stabilizer alternatives to ordinary portland cement and lime [3].