Aggregate Evaluation and Geochemical Investigation of Limestone for Construction Industries in Pakistan: An Approach for Sustainable Economic Development

Abstract

The present study investigates the aggregate suitability and geochemical characteristics of limestone (LS) from the Samana Suk Formation, Pakistan, for the construction industry. With the advent of CPEC, the demand for construction materials has seen a manifold increase. The Sheikh Budin Hills and Trans Indus Ranges comprise huge deposits of limestone and provide great potential for source rocks for construction materials in the region. In the Upper Indus Basin of Pakistan, the Samana Suk Formation is acknowledged as the most significant carbonate deposits of Mesozoic strata. The results of aggregate parameters reveal that specific gravity (SG = 2.6); water absorption (WA = 0.47%); bulk density (BD = 1.58 g/cm3); flakiness index (FI = 16.8%); elongation index (EI = 16.39%); soundness (S = 1.6%); aggregate impact value (AIV = 14%); Los Angeles Abrasion value (LAAV = 23.51%); clay lumps (CL = 0.35%); uniaxial compressive strength (UCS = 86.7 MPa); point load test (PLT = 5.18 MPa); ultrasonic pulse velocity (UPV = 5290 m/s); and Schmidt hammer rebound test (SHRT = 49 N) are in accordance with the ASTM, ISRM, and BSI. Petrographically, the LS is dominantly composed of ooids, peloids, bioclasts, and calcite mineral (CaCO3) with a trace concentration of dolomite [(Ca,Mg)CO3]. The mineralogical and geochemical study (n = 18) revealed that the LS is dominantly composed of calcite (95.81%); on average, it is composed of 52.08 wt.% CaO; 1.13 wt.% SiO2; 0.66 wt.% MgO; 0.80 wt.% Al2O3; and 0.76 wt.% Fe2O3, and loss on ignition (LOI) was recorded as 42.13 wt.%. On the other hand, P2O5, TiO2, MnO, K2O and Na2O were found in trace amounts. The regression analysis demonstrated that the empirical correlation equation for estimating uniaxial compressive strength with ultrasonic pulse velocity is more reliable than the Schmidt hammer rebound test and point load test. Consequently, the feasibility of using LS of the Samana Suk Formation as an aggregate for construction materials and cement manufacturing is recommended based on the testing results of mechanical, physical, and geochemical properties.