Building stone evaluation—A case study of the sub-Himalayas, Muzaffarabad region, Azad Kashmir, Pakistan

Abstract

Building stone is one of the oldest material used in construction. The present study evaluated the physical and mechanical characteristics of dolomite, limestone and sandstone as building stones. These rocks were selected from the foothills of Himalaya as a case study.Compressive strength, tensile strength, specific gravity, durability under wetting-drying, water absorption, pulse velocity and petrography of the selected rocks were evaluated. Relationships were established among these properties of the rocks. Total reserves of these rocks in the selected area were approximated and the influence of geological structures on the rock properties were also considered.Kashmir Boundary Thrust and Kawai Fault present in the study area have adversely affected the physico-mechanical characteristics of the rocks. Dolomite shows a higher water absorption and lower strength values than expected. Kamsar Dolomite shows high degree of fracturing and weathering which lowers its polishing character and degrades its quality as building and ornamental stone. However, Yadgar Dolomite reflects ‘fair’ degree of polishing and could be used as ornamental stone and as non-load bearing masonry units. Limestone also shows lower strength values but its ‘good’ degree of polishing and other characteristics are suggestive of its use in internal flooring, cladding, stone veneer, wall stone, tabletops, risers and treads. The most suitable rock proven as building stone is Pattika Sandstone due to its sound petrographic characters, higher tensile and compressive strengths, very high durability, and lower water absorption values. Deolian Sandstone should be avoid in load bearing masonry units because of its lower strength values. Pattika Sandstone can be used as curbs, copings, sills, facing stone, external pavements and as ashlar and rubble stone. Strength properties were found to be largely dependent on each other. Ultrasonic pulse velocity in these rocks shows close relation to the density than the strength characteristics. Durability under wetting-drying was found to be more relevant to the water absorption and less relevant to the strength of rocks. Sandstone has fairly large reserves in the study area, followed by dolomite and limestone.