Petrographic, Mineralogical and Geo-mechanical Characteristics of Marble from Mohmand District, Pakistan: Implications for its Use in Construction Industry

This study aims to evaluate the suitability of marble deposits from Mohmand district for use in theconstruction industry. By employing an integrated approach that combines petrographic analysis, chemicalassessments, and physico-mechanical testing, the study seeks to provide a comprehensive understanding of themarble's properties. Although, megascopically indistinguishable, the petrographic analysis identifies twovarieties of carbonate rocks: Calcitic-marble and dolomitic-marble. The marble from the Sapari quarry ispetrographically fine to medium grained and dominantly composed of subhedral to anhedral calcite (84-86%),dolomite (8-10%), quartz (6-8%) and trace amount of micrite and hence classified as calcitic-marble. Owing toless contents of dolomite and unstrained quartz, the calcitic-marble reveals very low reactive quartz andmagnesium in the rock, hence no expansion if used in concrete with ordinary Portland cement (OPC). Thepetrographic and chemical investigations, therefore, endorse their innocuous non-reactive character for bothalkali silica reactivity (ASR) and alkali carbonate reactivity (ACR). In contrast, the marble from QaroonGhundai quarry is mineralogically dolomitic and texturally fine grained, where subhedral to anhedral dolomiteconstitutes the major phase (97˗98 %), while quartz and micrite occur as the minor phases. The results of thecube test of the dolomitic-marble demonstrate an expansion by 0.28 % which lies above threshold limit of0.10% thus endorse the potential to initiate ACR. Hence, this marble is declared deleterious with respect toACR. With the exception of soundness value, the dolomitic-marble produces relatively higher values for UCS,specific gravity, bulk density, LA and Schmidt hammer as compared to the calcitic-marble. The comparativeanalysis shows that the calcitic-marble is suitable for high alkali cement-concrete and asphalt-works as a coarseaggregate. Alternatively, the dolomitic-marble is only declared suitable for asphalt-based concrete due to itsACR potential, which endorses the significance of mineralogy and textures in controlling the physical andmechanical properties of rocks.