The COMPARATIVE ANALYSIS OF MECHANICAL STRENGTH AND PETROGRAPHIC FEATURES OF ANDESITE AND BASALT FROM SAWABI AREA, N-W PAKISTAN: IMPLICATIONS FOR CONSTRUCTION ENGINEERING

This study delves into a comparative analysis of the mechanical properties and petrographic characteristics of andesite and basalt from the Sawabi area in North-West Pakistan, with a focus on uniaxial tensile strength (UTS) and uniaxial compressive strength (UCS). Mega-porphyritic and badinage textures, as well as a huge, fine-grained structure, define the basaltic rocks of Swabi. These rocks are mostly composed of ferro-magnesium minerals such as olivine, pyroxene, and amphibole; as accessory minerals, they also include quartz, plagioclase, and alkali feldspar. On the other hand, the andesitic rocks in the area have anhedral structures that are extremely fine-grained and have a variety of textures, including trachytic, porphyritic, dendritic, and graphic. These rocks are mostly composed of orthoclase and fine- to medium-grained amphibole, with other features including quartz phenocrysts and altered perthitic alkali feldspar. A thorough examination of the samples' mechanical and physical characteristics, such as their porosity, specific gravity, and water absorption, was conducted. The results showed that andesite, with its better mechanical strength and good petrographic features, was the better option than basalt for construction. When choosing suitable rock materials for regional infrastructure projects, engineers and construction professionals can benefit greatly from the insights provided by this research.