International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 11 Issue: 07 | July 2024
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p-ISSN: 2395-0072
Utilizing Regionally Available Materials to Enhance Pavement Sub-Base Performance Santosh Kumar Mahananda1, Akhand Pratap Singh2, Parmeshwar Sahu3 M.Tech. Scholar1, Assistant Professor2, Assistant Professor3 Department of Civil Engineering Shri Rawatpura Sarkar University, Raipur Chhattisgarh --------------------------------------------------------------------------***----------------------------------------------------------------------Abstract The depletion of natural resources has become a significant concern in the construction sector, including the road construction segment. Extensive road construction activities demand vast quantities of aggregates, leading to considerable energy consumption through blasting, quarrying, crushing, and transportation. Moreover, the rapid depletion and shortage of aggregate materials have intensified the need for sustainable alternatives. Concurrently, industrial wastes, byproducts, and locally available unused materials, often considered non-conventional, present environmental and disposal challenges but hold potential for road construction applications. This study explores the utilization of two regionally available materials: slag, a waste product from the steel industry, and locally abundant gravel (moorum), in pavement sub-base layers. The research examines the chemical and phase composition, as well as the presence of toxic and heavy metals in both slag and its leachate water. Gradation and other physical properties are analyzed using appropriate tests and techniques. Conventional crushed aggregates are combined with slag or moorum to meet the required grading specifications of the Ministry of Road Transport and Highways. The study identifies the optimal proportions of slag and moorum in the sub-base layer as 80% and 50%, respectively. Additionally, cement is used with moorum to achieve the desired strength. The physical properties of these materials indicate that both slag and hard moorum exhibit excellent characteristics for use as road aggregate, making them suitable for road base and sub-base applications.
Key words: Slag, Moorum, XRD analysis, Toxicity, Unconfined compressive strength, Sustainable construction, Aggregate alternatives. 1. Introduction 1.1 Background of the Study Road transportation is a critical driver of economic, industrial, social, and cultural development in a country. India, possessing the second-largest road network globally, has seen significant advancements due to extensive road construction programs led by the Government of India. These initiatives, including the National Highways Development Programme (NHDP) and Pradhan Mantri Gramin Sadak Yojna (PMGSY), facilitate the construction of thousands of kilometers of roads annually, enhancing both urban and rural connectivity (Indian Highways, May 2011). Pavement structures used in road construction are generally classified into two types: flexible and rigid. Flexible pavements consist of four main components: soil sub-grade, sub-base course, base course, and surface course. These components work together to transmit vertical loads from the top surface to the sub-grade. A well-compacted granular arrangement with well-graded aggregates forms a robust flexible pavement, efficiently distributing compressive stresses over a wider area. The base layer, positioned immediately below the surface layer, supports the pavement by transmitting loads to the underlying layers. The sub-base layer, situated below the base layer, provides additional support, transmits traffic loads to the sub-grade, and offers frost action and drainage capabilities. The sub-base generally consists of two layers: a lower filter layer, which prevents sub-grade soil intrusion, and an upper drainage layer composed of granular sub-base (GSB) materials to facilitate water drainage from surface cracks(Yoder & Witczak, Principles of Pavement Design). Rigid pavements, in contrast, typically consist of a cement concrete slab, with a granular base or sub-base course beneath it. This base or sub-base course serves to manage drainage, control pumping, frost action, and mitigate shrink and swell of the sub-grade. Unlike flexible pavements, rigid pavements distribute loads differently; the critical condition arises from
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