Physio-mechanical and aggregate properties of limestones from Pakistan

Physical characterization study was carried out on limestones from Samana Suk Formation, Shekhai Formation, Kawagarh Formation, Margala Hill Limestone and Lockhart Limestone to explore their potential for utilization as aggregate sources. Laboratory tests were performed in accordance with BS and ASTM standards to determine specific gravity, water absorption, total and effective porosities, Flakiness Index, Elongation Index, Los Angeles Abrasion value and Aggregate Impact values of these limestones. The evaluated physical properties were compared with standard specifications for their qualification as construction material. Mutual relationships between physical parameters have been described by simple regression analysis. Significant direct correlation of water absorption with Los Angeles abrasion value was noted. Direct relationship of total porosity with Aggregate Impact Value and Los Angeles abrasion value was also revealed. However, negative trends of Aggregate Impact Value with Flakiness Index and Los Angeles abrasion value with Elongation Index were observed. Petrographic study reveals that micrite and bioclasts contents vary directly while dolomite has an inverse relation with Los Angeles Abrasion values. However, calcite contents do not seem to affect mechanical properties of these limestones. The study indicates that the limestones of Samana Suk Formation, Kawagarh Formation, Lockhart Limestone and Shakhai Formation fall within the standard specification limits and can be utilized as aggregate sources for indigenous construction industry.