Executive Summary : | Pradhan Mantri Gram Sadak Yojana (PMGSY) is an ambitious road connectivity scheme of the Indian government with the aim of transforming socio-economic status of rural India. The successful implementation of this project requires a huge amount of granular materials that are resilient, environmentally friendly, and have lower initial construction costs. The base course is a critical structural layer of a flexible pavement, typically using a mix of natural crushed aggregates. However, the scarcity of quality natural aggregates raises sustainability concerns. Steel slag, a rock-like material produced in conjunction with steel (Das et al. 2007), can be a potential environment-friendly alternative (National Slag Association 2007). Owing to remarkable strength (Indraratna et al. 2018; Chamling et al. 2020) and stiffness (Qi et al. 2018; Chamling et al. 2022), it can be a structurally sound and sustainable material for rural road construction which is envisaged to be explored in the proposed study.
India, being the world's second-largest producer of steel, generates a huge amount of steel slag (expected to produce approximately 60 million tons in 2030 at a rate of 200 kg/ton, Indian Minerals Yearbook 2019). The use of steel slag in the construction of rural roads could be an opportunity to minimize the waste, so produced. The utilization will also be in line with India's ambitious climate commitments, focused on achieving the objectives set forth in the Paris Climate Agreement while simultaneously empowering a circular economy by cutting carbon emissions (https://pib.gov.in/PressReleaseIframePage.aspx?PRID=1847812 ).
When the subgrade is soft, the thickness requirement of the base course further increases. Utilizing geosynthetics alongside unconventional waste materials offers additional environmental advantages (Palmeira, 2016). Geocell being a 3D honeycomb-like structure with interconnected cells, can effectively contain and confine the aggregates effectively leading to reduced lateral spreading , and thereby increased rigidity of the system (Dash et al., 2008). Past studies by Mandal and Gupta (1994) and Dash et al. (2001, 2003) showed that geocell reinforcement can lead to an impressive 7-8 fold increase in the bearing capacity of foundations. Leveraging this promising approach, geocell reinforcement is expected to further reduce the thickness requirements of the granular base layer, making it a valuable technique in soft subgrade conditions.
Hence, the present study envisages to concentrate on understanding of the steel slag's geotechnical properties, the project aims to establish the suitability of steel slag for use in pavements as base course and to evaluate its performance improvement through application of geocell reinforcement. This could lead to more sustainable and cost-effective construction practices, reducing the reliance on traditional materials while offering environmental advantages. |