Characterization Of Limestone Waste for Use in Base and Sub-Base Layers of Flexible Pavements

Abstract

The present study comprises a comprehensive survey and experimental investigation carried out to quantify the limestone waste generation at quarry sites in two villages of Chittapur and Shahbad taluks, Kalaburagi district, and to assess its feasibility for application in flexible pavement construction. Survey findings indicate that approximately 20 lakh tonnes of limestone waste are produced annually in the region. To evaluate its suitability for road infrastructure, the collected limestone waste aggregates were subjected to detailed laboratory characterization. The experimental program included determining the physical properties of aggregates, developing Job Mix Formulae (JMF) for Granular Sub-Base (GSB) and Wet Mix Macadam (WMM) layers, conducting Modified Proctor Compaction tests to establish Maximum Dry Density (MDD) and Optimum Moisture Content (OMC), and performing California Bearing Ratio (CBR) and Direct Shear tests on GSB mixes. The performance of limestone waste aggregates was analytically compared with conventional basalt aggregates. Results confirm that limestone aggregates meet the MoRT&H (2001) specifications and can effectively serve as a complete replacement for basalt aggregates in both GSB and WMM layers. The utilization of limestone waste in pavement construction not only offers a sustainable solution for waste management but also helps address the aggregate demand–supply gap, conserves natural stone resources, and reduces environmental degradation caused by excessive quarrying. This study underscores the potential of limestone waste as an eco-friendly and cost-effective alternative material for road construction.