Geotechnical and Petrographic Characteristics of the Samana Suk Formation Limestone Aggregate in Southern Hazara Basin as Potential Road Construction Material

Abstract

_{This study evaluates the suitability of limestone from the Middle Jurassic Samana Suk Formation, located in Village Rani Wah, District Haripur, Hazara Basin, as a potential aggregate source for road construction in Pakistan. The initiative to investigate alternative aggregate sources stems from the rapid increase in demand associated with China-Pakistan Economic Corridor (CPEC) infrastructure projects. Geological and engineering tests were conducted to assess its performance as a road construction material. These tests included Los Angeles Abrasion (25.6%), Soundness (2.92%), Specific Gravity (2.64), Water Absorption (0.61%), Stripping of Bitumen (<5%), Bitumen Coating (>95%), Flakiness Index (10.5%), Elongation Index (12%), Clay Lump & Friable Particles (<1%), Loose Unit Weight (1.19 g/cm³), Rodded Unit Weight (1.43 g/cm³), Tensile Strength (5.48 MPa), and Unconfined Compressive Strength (53 MPa). All results met the acceptable limits defined by various International and National Standards, including ASTM, AASHTO, BS, and NHA standards, highlighting its suitability for aggregate use. Petrographic analysis revealed minor quantities of quartz and clay, minimizing the risk of Alkali-Silica Reaction (ASR), while dolomite content was limited to 1%, ruling out concerns of Alkali Carbonate Reaction (ACR) when used with regular Portland cement. Findings from this study provide a valuable addition to current knowledge on sustainable aggregate sources, demonstrating that the Samana Suk Formation limestone can effectively support road construction needs, including use in foundation layers, cement concrete, and asphalt applications.}